CD4 and systemic lupus erythematosus: Furthermore, the diagnostic value of two cell subclusters of CXCR5+ T cells, including CD4+CXCR5+ T cells and CD8+CXCR5+ T cells, when used as a combined diagnostic index, was as high in patients with SLE as it was in differentiating patients with LN (Figures 5C, D).