HLA-DP polymorphism in northern Italian celiac patients.

The contribution of HLA-DP genes to celiac disease susceptibility has been investigated in 95 Italian patients, 41 with childhood and 54 with adult disease onset. Polymerase chain reaction amplification, sequence-specific oligonucleotide probe hybridization and restriction fragment length polymorphism analyses have been carried out. All celiac patients and 56 out of 128 random healthy controls were DQw2-positive. The frequency of the DPB10101 allele was significantly increased (pc = 0.002, relative risk 5.21) in patients with celiac disease (23.2%) compared to the whole panel of controls (5.5%), but not to the 56 controls bearing DQw2 (10.7%). No significant difference in the frequency of DPB10101 was found between celiac patients with pediatric (24.4%) or adult (22.2%) onset. The DPB10101 allele was associated with both the DR3-DQw2 and DR7-DQw2 haplotypes. Moreover, our study has not confirmed the association with DPB10402 and DPB10301 previously reported in celiac children from southern Italy. The linkage of the DPB10101 allele with the DQ locus and the observation that the DP but not the DQ association appears to be ethnically dependent strongly support a secondary role of DP molecules in celiac disease susceptibility.