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BACKGROUND: The frequency of glomerular diseases is dynamic and varies according to geographic area. AIM: To evaluate the frequency of primary and secondary glomerulopathies, their demographic profile and main clinical characteristics. MATERIAL AND METHODS: Renal biopsies from native kidneys performed between 1999 and 2020 were retrospectively reviewed. Demographic characteristics, clinical presentation, most relevant laboratory tests, frequency of primary and secondary glomerulopathies were analyzed. RESULTS: We analyzed 550 kidney biopsies from patients with a median age of 48 years (64% females). Nephrotic syndrome was the main indication for renal biopsy. Primary and secondary glomerulopathies occurred with similar frequency. Within the primary glomerulopathies, membranous nephropathy (34.1%) was the most common, followed by IgA nephropathy (31.1%) and focal segmental glomerulosclerosis (14.1%). Among the secondary glomerulopathies, lupus nephropathy was the most common (41.7%), followed by pauciimmune glomerulonephritis (27.1%) and diabetic nephropathy (6.4%). When comparing the results with other regions, significant differences were observed with reported frequencies in United States, Europe, Asia and the rest of Latin America. CONCLUSIONS: The most common primary glomerulopathies were membranous nephropathy and IgA nephropathy. Among the secondary glomerulopathies lupus nephropathy and pauci-immune glomerulonephritis were the most common. Compared to international registries, we observed a high proportion of membranous nephropathy and pauci-immune glomerulonephritis.

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BACKGROUND: The frequency of glomerular diseases is dynamic and varies according to geographic area. AIM: To evaluate the frequency of primary and secondary glomerulopathies, their demographic profile and main clinical characteristics. MATERIAL AND METHODS: Renal biopsies from native kidneys performed between 1999 and 2020 were retrospectively reviewed. Demographic characteristics, clinical presentation, most relevant laboratory tests, frequency of primary and secondary glomerulopathies were analyzed. RESULTS: We analyzed 550 kidney biopsies from patients with a median age of 48 years (64% females). Nephrotic syndrome was the main indication for renal biopsy. Primary and secondary glomerulopathies occurred with similar frequency. Within the primary glomerulopathies, membranous nephropathy (34.1%) was the most common, followed by IgA nephropathy (31.1%) and focal segmental glomerulosclerosis (14.1%). Among the secondary glomerulopathies, lupus nephropathy was the most common (41.7%), followed by pauciimmune glomerulonephritis (27.1%) and diabetic nephropathy (6.4%). When comparing the results with other regions, significant differences were observed with reported frequencies in United States, Europe, Asia and the rest of Latin America. CONCLUSIONS: The most common primary glomerulopathies were membranous nephropathy and IgA nephropathy. Among the secondary glomerulopathies lupus nephropathy and pauci-immune glomerulonephritis were the most common. Compared to international registries, we observed a high proportion of membranous nephropathy and pauci-immune glomerulonephritis.

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Background and Objectives: We developed a predictive statistical model to identify donor-recipient characteristics related to kidney graft survival in the Chilean population. Given the large number of potential predictors relative to the sample size, we implemented an automated variable selection mechanism that could be revised in future studies as more national data is collected. Materials and Methods: A retrospective multicenter study was conducted to analyze data from 822 adult kidney transplant recipients from adult donors between 1998 and 2018. To the best of our knowledge, this is the largest kidney transplant database to date in Chile. A procedure based on a cross-validated regularized Cox regression using the Elastic Net penalty was applied to objectively identify predictors of death-censored graft failure. Hazard ratios were estimated by adjusting a multivariate Cox regression with the selected predictors. Results: Seven variables were associated with the risk of death-censored graft failure; four from the donor: age (HR = 1.02, 95% CI: 1.00-1.03), male sex (HR = 0.64, 95% CI: 0.46-0.90), history of hypertension (HR = 1.49, 95% CI: 0.98-2.28), and history of diabetes (HR = 2.04, 95% CI: 0.97-4.29); two from the recipient: years on dialysis log-transformation (HR = 1.29, 95% CI: 0.99-1.67) and history of previous solid organ transplantation (HR = 2.02, 95% CI: 1.18-3.47); and one from the transplant: number of HLA mismatches (HR = 1.13, 95% CI: 0.99-1.28). Only the latter is considered for patient prioritization in deceased kidney allocation in Chile. Conclusions: A risk model for kidney graft failure was developed and trained for the Chilean population, providing objective criteria which can be used to improve efficiency in deceased kidney allocation.

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Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.

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Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.

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BACKGROUND: Monoclonal gammopathy of renal significance (MGRS)-related lesions are infrequent entities. There are no publications on these disorders in Latin America (LA). The aim of this study was to describe epidemiological and clinical characteristics of these patients in LA. METHODS: We performed a multicentre retrospective study. Patients with diagnosis of MGRS between 2012 and 2018 were included. Epidemiological and clinical data were collected from clinical records. RESULTS: Twenty-seven patients from Chile, Argentina, Ecuador and Uruguay were included. Half debuted with a nephrotic syndrome, and 32% required dialysis. Proliferative glomerulonephritis with monoclonal immunoglobulin deposits was found in 33%, amyloidosis in 26% and monoclonal immunoglobulin deposition disease also in 26%. The immunoglobulin most frequently found in renal biopsies was IgG kappa. In 67% a paraprotein was found. Twenty patients received an anti-plasma cell regimen, and 3 a rituximab-based regimen (IgM-MGRS). Renal response (RR) was achieved in 56%. Early treatment (≤3 months) was associated with higher RR (75% vs 43%). Three patients relapsed within 21.5 months, and 3 progressed: 1 to multiple myeloma, 1 to systemic amyloidosis and another to systemic light-chain deposition disease. Two patients died, both due to infection during induction treatment. CONCLUSION: There was a higher than expected frequency of patients requiring dialysis. The most common MGRS-related lesion was PGNMD. Early treatment was associated with better response. As a rare disease, increasing awareness and promoting early diagnosis are necessary in LA to improve outcomes. SUMMARY AT A GLANCE A collection of 27 cases of MGRS from Latin America with information on epidemiology, clinical characteristics, treatment and outcome of patients diagnosed of MGRS-related renal lesions.

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ABSTRACT Background Renal failure (RF) is a common complication in patients with newly diagnosed multiple myeloma (NDMM). Aim To evaluate the frequency of RF in NDMM patients, and the prognostic impact of its reversibility. Material and Methods A retrospective study evaluating demographic and clinical characteristics of 154 consecutive patients with NDMM was carried out. Estimated glomerular filtration rate (eGFR) was calculated at the beginning and at the end of the induction therapy. In addition, we evaluated renal responses (RR) according to the International Myeloma Working Group (IMWG) criteria. The induction regimen was based on thalidomide in all cases. Results Fifty-three patients had RF (34.4%). Complete renal response (RR) was achieved in 51%. Three years overall survival in patients without RF, with RF and complete RR, and patients with RF and any other RR, was 66, 47 and 13%, respectively. Median survival was 53, 27 and 6 months, respectively (p < 0.01). In the multivariate analysis, RF and hypercalcemia were independent predictors of a worse outcome. Conclusions Achieving a complete RR in patients with NDMM, is associated with a better survival.

Antecedentes La falla renal (FR) es una complicación frecuente en pacientes con mieloma múltiple (MM). Objetivo Evaluar la frecuencia de FR en pacientes con reciente diagnóstico de MM y determinar la importancia pronóstica de su reversibilidad. Material y Métodos Se realizó un estudio retrospectivo de 154 pacientes consecutivos con MM. La función renal se evaluó mediante la tasa estimada de filtración glomerular al inicio y final de la terapia de inducción. Además, evaluamos las respuestas renales (RR) de acuerdo con los criterios del International Myeloma Working Group (IMWG). El régimen de inducción se basó en talidomida en todos los casos. Resultados Cincuenta y tres pacientes presentaron FR (34,4%) al diagnóstico. La RR completa se logró en 51%. La sobrevida global (SG) a 3 años en pacientes sin FR, con FR y RR completa, y pacientes con FR y cualquier otra RR, fue de 66, 47 y 13%, respectivamente. La SG media fue de 53, 27 y 6 meses (p < 0,01), respectivamente. En el análisis multivariado, la FR y la hipercalcemia fueron factores independientes de menor sobrevida. Conclusiones Lograr una RR completa en pacientes con MM recién diagnosticado se asocia con una mejor sobrevida.

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ABSTRACT Background: Immunoglobulin light chain (AL) amyloidosis is a rare and underdiagnosed entity. Aim: To characterize patients with AL amyloidosis in Chilean public health centers. Material and Methods: We conducted a retrospective, multicenter study. Public centers of the Chilean Monoclonal Gammopathies Cooperative Group were asked to search for patients with AL amyloidosis in their databases. Epidemiological, clinical and laboratory characteristics were evaluated. Results: Forty-two patients aged 22 to 84 years were found. Twenty four percent had localized AL amyloidosis; 64% had a lambda light chain clone; 47% were associated with multiple myeloma and 9% with non-Hodgkin lymphoma. The most commonly involved organ was the kidney (76%). Serum free light chains were measured in 31% and an echocardiogram was performed in 74% of patients. Seventeen percent of patients received only palliative care, 17% were treated with bortezomib, 21% with thalidomide, and 40% with melphalan. No patient was transplanted. The mean overall survival (OS) of the group was 19 months. The 5-year OS was 28%. Conclusions: It is important to obtain these realistic, national data to initiate strategies to improve early diagnosis and proper management of this disease.

La amiloidosis AL es una entidad poco frecuente y subdiagnosticada. Mientras todo el mundo discute sobre las nuevas herramientas diagnósticas y terapéuticas, en Chile y en América Latina en general, estamos lejos de esa realidad. El objetivo del presente estudio fue caracterizar a los pacientes con amiloidosis AL en centros del sistema público de nuestro país. Se realizó un estudio retrospectivo, multicéntrico, descriptivo. Los centros públicos del grupo cooperativo hematológico chileno buscaron en sus bases de datos pacientes diagnosticados con amiloidosis AL. Se evaluaron las características epidemiológicas, clínicas y de laboratorio. La edad media fue de 65 años. A 24% de los pacientes se les diagnosticó amiloidosis AL localizada; 64% tuvo paraproteína con cadena ligera lambda; 47% se asoció con mieloma múltiple y 9% con linfoma no Hodgkin. El órgano afectado con mayor frecuencia fue el riñón (76%). Las cadenas ligeras libres de suero se realizaron en 31% y ecocardiograma en 74%. El 17% recibió solo cuidados paliativos, 17% recibió tratamiento con bortezomib, 21% con talidomida y 40% con melfalán. Ningún paciente fue trasplantado. La media de sobrevida global (SG) del grupo fue de 19 meses. La SG a 5 años fue de 28%. Es importante reportar estos resultados nacionales para iniciar estrategias que mejoren tanto el diagnóstico temprano como el tratamiento de esta patología. Por lo tanto, mejorar la sospecha diagnóstica es crucial.

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BACKGROUND: Chronic kidney disease (CKD) is a growing public health concern, and available treatments are insufficient in limiting disease progression. New strategies, including regenerative cell-based therapies, have emerged as therapeutic alternatives. Results from several groups, including our own, have reported evidence of a supportive role for mesenchymal stromal cells (MSCs) in functional recovery and prevention of tissue damage in murine models of CKD. Prompted by these data, an open pilot study was conducted to assess the safety and efficacy of a single injection of autologous adipose tissue-derived MSCs (AT-MSCs) for treatment of CKD. METHODS: AT-MSCs were infused intravenously into six CKD patients at a dose of 1 million cells/kg. Patients were stabilized and followed for one year prior to MSC infusion and one year following infusion. RESULTS: No patients presented with adverse effects. Statistically significant improvement in urinary protein excretion was observed in AT-MSCs transplanted patients, from a median of 0.75 g/day (range, 0.15-9.57) at baseline to 0.54 g/day (range, 0.01-2.66) at month 12 (P = 0.046). The glomerular filtration rate was not significantly decreased post-infusion of AT-MSCs. CONCLUSION: Findings from this pilot study demonstrate that intravenous infusion of autologous expanded AT-MSCs into CKD patients was not associated with adverse effects and could benefit patients already undergoing standard medical treatment.

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Background Renal failure (RF) is a common complication in patients with newly diagnosed multiple myeloma (NDMM). Aim To evaluate the frequency of RF in NDMM patients, and the prognostic impact of its reversibility. Material and Methods A retrospective study evaluating demographic and clinical characteristics of 154 consecutive patients with NDMM was carried out. Estimated glomerular filtration rate (eGFR) was calculated at the beginning and at the end of the induction therapy. In addition, we evaluated renal responses (RR) according to the International Myeloma Working Group (IMWG) criteria. The induction regimen was based on thalidomide in all cases. Results Fifty-three patients had RF (34.4%). Complete renal response (RR) was achieved in 51%. Three years overall survival in patients without RF, with RF and complete RR, and patients with RF and any other RR, was 66, 47 and 13%, respectively. Median survival was 53, 27 and 6 months, respectively (p < 0.01). In the multivariate analysis, RF and hypercalcemia were independent predictors of a worse outcome. Conclusions Achieving a complete RR in patients with NDMM, is associated with a better survival.

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BACKGROUND: Immunoglobulin light chain (AL) amyloidosis is a rare and underdiagnosed entity. AIM: To characterize patients with AL amyloidosis in Chilean public health centers. MATERIAL AND METHODS: We conducted a retrospective, multicenter study. Public centers of the Chilean Monoclonal Gammopathies Cooperative Group were asked to search for patients with AL amyloidosis in their databases. Epidemiological, clinical and laboratory characteristics were evaluated. RESULTS: Forty-two patients aged 22 to 84 years were found. Twenty four percent had localized AL amyloidosis; 64% had a lambda light chain clone; 47% were associated with multiple myeloma and 9% with non-Hodgkin lymphoma. The most commonly involved organ was the kidney (76%). Serum free light chains were measured in 31% and an echocardiogram was performed in 74% of patients. Seventeen percent of patients received only palliative care, 17% were treated with bortezomib, 21% with thalidomide, and 40% with melphalan. No patient was transplanted. The mean overall survival (OS) of the group was 19 months. The 5-year OS was 28%. CONCLUSIONS: It is important to obtain these realistic, national data to initiate strategies to improve early diagnosis and proper management of this disease.

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BACKGROUND: Kidney transplantation of expanded criteria deceased donors (DCE) has become a common clinical practice. However, DCE outcomes are inferior compared to kidney transplants from standard criteria donors (DCS). AIM: To evaluate intermediate and long-term outcomes of DCE transplanted patients. MATERIAL AND METHODS: Cadaveric kidney transplants were evaluated using a retrospective cohort of eight consecutive years. Complications and long-term function of the transplant were assessed in DCE and DCS kidney recipients. RESULTS: Of 213 patients analyzed, 34 (16%) underwent DCE transplantation. DCS recipients spent more time on the waiting list for transplantation (p = 0.04). DCE recipients showed higher frequency of surgical complications (p = 0.04), vascular complications (p = 0.02), acute transplant rejection (p = 0.05), and hospitalizations (p = 0.01). Creatinine (mg/dL) in DCE and DCS recipients was 2.3 and 1.5 respectively at year one (p < 0.01) and 2.6 and 1.6 respectively at year five (p < 0.01). Graft survival in the DCE group was significantly lower at 5 years (61 and 89% respectively, p < 0.01). CONCLUSIONS: DCE grafts are associated with lower survival, higher hospitalization rate and commonly develop surgical complications and rejections.

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Background: Kidney transplantation of expanded criteria deceased donors (DCE) has become a common clinical practice. However, DCE outcomes are inferior compared to kidney transplants from standard criteria donors (DCS). Aim: To evaluate intermediate and long-term outcomes of DCE transplanted patients. Material and Methods: Cadaveric kidney transplants were evaluated using a retrospective cohort of eight consecutive years. Complications and long-term function of the transplant were assessed in DCE and DCS kidney recipients. Results: Of 213 patients analyzed, 34 (16%) underwent DCE transplantation. DCS recipients spent more time on the waiting list for transplantation (p = 0.04). DCE recipients showed higher frequency of surgical complications (p = 0.04), vascular complications (p = 0.02), acute transplant rejection (p = 0.05), and hospitalizations (p = 0.01). Creatinine (mg/dL) in DCE and DCS recipients was 2.3 and 1.5 respectively at year one (p < 0.01) and 2.6 and 1.6 respectively at year five (p < 0.01). Graft survival in the DCE group was significantly lower at 5 years (61 and 89% respectively, p < 0.01). Conclusions: DCE grafts are associated with lower survival, higher hospitalization rate and commonly develop surgical complications and rejections.

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AIM: To describe the long term follow-up of kidney allograft recipients receiving ketoconazole with calcineurin inhibitors (CNI) alone or combined with everolimus. METHODS: This is an open-label, prospective observational clinical trial in low immunologic risk patients who, after signing an Institutional Review Board approved consent form, were included in one of two groups. The first one (n = 59) received everolimus (target blood level, 3-8 ng/mL) and the other (n = 114) azathioprine 2 mg/kg per day or mycophenolate mofetyl (MMF) 2 g/d. Both groups also received tapering steroids, the cytochrome P-450 3A4 (CYP3A4) modulator, ketoconazole 50-100 mg/d, and cyclosporine with C0 targets in the everolimus group of 200-250 ng/mL in 1 mo, 100-125 ng/mL in 2 mo, and 50-65 ng/mL thereafter, and in the azathioprine or MMF group of 250-300 ng/mL in 1 mo, 200-250 ng/mL in 2 mo, 180-200 ng/mL until 3-6 mo, and 100-125 ng/mL thereafter. Clinical visits were performed monthly the first year and quarterly thereafter by treating physicians and all data was extracted by the investigators. RESULTS: The clinical characteristics of these two cohorts were similar. During the follow up (66 + 31 mo), both groups showed comparable clinical courses, but the biopsy proven acute rejection rate during the full follow-up period seemed to be lower in the everolimus group (20% vs 36%; P = 0.04). The everolimus group did not show a higher surgical complication rate than the other group. By the end of the follow-up period, the everolimus group tended to show a higher glomerular filtration rate. Nevertheless, we found no evidence of a consistent negative slope of the temporal allograft function estimated by the modification of the diet in renal disease formula in any of both groups. At 6 years of follow-up, the uncensored and death-censored graft survivals were 91% and 93%, and 91% and 83% in the everolimus plus cyclosporine, and cyclosporine alone groups, respectively. The addition of ketoconazole saved 80% of cyclosporine and 56% of everolimus doses. CONCLUSION: Combining CYP3A4 modulators with CNI or mammalian target of rapamycin inhibitor, in low immunological risk kidney transplant recipients is feasible, effective, safe and affordable even in the long term.