CD4 and systemic lupus erythematosus: Although the etiology of SLE remains to be elucidated, accumulating studies have indicated that dysfunction of CD4+ T cells is crucial in the onset and development of SLE by facilitating lymphocytic organ infiltration and promoting B cells in producing autoantibodies that eventually lead to tissue injury (Enghard et al., 2009; Engler et al., 2011; Weinstein et al., 2012).