Evaluation of the Frequency of HLA-DQ2/DQ8 Genes Among Patients with Celiac Disease and Those on a Gluten-Free Diet

Background: Celiac disease (CD) is a chronic, permanent, gluten-dependent disease that manifests itself with inflammation of the small intestine and malabsorption in genetically predisposed individuals with HLA-DQ2 and -DQ8 (human leukocyte antigen) histocompatibility antigens. Objective: The diagnostic criteria for celiac disease have undergone numerous modifications over the years. The aim of the study is to evaluate the frequency of HLA-DQ2/DQ8 genes in a group of patients with celiac disease diagnosed in 1980-2010 in order to verify the primary diagnosis of CD. Methods: The study group included 50 patients, 13 men and 37 women, who had been diagnosed with celiac disease many years ago based on histopathological criteria and improvement of health condition after receiving a gluten-free diet. The control group consisted of 31 healthy volunteers, 18 women and 13 men. All subjects underwent a genetic analysis assessing the presence of histocompatibility antigens HLA-DQ2.2, -DQ2.5, and -DQ8, along with the assessment of alleles encoding the alpha and beta subunits of the antigens, according to European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines from 2020, using the EUROarray technique at EUROIMMUNE (R). Results: In the study group, 12 (24%) patients did not meet the genetic criteria. Among the remaining patients (Group 1) with celiac disease, the presence of HLA-DQ2.5 (50.0% vs. 9.68%; p < 0.01) and the co-occurrence of both alleles of HLA-DQ2 (31.6% vs. 6.45%; p < 0.05) were detected significantly more frequently than in the control group. Among patients with celiac disease, the prevalence of HLA-DQ8 was also slightly more frequent (13.2% vs. 3.23%; p > 0.05). Patients who did not meet the genetic criteria for celiac disease (Group 2) had a single string alpha-HLA-DQ2.5 significantly more often than control subjects (66.67% vs. 38.71%; p < 0.05). Conclusions: Among patients with celiac disease diagnosed before 2010, based on the 2020 ESPGHAN criteria, it is advisable to verify the previous diagnosis, taking into account genetic criteria.