We found that the frequency of IL-21+ cells within the memory CD45RA− Teff cell population was increased in type 1 diabetes patients (geometric mean 5.92% [95% CI 5.44, 6.44]) compared with healthy donors (geometric mean 4.88% [95% CI 4.33, 5.50], p = 3.9 × 10−3; Fig. 1b and Table 3). The gene discussed is IL21; the disease is type 1 diabetes mellitus.