CD4 and systemic lupus erythematosus: Among aberrant T cells of MRL/lpr mice, double-negative (DN) T cells, defined by the absence of CD4 and CD8, are the major pathogenic immune cell subset and have the ability to produce proinflammatory cytokines like IFN-γ and IL-17 which has been linked to lupus pathogenesis both human and mice (16).