Detection of soluble immune complexes by the technique of ADCC inhibition in human diseases.

Soluble immune complexes were detected using inhibition of antibody-dependent cell-mediated cytotoxicity (ADCC) in sera of patients with various diseases. Results were positive in 32/41 patients with rheumatoid arthritis (78%), in 27/38 systemic lupus erythematosus patients (71%), in 7/10 cutaneous lupus erythematosus patients (70%), in 6/8 mixed connective tissue disease patients (75%), in 11/26 membranous glomerulonephritis patients (42%), in 6/20 membranoproliferative glomerulonephritis patients (30%) and in 3/12 multiple sclerosis patients (25%). ADCC inhibition was compared with PEG precipitation technique and was found to be more sensitive for detecting soluble immune complexes. Various pitfalls are discussed.