Studies on macrophage function in in vitro immune response Part 2. Functional analysis of macrophage from patients with systemic lupus erythematosus.

To analyse the function of macrophages (MΦ) from systemic lupus erythematosus (SLE) patients, spontaneous IgG synthesis, PWM-induced IgG production and Staphylococcal phage lysate (SPL)-induced DNA synthesis by MΦ depleted mononuclear cell (MNC) fraction or unfractionated MNC were examined. The depletion of MΦ enhanced the spontaneous IgG synthesis reaction in inactive SLE, but reduced it in active SLE. The depletion of MΦ restored the ability of SLE MNC to respond to PWM, although the IgG production by unfractionated MNC was suppressed by the addition of PWM. The presence of normal or SLE 10% MΦ enhanced SPL-induced DNA synthesis, but the enhancement obtained by SLE MΦ was less than that obtained by normal MΦ. These results　suggest that in inactive SLE, MΦ may show a suppressive effect on spontaneous B cell hyperactivity, but in active SLE, MΦ may loose this effect and/or reveal an enhancing effect. SLE MΦ seem to suppress the PWM-induced IgG synthesis reaction by SLE MNC in the presence of PWM. In addition, SLE MΦ have certain functional defects in promoting SPL-induced DNA synthesis.