Celiac Disease: Cytokine Profile of Intraepithelial Gamma Delta T Cells in Disease Severity.

γδ+ intraepithelial lymphocytes (IELs) are persistently expanded in the intestinal epithelium of patients with active celiac disease (ACeD), but their functional profile during active inflammation remains poorly defined. This study investigated the expression of pro- and anti-inflammatory cytokines in γδ+ IELs isolated from the intestinal epithelium of ACeD patients at different stages of mucosal damage. Frozen jejunum sections were obtained from 14 ACeD patients (7 Marsh II and 7 Marsh III) and 10 treated celiac disease (CeD) patients. γδ+ IELs from ACeD biopsies and intestinal enterocytes (IEs) from treated CeD biopsies were isolated by laser capture microdissection on mirror sections, followed by RNA extraction and quantitative real-time RT-PCR analysis of IL-15, IL-17A, IL-21, IFN-γ, TNF-α, IL-10, and TGF-β. Foxp3 expression was assessed by immunohistochemistry. γδ+ IELs from Marsh III biopsies showed significantly increased mRNA levels of IL-15, IL-17A, IL-21, IFN-γ, and TGF-β compared with IEs, whereas IL-10 expression was significantly higher in Marsh II γδ+ IELs compared with Marsh III and IEs. IL-21 and TGF-β were also higher in Marsh III than Marsh II γδ+ IELs. All γδ+ IELs were Foxp3-. These findings indicate a stage-dependent functional polarization of γδ+ IELs in ACeD, with an IL-10-associated regulatory profile in Marsh II and a predominant pro-inflammatory cytokine signature in Marsh III.