Complement activation products and factors influencing phagocyte migration in synovial fluids from children with...

Synovial fluids from children with chronic arthritis were examined simultaneously for the presence of complement activation products and factors affecting phagocyte migration. The concentrations of C3a and C5a, but not C4a, were found to be elevated relative to normal plasma. However, the C3a and C5a concentrations in synovial fluid did not correlate with C1q binding values or with degree of migration inhibition or chemoattraction caused by that fluid. Although this data implies complement activation occurs in inflamed joints in juvenile arthritis, the specific role of immune complexes remains unproven.