HLA class II polymorphism in children with coeliac disease in Tunisia: is there any influence on clinical manifestation?

OBJECTIVE

To elucidate the HLA DRB1, DQB1 and DQA1 polymorphism in Tunisian children with typical form of coeliac disease (CD) in comparison with those from mass screening (atypical and silent CD).

MATERIALS AND METHODS

We recruited three groups: group I: 40 CD children diagnosed according to the ESPGHAN criteria. group II: 40 healthy controls matched with sex, age and geographic origin. group III: 38 CD children coming from mass screening in schoolchildren. HLA class II DRB1, DQB1 and DQA1 alleles were typed by PCR-sequence-specific primer.

RESULTS

Comparing the groups I and II, we found a pronounced increase of the susceptible alleles HLA DRB103 (relative risk, RR = 4.18, Pc = 0.001), DQB102 (RR = 7.9, Pc<0.0001) and DQA10501 (RR = 4.1, Pc = 0.001). As for protective alleles, we detected a high frequency of DRB113 (RR = 0.059, Pc = 0.001), DQA10102 (RR = 0.071, Pc = 0.009) and DQB106 (RR = 0.125, Pc = 0.0042). Haplotype analysis showed that the main combination observed was the conformation of DQ2 (DQA10501-DQB102) in 36 patients from group I and 30 from group III. There was no statistically significant difference between the groups I and III according to the distribution of the different alleles.

CONCLUSION

We confirmed in this study the high frequency of DQ2 haplotype in CD patients and we identified new protective alleles DRB113, DQA10102 and DQB1*06. However, HLA polymorphism seems to have no evident impact on clinical outcome of CD.