Precipitin Reactions of the Clq with the Sera and Cryoglobulins Obtained from the Patients with Systemic Lupus Erythematosus

Abstract

IgG mixed with IgM cryoglobulin (GM type) and sera obtained from 5 patients with active SLE showed positive precipitin reactions with Clq blobulin, whereas IgG cryoglobulin (G type) and sera from 5 patients with inactive SLE did not. Three out of 5 cases of GM type were of IgG-IgM-Clq mixed type and a case of IgG-Clq type through G type reacted with Clq. The Clq precipitin reactions of the sera did not occur when GM type were excluded by centrifugation from precipitation positive sera. The precipitin reactions of the Clq with heat inactivated cryoglobulin became stronger than those with untreated. The precipitin lines with Clq disappeared when the agarose gel plates were kept at 37℃, but a part of precipitin lines were reproduced when these plates were incubated at 4℃ again. The Clq precipitin reactions remained positive after DNase treatment of the GM type cryoglobulin and sera, but they disappeared after 2-ME treatment. As mentioned above, the precipitin reactions of the Clq with the sera and cryoglobulins occured simultaneasly and the positive reactions of Clq with the sera disappeared by the exclusion of cryoglobulin from sera. It is presumed that the Clq reactants in the sera of SLE patients are cryoglobulins with binding activity with complement component. GMClq type may correspond to the so called high molecular weight Clq reactant and GClq type to the low molecular reactant.