Compromised fidelity of B-cell tolerance checkpoints in AChR and MuSK myasthenia gravis

Myasthenia gravis () is an autoimmune condition in which neurotransmission is impaired by binding of autoantibodies to acetylcholine receptors (hR) or, in a minority of patients, to muscle specific kinase (Mu). There are differences in the dominant IgG subclass, pathogenic mechanisms, and treatment responses between the two subtypes (hR or Mu). The antibodies are thought to be T-cell dependent, but the mechanisms underlying their production are not well understood. One aspect not previously described is whether defects in central and peripheral tolerance checkpoints, which allow autoreactive B cells to accumulate in the naive repertoire, are found in both or either form of . An established set of assays that measure the frequency of both polyreactive and autoreactive B cell receptors () in naive populations was applied to specimens collected from patients with either hR or Mu and healthy controls. Radioimmuno- and cell-based assays were used to measure binding to hR and Mu. The frequency of polyreactive and autoreactive s (n = 262) was higher in both hR and Mu patients than in healthy controls. None of the -derived s bound hR or Mu. The results indicate that both these subtypes harbor defects in central and peripheral B cell tolerance checkpoints. Defective B cell tolerance may represent a fundamental contributor to autoimmunity in and is of particular importance when considering the durability of myasthenia gravis treatment strategies, particularly biologics that eliminate B cells

High-throughput investigation of molecular and cellular biomarkers in NMOSD.

ObjectiveTo identify candidate biomarkers associated with neuromyelitis optica spectrum disorder (NMOSD) using high-throughput technologies that broadly assay the concentrations of serum analytes and frequencies of immune cell subsets.MethodsSera, peripheral blood mononuclear cells (PBMCs), and matched clinical data from participants with NMOSD and healthy controls (HCs) were obtained from the Collaborative International Research in Clinical and Longitudinal Experience Study NMOSD biorepository. Flow cytometry panels were used to measure the frequencies of 39 T-cell, B-cell, regulatory T-cell, monocyte, natural killer (NK) cell, and dendritic cell subsets in unstimulated PBMCs. In parallel, multiplex proteomics assays were used to measure 46 serum cytokines and chemokines in 2 independent NMOSD and HC cohorts. Multivariable regression models were used to assess molecular and cellular profiles in NMOSD compared with HC.ResultsNMOSD samples had a lower frequency of CD16+CD56+ NK cells. Both serum cohorts and multivariable logistic regression revealed increased levels of B-cell activating factor associated with NMOSD. Interleukin 6, CCL22, and CCL3 were also elevated in 1 NMOSD cohort of the 2 analyzed. Multivariable linear regression of serum analyte levels revealed a correlation between CX3CL1 (fractalkine) levels and the number of days since most recent disease relapse.ConclusionsIntegrative analyses of cytokines, chemokines, and immune cells in participants with NMOSD and HCs provide congruence with previously identified biomarkers of NMOSD and highlight CD16+CD56+ NK cells and CX3CL1 as potential novel biomarker candidates

High-throughput investigation of molecular and cellular biomarkers in NMOSD.

To identify candidate biomarkers associated with neuromyelitis optica spectrum disorder (NMOSD) using high-throughput technologies that broadly assay the concentrations of serum analytes and frequencies of immune cell subsets. Sera, peripheral blood mononuclear cells (PBMCs), and matched clinical data from participants with NMOSD and healthy controls (HCs) were obtained from the Collaborative International Research in Clinical and Longitudinal Experience Study NMOSD biorepository. Flow cytometry panels were used to measure the frequencies of 39 T-cell, B-cell, regulatory T-cell, monocyte, natural killer (NK) cell, and dendritic cell subsets in unstimulated PBMCs. In parallel, multiplex proteomics assays were used to measure 46 serum cytokines and chemokines in 2 independent NMOSD and HC cohorts. Multivariable regression models were used to assess molecular and cellular profiles in NMOSD compared with HC. NMOSD samples had a lower frequency of CD16+CD56+ NK cells. Both serum cohorts and multivariable logistic regression revealed increased levels of B-cell activating factor associated with NMOSD. Interleukin 6, CCL22, and CCL3 were also elevated in 1 NMOSD cohort of the 2 analyzed. Multivariable linear regression of serum analyte levels revealed a correlation between CX3CL1 (fractalkine) levels and the number of days since most recent disease relapse. Integrative analyses of cytokines, chemokines, and immune cells in participants with NMOSD and HCs provide congruence with previously identified biomarkers of NMOSD and highlight CD16+CD56+ NK cells and CX3CL1 as potential novel biomarker candidates

Compromised fidelity of B-cell tolerance checkpoints in AChR and MuSK myasthenia gravis

Myasthenia gravis () is an autoimmune condition in which neurotransmission is impaired by binding of autoantibodies to acetylcholine receptors (hR) or, in a minority of patients, to muscle specific kinase (Mu). There are differences in the dominant IgG subclass, pathogenic mechanisms, and treatment responses between the two subtypes (hR or Mu). The antibodies are thought to be T-cell dependent, but the mechanisms underlying their production are not well understood. One aspect not previously described is whether defects in central and peripheral tolerance checkpoints, which allow autoreactive B cells to accumulate in the naive repertoire, are found in both or either form of . An established set of assays that measure the frequency of both polyreactive and autoreactive B cell receptors () in naive populations was applied to specimens collected from patients with either hR or Mu and healthy controls. Radioimmuno- and cell-based assays were used to measure binding to hR and Mu. The frequency of polyreactive and autoreactive s (n = 262) was higher in both hR and Mu patients than in healthy controls. None of the -derived s bound hR or Mu. The results indicate that both these subtypes harbor defects in central and peripheral B cell tolerance checkpoints. Defective B cell tolerance may represent a fundamental contributor to autoimmunity in and is of particular importance when considering the durability of myasthenia gravis treatment strategies, particularly biologics that eliminate B cells