Background: Since functional differences were found among three major haptoglobin phenotypes, haptoglobin polymorphism was reported to be associated with the risk and clinical course of different inflammatory diseases. The aim of the study was to investigate the Hp polymorphism distribution in Hungarian Crohn's disease patients.
Methods: 511 Hungarian IBD patients were investigated (Crohn's disease patients: 468, m/f ratio: 233/235, duration 8.2 +/- 6.7 ys, and ulcerative colitis patients: 43, m/f: 22/21, duration: 9.5 +/- 10.6 ys) and 384 healthy subjects served as controls. Hp phenotypes were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis of sera followed by immunoblotting. Clinical data were come by the questionnaires prepared by the physicians.
Results: The frequency of haptoglobin-1 allele was significantly higher in Crohn's disease (0.395) compared to the controls (0.345; OR: 1.24, 95%CI: 1.02-1.52, p = 0.03), but the phenotype distribution showed no such differences. Haptoglobin phenotype was associated to disease behavior in Crohn's disease (B1 and B2, in haptoglobin 1-1 and 2-2: 36.6%-34.3% and 32.4%-32.5% vs. in 2-1: 44.9% and 20.3%; ORB1Hp2-1 vs. others: 2.06, 95%CI: 1.29-3.28). Furthermore, an increased frequency of primary sclerosing cholangitis was observed in haptoglobin 2-2, compared to the 1-1 (6.5% vs. 0.0%, p = 0.039). No associations were found in ulcerative colitis.
Conclusions: haptoglobin-1 allele was associated with Crohn's disease, whereas the phenotypes with the disease behavior and frequency of primary sclerosing cholangitis, exhibiting a disease-modifying effect.