IgM Autoantibodies Specific for Xanthine Oxidase Are Not 0Increased in Preeclampsia

Abstract

Objectives: The oxidase form of xanthine dehydrogenase/oxidase produces uric acid and free radicals. We hypothesized that increased xanthine oxidase is involved in the pathogenesis of preeclampsia and in the hyperuricemia which accompanies the disease. We assayed serum of normal and preeclamptic women for presence of IgM specific for xanthine oxidase, which has been used as a marker for xanthine oxidase released from ischemic tissue.

Methods: Specific IgM antibodies were assayed by ELISA. A reference serum, high in concentration of antibody against xanthine oxidase, was used to standardize the assay.

Results: Specific IgM antibody and total IgM were measured in 10 preeclamptic and 10 normal pregnant women. No significant difference was found in the concentration of IgM specific to xanthine oxidase or in the relative amount of the specific IgM to total IgM. There was a significant correlation between the IgM specific for xanthine oxidase and uric acid concentration in preeclamptic women (P = 0.02, r² = 0.5), indicating 50% of the variation in uric acid could be accounted for by antibodies to xanthine oxidase. No such correlation was found for normal women (P = 0.14, r² = 0.27).

Conclusions: Our data do not support the hypothesis of increased xanthine oxidase release in preeclampsia but suggest that xanthine oxidase may increase production of uric acid and contribute to the hyperuricemia and oxidative stress of preeclampsia.

Key Words:

• Preeclampsia
• Uric acid
• Xanthine oxidase