COMPLEMENT-MEDIATED SOLUBILIZATION IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS, NEPHRITIS OR VASCULITIS

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  • 1 January 1981
    • journal article
    • research article
    • Vol. 46  (3) , 557-564
Abstract
Solubilization of an immune precipitate by serum is a complement function mediated by the alternative pathway and enhanced by the classical pathway, it provides the basis of a simple quantitative assessment of the integrity of complement function. Using a preformed radiolabeled precipitate of BSA[bovine serum albumin]-.alpha.BSA Ab, the solubilization capacity of serial sera from 75 patients with various immune complex diseases or diseases associated with hypocomplementemia was investigated to correlate this assay of complement function prospectively with disease activity and with measurements of circulating immune complexes (CIC). Reduction in solubilization, defined by > 25% of values in a given patient being below the normal range, was found in 11 of 12 patients with active SLE [systemic lupus erythematosus], 2 of 19 patients with active systemic vasculitis, 3 of 3 patients with post-streptococcal glomerulonephritis and in 3 of 6 patients with nephrotic syndrome due to to other types of nephritis. In serial studies, solubilization correlated with disease activity in patients with SLE (P < 0.005), systemic vasculitis (P < 0.05) and post-streptococcal glomerulonephritis (P < 0.05). CIC were found more frequently than abnormalities in solubilization; the solubilization assay identified a population of patients with CIC more likely to have active disease. This simple assay of complement function provides data on an aspect of immune complex disease not readily apparent from standard estimations of circulating immune complexes, and appears to be a better measure of their potential phlogistic effects.