CD4 and systemic lupus erythematosus: In lupus, an increase of circulating CD4+CXCR5 + PD-1high T lymphocytes was evidenced in patients with a more severe disease phenotype [21] and a correlation between the expansion of both circulating CXCR5 + Bcl6 + CD4+ T cells and circulating GC B cells was reported [22].