Objective To investigate the immunological characteristics and their clinical relevance in anti-myelin oligodendrocyte glycoprotein (MOG)-IgG-associated and anti-aquaporin-4 (AQP4)-IgG-associated disorders (MOGAD and AQPAD) and multiple sclerosis (MS).

Methods We measured peripheral blood helper T cell subsets (Th1, Th2, Th17 and regulatory T cell (Treg)) in patients with MOGAD (n=26), AQPAD (n=32) and MS (n=28) in the attack and remission phases by flow cytometry with intracellular cytokine staining. We also studied their correlation with clinical parameters. Ten normal subjects served as healthy controls.

Results In all the three disorders, Th17 significantly increased at attack, and downregulated in the remission phases, although still elevated compare with healthy controls. MOGAD and AQPAD patients shared the common T cell profiles, while the extent of Th17 shift was more prominent in AQPAD. Patients with MS showed decreased Th2 than ones with MOGAD and AQPAD at attack. In terms of clinical correlation, MS patients showed that higher Th1 and Th17 proportion was associated with more frequent relapse and more severe clinical disability, whereas in MOGAD, higher Treg was associated with milder clinical severity. In AQPAD, no obvious correlation of Th profiles with clinical manifestation was found.

Conclusions The present study first investigated intracellular cytokine levels among MOGAD, AQPAD and MS. The different patterns and extent of helper T cell profiles could reflect the pathogenesis of each disorders, and may affect disease severity and activity.