HLA-DR AND HLA-DQ GENE POLYMORPHISM IN LATVIAN PATIENTS WITH INSULIN-DEPENDENT DIABETES-MELLITUS

Latvian insulin-dependent diabetes mellitus (IDDM) patients (n=101) an d healthy controls (n=111) were analyzed for HLA-DR and DQ polymorphis m. DR3-DQ2 and DR4-DQ8 were positively associated and DR15-DQ6, DR13-D Q6, DR1-DQ5 and DQ7 negatively associated with the disease. The incide nce of IDDM in Latvia is very low (6.5 per 100,000) compared to Sweden (24.4 per 100,000), even though Latvia is close to Sweden. The reason s for the decreased incidence are not clear. When the negatively assoc iated DQ were taken together in the healthy controls, more than 75% of the healthy controls were positive for one of the four negatively ass ociated DQ molecules. The excess frequency of the negatively associate d DQ molecules in the general population could explain the lower incid ence of IDDM in Latvia. Association of HLA-DR and DQ genes with autoan tibody markers shows DR3, but not DQ2, to be increased in GAD65 antibo dy-positive compared to antibody-negative patients. This association w as not observed with ICA512 antibodies.