Human Leukocyte Antigen Haplotypes Predisposing to Celiac Disease in Patients With Endometriosis

Immunological abnormalities are well recognized in the pathogenesis of endometriosis and the co-existence of endometriosis with inflammatory bowel disease (IBD) and celiac disease (CD), along with other systemic immune disorders, is clinically relevant. Recent genetic studies revealed some shared genetic traits associated with the co-occurrence of endometriosis with different gastrointestinal or autoimmune disorders, highlighting common biological pathways. Since class II human leukocyte antigen (HLA) genes, HLA-DQ2 and -DQ8, show the strongest and best-characterized genetic susceptibility for CD, the present study aims to explore the presence of these haplotypes in non-celiac patients with endometriosis.

A group of patients with endometriosis (n = 126) participated in the study and were compared to healthy women (n = 379), as controls. Subjects who were diagnosed with CD or who tested positive for CD antibodies were excluded. All patients and controls were genotyped for HLA haplotypes predisposing to CD (DQ2, DQ8). In the group of endometriosis patients who tested positive for DQ2 and/or DQ8, symptoms were also investigated.

At least one of the HLA-DQ2 and -DQ8 genotypes was detected in 43.3% of non-celiac endometriosis patients (OR: 1.82, 95% CI: 1.11-2.81), whereas 29.5% (p < 0.01) of healthy women presented HLA haplotypes predisposing to CD. In endometriosis patients, no significant difference was shown between positive and negative in terms of endometriosis phenotype, or gynecological, and non-gynecological symptoms.

Our data revealed a significantly greater prevalence of predisposing haplotypes for CD in non-celiac patients with endometriosisthan in healthy subjects, suggesting that a common genetic background may explain the co-occurrence of endometriosis and CD.