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Article

Association between sHLA-G and HLA-G 14-bp deletion/insertion polymorphism in Crohn’s disease

ZIDI Inès, BEN YAHIA Hamza, BORTOLOTTI Daria, MOUELHI Leila, LAARIBI Ahmed Baligh, AYADI Shema, ZIDI Nour, HOUISSA Fatma, DEBBECH Radhouane, BOUDABOUS Abdellatif, NAJJAR Taoufik, DI LUCA Daria, RIZZO Roberta, 2015

International Immunology, 27, 6, 289-296, Juin 2015

Résumé

The aim of this study was to evaluate the association between the HLA-G 14-bp deletion/insertion (Del/Ins) polymorphism and soluble (s) HLA-G production in patients with Crohn’s disease (CD). We analyzed also the sHLA-G molecules by ELISA and western blot in plasma samples. Among unselected patients, the 14-bp Del/Ins polymorphism was not significantly associated with increased CD risk neither for alleles (P = 0.371) nor for genotypes (P = 0.625). However, a significant association was reported between the 14-bp Del/Ins polymorphism and CD, in particular in youngonset CD patients for alleles [P = 0.020, odds ratio (OR) = 2.438, 95% confidence interval (CI): 1.13– 5.25] but not with adult-onset CD patients. A significant association was reported concerning the genotype Ins/Ins for young-onset CD patients (P = 0.029, OR = 3.257, 95% CI: 1.08–9.77). We observed also a significant increase in sHLA-G measured by ELISA in CD patients compared to controls (P = 0.002). The 14-bp Del/Del and 14-bp Del/Ins genotypes are the high HLA-G producers. Among sHLA-Gpositive patients, 43% of subjects present dimers of HLA-G. The presence of dimers seems to be related to the advanced stages of the disease. The 14-bp Del/Ins polymorphism is associated with an increased risk of CD particularly in young-onset CD patients and controls sHLA-G plasma levels. Dimers of sHLA-G are frequent in advanced disease stages. The above findings indicate that the genetic 14-bp Del/Ins polymorphism in exon 8 of the HLA-G gene is associated with the risk of CD and suggest a role for sHLA-G as a prognostic marker for progressive disease.