Serum factors causing impaired macrophage function in systemic lupus erythematosus.

Leukocytes from patients with systemic lupus erythematosus (SLE) and healthy controls were cultured for 4 days in either SLE serum or control serum. The remaining monolayer of monocyte-derived macrophages was allowed to ingest yeast cells. Macrophages (from SLE patients or controls) incubated in SLE sera presented impaired phagocytic activity and glass adherence compared with cells grown in control sera. SLE sera contain one or more factors that impair macrophage function; IgG-containing immune complexes may be one such factor.