COVID-19 caused by SARS-CoV-2 is still prevalent worldwide. In Japan, two types of mRNA vaccines, BNT162b2 and mRNA-1273, have been widely administered. Neuromyelitis optica spectrum disorder (NMOSD) and myasthenia gravis (MG) are representative autoantibody-mediated neuroimmunological diseases. Majority of the patients are required to take immunosuppressive medication. In this regard, there is an urgent need to clarify the immune responses elicited by SARS-CoV-2 mRNA vaccination to elucidate its efficacy and the potential immune flare in these patients. Insufficient humoral immune responses and potent SARS-CoV-2 spike (S)-specific CD4+ T-cell responses were shown in patients with NMOSD. Alteration of follicular helper T (Tfh) cell phenotype may attenuate the production of anti-S antibody and indicate potential risk of immune flare of the disease activity.

Demographic and clinical characteristics of the patients were shown in online supplemental table 1. One patient in each of NMOSD and MG groups developed COVID-19 within 6 months after the first vaccination. No COVID-19 case was recorded in controls. In the NMOSD group, recurrence was observed in one patient (5%) by 1 month after the second vaccination.

[jnnp-2022-330478supp001.pdf]

Anti-S IgG titre was significantly lower in patients with NMOSD and MG compared with controls (figure 1A). SARS-CoV-2 S-receptor binding domain (RBD)-specific ratio in B cells increased after vaccination only in controls (online supplemental figure 1A). When NMOSD and MG cohorts were categorised by treatment regimens, significant reduction in anti-S IgG titre was observed in patients receiving prednisolone as well as prednisolone and tacrolimus combination therapy (figure 1B). Significant negative correlation was found between the dose of prednisolone and anti-S IgG titre (Spearman’s rank, r=−0.396, p=0.033).

Anti-SARS-CoV-2 S-IgG response after the second dose of vaccination in the control, NMOSD and MG groups (A). Anti-SARS-CoV-2 S-IgG response after the …