SERUM HYPOXANTHINE AND XANTHINE CONCENTRATIONS IN HORSES HETEROZYGOUSFOR COMBINED IMMUNODEFICIENCY

A group of diseases termed combined immunodeficiency (CID) results in a severe form of immunodeficiency. While CID in humans has two genetic s bases, in Arabian it is inherited in an autosomal recessive manner. KETTLER et al. (1989) determined that uric acid was significantly (p < .001) greater in the serum of carrier Arabian horses than in non-carr ier horses. The current study measured serum levels of hypoxanthine an d xanthine two other products of this pathway. There were no significa nt differences (p > 0.05) between carrier and non-carrier horse's seru m levels of hypoxanthine or xanthine. These data, combined with our pr evious ones suggest that an enzymatic lesion in the purine salvage pat hway may occur at the urate oxidase step.