CD4 and systemic lupus erythematosus: Our prior study found that lymphocyte subsets, including NK cells, T cells, and B cells, were decreased among SLE patients with OIs compared with uninfected patients with SLE.[17] This finding was consistent with other studies that directly measured specific lymphocyte subsets, such as CD4+ T lymphocytes,[18,19] and found CD4+T lymphocyte levels decreased after patients developed severe OIs.