Circulating gliadin-specific T-cells are increased in active disease with ileal inflammation
ARTE technology was applied to all blood samples (Figure 1A ) for various nutritional antigens, including controls for antigen-specific T-cell enrichment and T‑cell activation. Moreover, we could clearly demonstrate the necessity for T-cell enrichment to allow for deeper cell analysis and therefore the advantage of this method over direct staining protocols for rare antigen-specific cell populations (Figure 1B ). With the overall frequency of CD4+ T-cells remaining stable in the various disease conditions (Figure 1C ), the frequency of gliadin-specific CD154+ T-cells among CD4+ T-cells in PBMC was expectedly highest in active CeD (aCeD), i.e. without GFD, as well as in refractory CeD patients (Refr). aCeD are rare patients as we did not actively initiate a gluten-re-challenge. Moreover the frequencies were also significantly increased in CeD patients on a GFD without clinical symptoms, when compared to healthy controls. Remarkably, a similar frequency to active CeD patients was observed in active CD patients with ileal inflammation (Figure 2A ).
The frequency was significantly lower in CD patients in remission, in UC patients, independent of their inflammatory state and in healthy controls. Interestingly, first-degree relatives (FDR) of CeD patients, considered healthy by standard diagnostics, revealed a significant increase in the frequency of gliadin-specific T-cells compared to controls without familiar predisposition of CeD. Of notice, RA as auto-inflammatory control without intestinal inflammation, did not differ from healthy controls.