Identification of antinative DNA antibodies in cryoglobulinemic states

Abstract

Anti-native DNA antibodies were previously demonstrated in serum and cryoglobulins of patients with systemic lupus erythematosus. Serum and isolated cryoglobulins from patients with bacterial infection (4 patients), essential mixed cryoglobulinemia (4 patients), glomerulonephritis (4 patients) and systemic lupus erythematosus (4 patients) were studied and analyzed for the presence of anti-nuclear and anti-native DNA antibodies. Although 6 of 16 patients'' cryoglobulins had peripheral anti-nuclear antibodies (ANA) at neutral pH, in 15 of 16 patients'' specimens ANA was demonstrable after pre-incubation with acid buffer. Anti-native DNA antibodies of the Ig[immunoglobulin]G class were demonstrable in 4 of 16 cryoprecipitates at neutral pH, whereas 15 of 16 were positive for IgG anti-native DNA after acid incubation. IgG anti-native DNA antibodies were concentrated in the cryoprecipitate with respect to serum antibody content. Native DNA was present in the cryoglobulins of 13 of 14 patients. Anti-native DNA antibodies are present in cryoglobulins in disease states other than systemic lupus erythematosus. The acid incubation technique, which was employed in the determination of cryoglobulin antibody content, enhanced the measurable antibody titer, suggesting immune-bound antibodies.