A new PCR-SSP method for HLA DR-DQ risk assessment for celiac disease

Background: Susceptibility to celiac disease is essentially restricted to carriers of specific HLA DQA1 and DQB1 alleles. We have developed a semi-automated sequence specific primer (SSP) PCR method for clinical HLA typing and compared the test results with those from a commercial method. Methods: Primers for each DQA1 and DQB1 allele group were included in our PCR-SSP reaction to allow differentiation of homozygous from heterozygous carriers of risk alleles. Primers detecting the tightly linked DRB1*04, *03, *07 and *09 alleles were included to resolve potentially ambiguous results. Fluorescently labeled PCR products of 119 clinical samples were analyzed by capillary electrophoresis, and results were compared to those previously obtained from the DELFIA® Type 1 Diabetes Genetic Predisposition assay. Results: The risk assessment derived from the two methods was 100% concordant. One previously unreported haplotype was detected and haplotype assignments in two of the 119 samples were improved from previous reports. Conclusions: The use of three PCR reactions and a single electrophoretic step for DQA1, DQB1 and DRB1 typing provides distinction of celiac disease associated alleles and their homo- or heterozygous status. This multiplex analysis reduces reagent costs, personnel and instrument time, while enabling improved allelic assignment through HLA-DR-DQ haplotype association