Serum levels of IL-21 are elevated in a subset of patients with IM Serum levels of IL-21 are elevated in a subset of patients with IM. (A) Serum levels of IL-21 in patients with IM (n = 51) and healthy donors (HD) (n = 20) were analyzed by ELISA. Statistical analyses of the results were performed by Mann–Whitney U test. *p < 0.05. Serum levels of IL-21 are elevated in a subset of patients with IM. (A) Serum levels of IL-21 in patients with IM (n = 51) and healthy donors (HD) (n = 20) were analyzed by ELISA. Statistical analyses of the results were performed by Mann–Whitney U test. *p < 0.05. (B) Serum levels of IL-21 in patients with PM/DM (n = 41), CADM (n = 10), and HD (n = 20). The cohort used in (B) is identical to (A). Serum IL-21 was detected in 15 of 41 in PM/DM patients, 2 of 10 in CADM patients, and 2 of 20 in HD. Because y-axis is expressed on a logarithmic scale, only values >0 were plotted. Statistical analyses were performed by Kruskal–Wallis test and Dunn multiple comparisons test. *p < 0.05. n.s., not significant. Takahiro Kageyama et al. ImmunoHorizons 2017;1:176-187 Copyright © 2017 The Authors