Asunto(s)

Anticuerpos Anticitoplasma de Neutrófilos , Anticuerpos Monoclonales , Glomerulonefritis por IGA , Humanos , Glomerulonefritis por IGA/tratamiento farmacológico , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/diagnóstico , Anticuerpos Anticitoplasma de Neutrófilos/sangre , Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Resultado del Tratamiento , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales/efectos adversos , Masculino , Biomarcadores/sangre , Biopsia , Inhibidores del Factor de Necrosis Tumoral/efectos adversos , Inhibidores del Factor de Necrosis Tumoral/uso terapéutico , Inmunosupresores/uso terapéutico , Inmunosupresores/efectos adversos , Femenino , Persona de Mediana Edad

RESUMEN

Background: The relationship between peripheral immune cells and immunoglobulin A nephropathy (IgAN) is widely known; however, causal evidence of this link is lacking. Here, we aimed to determine the causal effect of peripheral immune cells, specifically total white blood cells, lymphocytes, monocytes, basophils, eosinophils, and neutrophils, as well as lymphocyte subset traits, on the IgAN risk using a Mendelian randomization (MR) analysis. Methods: The inverse-variance weighted (IVW) method was used for the primary analysis. We applied three complementary methods, including the weighted median, MR-Egger regression, and MR-PRESSO, to detect and correct for the effect of horizontal pleiotropy. Additionally, we performed a multivariable MR (MVMR) analysis, adjusting for the effects of C-reactive protein (CRP) levels. The roles of specific lymphocyte subtypes and their significance have garnered interest. Bidirectional two-sample MR analysis was performed to test the potential causal relationships between immune traits, including median fluorescence intensities (MFIs) and the relative cell count (AC), and IgAN. Results: The IVW-MR analysis suggested a potential causal relationship between lymphocyte counts and IgAN in Europe (OR per 1-SD increase: 1.43, 95% CI: 1.08-1.88, P = 0.0123). The risk effect of lymphocytes remained even after adjusting for CRP levels using the MVMR method (OR per 1-SD increase: 1.44, 95% CI: 1.05-1.96, P = 0.0210). The other sensitivity analyses showed a consistent trend. The largest GWAS published to date was used for peripheral blood immunophenotyping to explore the potential causal relationship between peripheral immune cell subsets and IgAN. Six AC-IgAN and 14 MFI-IgAN pairs that reached statistical significance (P < 0.05) were detected. Notably, CD3, expressed in eight subsets of T cells, consistently showed a positive correlation with IgAN. The bidirectional MR analysis did not reveal any evidence of reverse causality. According to the sensitivity analysis, horizontal pleiotropy was unlikely to distort the causal estimates. Conclusions: Genetically determined high lymphocyte counts were associated with IgAN, supporting that high lymphocyte counts is causal risk factor for IgAN.

Asunto(s)

Glomerulonefritis por IGA , Análisis de la Aleatorización Mendeliana , Humanos , Glomerulonefritis por IGA/genética , Glomerulonefritis por IGA/inmunología , Estudio de Asociación del Genoma Completo , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple

RESUMEN

The lack of understanding of the mechanism of renal injury in IgA nephropathy (IgAN) hinders the development of personalized treatment plans and targeted therapies. Improved insight into the cause of renal dysfunction in IgAN is necessary to enhance the effectiveness of strategies for slowing the progression of the disease. This study examined single cell RNA sequencing (scRNA seq) and bulk-RNA seq data and found that the gene expression of renal intrinsic cells (RIC) was significantly changed in patients with renal impairment, with a primary focus on energy metabolism. We discovered a clear metabolic reprogramming of RIC during renal function impairment (RF) using the 'scMetabolism' package, which manifested as a weakening of oxidative phosphorylation, alterations in fatty acid metabolism, and changes in glycolysis. Cellular communication analysis revealed that communication between macrophages (Ma) and RIC became more active and impacted cell function through the ligand-receptor-transcription factor (L-R-TF) axis in patients with RF. Our studies showed a notable upsurge in the expression of gene CLU and the infiltration of CLU+ Ma in patients with RF. CLU is a multifunctional protein, extensively involved in processes such as cell apoptosis and immune responses. Data obtained from the Nephroseq V5 database and multiplex immunohistochemistry (mIHC) were used to validate the findings, which were found to be robustly correlated with estimated glomerular filtration rate (eGFR) of the IgAN patients, as demonstrated by linear regression (LR). This study provides new insights into the cellular and molecular changes that occur in IgAN during renal impairment, revealing that elevated expression of CLU and CLU+ Ma percolation are common features in patients with RF. These findings offer potential targets and strategies for personalized management and targeted therapy of IgAN.

Asunto(s)

Glomerulonefritis por IGA , Macrófagos , Glomerulonefritis por IGA/metabolismo , Glomerulonefritis por IGA/inmunología , Humanos , Macrófagos/inmunología , Macrófagos/metabolismo , Riñón/patología , Riñón/metabolismo , Riñón/inmunología , Masculino , Femenino , Tasa de Filtración Glomerular , Adulto , Análisis de la Célula Individual

RESUMEN

IgA nephropathy (IgAN) is considered the most common primary glomerulonephritis worldwide with a predilection for Asian-Pacific populations and relative rarity in those of African descent. Perhaps 20%-50% of patients progress to kidney failure. The pathogenesis is incompletely understood. Mesangial deposition of immune complexes containing galactose-deficient IgA1 complexed with anti-glycan IgG or IgA antibodies results in mesangial cell activation and proliferation, inflammatory cell recruitment, complement activation, and podocyte damage. Diagnosis requires a biopsy interpreted by the Oxford criteria. Additional pathologic features include podocytopathy, thrombotic microangiopathy, and C4d staining. Biomarkers predicting adverse outcomes include proteinuria, reduced GFR, hypertension, and pathology. Acceptable surrogate endpoints for therapeutic trials include ongoing proteinuria and rate of eGFR decline. The significance of persisting hematuria remains uncertain. The mainstay of therapy is supportive, consisting of lifestyle modifications, renin-angiotensin inhibition (if hypertensive or proteinuric), sodium-glucose-transporter 2 inhibition (if GFR reduced or proteinuric), and endothelin-receptor antagonism (if proteinuric). Immunosuppression should be considered for those at high risk after maximal supportive care. Corticosteroids are controversial with the most positive results observed in Chinese. They carry a high risk of serious side effects. Similarly, mycophenolate may be most effective in Chinese. Other immunosuppressants are of uncertain benefit. Tonsillectomy appears efficacious in Japanese. Active areas of investigation include B-cell inhibition with agents targeting the survival factors BAFF and APRIL and complement inhibition with agents targeting the alternate pathway (Factors B and D), the lectin pathway (MASP-2), and the common pathway (C3 and C5). Hopefully soon, the who and the how of immunosuppression will be clarified, and kidney failure can be forestalled.

Asunto(s)

Glomerulonefritis por IGA , Humanos , Glomerulonefritis por IGA/terapia , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/diagnóstico , Glomerulonefritis por IGA/etiología , Terapia de Inmunosupresión

RESUMEN

Introduction: Galactose-deficient IgA1 (GdIgA1) is critical in the formation of immunodeposits in IgA nephropathy (IgAN), whereas the origin of GdIgA1 is unknown. We focused on the immune response to fecal microbiota in patients with IgAN. Methods: By running 16S ribosomal RNA gene sequencing, we compared IgAN samples to the control samples from household-matched or non-related individuals. Levels of plasma GdIgA1 and poly-IgA complexes were measured, and candidate microbes that can either incite IgA-directed antibody response or degrade IgA through specific IgA protease activities were identified. Results: The IgAN group showed a distinct composition of fecal microbiota as compared to healthy controls. Particularly, high abundance of Escherichia-Shigella was associated with the disease group based on analyses using receiver operating characteristic (area under curve, 0.837; 95% CI, 0.738-0.914), principle coordinates, and the linear discriminant analysis effect size algorithm (linear discriminant analysis score, 4.56; p < 0.001). Accordingly, the bacterial levels directly correlated with high titers of plasma GdIgA1(r = 0.36, p < 0.001), and patients had higher IgA1 against stx2(2.88 ± 0.46 IU/mL vs. 1.34 ± 0.35 IU/mL, p = 0.03), the main antigen of Escherichia-Shigella. Conversely, the healthy controls showed relatively higher abundance of the commensal bacteria that produce IgA-degrading proteases. Particularly, the abundance of some intestinal bacteria expressing IgA proteases showed an inverse correlation with the levels of plasma GdIgA1 in IgAN. Conclusion: Our data suggest that mucosal IgA production, including those of GdIgA1, is potentially linked to the humoral response to gut Escherichia-Shigella as one of the sources of plasma GdIgA1. Conversely, the IgA protease-producing microbiota in the gut are suppressed in patients with IgAN.

Asunto(s)

Galactosa , Microbioma Gastrointestinal , Glomerulonefritis por IGA , Inmunidad Humoral , Inmunoglobulina A , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/microbiología , Humanos , Microbioma Gastrointestinal/inmunología , Inmunoglobulina A/inmunología , Inmunoglobulina A/sangre , Masculino , Femenino , Adulto , Heces/microbiología , Persona de Mediana Edad , ARN Ribosómico 16S/genética

RESUMEN

We evaluated the concentration of AT2R antibodies in 136 patients with primary and secondary glomerular diseases: membranous nephropathy (n = 18), focal and segmental glomerulosclerosis (n = 25), systemic lupus erythematosus (n = 17), immunoglobulin A (IgA) nephropathy (n = 14), mesangial (non-IgA) proliferative nephropathy (n = 6), c-ANCA vasculitis (n = 40), perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) vasculitis (n = 16), and compared it with a healthy control group (22 patients). Serum creatinine levels, proteinuria, serum albumin, and total protein concentrations were prospectively recorded for 2 years. The mean levels of AT2R antibodies in the lupus nephropathy group were significantly higher compared to the control group, 64.12 ± 26.95 units/mL and 9.72 ± 11.88 units/mL, respectively. There was no association between this level and the clinical course of the disease. The AT2R levels in other kinds of glomerular disease were no different from the control group. We found significant correlations between AT1R and AT2R in patients with membranous nephropathy (r = 0.66), IgA nephropathy (r = 0.61), and c-ANCA vasculitis (r = 0.63). Levels of AT2R antibodies in systemic lupus erythematosus are higher compared to other types of glomerulonephritis, vasculitis, and a healthy control group. Levels of AT2R antibodies correlate with AT1R antibodies in the groups of patients with membranous nephropathy, IgA nephropathy, and c-ANCA vasculitis. These kinds of AT2R antibodies have a stimulative effect on AT2R, but we have not found the influence of these antibodies on the clinical course of glomerular diseases.

Asunto(s)

Autoanticuerpos , Receptor de Angiotensina Tipo 2 , Humanos , Femenino , Masculino , Persona de Mediana Edad , Adulto , Receptor de Angiotensina Tipo 2/inmunología , Receptor de Angiotensina Tipo 2/metabolismo , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Anciano , Glomérulos Renales/inmunología , Glomérulos Renales/patología , Glomerulonefritis Membranosa/inmunología , Glomerulonefritis Membranosa/sangre , Glomerulonefritis/inmunología , Glomerulonefritis/sangre , Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Anticuerpos Anticitoplasma de Neutrófilos/sangre , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/sangre , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/sangre , Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/inmunología , Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/sangre , Nefritis Lúpica/inmunología , Receptor de Angiotensina Tipo 1/inmunología , Adulto Joven , Enfermedades Renales/inmunología

RESUMEN

The significance of glomerular IgM deposit intensity in IgA Nephropathy (IgAN) remained ambiguous and requires further research. Patients with biopsy-proven IgAN in our hospital from January 2018 to May 2023 were recruited into this retrospective single-center study. Patients who presented with positive IgM deposit were included in IgM + cohort while patients with negative IgM deposit were included in IgM- cohort. Of the IgM+, patients whose IF intensity of IgM deposits exceeded 1+ formed IgM-H cohort while patients whose IF intensity of IgM deposits was equal to 1+ consisted IgM-L cohort. Pairwise comparisons were performed among these cohorts to determine clinical disparities, following the propensity score matching process. Among 982 IgAN patients, 539 patients presented with positive IgM deposit. The Kaplan-Meier analysis showed that the IgM deposit did not contribute adversely to the outcomes (eGFR decreased from the baseline ≥ 50% continuously or reached end-stage renal disease). However, the Cox regression analysis showed that increased intensity of IgM deposit was an independent risk factor (p = 0.03) in IgM+. The IgM-H exhibited more pronounced segmental glomerulosclerosis (p = 0.02) than the IgM-L, which may also be associated more directly with higher urine protein levels (p = 0.02). Moreover, our generalized linear mixed model demonstrated a remarkably higher urine albumin/creatinine ratio (p < 0.01) and serum creatinine (p = 0.04) levels as well as lower serum albumin (p < 0.01) level in IgM-H persistently during the 5-year follow-up. This study concluded that increased intensity of glomerular IgM deposits may contribute adversely to clinicopathologic presentation and outcome in those IgM + patients.

Asunto(s)

Tasa de Filtración Glomerular , Glomerulonefritis por IGA , Inmunoglobulina M , Glomérulos Renales , Humanos , Inmunoglobulina M/sangre , Masculino , Glomerulonefritis por IGA/inmunología , Femenino , Estudios Retrospectivos , Adulto , Estudios de Seguimiento , Glomérulos Renales/patología , Glomérulos Renales/inmunología , Persona de Mediana Edad , Factores de Riesgo , Fallo Renal Crónico/etiología , Fallo Renal Crónico/inmunología , Estimación de Kaplan-Meier , Progresión de la Enfermedad , Biopsia , Relevancia Clínica

RESUMEN

Introduction: Anti-GBM diseases with IgA deposition in the mesangial region are rarely described.The factors influencing renal prognosis in patients with anti-GBM disease combined with mesangial IgA deposition are unknown. Methods: We searched the pathological reports of the First Affiliated Hospital of Zhengzhou University from 2015 to 2023 and found that a total of 72 patients with the anti-GBM disease and 25 patients combined with mesangial IgA deposition. We studied the clinical and pathological features, renal prognosis, and the factors affecting renal prognosis in patients with anti-GBM disease combined with mesangial IgA deposition. Results: Their median age was 44 years, and their age distribution was unimodal. The proportion of oliguria or anuria in patients with anti-GBM disease combined with mesangial IgA deposition was significantly lower than that in patients with classic anti-GBM disease (13.04 vs. 42.31%, p=0.030). Their 24-hour urinary protein excretion was significantly higher [median:3.25 vs. 1.12g/24h, Interquartile range(IQR):1.032~3.945 vs. 0.63~1.79g/24h, p=0.020], serum creatinine (SCr) level at the initial diagnosis was lower(median:456.0 vs. 825.5µmol/L, IQR:270.0~702.0 vs. 515.8~1231.2µmol/L, p=0.002), peak SCr level was lower (median: 601.0 vs. 907.2µmol/L, IQR: 376.5~937.0 vs. 607.0~1361.2µmol/L, p=0.007), and their serum complement 3(C3) level was higher(median: 1.275 vs. 1.015g/L, IQR:1.097~1.462 vs. 0.850~1.220g/L, p=0.027). They had better renal outcomes during follow-up (p<0.001). After adjustment for hypertension, oliguria or anuria, and crescents%, IgA deposition in the mesangial region was still an independent protective factor (p=0.003) for ESRD in anti-GBM patients. Hypertension (p=0.026) and SCr levels at initial diagnosis (p=0.004) were risk factors for renal prognosis in patients with anti-GBM disease combined with mesangial IgA deposition. Discussion: Patients with anti-GBM disease combined with mesangial IgA deposition have less severe renal impairment and better renal prognosis than patients with classic anti-GBM disease.

Asunto(s)

Inmunoglobulina A , Humanos , Masculino , Femenino , Adulto , Pronóstico , Persona de Mediana Edad , Enfermedad por Anticuerpos Antimembrana Basal Glomerular/inmunología , Enfermedad por Anticuerpos Antimembrana Basal Glomerular/diagnóstico , Mesangio Glomerular/patología , Mesangio Glomerular/inmunología , Mesangio Glomerular/metabolismo , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/diagnóstico , Glomerulonefritis por IGA/patología , Estudios Retrospectivos

RESUMEN

IgA nephropathy (IgAN) and Sjogren's syndrome (SS) are two autoimmune diseases with undetermined etiology and related to abnormal activation of lymphocytes. This study aims to explore the crucial genes, pathways and immune cells between IgAN and SS. Gene expression profiles of IgAN and SS were obtained from the Gene Expression Omnibus and Nephroseq data. Differentially expressed gene (DEG) and weighted gene co-expression network analyses (WGCNA) were done to identify common genes. Enrichment analysis and protein-protein interaction network were used to explore potential molecular pathways and crosstalk genes between IgAN and SS. The results were further verified by external validation and immunohistochemistry (IHC) analysis. Additionally, immune cell analysis and transcription factor prediction were also conducted. The DEG analysis revealed 28 commonly up-regulated genes, while WGCNA identified 98 interactively positive-correlated module genes between IgAN and SS. The enrichment analysis suggested that these genes were mainly involved in the biological processes of response to virus and antigen processing and presentation. The external validation and IHC analysis identified 5 hub genes (PSMB8, PSMB9, IFI44, ISG15, and CD53). In the immune cell analysis, the effector memory CD8 T and T follicular helper cells were significantly activated, and the corresponding proportions showed positively correlations with the expressions of the 5 hub genes in the two autoimmune diseases. Together, our data identified the crosstalk genes, molecular pathways, and immune cells underlying the IgAN and SS, which provides valuable insights into the intricate mechanisms of these diseases and offers potential intervention targets.

Asunto(s)

Biología Computacional , Glomerulonefritis por IGA , Inmunohistoquímica , Mapas de Interacción de Proteínas , Síndrome de Sjögren , Humanos , Glomerulonefritis por IGA/genética , Glomerulonefritis por IGA/metabolismo , Glomerulonefritis por IGA/patología , Glomerulonefritis por IGA/inmunología , Síndrome de Sjögren/genética , Síndrome de Sjögren/inmunología , Síndrome de Sjögren/metabolismo , Perfilación de la Expresión Génica , Redes Reguladoras de Genes

RESUMEN

AIMS: The clinicopathological significance of IgG subclass staining is unclear in IgG immunofluorescence (IF)-positive IgA nephropathy (IgAN). This study investigated IgG subclass distribution in IgG IF-positive IgAN by IF staining and examined their clinicopathological significance. MATERIALS AND METHODS: From January 2015 to December 2020, 27 biopsies from 26 patients with IgG IF-positive IgAN who were IF-positive for any IgG subclass staining were collected. We compared the clinicopathological findings between cases with and without IF positivity for each IgG subclass. RESULTS: Of the 27 biopsies with IgG IF-positive IgAN, 20 (74.1%) were IF-positive for IgG1, 10 (37.0%) were positive for IgG2, 7 (25.9%) were positive for IgG3, and none were positive for IgG4. Oxford E and C scores were significantly higher in cases of IgG IF-positive IgAN than IgG IF-negative IgAN. The age at biopsy had a negative correlation with IgG1 IF intensity (γ = -0.604, p = 0.001). The levels of proteinuria and microscopic hematuria as well as Oxford classification score were not significantly different between cases with or without positive staining for each IgG subclass. IgG IF intensity had a positive correlation with IgG1 IF intensity (γ = 0.741, p < 0.001). CONCLUSION: IgG1-positive IF staining intensity was highest among each IgG subclass in IgG IF-positive IgAN biopsies. A negative correlation was revealed between the age at biopsy and IgG1 IF intensity. Oxford E and C scores were higher in patients with IgG IF-positive IgAN than in those with IgG IF-negative IgAN. The Oxford score was not significantly different between the IgG subclasses, but the IF intensity of IgG had a positive correlation with the IF intensity of IgG1 in IgG IF-positive IgAN biopsies. Further studies should assess relationships between IgG subclass IF deposition and examine the pathogenesis of IgAN.

Asunto(s)

Técnica del Anticuerpo Fluorescente , Glomerulonefritis por IGA , Inmunoglobulina G , Humanos , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/patología , Inmunoglobulina G/análisis , Inmunoglobulina G/sangre , Masculino , Femenino , Adulto , Persona de Mediana Edad , Biopsia , Estudios Retrospectivos , Adulto Joven

RESUMEN

Objective To investigate the effects of astragaloside IV(AS-IV) on the balance of T helper type 1 (Th1) and Th2 cells in mice with IgA nephropathy (IgAN) and its possible mechanism. Methods The IgAN model of BALB/c mice was established. Successfully modeled mice were randomly divided into four groups: model, AS-IV low dose, AS-IV medium dose and AS-IV high dose groups, with 10 mice in each group. Another 10 mice served as the control group. Mice in the low, medium and high dose groups were administered 12.5, 25 and 50 mg/kg AS-IV suspension (prepared in normal saline) by gavage, while the control and model groups were given an equivalent volume of normal saline. The 24-hour urinary protein (24 h UPr) content and urine red blood cell count were measured in each group. The levels of blood urea nitrogen (BUN), serum creatinine (Scr) and albumin (ALB) were determined. Serum interferon γ (IFN-γ), interleukin 4 (IL-4) and IL-10 levels were detected by ELISA. The ratio of Th1/Th2 cells in peripheral blood of mice was detected using flow cytometry. Histopathological changes in the kidney of mice were observed by HE staining. RT-PCR and Western blot were used to detect the mRNA and protein expressions of T cell immunoglobulin and mucin domain gene 1 (TIM-1), Toll-like receptor 4 (TLR4) in mouse kidney tissue. Results Compared with the model group, in weeks 12 and 15, the urine red blood cell count, 24 h UPr, BUN, Scr, levels of IL-4 and IL-10, the proportion of Th2 cells, as well as the mRNA and protein expression levels of TIM-1 and TLR4 were significantly decreased in the low, medium and high dose groups of AS-IV, and the levels of ALB, IFN-γ, the proportion of Th1 cells and Th1/Th2 cell ratio were increased, with the high-dose group showing the best effects. Conclusion AS-IV can inhibit TIM-1 signaling pathway, increase the Th1/Th2 cell ratio, inhibit the inflammatory reaction, and alleviate the renal injury in IgAN mice.

Asunto(s)

Glomerulonefritis por IGA , Receptor Celular 1 del Virus de la Hepatitis A , Ratones Endogámicos BALB C , Saponinas , Transducción de Señal , Células TH1 , Células Th2 , Triterpenos , Animales , Receptor Celular 1 del Virus de la Hepatitis A/metabolismo , Receptor Celular 1 del Virus de la Hepatitis A/genética , Triterpenos/farmacología , Glomerulonefritis por IGA/tratamiento farmacológico , Glomerulonefritis por IGA/metabolismo , Glomerulonefritis por IGA/inmunología , Saponinas/farmacología , Células TH1/efectos de los fármacos , Células TH1/inmunología , Células TH1/metabolismo , Transducción de Señal/efectos de los fármacos , Células Th2/efectos de los fármacos , Células Th2/inmunología , Células Th2/metabolismo , Ratones , Receptor Toll-Like 4/metabolismo , Receptor Toll-Like 4/genética , Interleucina-4/genética , Interleucina-4/metabolismo , Riñón/efectos de los fármacos , Riñón/patología , Riñón/metabolismo , Interleucina-10/genética , Interleucina-10/metabolismo , Interferón gamma/metabolismo , Interferón gamma/genética , Masculino , Femenino

RESUMEN

BACKGROUND: Previous observational studies have shown that immune cells play an important role in IgA nephropathy. However, the specific causal relationship between the two is inconsistent. METHODS: We used a two-sample mendelian randomization(MR) analysis to investigate the causal association between 731 immune cell signatures and IgA nephropathy in this study. Based on published GWAS data, immune cells were characterized by four immune types absolute cell (AC) counts, median fluorescence intensity (MFI), morphological parameters (MP), relative cell (RC) counts. Meanwhile, heterogeneity test, horizontal pleiotropy and sensitivity test were used to evaluate the robustness and reliability of the results. RESULTS: An important causal association was achieved for 14 RC traits/IgA nephropathy, 3 AC traits/IgA nephropathy, 10 MFI traits/IgA nephropathy, and 1 MP trait/IgA nephropathy. However, after false discovery rate (FDR) correction, only one immunophenotype was found to be protective against IgA nephropathy. The OR of herpesvirus entry mediator (HVEM) on terminally differentiated CD4+ T cell (maturation stages of T-cell panel) on IgA nephropathy risk was estimated to be 0.727 (95%CI: 0.624-0.847, p = 4.20e - 05, PFDR = 0.023) according to inverse variance weighting (IVW) method, and the weighted-median method yielded similar results (OR = 0.743, 95% CI: 0.596-0.927, p = 0.008). Although not statistically significant, the association was consistent with MR-Egger, simple mode and weighted mode. CONCLUSIONS: Our study further confirmed that immune cells play a complex and important role in the pathogenesis of IgA nephropathy, providing evidence for clinical research.

Asunto(s)

Estudio de Asociación del Genoma Completo , Glomerulonefritis por IGA , Análisis de la Aleatorización Mendeliana , Glomerulonefritis por IGA/genética , Glomerulonefritis por IGA/inmunología , Humanos , Polimorfismo de Nucleótido Simple , Linfocitos T CD4-Positivos/inmunología , Inmunofenotipificación

RESUMEN

BACKGROUND: Immune and inflammatory factors are considered the basic underlying mechanisms of IgA nephropathy (IgAN). The systemic immune inflammation index (SII) is a new inflammatory biomarker and has been identified as a prognostic indicator for various diseases. However, limited studies have been conducted on the prognostic value of the SII in patients with IgAN, and we aimed to address this gap. METHODS: A total of 374 patients with IgAN confirmed by renal biopsy performed from 1 January 2015 to 1 April 2019, were retrospectively included. The follow-up period of all patients was at least 12 months after diagnosis, and the endpoint was defined as end-stage kidney disease (ESKD). Patients were further divided into a high-risk group (SII ≥ 456.21) and a low-risk group (SII < 456.21) based on the optimal cutoff value of the SII determined by receiver operating characteristic (ROC) curve analysis. Baseline clinicopathological parameters were compared between the groups, and Cox proportional hazards analyses and Kaplan-Meier analysis were performed to assess renal survival in IgAN patients. RESULTS: After a median follow-up period of 32.5 months, a total of 53 patients eventually reached ESKD. Patients in the high-SII group tended to have a lower hemoglobin level (p = 0.032) and eGFR (p < 0.001), a higher serum creatinine level (p = 0.023) and 24-hour total protein level (p = 0.004), more severe tubular atrophy and interstitial fibrosis (p = 0.002) and more crescents (p = 0.030) than did those in the low-SII group. Univariate and multivariate Cox regression analyses demonstrated that an SII ≥456.21 was an independent risk factor for poor renal survival in IgAN patients (HR 3.028; 95% CI 1.486-6.170; p = 0.002). Kaplan-Meier analysis revealed that a high SII was significantly associated with poor renal prognosis (p < 0.001) and consistently exhibited remarkable discriminatory ability across different subgroups in terms of renal survival. CONCLUSION: A high SII was associated with more severe baseline clinical and pathological features, and an SII ≥456.21 was an independent risk factor for progression to ESKD in IgAN patients.

Asunto(s)

Glomerulonefritis por IGA , Fallo Renal Crónico , Adulto , Femenino , Humanos , Masculino , Biomarcadores/sangre , Biopsia , Progresión de la Enfermedad , Tasa de Filtración Glomerular , Glomerulonefritis por IGA/complicaciones , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/sangre , Glomerulonefritis por IGA/patología , Inflamación/sangre , Inflamación/inmunología , Estimación de Kaplan-Meier , Riñón/patología , Riñón/inmunología , Fallo Renal Crónico/inmunología , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Factores de Riesgo , Curva ROC

RESUMEN

IgA nephropathy, presently recognized as the foremost primary glomerular disorder, emerges as a principal contributor to renal failure globally, with its pathogenesis yet to be fully elucidated. Extensive research has highlighted the critical role of gut microbiome in the onset and progression of IgA nephropathy, underscoring its importance in accurately delineating the disease's etiology. For example, gut microbiome dysbacteriosis can lead to the production of nephritogenic IgA1 antibodies, which form immune complexes that deposit in the kidneys, causing inflammation and damage. The gut microbiome, a source of numerous bioactive compounds, interacts with the host and plays a regulatory role in gut-immune axis modulation, earning it the moniker of the "second brain." Recent investigations have particularly emphasized a significant correlation between IgA nephropathy and gut microbiome dysbacteriosis. This article offers a detailed overview of the pathogenic mechanisms of IgA nephropathy, specifically focusing on elucidating how alterations in the gut microbiome are associated with anomalies in the intestinal mucosal system in IgA nephropathy. Additionally, it describes the possible influence of gut microbiome on recurrent IgA nephropathy following kidney transplantation. Furthermore, it compiles potential therapeutic interventions, offering both theoretical and practical foundations for the management of IgA nephropathy. Lastly, the challenges currently faced in the therapeutic approaches to IgA nephropathy are discussed.

Asunto(s)

Disbiosis , Microbioma Gastrointestinal , Glomerulonefritis por IGA , Inmunidad Mucosa , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/microbiología , Humanos , Microbioma Gastrointestinal/inmunología , Disbiosis/inmunología , Disbiosis/complicaciones , Inmunidad Mucosa/inmunología , Mucosa Intestinal/inmunología , Mucosa Intestinal/microbiología , Trasplante de Riñón

RESUMEN

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is an autoimmune disease characterized by the production of galactose­deficient IgA1 (Gd­IgA1) and the deposition of immune complexes in the kidney. Exploring the landscape of immune dysregulation in IgAN is valuable for pathogenesis and disease treatment. We conducted Mendelian randomization (MR) to assess the causal correlations between inflammation and IgAN. METHODS: Based on available genetic datasets, we investigated potential causal links between inflammation and the risk of IgAN using two-sample MR. We used genome-wide association study (GWAS) summary statistics of 5 typical inflammation markers, 41 inflammatory cytokines, and 731 immune cell signatures, accessed from the public GWAS Catalog. The primary method employed for MR analysis was Inverse Variance Weighted (IVW). To confirm consistency across results, four supplementary MR methods were also conducted: MR-Egger, Weighted Median, Weighted Mode, and Simple Mode. To assess pleiotropy, we used the MR-Egger regression intercept test and Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test. Cochrane's Q statistic was applied to evaluate heterogeneity. Additionally, the stability of the MR findings was verified through the leave-one-out sensitivity analysis. RESULTS: This study revealed that interleukin-7 (IL-7) and stem cell growth factor beta (SCGF-ß) were possibly associated with the risk of IgAN according to the IVW approach, with estimated odds ratios (OR) of 1.059 (95 % confidence interval [CI] 1.015 to 1.104, P = 0.008) and 1.043 (95 % CI 1.002 to 1.085, P = 0.037). Five immune traits were identified that might be linked to IgAN risk, each with P-values below 0.01, including natural killer T %T cell (OR = 1.058, 95 % CI: 1.020 to 1.097, P = 0.002), natural killer T %lymphocyte (OR = 1.055, 95 % CI: 1.016 to 1.096, P = 0.006), CD25++ CD8+ T cell %T cell (OR = 1.057, 95 % CI: 1.016 to 1.099, P = 0.006), CD3 on effector memory CD4+ T cell (OR = 1.045, 95 % CI: 1.019 to 1.071, P = 0.001), and CD3 on CD28+ CD45RA+ CD8+ T cell (OR = 1.042, 95 % CI: 1.016 to 1.068, P = 0.001). CD4 on central memory CD4+ T cell might be a protective factor for IgAN (OR = 0.922, 95 % CI: 0.875 to 0.971, P = 0.002). Moreover, IgAN may be implicated in a high risk of elevated granulocyte colony-stimulating factor (G-CSF) (OR = 1.114, 95 % CI 1.002 to 1.239, P = 0.046). CONCLUSION: Our study revealed exposures among typical inflammation markers, inflammatory cytokines, and immune cell signatures that may potentially linked to IgAN risk by MR analysis. This insight may advance our understanding of the etiology of IgAN and support the development of targeted therapeutic strategies.

Asunto(s)

Estudio de Asociación del Genoma Completo , Glomerulonefritis por IGA , Inflamación , Análisis de la Aleatorización Mendeliana , Humanos , Glomerulonefritis por IGA/genética , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/diagnóstico , Inflamación/genética , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Citocinas/genética , Citocinas/metabolismo , Inmunoglobulina A/sangre

RESUMEN

INTRODUCTION: IgA nephropathy (IgAN) is a kidney disorder characterized by the deposition of circulating immune complexes of IgG bound to galactose-deficient IgA1 (Gd-IgA1) in the mesangial glomeruli. However, limited research has been conducted on the levels of IgA binding in relation to the various sialylation profiles of IgG in IgAN. MATERIALS AND METHODS: Sialylated IgG (SA-IgG) and desialylated IgG (DSA-IgG) were isolated from IgAN patients. The IgG-IgA immune complex (IgG-IgA-IC) was detected using two customized commercial ELISA kits. Additionally, IgG was enzymatically digested with neuraminidase to produce DSA-IgG. Subsequently, the binding capacities of both intact IgG and the neuraminidase-digested DSA-IgG with Gd-IgA1 were determined using ELISA kits. RESULTS: Our research revealed that SA-IgG levels were negatively correlated with Gd-IgA1 (R = -0.16, p = 0.03) in IgAN patients. The optical density (OD) levels of IgG-IgA complexes in SA-IgG samples were significantly lower (0.58 ± 0.09) compared to those in DSA-IgG samples (0.78 ± 0.12) when using the Gd-IgA1 assay kit. These results were confirmed using an IgG assay kit, which showed that the SA-IgG groups had significantly lower IgA indices (0.31 ± 0.12) compared to the DSA-IgG groups (0.57 ± 0.19). Furthermore, we investigated the binding capacity of IgG with different sialic acid levels to Gd-IgA1. The results revealed that neuraminidase digestion of IgG increased its propensity to bind to Gd-IgA1. Additionally, we examined the binding capacity of both intact IgG and DSA-IgG to Gd-IgA1 at different mix ratios (IgG 1.5 µg and Gd-IgA1 1.5 µg, IgG 1.5 µg and Gd-IgA1 3 µg, IgG 3 µg and Gd-IgA1 1.5 µg). Interestingly, DSA-IgG demonstrated significantly higher binding capacity to Gd-IgA1 compared to intact IgG at all mix ratios tested. CONCLUSION: The preliminary findings from our present study indicate that the binding level of IgA in purified sialylated IgG is lower than that in desialylated IgG.

Asunto(s)

Glomerulonefritis por IGA , Inmunoglobulina A , Inmunoglobulina G , Humanos , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/metabolismo , Inmunoglobulina A/metabolismo , Inmunoglobulina A/inmunología , Inmunoglobulina G/metabolismo , Inmunoglobulina G/inmunología , Inmunoglobulina G/sangre , Masculino , Femenino , Adulto , Persona de Mediana Edad , Complejo Antígeno-Anticuerpo/metabolismo , Complejo Antígeno-Anticuerpo/inmunología , Adulto Joven , Ensayo de Inmunoadsorción Enzimática , Ácido N-Acetilneuramínico/metabolismo , Neuraminidasa/metabolismo , Neuraminidasa/inmunología

RESUMEN

IgA nephropathy (IgAN), which has been confirmed as a complement mediated autoimmune disease, is also one form of glomerulonephritis associated with COVID-19. Here, we aim to investigate the clinical and immunological characteristics of patients with IgAN after COVID-19. The level of plasma level of C5a (p < 0.001), soluble C5b-9 (p = 0.018), FHR5 (p < 0.001) were all significantly higher in Group CoV (33 patients with renal biopsy-proven IgAN experienced COVID-19) compared with Group non-CoV (44 patients with IgAN without COVID-19), respectively. Compared with Group non-CoV, the intensity of glomerular C4d (p = 0.017) and MAC deposition (p < 0.001) and Gd-IgA1 deposition (p = 0.005) were much stronger in Group CoV. Our finding revealed that for IgAN after COVID-19, mucosal immune responses to SARS-CoV-2 infection may result in the overactivation of systemic and renal local complement system, and increased glomerular deposition of Gd-IgA1, which may lead to renal dysfunction and promote renal progression in IgAN patients.

Asunto(s)

COVID-19 , Glomerulonefritis por IGA , SARS-CoV-2 , Humanos , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/sangre , COVID-19/inmunología , COVID-19/complicaciones , Femenino , Masculino , Adulto , SARS-CoV-2/inmunología , Persona de Mediana Edad , Activación de Complemento/inmunología , Proteínas del Sistema Complemento/inmunología , Proteínas del Sistema Complemento/metabolismo , Inmunoglobulina A/sangre , Inmunoglobulina A/inmunología , Glomérulos Renales/patología , Glomérulos Renales/inmunología , Complemento C5a/inmunología , Complemento C5a/metabolismo

RESUMEN

Immunoglobulin A nephropathy is a complex autoimmune disease with various underlying causes and significant clinical heterogeneity. There are large individual differences in its development, and the etiology and pathogenesis are still poorly understood. While it is known that immunobiological factors play a significant role in the pathophysiology of immunoglobulin A nephropathy, the specific nature of these factors has yet to be fully elucidated. Numerous investigations have verified that CD4+ and CD8+ T lymphocytes are involved in the immunopathogenesis of immunoglobulin A nephropathy. Furthermore, certain data also point to γδT cells' involvement in the pathophysiology of immunoglobulin A nephropathy. By thoroughly examining the mechanisms of action of these T cells in the context of immunoglobulin A nephropathy, this review sheds light on the immunopathogenesis of the disease and its associated factors. The review is intended to provide reference value for the future research in this field and promising treatment clues for clinical patients.

Asunto(s)

Glomerulonefritis por IGA , Humanos , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/patología , Animales , Linfocitos T/inmunología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD4-Positivos/inmunología

RESUMEN

The role of RNA N6-methyladenosine (m6A) modification in immunity is being elucidated. This study aimed to explore the potential association between m6A regulators and the immune microenvironment in IgA nephropathy (IgAN). The expression profiles of 24 m6A regulators in 107 IgAN patients were obtained from the Gene Expression Omnibus (GEO) database. The least absolute shrinkage and selection operator (LASSO) regression and logistic regression analysis were utilized to construct a model for distinguishing IgAN from control samples. Based on the expression levels of m6A regulators, unsupervised clustering was used to identify m6A-induced molecular clusters in IgAN. Gene set enrichment analysis (GSEA) and immunocyte infiltration among different clusters were examined. The gene modules with the highest correlation for each of the three clusters were identified by weighted gene co-expression network analysis (WGCNA). A model containing 10 m6A regulators was developed using LASSO and logistic regression analyses. Three molecular clusters were determined using consensus clustering of 24 m6A regulators. A decrease in the expression level of YTHDF2 in IgAN samples was significantly negatively correlated with an increase in resting natural killer (NK) cell infiltration and was positively correlated with the abundance of M2 macrophage infiltration. The risk scores calculated by the nomogram were significantly higher for cluster-3, and the expression levels of m6A regulators in this cluster were generally low. Immunocyte infiltration and pathway enrichment results for cluster-3 differed significantly from those for the other two clusters. Finally, the expression of YTHDF2 was significantly decreased in IgAN based on immunohistochemical staining. This study demonstrated that m6A methylation regulators play a significant role in the regulation of the immune microenvironment in IgAN. Based on m6A regulator expression patterns, IgAN can be classified into multiple subtypes, which might provide additional insights into novel therapeutic methods for IgAN.

Asunto(s)

Adenosina , Adenosina/análogos & derivados , Glomerulonefritis por IGA , Glomerulonefritis por IGA/genética , Glomerulonefritis por IGA/inmunología , Glomerulonefritis por IGA/patología , Humanos , Adenosina/metabolismo , Metilación , Perfilación de la Expresión Génica , Femenino , Redes Reguladoras de Genes , Masculino , Regulación de la Expresión Génica , Adulto , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Proteínas de Unión al ARN/genética , Metilación de ARN

RESUMEN

Immune checkpoint inhibitors (ICIs) dramatically improve the prognosis of many malignancies but at the cost of numerous side effects, which may limit their benefits. Acute kidney injury associated with immune checkpoint inhibitors most frequently are acute tubulointerstitial nephritis (ATIN), but various cases of glomerulonephritis have also been reported. Herein, we report a case of severe IgA nephropathy (IgAN) associated with ICIs and carry out a literature review. IgAN was diagnosed in a median time of 5 months (range 1-12 months) after the initiation of ICIs, with heterogeneous severity, and usually treated by corticosteroid and discontinuation of ICIs. In contrast to our case, renal outcomes in literature were often favorable, with recovery of renal function and a reduction in proteinuria on treatment. Although IgAN related to ICIs is a much rarer complication than ATIN, it may still be underdiagnosed. Careful questioning and screening for asymptomatic hematuria should be performed before using ICIs.

Asunto(s)

Glomerulonefritis por IGA , Inhibidores de Puntos de Control Inmunológico , Anciano , Humanos , Masculino , Glomerulonefritis por IGA/diagnóstico , Glomerulonefritis por IGA/tratamiento farmacológico , Glomerulonefritis por IGA/inmunología , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Neoplasias/tratamiento farmacológico , Neoplasias/inmunología