NCF4 and systemic lupus erythematosus: No less than three of the regulatory subunits of Nox2, as well as gp91 itself, have been found to be associated with different well-known chronic inflammatory diseases: a defect of gp91phox is associated with systemic lupus erythematosus (SLE) in human patients and genetically modified mice [26]; p47 (Ncf1) is correlated with chronic arthritis (reviewed in [25]); p67 (Ncf2) is correlated with SLE [27]; and p40 (NCF4) is correlated with atopic dermatitis [28] and inflammatory bowel disease [29].