CD4 and systemic lupus erythematosus: Examination of peripheral blood mononuclear cells (PBMC) from systemic lupus erythematosus (SLE) patients has revealed reduced expression of LILRB1 on CD4+ and CD8+ T cells, B cells and DCs, with LILRB1 on these cells demonstrating a diminished inhibitory function compared to healthy donors (141, 142).