HLA antigens in alkaptonuric patients.

ABSTRACT

BACKGROUND: In alkaptonuric patients a disabling ochronotic arthropathy develops, due to the deposit of a pigmented polymer of homogentisic acid. Since in inherited diseases the clinical expressions may be multifactorial, involving genetic and environmental factors, where the HLA system may play a role, we studied HLA antigens in ochronotic patients. METHODS: The study was carried out in 21 members of three families of six ochronotic patients and in two isolated ochronotic patients. The HLA typing has been done testing for antigens from loci A, B and C, by international standard microlymphocytotoxicity method, and for loci DR and DQ, by fluorescence method on immunologically isolated cells by means of antibody-coated microspheres. The chi square test was used for statistical analysis, with Yates correction due to the low number of observations. RESULTS: Despite the limited number of subjects, due to the rarity of the disease, a significantly higher prevalence of HLA-DR7 antigen was found in the alkaptonuric patients when compared to a general population (p<0.02), suggesting a possible association, while the prevalence of HLA A, B, C and DQ showed no significant differences. CONCLUSIONS: It might play a role in the pathophysiology and in the clinical expression of the disease.