CD8A and systemic lupus erythematosus: To determine the effect of SH3BP2 on T cells, we examined T cell subsets in lymph nodes from lupus-prone mice and found the ratios of CD4+ T cells, CD8+ T cells, and CD4+CD25+ T cells to be comparable between Faslpr/lpr and Sh3bp2KI/+Faslpr/lpr mice (Figure 6a).