Increased serum IL-27 concentrations and IL-27-producing cells in MG patients with positive AChR-Ab

•Ha-Neul Jeong et al. found that serum IL-27 levels were significantly higher in MG patients, especially in generalized MG and early-onset MG patients. However, the association between serum IL-27 levels and clinical score, and the frequencies of IL-27-producing cells on peripheral blood mononuclear cells (PBMCs) remains unknown in AChR-MG.•We found that both serum IL-27 concentrations and the frequencies of IL-27+ lymphocytes were significantly elevated in AChR-MG patients than those in HCs, and were both significantly declined after IVIG treatment. In addition, we also observed that both the frequencies of IL-27-producing T cells and IL-27-producing B cells were significantly elevated in AChR-MG patients as compared to those in HCs, but only the frequencies of IL-27-producing T cells were significantly decreased after IVIG treatment. Furthermore, there was no significant associations between serum IL-27 concentrations and MG-ADL score, whereas the frequencies of IL-27+ lymphocytes significantly correlated with MG-ADL score.•In conclusion, we speculated that IL-27 may play an important role in the pathological process in AChR-MG patients, and the frequencies of IL-27-producing (CD3+IL-27+) T cells may be a potential biomarker for predicting the severity of AChR-MG.