Responder cells in the human autologous mixed lymphocyte reaction (AMLR). Characterization and interactions in healthy individuals and patients with systemic lupus erythematosus.

In the course of a primary AMLR, purified T4 cells, but not purified T8 cells, proliferate to the non-T cell stimuli; however, in the presence of T4 cells or helper factors secreted by T4 cells, also T8 lymphocytes are able to proliferate in the AMLR. These observations together with findings on immunoregulatory capacities of AMLR-activated T cells suggest that the AMLR represents a model inducer circuit. In patients with SLE, our preliminary data indicate a deficient response of T4 cells upon stimulation with non-T cells. In addition, in occasional patients activation of T8 lymphocytes may be defective as well. In one patient with a low T4/T8 ratio, elimination of excess T8 cells increased the AMLR dramatically when compared to unfractionated T cells. Thus, the AMLR using unfractionated T cells may not necessarily represent the intrinsic capacity of SLE T cells to respond to the non-T stimulus. Our data suggest that immune regulation in SLE is deficient on the inducer cell level; moreover, individual patients may have additional abnormalities, supporting the concept of the heterogeneity of SLE.