Abstract
OBJECTIVE: Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies against neuromuscular junctions. Myasthenic crisis (MC) represents the most severe state of MG with high in-hospital mortality. We aimed to identify immune signatures using in-depth profiling in MC, and to assess the correlations between immune biomarkers with clinical severity longitudinally. METHODS: We studied 181 participants including 57 healthy controls, 96 patients with MG who never experienced crisis and 28 MC patients from December 2018 through June 2020. Follow-up visits occurred prospectively from crisis to 6 months off-mechanical ventilation. The frequencies of 20 CD4(+) T subpopulations and 18 serum cytokines were associated with clinical scores using correlations and principal component analysis. RESULTS: Patients in crisis exhibited a proinflammatory CD4(+) T response with elevated Th1 (P = 0.026), and Th17 cells (P = 0.032); decreased T follicular helper 2 (Tfh2) cells (P < 0.001), Tnaive in Tfh cells (P < 0.001), ICOS(-) Tfh cells (P = 0.017), and T central memory in Tfh (P = 0.022) compared with controls, and increased frequencies of Tregs (P = 0.026) and Tfh17 (P = 0.045) compared with non-crisis MG. Cytokine cascade was identified in crisis including the ones associated with Th1 (IL-1β/2/12p70/18/27/IFN-γ/TNF-α), Th2 (IL-4/5/13), Th17 (IL-6/17A/21/22/23/GM-CSF), Th9 (IL-9), and Treg (IL-10). Longitudinally, seven immune biomarkers including Tregs, IL-2/4/17A/IFN-γ/TNF-α/GM-CSF had significant correlations with MG-activities of daily living score. INTERPRETATION: Vigorous inflammatory CD4(+) T signatures were identified in MC and are associated with clinical severity. Future research is needed to explore its potential candidacy for therapeutic intervention and predicting impending crisis.