HLA-DQ typing in the diagnostic algorithm of celiac disease

celiac disease (CD) is an immune-mediated chronic inflammatory disease associated with HLA-DQ2 and DQ8 molecules. We evaluated the role of HLA in the CD diagnostic algorithm in order to contribute to the development of practical indications for the use of HLA typing.

we selected 317 subjects typed for DR-DQ genes. CD was present in 123 patients, and 89 were included in the study; a control sample of 70 healthy individuals was recruited.

64% of patients with CD carried DQ2 heterodimer (α5β2), 13.5% carried DQ8 heterodimer without DQ2, 21.4% only showed β2 chain and 1.1% were positive for DQ2 α5 chain. The only presence of α5 chain did not predispose to CD, while DQB1*02 allele resulted more frequent than in other reports, pointing out the intrinsic correlation between β2 chain and CD. In the case-control study we observed a progression of increased risk, ranging from 1:7 for HLA-DQ2 homozygous to 1:85 for DQ8 heterozygous subjects. Overall, 8,6% of first degree family members were affected, exclusively in presence of HLA-DQ2, -DQ8 or DQB1*02, and CD was significantly more frequent among siblings than parents. Finally, considering the different patterns of clinical presentation among the HLA-DQ risk classes identified we found no relationship between CD clinical presentation and HLA-DQ risk categories.

our results strengthen the evidence that HLA-DQ status strongly influences the development of CD and demonstrate that knowledge of a patient's HLA-DQ genotype allows to establish clinically relevant genetic risk profiles.