Background & aims: Whipple's disease is a systemic, chronic, relapsing disorder caused by a combination of environmental (Tropheryma whipplei) and unknown host factors. Because it is a rare disease, the association between HLA type and Whipple's disease has been studied in only small numbers of patients; these studies have led to conflicting results. We aimed to investigate whether disease phenotype and outcome are associated with HLA type in 122 patients with Whipple's disease.
Methods: Genomic DNA was collected from 103 German, 11 Italian, and 8 Austrian patients with Whipple's disease, along with 62 healthy Austrian workers exposed to T whipplei (14 stool samples contained the bacterium). HLA class I and II alleles were identified by polymerase chain reaction analysis. Patient genotypes were compared with those of healthy German and Austrian populations; data for Italian controls were obtained from the Pavia HLA bone marrow donors' bank.
Results: HLA-DRB1*13 and DQB1*06 alleles occurred significantly more frequently in patients with Whipple's disease but not in healthy individuals who had been exposed to T Whipplei. The cumulative odds ratios for disease were 2.23 for the DRB1*13 allele (P < .0001) and 2.25 for the DQB1*06 allele (P < .0001).
Conclusions: DRB1*13 and DQB1*06 alleles were found to be risk factors in the largest HLA study ever performed in patients with Whipple's disease.