CD19 and type 1 diabetes mellitus: In particular, we found no difference in the frequency of naive [P = 0·52, mean of differences = −1·15, 95% confidence interval (CI) = −4·71 to 2·41] or memory (P = 0·54, mean of differences = 1·04, 95% CI = −2·38 to 4·46) B cells or in the two subsets of B cells with a suspected regulatory function, CD19+CD27−CD24hiCD38hi (P = 0·50, mean of differences = −0·36, 95% CI = −1·42 to 0·71) and CD5+ (P = 0·25, mean of differences = 2·34, 95% CI = −1·70 to 6·37) B cells, previously linked 24,29 with T1D (Fig. 2 and Table 2).