NKG2D ligands expression patterns in gut mucosa from patients with coeliac disease

Introduction

The activating MICA/NKG2D interaction is involved in the response of intraepithelial lymphocytes (IELs) in coeliac disease (CD). The aim of this study was to investigate the expression of NKG2D ligands (MICA, MICB), IL-15 and NKG2D receptor in gut mucosa of CD patients, and the correlation with the severity of histological damage.

Patients and methods

Intestinal biopsies from 20 CD patients and five healthy controls were selected. All patients were positive for anti-transglutaminase 2 antibodies and for DQ2 or DQ8. Patients were divided into two groups according to their grade of mucosal impairment: ten each with mild and severe mucosal damage (MMD and SMD, respectively). The expression of proposed genes was determined at mRNA level. MICA expression was also determined by immunohistochemistry.

Results

Overexpression of MICA and MICB was observed in biopsies from coeliac patients compared to healthy controls (P < 0.001). Nevertheless, the expression was considerably higher in the group of patients with MMD (P < 0.0001) than in those with SMD. The levels of NKG2D receptor and IL-15 were also higher in patients than in controls, but no relationship with the severity of the mucosal lesion was found.

Conclusions

Our results suggest that NKG2D ligands may play an important role during the onset of the inflammatory process in the early stages of the development of coeliac disease.