Inhibition of human neutrophil migration by aggregated gammaglobulin

Heat-aggregated human gammaglobulin has been shown to inhibit the random migration of human neutrophils in serum-containing medium. This inhibition was not due to metabolic exhaustion or deactivation of the cells, since migration in the presence of aggregated gammaglobulin and casein as a chemotactic stimulus was not inhibited. The inhibition of migration was not mediated by a negative chemotactic gradient produced as a result of complement activation, and could be demonstrated in complement-depleted serum. Sera obtained from patients with rheumatoid arthritis with evidence of circulating immune complexes are able to significantly inhibit neutrophil migration, indicating that this phenomenon may be a useful means for the detection of circulating immune complexes. It is suggested that aggregated gammaglobulin or immune complexes can inhibit the chemokinetic effect of serum on neutrophils by a reversible interaction with the neutrophil surface, and that this inhibition could contribute to the accumulation of neutrophils as sites of immune complex deposition in vivo.