From these studies, salient features of which are summarized in Table 2, it is apparent that in the MRL/lpr model of autoimmunity resembling human SLE, γδ play both a regulatory role dampening pathogenic effects of αβ T cells, perhaps via apoptotic mechanisms, but may also have, in situations in which conventional T cells are suppressed, a pathogenic role that is partly controlled by the BLK gene. The gene discussed is BLK; the disease is systemic lupus erythematosus.