Specification andquantitation ofcirculating immunecomplexes intheserumofpatients with active pulmonary sarcoidosis

Background -Circulating immunecomplexes canbeelevated inserumsamples ofpatients withsarcoidosis andareassociated withdisease activity, buttheir diagnostic significance isnotunderstood. Methods-Thedifferent classes ofcirculating immunecomplexes containing immunoglobulin A,G,orM,andthecontent ofcomplementincirculating immune complexes (polyethylene glycol precipitation) aswellaslevels ofcomplement binding circulating immune complexes (complement binding assay) weredetermined in 19 patientswith active, untreated pulmonarysarcoidosis. The results werecomparedwithotherparametersintheserum(soluble interleukin 2 receptor, angiotensin converting enzyme,immunoglobulin A,G,andM)and thebronchoalveolar lavagefluid (lymphocytes, helpercells, suppressor cells, activated T cells), andwithradiological stageandfunctional parameters (FEV1, vitalcapacity, totallung capacity, transfercoefficient (Kco),and the alveolar-arterial oxygendifference dur