CD4 and systemic lupus erythematosus: Iron overload promotes pathogenic T-cell differentiation and accelerates disease in lupus-prone models (215): 1) In MRL/MpJ-Fas (lpr)/J (MRL/lpr) mice, iron overload expands T follicular helper (Tfh) cells, germinal center (GC) B cells, and pro-inflammatory cytokine-secreting CD4 T cells.