Cryoglobulin studies in systemic lupus erythematosus.

Twenty-two patients with systemic lupus erythematosus (SLE) were investigated to study the incidence and immunochemical nature of circulating immune complexes. In 68.18% of patients, the immune complexes were detected as cryoglobulins. A significantly high value of serum IgG and IgA (1980.64 +/- 1031.53 and 283.81 +/- 131.02 mg% respectively) were observed in these patients compared to those in normal (1097.04 +/- 298.10 and 200.93 +/- 89.96 mg% respectively). The patients also had significantly low levels of serum complement fraction C3 (61.35 +/- 22.64 mg%). Correlation of these parameters could help in understanding of the role of immunochemical factors in the pathogenesis of the disease.