Three-loci HLA haplotypes in Spanish celiac children and healthy subjects:Estimation of linkage disequilibrium and haplotype frequencies

OBJECTIVES: The aim of this study was to compare the linkage disequilibrium parameters and the frequencies of the three-loci HLA haplotypes in childre n with celiac disease and in a control population within the same geographi cal area. METHODS: A total of 38 celiac children were studied. HLA typing was perform ed by microlymphocytotoxicity assay using T and B cells separated by monocl onal antibody labeled immunomagnetic particles (IMB). Three-loci haplotype frequency (pABC) depend on each gene frequency (pA, pB, and pC), and a corr ection factor (Delta) and takes the form: pABC = pA X pB X pC + Delta ABC. The existence of a linkage disequilibrium was assessed by chi (2) test usin g 2 X 2 X 2 contingency tables for gametic association. RESULTS: There was a higher frequency of A1/B8/Cw7, A1/B8/DR3, A1/B8/DQ2, A 19/B12/DQ2, B8/Cw7/DR3, B8/Cw7/DQ2, B8/DR3/DQ2, and B12/DR7/DQ2 in celiac c hildren than in the control population. CONCLUSIONS: From the comparative study of celiac and healthy population wi thin the same area, we conclude that these three-loci haplotypes could dete rmine genetic susceptibility to celiac disease. (C) 2001 by Am. Cell. of Ga stroenterology.