Immune responses to hapten-modified self and their regulation in normal individuals and patients with systemic lupus erythematosus.

Purified T cells from normal subjects and patients with systemic lupus erythematosus (SLE) were studied for their abilities to respond to hapten modified self antigens and to antigens on autologous non T cells. Primary and secondary proliferative T cell responses to trinitrophenyl modified (TNP) non T cells were markedly impaired in patients with active SLE as compared with normal subjects or patients with inactive SLE. In contrast, patients with active SLE had significantly stronger cytotoxic activity against TNP modified autologous non T cells. Patients with active SLE had impaired proliferative responses to nonmodified autologous non T cells (auto-MLR). A significant negative correlation was observed between the degree of the auto-MLR and the degree of cytotoxic ability against TNP modified autologous cells in patients with SLE. This observation suggests that cells capable of proliferating in the auto-MLR might regulate the generation of cytotoxic T cell responses against modified self. We then analyzed the ability of anti T cell antibodies from patients with active SLE to preferentially interfere with this naturally occurring suppressor T cell function.