Background and aim: Human leukocyte antigen (HLA)-DQ2 and/or -DQ8 is an essential risk factor for celiac disease (CD). About 90-95% of patients with CD carry HLA-DQ2/-DQ8 alleles, and HLA-DQ typing is considered an additional diagnostic test. Conventional polymerase chain reaction (PCR)-based HLA-DQ typing methods are expensive, complex, and a time-consuming process. We assessed the efficacy of a novel HLA-DQ typing method, "Celiac Gene Screen," for the detection of CD-associated HLA haplotypes.
Methods: To assess the diagnostic performance of the Celiac Gene Screen test, 100 ethylenediaminetetraacetic acid (EDTA) blood samples, already characterized by the conventional HLA-DQ typing method, that is, PCR sequence-specific oligonucleotide probes (PCR-SSOP), a concordance between both the methods were explored. For validity, a further 300 EDTA blood samples with unknown HLA-DQ status were genotyped using the Celiac Gene Screen test, including 141 samples from CD, 56 first-degree relatives (FDRs) of CD and 103 samples from controls.
Results: Of the 100 samples with known status of HLA-DQ alleles, 79 samples were HLA-DQ2 and/or -DQ8 positive, and 21 samples were HLA-DQ2 and/or -DQ8 negative by conventional PCR. These 100 samples were re-typed using the Celiac Gene screen kit; all 79 positives were typed positive, and 21 negatives were typed negative for HLA-DQ alleles. Among 300 samples with unknown HLA-DQ status, 118 of 141 (84%) patients with CD, 48 of 56 (86%) FDRs of CD, and 52 of 103 (50%) controls typed positive for HLA-DQ alleles.
Conclusions: The Celiac Gene Screen HLA-DQ typing method showed excellent concordance with the conventional HLA-DQ typing method and could be a cost-reducing and effective method for CD-associated HLA screening.
Keywords: HLA; alleles; celiac disease; genotyping; polymerase chain reaction; susceptibility.