Immune complex deposition in the development of acute synovitis in the rabbit knee joint: quantitative, kinetic and morphological aspects.

The pathology of acute synovitis induced by immune complexes was investigated in this study. The reversed passive Arthus method of lesion induction was utilized, in conjunction with radiolabeled cell and protein markers, to quantitate inflammatory parameters and ascertain their kinetics in the synovial tissues of the rabbit. The rates of increased vessel permeability, polymorphonuclear leukocyte infiltration and platelet deposition were studied using 125-I-albumin, 51-CR-PMN-leukocytes and 111-In-platelets, respectively. Increase in vessel permeability over time was found to directly correlate with increased leukocyte infiltration (r = 9.08; P less than 0.01). Similar correlations between vascular permeability and platelet accumulation, and leukocyte infiltration and platelet accumulation, were not observed. The histological evaluation of synovial lesions corroborated the kinetic findings.