Autoimmune neurologic diseases
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system, in which T helper 1 (Th1) cells have a pivotal pathogenic role targeting oligodendrocytes. Although plasmapheresis is effective in some patients with MS, it is still difficult to predict treatment response. Here, we analyzed lymphocytes in the peripheral blood of 21 patients who were treated with immunoadsorption plasmapheresis (IAPP). Twelve patients (57.1%) responded to IAPP with objective improvement in EDSS (Expanded Disability Status Scale). There was no significant difference in clinical parameters such as sex, age, disease duration, disease severity between responders and non-responders. The frequency of Th1 cells (IFN-γ+ memory CD4+ T cells) in the peripheral blood just before treatment was significantly higher in responders than in non-responders (14.9±8.1% vs 3.9±2.0% (average±SD), p<0.01). There was no difference in the frequencies of Th2, Th17, regulatory T, and several B cell subsets. The Th1 cell frequency was not significantly changed by the treatment. In contrast, several key transcripts including IFNG, STAT1, and STAT4 in Th1 cells decreased after plasmapheresis (p=0.016, 0.002, 0.013, respectively). This study suggests that the Th1 cell frequency could be used to predict responders to IAPP (Area under the ROC curve (AUC): 0.95). Moreover, the effect of IAPP might be mediated by phenotypic change of Th1 cells in addition to removal of autoreactive antibodies.