The immunologic responses, both cell-mediated and humoral, to exogenous antigens reflect a crucial balance between extrinsic forces which can either augment or suppress the reactivity of T and B effector cells. It is probable that similar immunoregulatory influences play a key role in maintaining tolerance to some self-antigens. Thus, despite the presence of cells potentially capable of reacting to autologous antigens, lack of autoimmunity might reflect either an absence of amplifying or a preponderance of suppressive immunoregulatory forces. Within this framework, data obtained indicating aberrances of immunoregulation in patients with systemic lupus erythematosus are discussed, specifically as the aberrances may be causally related to the autoimmune nature of this disease.