Lymphocyte activation as measured by interleukin‐2 receptor expression to gluten fraction 111 in coeliac disease

Lymphocyte activation was examined by interleukin‐2 (IL‐2) receptor expression on peripheral blood mononuclear cells from coeliac and control subjects. Purified T cells were incubated with gluten fraction 111 (a known toxic peptide for coeliac subjects), soyabean hydrolysate (an unrelated hydrolysed food antigen), and Concanavalin‐A (Con‐A, a non‐specific mitogen). After 1–5 days incubation, expression of IL‐2 receptors was assessed using a cellular enzyme‐linked immunosorbent assay (ELISA). Gluten fraction 111 induced expression of IL‐2 receptors on T lymphocytes from coeliac but not from normal subjects (P= 0·0005), whereas soyabean hydrolysate did not induce IL‐2 receptor expression. Lymphocytes from both coeliac and normal subjects had similar increased IL‐2 receptor expression after incubation with Con‐A. Flow cytometry was also used to confirm specific expression of IL‐2 receptor expression of lymphocytes from coeliac subjects. Interlcukin‐2 receptor expression increased from 0 to 5·4% of cultured mononuclear cells after 7 days incubation with gluten fraction III. These cells were CD3‐positive and CD4‐positive. We conclude that peripheral blood lymphocytes from coeliac subjects are sensitized specifically to gluten fraction III.