CD4 and systemic lupus erythematosus: We previously identified an epitope between residues 131–151 present within its RNA recognition motif and targeted early during the progression of the disease by IgG antibodies and CD4+ lymph node cells (LNCs) from H-2k MRL/lpr and H-2d/z (NZBxNZW)F1 lupus-prone mice [1], [2].