LBA:01:41 Genetic predisposition to celiac disease in systemic lupus erythematosus: prevalence of HLA-DQ2 and HLA-DQ8 haplotypes in a case-control study in the Greek population

Objectives Emerging data suggest higher celiac disease(CD) prevalence in SLE, indicating the existence of shared genetic risk factors between the two disorders. The human leukocyte antigen (HLA)-DQ2 and DQ8 genotypes are strongly linked to CD, present in almost all CD patients. We aimed to investigate the distribution of HLA-DQ2 and HLA-DQ8 in SLE patients and in healthy individuals in central Greece.Methods We conducted a 1:1 gender and ethnic background paired case-control study. SLE patients fulfilled the EULAR/ACR Criteria for SLE and were recruited from our department. Genomic DNA was extracted from peripheral blood samples and HLA DQ2 and DQ8 alleles were detected using multiplex PCR with a commercially available kit targeting HLA-DQQA1 and HLA-DQB1 loci. HLA status was classified as DQ2+, DQ8+, DQ2+DQ8+ or negative and the primary exposure was DQ-positivity, defined as presence of DQ2 and/or DQ8. For the paired comparison of DQ-positivity between cases and controls the McNemar’s test was utilized (two-sided alpha=0.05). A matched odds ratio (OR) was calculated from discordant pairs with a 95% confidence interval(CI).Results One hundred participants were included, comprised of 50 SLE cases and 50 controls (88% females in both groups). DQ2 and/or DQ8 positivity was present in 34%(17/50) of SLE cases versus 26%(13/50) of controls. Specifically, DQ2 sole positivity was detected in 32% of SLE cases and 22% of controls, while DQ8 sole positivity was uncommon, observed in 2% in both groups. The combined DQ2/DQ8 genotype occurred only in one participant from the control group. In the matched-pair analysis of DQ positivity, McNemar’s test showed no significant difference between groups (p=0.56). The matched OR was 1.36(95% CI 0.59-3.28). When DQ2 sole positivity was examined, SLE patients did not differ from controls (p=0.4), while the matched OR was 1.56(95% CI 0.63-4.1).Abstract LBA:01:41 Figure 1Conclusions This case-control study identifies higher HLA-DQ2 positivity in SLE patients compared to a matched control group population in Central Greece. However, this difference was not significant. Given the relatively small sample size, the observed increase (32% vs 22%) warrants larger-scale studies to determine whether SLE presents increased genetic predisposition for developing CD in this geographical region.