Serum IL-21 levels decrease with glucocorticoid treatment in myasthenia gravis

This study aimed to observe the changes of IL-21/21R in peripheral blood of myasthenia gravis (MG) patients with glucocorticoid treatment and further clarify its role in pathogenesis of MG. 20 MG patients and 15 healthy controls were enrolled in this prospective study. Measurement of serum IL-21 concentration in healthy controls and MG patients before and after glucocorticoid treatment was done using ELISA, whereas expression of IL-21R mRNA was determined by RT-PCR. In addition, serum levels of specific anti-AChR-IgG and its subclasses IgG1, IgG2, IgG3 were also determined by ELISA as follows: (1) serum IL-21 concentration in MG patients was higher before treatment 86.94 ± 14.47 (pg/ml) and decreased significantly after glucocorticoid treatment 35.84 ± 16.13 (pg/ml) (p < 0.05), (2) relative OD values of IL-21R mRNA expressed in PBMCs of MG patients was higher 0.137 ± 0.023 and significantly decreased after glucocorticoid treatment 0.114 ± 0.023 (p < 0.05), while it was 0.107 ± 0.025 in control group, (3) serum concentration of IL-21 showed positive correlation with specific serum anti-AchR-IgG1 levels. The results indicate that the serum IL-21 decreases with glucocorticoid treatment and might be crucial in pathogenesis of mechanism of glucocorticoid treatment on MG patients.