For example, in SLE-prone BXSB-Yaa mice, although selective ablation of IL-21R expression in B cells protects the mice from developing disease manifestations, IL-21 signaling supports the expansion of CD8+ suppressor T cells in these mice and, as a result, selective ablation of IL-21R in CD8+ T cells also promotes pathogenesis of the disease55. Here, IL21 is linked to systemic lupus erythematosus.