HLA-DP polymorphism in northern Italian celiac patients.

Area of Science:

• Immunogenetics
• Gastroenterology
• Human genetics

Background:

• Celiac disease (CD) is an autoimmune disorder triggered by gluten ingestion.
• Human Leukocyte Antigen (HLA) genes, particularly HLA-DQ, are strongly associated with CD susceptibility.
• The role of other HLA genes, like HLA-DP, remains less understood.

Purpose of the Study:

• To investigate the contribution of HLA-DP genes to celiac disease susceptibility in an Italian cohort.
• To determine if specific HLA-DP alleles are associated with disease onset in childhood versus adulthood.

Main Methods:

• Genotyping of 95 Italian celiac disease patients and 128 healthy controls using polymerase chain reaction (PCR) and sequence-specific oligonucleotide probe hybridization.
• Analysis of restriction fragment length polymorphism (RFLP) for HLA-DP alleles.
• Statistical analysis including relative risk and p-values to assess allele frequencies.

Main Results:

• The HLA-DPB1*0101 allele frequency was significantly higher in celiac patients (23.2%) compared to the overall control group (5.5%).
• This association was not significant when compared to DQw2-positive controls (10.7%), suggesting linkage with DQw2.
• No significant difference in DPB1*0101 frequency was observed between pediatric and adult-onset celiac disease patients.
• DPB1*0101 was associated with DR3-DQw2 and DR7-DQw2 haplotypes, and previous associations with DPB1*0402 and DPB1*0301 were not confirmed.

Conclusions:

• The HLA-DPB1*0101 allele is associated with celiac disease susceptibility in the Italian population, likely due to its linkage with the HLA-DQ locus.
• The association of HLA-DP with celiac disease appears to be ethnically dependent and secondary to the primary role of HLA-DQ.
• DP molecules may play a modifying or secondary role in celiac disease pathogenesis.