ObjectiveThe objective of this study was to identify new causes of Charcot–Marie–Tooth (CMT) disease in patients with autosomal‐recessive (AR) CMT.MethodsTo efficiently identify novel causative genes for AR‐CMT, we analyzed 303 unrelated Japanese patients with CMT using whole‐exome sequencing and extracted recessive variants/genes shared among multiple patients. We performed mutation screening of the newly identified membrane metalloendopeptidase (MME) gene in 354 additional patients with CMT. We clinically, genetically, pathologically, and radiologically examined 10 patients with the MME mutation.ResultsWe identified recessive mutations in MME in 10 patients. The MME gene encodes neprilysin (NEP), which is well known to be one of the most prominent beta‐amyloid (Aβ)‐degrading enzymes. All patients had a similar phenotype consistent with late‐onset axonal neuropathy. They showed muscle weakness, atrophy, and sensory disturbance in the lower extremities. All the MME mutations could be loss‐of‐function mutations, and we confirmed a lack/decrease of NEP protein expression in a peripheral nerve. No patients showed symptoms of dementia, and 1 patient showed no excess Aβ in Pittsburgh compound‐B positron emission tomography imaging.InterpretationOur results indicate that loss‐of‐function MME mutations are the most frequent cause of adult‐onset AR‐CMT2 in Japan, and we propose that this new disease should be termed AR‐CMT2T. A loss‐of‐function MME mutation did not cause early‐onset Alzheimer's disease. Identifying the MME mutation responsible for AR‐CMT could improve the rate of molecular diagnosis and the understanding of the molecular mechanisms of CMT. Ann Neurol 2016;79:659–672

No abstract

No abstract

Objective The aim was to study the pathological role of lymphocytes with a peripheral T helper-cell-like phenotype (PD-1 + CXCR5 − CD4 + ) in IgG4-related disease (IgG4-RD). Methods PD-1 + CXCR5 − CD4 + T cells in the blood of patients with IgG4-RD ( n = 53), patients with SS ( n = 16) and healthy volunteers ( n = 34) as controls were analysed by flow cytometry. Correlations between results obtained by flow cytometry and clinical parameters relevant to IgG4-RD were also analysed. Results The percentage and absolute number of PD-1 + CXCR5 − cells within total CD4 + T cells in IgG4-RD patients were significantly increased compared with those in healthy volunteers. Further analysis showed that there were marked positive correlations of the percentage of PD-1 + CXCR5 − CD4 + T cells with the serum level of IgG4 and the number of organs involved. Interestingly, granzyme A (GZMA) + cells were enriched in PD-1 + CXCR5 − CD4 + T cells, and the percentage and absolute number of GZMA + PD-1 + CXCR5 − CD4 + T cells were significantly elevated in IgG4-RD patients. Although no obvious change was observed in the percentage of total CD4 + T cells, the percentage and absolute number of PD-1 + CXCR5 − CD4 + T cells decreased in accordance with a reduction of serum IgG4 level after treatment with glucocorticoids. Conclusion In IgG4-RD, circulating CD4 + T-cell populations were composed of PD-1 + CXCR5 − cells, and the ratios of these cells were correlated with clinical manifestations of IgG4-RD. Further analysis of GZMA + PD-1 + CXCR5 − CD4 + T cells might lead to a deeper understanding of the pathogenesis of ectopic lymphoid follicles and the persistent inflammation in IgG4-RD.

BackgroundT follicular helper (Tfh) cells have been identified as a new category of helper T cells, which express CXCR5 on their surface and induce the production of antigen-specific antibodies. Many investigations have found morbid proliferation and/or activation of Tfh cells in systemic autoimmune and allergic diseases. It is also known that Tfh cells are regulated by regulatory B (Breg) cells in the deteriorating such diseases. Recently, CXCL13, a ligand of CXCR5, has been reported to increase in the peripheral blood and lungs of patients with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the involvement of Tfh cells and Breg cells in IPF.MethodsPeripheral blood samples were obtained from 18 patients with IPF. We isolated heparinized peripheral blood mononuclear cells and investigated the proportions of Breg cells, Tfh cells, PD-1+ICOS+ Tfh cells (activated form of Tfh cells), and the Tfh-cell subsets by flow cytometry. These cell profiles were compared with those of 21 healthy controls. Furthermore, we investigated the correlations between profiles of lymphocytes and lung physiology.ResultsThe median proportions of Tfh cells per total CD4+ T cells and of PD-1+ICOS+ proportion of Tfh cells per total Tfh cells was significantly more in the IPF patients (20.4 and 5.2%, respectively) compared with healthy controls (15.4 and 2.1%, respectively; p = 0.042 and p = 0.004, respectively). The proportion of Tfh2 cells per total Tfh cells was significantly higher and the proportion of Tfh17 was smaller in the IPF patients than healthy controls. The percentage of Breg cells to total B cells was significantly decreased in the IPF patients (median, 8.5%) compared with that in the controls (median, 19.7%; p < 0.001). The proportion of Breg cells was positively correlated with the annual relative change in diffusing capacity of the lungs for carbon monoxide in the IPF patients (r = 0.583, p = 0.018).ConclusionProliferation and activation of Tfh cells and a decrease in Breg cells were observed in the peripheral blood of patients with IPF. The profile of the Tfh-cell subset also changed. Specific humoral immunity aberration would likely underlie complicated pathophysiology of IPF.