Out of fifteen carriers of X-linked chronic granulomatous disease five had discoid lupus erythematosus-like skin lesions together with recurrent aphthous-like stomatitis, another five had only recurrent aphthous-like stomatitis, and the remainder were symptom-free. In individual carriers monocytes and neutrophils were equally reduced in their capacity for superoxide production, [1-14C]glucose oxidation and antibody-dependent cytotoxicity; but within he group of carriers a broad spectrum of depression was found. The degree of depression was closely related to the manifestations of clinical disease. It is suggested that the defective oxygen-dependent metabolism might play an aetiological role in the development of inflammatory diseases in carriers of chronic granulomatous disease. Two out of 10 unselected females with discoid lupus erythematosus were shown to be carriers of X-linked chronic granulomatous disease. Screening for this carrier state might therefore be of importance in these patients.