Autoantibodies specific to beta-2-microglobulin inhibit the Fc receptor-dependent phagocytosis of human monocytes.

Effect of anti-beta2-microglobulin (beta2m) antibodies was investigated on the in vitro Fc and C3 receptor dependent phagocytic capacity of human peripheral monocytes. Both rabbit and human anti-beta2m antibodies inhibit the Fc receptor-mediated phagocytosis. Anti-beta2m antibodies do not influence the spontaneous or C3b receptor-mediated ingestion. The inhibitory activity by human autoantibodies but not by rabbit anti-human beta2m antibodies was diminished when incubation was performed at 37 degrees C instead of 20 degrees C.