IL15 and systemic lupus erythematosus: To elucidate the role of γ chain cytokines in SLE, we analyzed a published single-cell transcriptome data, which covers 27 immune cell types from 62 SLE and 79 healthy donors.25 IL-21, IL-15, and IL-7 exhibited significant increases in several T and B cell subtypes of SLE, including Naive B, Naive CD4+ T, Memory CD4+ T, Th17, Tfh, Th1 and CD8+ TCM cells, among which IL-21 increased most significantly (Fig. 1g).