Inhibition of neutrophil migration by sera from patients with rheumatoid arthritis

Sera from patients with rheumatoid arthritis inhibited the migration of human neutrophils in 63% (twenty-two out of thirty-five) of the cases tested. The inhibition was not due to a toxic effect of the serum as it was reversed by a chemotactic stimulus. There was a strong correlation between the degree of inhibition of neutrophil migration and the amount of immune complexes present in the sera as determined by the C1q binding activity. It is suggested that the inhibition of neutrophil migration is due to the presence of circulating immune complexes, and that the capacity of immune complexes to inhibit neutrophil migration in vitro may also contribute to the accumulation of neutrophils at sites of immune complex formation in vivo.