RESUMEN
BACKGROUND AND PURPOSE: Spinal muscular atrophy (SMA) as the second most common neurodegenerative disorder in childhood is characterized by the deficiency of survival of motor neuron (SMN) protein leading predominantly to degeneration of alpha motor neurons and consequently to progressive muscle weakness and atrophy. Besides some biomarkers like SMN2 copy number therapeutic biomarkers for SMA with known relevance for neuromuscular transmission are lacking. Here, we examined the potential of Thrombospondin-4 (TSP4) to serve as a cerebrospinal fluid (CSF) biomarker, which may also indicate treatment response. METHODS: We used untargeted proteomic analyses to determine biomarkers in CSF samples derived from pediatric pre-symptomatic (n = 6) and symptomatic (n = 4) SMA patients. The identified biomarker TSP4 was then validated in additional 68 CSF samples (9 adult and 24 pediatric SMA patients, 5 adult and 13 pediatric non-disease controls in addition to 17 pediatric disease controls) by enzyme-linked immunosorbent assay (ELISA) as an additional analytical approach. RESULTS: Untargeted proteomic analyses of CSF identified a dysregulation of TSP4 and revealed a difference between pre-symptomatic SMA patients and patients identified after the onset of first symptoms. Subsequent ELISA-analyses showed that TSP4 is decreased in pediatric but not adult SMA patients. CSF of pediatric patients with other neurological disorders demonstrated no alteration of TSP4 levels. Furthermore, CSF TSP4 levels of pediatric SMA patients increased after first dose of Nusinersen. CONCLUSIONS: We found that TSP4 levels are exclusively reduced in CSF of pediatric SMA patients and increase after treatment, leading us to the hypothesis that TSP4 could serve as a CSF biomarker with the potential to monitor treatment response in pediatric SMA patients. Moreover, TSP4 enable to distinguish pre-symptomatic and symptomatic patients suggesting a potential to serve as a stratification marker.
RESUMEN
BACKGROUND: Chronic inflammatory demyelinating polyneuropathy (CIDP) is an inflammatory disease affecting the peripheral nerves and the most frequent autoimmune polyneuropathy. Given the lack of established biomarkers or risk factors for the development of CIDP and patients' treatment response, this research effort seeks to identify potential clinical factors that may influence disease progression and overall treatment efficacy. METHODS: In this multicenter, retrospective analysis, we have screened 197 CIDP patients who presented to the University Hospitals in Düsseldorf, Berlin, Cologne, Essen, Magdeburg and Munich between 2018 and 2022. We utilized the respective hospital information system and examined baseline data with clinical examination, medical letters, laboratory results, antibody status, nerve conduction studies, imaging and biopsy findings. Aside from clinical baseline data, we analyzed treatment outcomes using the Standard of Care (SOC) definition, as well as a comparison of an early (within the first 12 months after manifestation) versus late (more than 12 months after manifestation) onset of therapy. RESULTS: In terms of treatment, most patients received intravenous immunoglobulin (56%) or prednisolone (39%) as their first therapy. Patients who started their initial treatment later experienced a worsening disease course, as reflected by a significant deterioration in their Inflammatory Neuropathy Cause and Treatment (INCAT) leg disability score. SOC-refractory patients had worse clinical outcomes than SOC-responders. Associated factors for SOC-refractory status included the presence of fatigue as a symptom and alcohol dependence. CONCLUSION: Timely diagnosis, prompt initiation of treatment and careful monitoring of treatment response are essential for the prevention of long-term disability in CIDP and suggest a "hit hard and early" treatment paradigm.
Asunto(s)
Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante , Humanos , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/diagnóstico , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/terapia , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante/tratamiento farmacológico , Masculino , Femenino , Persona de Mediana Edad , Anciano , Estudios Retrospectivos , Adulto , Progresión de la Enfermedad , Inmunoglobulinas Intravenosas/uso terapéutico , Inmunoglobulinas Intravenosas/administración & dosificación , Estudios de Cohortes , Prednisolona/uso terapéutico , Prednisolona/administración & dosificaciónRESUMEN
BACKGROUND: The clinical heterogeneity of myasthenia gravis (MG), an autoimmune disease defined by antibodies (Ab) directed against the postsynaptic membrane, constitutes a challenge for patient stratification and treatment decision making. Novel strategies are needed to classify patients based on their biological phenotypes aiming to improve patient selection and treatment outcomes. METHODS: For this purpose, we assessed the serum proteome of a cohort of 140 patients with anti-acetylcholine receptor-Ab-positive MG and utilised consensus clustering as an unsupervised tool to assign patients to biological profiles. For in-depth analysis, we used immunogenomic sequencing to study the B cell repertoire of a subgroup of patients and an in vitro assay using primary human muscle cells to interrogate serum-induced complement formation. FINDINGS: This strategy identified four distinct patient phenotypes based on their proteomic patterns in their serum. Notably, one patient phenotype, here named PS3, was characterised by high disease severity and complement activation as defining features. Assessing a subgroup of patients, hyperexpanded antibody clones were present in the B cell repertoire of the PS3 group and effectively activated complement as compared to other patients. In line with their disease phenotype, PS3 patients were more likely to benefit from complement-inhibiting therapies. These findings were validated in a prospective cohort of 18 patients using a cell-based assay. INTERPRETATION: Collectively, this study suggests proteomics-based clustering as a gateway to assign patients to a biological signature likely to benefit from complement inhibition and provides a stratification strategy for clinical practice. FUNDING: CN and CBS were supported by the Forschungskommission of the Medical Faculty of the Heinrich Heine University Düsseldorf. CN was supported by the Else Kröner-Fresenius-Stiftung (EKEA.38). CBS was supported by the Deutsche Forschungsgemeinschaft (DFG-German Research Foundation) with a Walter Benjamin fellowship (project 539363086). The project was supported by the Ministry of Culture and Science of North Rhine-Westphalia (MODS, "Profilbildung 2020" [grant no. PROFILNRW-2020-107-A]).
Asunto(s)
Autoanticuerpos , Miastenia Gravis , Fenotipo , Proteómica , Receptores Colinérgicos , Humanos , Miastenia Gravis/sangre , Miastenia Gravis/diagnóstico , Miastenia Gravis/inmunología , Miastenia Gravis/metabolismo , Receptores Colinérgicos/inmunología , Receptores Colinérgicos/metabolismo , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Proteómica/métodos , Femenino , Masculino , Persona de Mediana Edad , Adulto , Análisis por Conglomerados , Proteoma , Anciano , Linfocitos B/metabolismo , Linfocitos B/inmunología , Activación de ComplementoRESUMEN
AIMS: Diagnosis of idiopathic inflammatory myopathies (IIM) is based on morphological characteristics and the evaluation of disease-related proteins. However, although broadly applied, substantial bias is imposed by the respective methods, observers and individual staining approaches. We aimed to quantify the protein levels of major histocompatibility complex (MHC)-1, (MHC)-2 and intercellular adhesion molecule (ICAM)-1 using an automated morphometric method to mitigate bias. METHODS: Double immunofluorescence staining was performed on whole muscle sections to study differences in protein expression in myofibre and endomysial vessels. We analysed all IIM subtypes including dermatomyositis (DM), anti-synthetase syndrome (ASyS), inclusion body myositis (IBM), immune-mediated-necrotising myopathy (IMNM), dysferlinopathy (DYSF), SARS-CoV-2 infection and vaccination-associated myopathy. Biopsies with neurogenic atrophy (NA) and normal morphology served as controls. Bulk RNA-Sequencing (RNA-Seq) was performed on a subset of samples. RESULTS: Our study highlights the significance of MHC-1, MHC-2 and ICAM-1 in diagnosing IIM subtypes and reveals distinct immunological profiles. RNASeq confirmed the precision of our method and identified specific gene pathways in the disease subtypes. Notably, ASyS, DM and SARS-CoV-2-associated myopathy showed increased ICAM-1 expression in the endomysial capillaries, indicating ICAM-1-associated vascular activation in these conditions. In addition, ICAM-1 showed high discrimination between different subgroups with high sensitivity and specificity. CONCLUSIONS: Automated morphometric analysis provides precise quantitative data on immune-associated proteins that can be integrated into our pathophysiological understanding of IIM. Further, ICAM-1 holds diagnostic value for the detection of IIM pathology.
Asunto(s)
Molécula 1 de Adhesión Intercelular , Músculo Esquelético , Miositis , Humanos , Molécula 1 de Adhesión Intercelular/metabolismo , Miositis/patología , Miositis/diagnóstico , Miositis/metabolismo , Músculo Esquelético/patología , Músculo Esquelético/metabolismo , COVID-19/patología , COVID-19/diagnóstico , Masculino , Femenino , Diagnóstico Diferencial , Antígenos de Histocompatibilidad Clase II/metabolismoRESUMEN
Idiopathic inflammatory myopathies (IIM) are rare diseases (incidence 1:100,000) with a wide range of clinical symptoms and manifestations. Typical indicators of IIM are proximally emphasized muscle weakness and myalgias, which are usually accompanied by elevated creatine kinase levels and muscle atrophy. The autoantibody diagnostics separate IIM into different entities, which are each associated with a typical risk of organ manifestations and the occurrence of tumors. The IIM represents an interdisciplinary challenge and the diagnostics and treatment require the involvement of several disciplines including rheumatology, neurology, neuropathology, dermatology and pneumology. An accurate diagnosis and careful tumor screening are essential because of the association between certain subgroups of IIM and the occurrence of malignant tumors.
Asunto(s)
Miositis , Grupo de Atención al Paciente , Humanos , Miositis/diagnóstico , Miositis/terapia , Miositis/inmunología , Diagnóstico Diferencial , Medicina Basada en la Evidencia , ReumatologíaRESUMEN
Myasthenia gravis is a chronic antibody-mediated autoimmune disease disrupting neuromuscular synaptic transmission. Informative biomarkers remain an unmet need to stratify patients with active disease requiring intensified monitoring and therapy; their identification is the primary objective of this study. We applied mass spectrometry-based proteomic serum profiling for biomarker discovery. We studied an exploration and a prospective validation cohort consisting of 114 and 140 anti-acetylcholine receptor antibody (AChR-Ab)-positive myasthenia gravis patients, respectively. For downstream analysis, we applied a machine learning approach. Protein expression levels were confirmed by ELISA and compared to other myasthenic cohorts, in addition to myositis and neuropathy patients. Anti-AChR-Ab levels were determined by a radio receptor assay. Immunohistochemistry and immunofluorescence of intercostal muscle biopsies were employed for validation in addition to interactome studies of inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3). Machine learning identified ITIH3 as potential serum biomarker reflective of disease activity. Serum levels correlated with disease activity scores in the exploration and validation cohort and were confirmed by ELISA. Lack of correlation between anti-AChR-Ab levels and clinical scores underlined the need for biomarkers. In a subgroup analysis, ITIH3 was indicative of treatment responses. Immunostaining of muscle specimens from these patients demonstrated ITIH3 localization at the neuromuscular endplates in myasthenia gravis but not in controls, thus providing a structural equivalent for our serological findings. Immunoprecipitation of ITIH3 and subsequent proteomics lead to identification of its interaction partners playing crucial roles in neuromuscular transmission. This study provides data on ITIH3 as a potential pathophysiological-relevant biomarker of disease activity in myasthenia gravis. Future studies are required to facilitate translation into clinical practice.
Asunto(s)
Biomarcadores , Miastenia Gravis , Humanos , Miastenia Gravis/sangre , Miastenia Gravis/diagnóstico , Miastenia Gravis/patología , Miastenia Gravis/metabolismo , Biomarcadores/sangre , Biomarcadores/metabolismo , Masculino , Femenino , Persona de Mediana Edad , Adulto , Anciano , Autoanticuerpos/sangre , Receptores Colinérgicos/inmunología , Receptores Colinérgicos/metabolismo , Proteómica/métodos , Estudios de Cohortes , Adulto Joven , Proteínas Inhibidoras de Proteinasas Secretoras/sangre , Aprendizaje AutomáticoRESUMEN
BACKGROUND AND OBJECTIVES: Relapse and MRI activity usually decline with aging but are replaced by progression independent of relapse activity (PIRA) in patients with multiple sclerosis (PwMS). However, several older PwMS continue to experience clinical relapses, and the impact on their disease remains undetermined. We aimed to determine the impact of an index relapse on disease outcomes in patients older than 50 years and to identify risk factors of disadvantageous outcomes. METHODS: We performed a secondary analysis from 3 prospective cohorts in Germany. We evaluated all PwMS 50 years and older with a relapse ≤60 days before a baseline visit and at least 18 months of follow-up compared with a control cohort of PwMS without a relapse. Patients were stratified according to age ("50-54" vs "55-59" vs "60+") or disease outcomes ("stable" vs "active" vs "progressive," according to the Lublin criteria). We analyzed relapses, MRI activity, relapse-associated worsening, and PIRA. Regression analysis was performed to evaluate the association of specific baseline risk factors and treatment regimen changes with disease outcomes at month 18. RESULTS: A total of 681 patients were included in the "relapse cohort" (50+: 361; 55+: 220; 60+: 100). The "control cohort" comprised 232 patients (50+: 117; 55+: 71; 60+: 44). Baseline epidemiologic parameters were balanced among cohorts and subgroups. We observed increased abundance of inflammatory activity and relapse-independent disability progression in the "relapse" vs "control" cohort. In the "relapse" cohort, we identified 273 patients as "stable" (59.7%), 114 patients as "active" (24.9%), and 70 patients as "progressive" (15.3%) during follow-up. Cardiovascular risk factors (CVRFs) and older age at baseline were identified as risk factors of progressive, whereas disease-modifying treatment (DMT) administration at baseline favored stable disease. DMT during follow-up was associated with stable over active, but not over progressive disease. DISCUSSION: A relapse-suggesting underlying active disease-in PwMS older than 50 years was associated with continued disease activity and increased risk of PIRA. Presence of CVRF and absence of DMT at baseline appeared as risk factors of disadvantageous disease courses. An escalation of DMT switch was associated with stable over active but not progressive disease.
Asunto(s)
Progresión de la Enfermedad , Recurrencia , Humanos , Persona de Mediana Edad , Femenino , Masculino , Imagen por Resonancia Magnética , Factores de Riesgo , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/epidemiología , Estudios Prospectivos , Anciano , Alemania/epidemiología , Estudios de Cohortes , Factores de Edad , Esclerosis Múltiple Recurrente-Remitente/diagnóstico por imagen , Esclerosis Múltiple Recurrente-Remitente/epidemiologíaRESUMEN
Fatigue is commonly associated with myasthenia gravis (MG), but factors contributing to fatigue development in MG are incompletely understood. This nationwide cross-sectional registry study included 1464 patients diagnosed with autoimmune MG, recruited between February 2019 and April 2023. Frequency and severity of fatigue was assessed at study inclusion using the patient-reported Chalder Fatigue Questionnaire (CFQ). Frequency of fatigue was 59%. Fatigue severity strongly correlated with both patient-reported and physician-assessed MG outcome measures (MG-ADL, MG-QoL15, QMG and MGFA classes) and was associated with a history of myasthenic exacerbation and/or myasthenic crises and a delay in diagnosis of more than 1 year after symptom onset. Fatigue was more prevalent in women and coincided with symptoms of depression, anxiety, and sleep dissatisfaction. Differences in fatigue severity were observed between antibody (ab) subgroups, with highest fatigue severity in LRP4-ab-positive patients and lowest fatigue severity in AChR-ab-positive patients. Fatigue is a frequent and clinically highly relevant symptom of MG. Early diagnosis and prevention of MG crises may limit the long-term burden of fatigue in patients with MG.
Asunto(s)
Fatiga , Miastenia Gravis , Sistema de Registros , Humanos , Miastenia Gravis/epidemiología , Miastenia Gravis/complicaciones , Femenino , Fatiga/etiología , Fatiga/epidemiología , Masculino , Persona de Mediana Edad , Estudios Transversales , Adulto , Anciano , Índice de Severidad de la EnfermedadRESUMEN
5q-associated spinal muscular atrophy (SMA) is a motoneuron disease caused by mutations in the survival motor neuron 1 (SMN1) gene. Adaptive immunity may contribute to SMA as described in other motoneuron diseases, yet mechanisms remain elusive. Nusinersen, an antisense treatment, enhances SMN2 expression, benefiting SMA patients. Here we have longitudinally investigated SMA and nusinersen effects on local immune responses in the cerebrospinal fluid (CSF) - a surrogate of central nervous system parenchyma. Single-cell transcriptomics (SMA: N = 9 versus Control: N = 9) reveal NK cell and CD8+ T cell expansions in untreated SMA CSF, exhibiting activation and degranulation markers. Spatial transcriptomics coupled with multiplex immunohistochemistry elucidate cytotoxicity near chromatolytic motoneurons (N = 4). Post-nusinersen treatment, CSF shows unaltered protein/transcriptional profiles. These findings underscore cytotoxicity's role in SMA pathogenesis and propose it as a therapeutic target. Our study illuminates cell-mediated cytotoxicity as shared features across motoneuron diseases, suggesting broader implications.
Asunto(s)
Encéfalo , Células Asesinas Naturales , Neuronas Motoras , Atrofia Muscular Espinal , Oligonucleótidos , Humanos , Atrofia Muscular Espinal/tratamiento farmacológico , Atrofia Muscular Espinal/patología , Atrofia Muscular Espinal/genética , Neuronas Motoras/efectos de los fármacos , Neuronas Motoras/patología , Neuronas Motoras/metabolismo , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/efectos de los fármacos , Encéfalo/patología , Encéfalo/efectos de los fármacos , Femenino , Masculino , Proteína 2 para la Supervivencia de la Neurona Motora/genética , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/efectos de los fármacos , Proteína 1 para la Supervivencia de la Neurona Motora/genética , Proteína 1 para la Supervivencia de la Neurona Motora/metabolismo , Análisis de la Célula Individual , Citotoxicidad Inmunológica/efectos de los fármacos , Lactante , Preescolar , Niño , TranscriptomaRESUMEN
Background: Immune-mediated peripheral nervous system (PNS) disorders pose diagnostic and therapeutic challenges, necessitating collaborative, patient-centered care. Limited access to specialized centers leads to delayed diagnosis and care, as seen during the COVID-19 pandemic. To address these challenges, accessible specialized care is crucial. On-site support plays a vital role in advising and assisting patients and caregivers, enabling multidisciplinary care for PNS diseases. Recent Findings: The PNS Nurse Education Program tackles these complexities, using specialized nurses experienced in multiple sclerosis and Parkinson disease. Focusing on peripheral neuroimmunologic disorders, PNS nurses monitor disease severity, optimize communication, and provide therapeutic support in the recently started era of available immunotherapies. Collaboration with other healthcare sectors and support groups further enhances patient care. Implications for Practice: Ultimately, the PNS Nurse Education Program aims to bridge the gap between complex treatments and limited specialized care, improving patient outcomes and relieving burdens on patients, caregivers, and healthcare systems.
RESUMEN
Background: NEFL encodes for the neurofilament light chain protein. Pathogenic variants in NEFL cause demyelinating, axonal and intermediate forms of Charcot-Marie-Tooth disease (CMT) which present with a varying degree of severity and somatic mutations have not been described yet. Currently, 34 different CMT-causing pathogenic variants in NEFL in 174 patients have been reported. Muscular involvement was also described in CMT2E patients mostly as a secondary effect. Also, there are a few descriptions of a primary muscle vulnerability upon pathogenic NEFL variants. Objectives: To expand the current knowledge on the genetic landscape, clinical presentation and muscle involvement in NEFL-related neurological diseases by retrospective case study and literature review. Methods: We applied in-depth phenotyping of new and already reported cases, molecular genetic testing, light-, electron- and Coherent Anti-Stokes Raman Scattering-microscopic studies and proteomic profiling in addition to in silico modelling of NEFL-variants. Results: We report on a boy with a muscular phenotype (weakness, myalgia and cramps, Z-band alterations and mini-cores in some myofibers) associated with the heterozygous p.(Phe104Val) NEFL-variant, which was previously described in a neuropathy case. Skeletal muscle proteomics findings indicated affection of cytoskeletal proteins. Moreover, we report on two further neuropathic patients (16 years old girl and her father) both carrying the heterozygous p.(Pro8Ser) variant, which has been identified as 15% somatic mosaic in the father. While the daughter presented with altered neurophysiology,neurogenic clump feet and gait disturbances, the father showed clinically only feet deformities. As missense variants affecting proline at amino acid position 8 are leading to neuropathic manifestations of different severities, in silico modelling of these different amino acid substitutions indicated variable pathogenic impact correlating with disease onset. Conclusions: Our findings provide new morphological and biochemical insights into the vulnerability of denervated muscle (upon NEFL-associated neuropathy) as well as novel genetic findings expanding the current knowledge on NEFL-related neuromuscular phenotypes and their clinical manifestations. Along this line, our data show that even subtle expression of somatic NEFL variants can lead to neuromuscular symptoms.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth , Proteínas de Neurofilamentos , Fenotipo , Humanos , Masculino , Proteínas de Neurofilamentos/genética , Enfermedad de Charcot-Marie-Tooth/genética , Músculo Esquelético/patología , Músculo Esquelético/metabolismo , Estudios Retrospectivos , Niño , Adolescente , Femenino , MutaciónRESUMEN
INTRODUCTION: Efgartigimod and ravulizumab, both approved for treating acetylcholine receptor auto-antibody-positive (AChR-Ab+) generalized myasthenia gravis (gMG), have not been directly compared. This paper assessed comparative effects of efgartigimod vs. ravulizumab for treating adults with AChR-Ab+ gMG using indirect treatment comparison methods. METHODS: The matching-adjusted indirect comparison used data from two randomized trials of adult men and women. The ADAPT (efgartigimod vs. placebo; individual patient data available) population was reweighted to match the CHAMPION (ravulizumab vs. placebo; index study; aggregate data available) population. The relative effect of efgartigimod versus placebo was estimated in this reweighted population and compared with the observed ravulizumab versus placebo effect to estimate the efgartigimod versus ravulizumab effect. The outcomes were Myasthenia Gravis Activities of Daily Living (MG-ADL), Quantitative Myasthenia Gravis (QMG), and Myasthenia Gravis Quality of Life 15-item-revised scale (MG-QoL15r) assessed as cumulative effect (area under the curve; AUC) over 26 weeks (primary) and change from baseline at 4 weeks and time of best response (week 4 for efgartigimod; week 26 for ravulizumab). RESULTS: For MG-QoL15r, efgartigimod had a statistically significant improvement compared with ravulizumab over 26 weeks [mean difference (95% confidence interval): - 52.6 (- 103.0, - 2.3)], at week 4 [- 4.0 (- 6.6, - 1.4)], and at time of best response [- 3.9 (- 6.5, - 1.3)]. Efgartigimod had a statistically significant improvement over ravulizumab in MG-ADL at week 4 [- 1.9 (- 3.3, - 0.5)] and at time of best response [- 1.4 (- 2.8, 0.0)] and in QMG at week 4 [- 3.2 (- 5.2, - 1.2)] and at time of best response [- 3.0 (- 5.0, - 1.0)]. For AUC over 26 weeks, improvements were not significantly different between efgartigimod and ravulizumab for MG-ADL [- 8.7 (- 36.1, 18.8)] and QMG [- 13.7 (- 50.3, 22.9)]. CONCLUSION: Efgartigimod may provide a faster and greater improvement over 26 weeks in quality of life than ravulizumab in adults with AChR-Ab+ gMG. Efgartigimod showed faster improvements in MG-ADL and QMG than ravulizumab.
Asunto(s)
Anticuerpos Monoclonales Humanizados , Miastenia Gravis , Receptores Colinérgicos , Humanos , Miastenia Gravis/tratamiento farmacológico , Masculino , Femenino , Anticuerpos Monoclonales Humanizados/uso terapéutico , Persona de Mediana Edad , Receptores Colinérgicos/inmunología , Adulto , Autoanticuerpos , Resultado del Tratamiento , Anciano , Actividades Cotidianas , Calidad de VidaRESUMEN
Bi-allelic variants in VWA1, encoding Von Willebrand Factor A domain containing 1 protein localized to the extracellular matrix (ECM), were linked to a neuromuscular disorder with manifestation in child- or adulthood. Clinical findings indicate a neuromyopathy presenting with muscle weakness. Given that pathophysiological processes are still incompletely understood, and biomarkers are still missing, we aimed to identify blood biomarkers of pathophysiological relevance: white blood cells (WBC) and plasma derived from six VWA1-patients were investigated by proteomics. Four proteins, BET1, HNRNPDL, NEFM and PHGDH, known to be involved in neurological diseases and dysregulated in WBC were further validated by muscle-immunostainings unravelling HNRNPDL as a protein showing differences between VWA1-patients, healthy controls and patients suffering from neurogenic muscular atrophy and BICD2-related neuromyopathy. Immunostaining studies of PHGDH indicate its involvement in apoptotic processes via co-localisation with caspase-3. NEFM showed an increase in cells within the ECM in biopsies of all patients studied. Plasma proteomics unravelled dysregulation of 15 proteins serving as biomarker candidates among which a profound proportion of increased ones (6/11) are mostly related to antioxidative processes and have even partially been described as blood biomarkers for other entities of neuromuscular disorders before. CRP elevated in plasma also showed an increase in the extracellular space of VWA1-mutant muscle. Results of our combined studies for the first time describe pathophysiologically relevant biomarkers for VWA1-related neuromyopathy and suggest that VWA1-patient derived blood might hold the potential to study disease processes of clinical relevance, an important aspect for further preclinical studies.
Asunto(s)
Biomarcadores , Proteómica , Humanos , Biomarcadores/sangre , Proteómica/métodos , Femenino , Masculino , Adulto , Enfermedades Neuromusculares/sangre , Enfermedades Neuromusculares/genética , Enfermedades Neuromusculares/metabolismo , Persona de Mediana Edad , Proteoma/metabolismo , Leucocitos/metabolismoRESUMEN
One of the biggest challenges in managing multiple sclerosis is the heterogeneity of clinical manifestations and progression trajectories. It still remains to be elucidated whether this heterogeneity is reflected by discrete immune signatures in the blood as a surrogate of disease pathophysiology. Accordingly, individualized treatment selection based on immunobiological principles is still not feasible. Using two independent multicentric longitudinal cohorts of patients with early multiple sclerosis (n = 309 discovery and n = 232 validation), we were able to identify three distinct peripheral blood immunological endophenotypes by a combination of high-dimensional flow cytometry and serum proteomics, followed by unsupervised clustering. Longitudinal clinical and paraclinical follow-up data collected for the cohorts revealed that these endophenotypes were associated with disease trajectories of inflammation versus early structural damage. Investigating the capacity of immunotherapies to normalize endophenotype-specific immune signatures revealed discrete effect sizes as illustrated by the limited effect of interferon-ß on endophenotype 3-related immune signatures. Accordingly, patients who fell into endophenotype 3 subsequently treated with interferon-ß exhibited higher disease progression and MRI activity over a 4-year follow-up compared with treatment with other therapies. We therefore propose that ascertaining a patient's blood immune signature before immunomodulatory treatment initiation may facilitate prediction of clinical disease trajectories and enable personalized treatment decisions based on pathobiological principles.
Asunto(s)
Esclerosis Múltiple , Humanos , Esclerosis Múltiple/genética , Esclerosis Múltiple/tratamiento farmacológico , Endofenotipos , Interferón beta/uso terapéuticoRESUMEN
Myasthenia gravis (MG) is a prototypical autoimmune disease of the neuromuscular junction (NMJ). The study of the underlying pathophysiology has provided novel insights into the interplay of autoantibodies and complement-mediated tissue damage. Experimental autoimmune myasthenia gravis (EAMG) emerged as a valuable animal model, designed to gain further insight and to test novel therapeutic approaches for MG. However, the availability of native acetylcholine receptor (AChR) protein is limited favouring the use of recombinant proteins. To provide a simplified platform for the study of MG, we established a model of EAMG using a recombinant protein containing the immunogenic sequence of AChR in mice. This model recapitulates key features of EAMG, including fatigable muscle weakness, the presence of anti-AChR-antibodies, and engagement of the NMJ by complement and a reduced NMJ density. Further characterization of this model demonstrated a prominent B cell immunopathology supported by T follicular helper cells. Taken together, the herein-presented EAMG model may be a valuable tool for the study of MG pathophysiology and the pre-clinical testing of therapeutic applications.
Asunto(s)
Miastenia Gravis Autoinmune Experimental , Receptores Colinérgicos , Ratones , Animales , Miastenia Gravis Autoinmune Experimental/tratamiento farmacológico , Miastenia Gravis Autoinmune Experimental/metabolismo , Unión Neuromuscular/patología , Proteínas del Sistema Complemento , Autoanticuerpos , InmunizaciónRESUMEN
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) of still unclear etiology. In recent years, the search for biomarkers facilitating its diagnosis, prognosis, therapy response, and other parameters has gained increasing attention. In this regard, in a previous meta-analysis comprising 22 studies, we found that MS is associated with higher nitrite/nitrate (NOx) levels in the cerebrospinal fluid (CSF) compared to patients with non-inflammatory other neurological diseases (NIOND). However, many of the included studies did not distinguish between the different clinical subtypes of MS, included pre-treated patients, and inclusion criteria varied. As a follow-up to our meta-analysis, we therefore aimed to analyze the serum and CSF NOx levels in clinically well-defined cohorts of treatment-naïve MS patients compared to patients with somatic symptom disorder. To this end, we analyzed the serum and CSF levels of NOx in 117 patients (71 relapsing-remitting (RR) MS, 16 primary progressive (PP) MS, and 30 somatic symptom disorder). We found that RRMS and PPMS patients had higher serum NOx levels compared to somatic symptom disorder patients. This difference remained significant in the subgroup of MRZ-negative RRMS patients. In conclusion, the measurement of NOx in the serum might indeed be a valuable tool in supporting MS diagnosis.
Asunto(s)
Enfermedades Autoinmunes , Síntomas sin Explicación Médica , Esclerosis Múltiple Recurrente-Remitente , Esclerosis Múltiple , Humanos , Esclerosis Múltiple/diagnóstico , Estrés Nitrosativo , Sistema Nervioso CentralRESUMEN
Histopathological analysis stands as the gold standard for the identification and differentiation of inflammatory neuromuscular diseases. These disorders continue to constitute a diagnostic challenge due to their clinical heterogeneity, rarity and overlapping features. To establish standardized protocols for the diagnosis of inflammatory neuromuscular diseases, the development of cost-effective and widely applicable tools is crucial, especially in settings constrained by limited resources. The focus of this review is to emphasize the diagnostic value of major histocompatibility complex (MHC) and complement patterns in the immunohistochemical analysis of these diseases. We explore the immunological background of MHC and complement signatures that characterize inflammatory features, with a specific focus on idiopathic inflammatory myopathies. With this approach, we aim to provide a diagnostic algorithm that may improve and simplify the diagnostic workup based on a limited panel of stainings. Our approach acknowledges the current limitations in the field of inflammatory neuromuscular diseases, particularly the scarcity of large-scale, prospective studies that validate the diagnostic potential of these markers. Further efforts are needed to establish a consensus on the diagnostic protocol to effectively distinguish these diseases.
Asunto(s)
Miositis , Enfermedades Neuromusculares , Humanos , Estudios Prospectivos , Enfermedades Neuromusculares/diagnóstico , Complejo Mayor de Histocompatibilidad , Antígenos de Histocompatibilidad Clase I/análisisRESUMEN
Background: The NADH dehydrogenase [ubiquinone] iron-sulfur protein 6 (NDUFS6) gene encodes for an accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (complex I). Bi-allelic NDUFS6 variants have been linked with a severe disorder mostly reported as a lethal infantile mitochondrial disease (LMID) or Leigh syndrome (LS). Objective: Here, we identified a homozygous variant (c.309â+â5âGâ>âA) in NDUFS6 in one male patient with axonal neuropathy accompanied by loss of small fibers in skin biopsy and further complicated by optic atrophy and borderline intellectual disability. Methods: To address the pathogenicity of the variant, biochemical studies (mtDNA copy number quantification, ELISA, Proteomic profiling) of patient-derived leukocytes were performed. Results: The analyses revealed loss of NDUFS6 protein associated with a decrease of three further mitochondrial NADH dehydrogenase subunit/assembly proteins (NDUFA12, NDUFS4 and NDUFV1). Mitochondrial copy number is not altered in leukocytes and the mitochondrial biomarker GDF15 is not significantly changed in serum. Conclusions: Hence, our combined clinical and biochemical data strengthen the concept of NDUFS6 being causative for a very rare form of axonal neuropathy associated with optic atrophy and borderline intellectual disability, and thus expand (i) the molecular genetic landscape of neuropathies and (ii) the clinical spectrum of NDUFS6-associated phenotypes.