Abnormal intestinal intraepithelial lymphocytes in refractory sprue

Background and Aims: The etiology of refractory sprue is unclear. To gain insight into its pathogenesis, the phenotype and T-cell receptor (TCR) gene rearrangement status of intestinal lymphocytes were analyzed in a group of patients with clinical or biological features of celiac disease but either initially or subsequently refractory to a gluten-free diet. Methods: Intestinal biopsy specimens were obtained from 26 adults: 6 patients with refractory sprue, 7 patients with active celiac disease, and 13 normal controls. The phenotype of intestinal lymphocytes was studied by immunohistochemistry and, in 3 patients with refractory sprue, by cytometry of lymphocytes purified from intestinal biopsy specimens. TCR rearrangements were assessed by studying TCRγV-J junctional regions from DNA extracted from intestinal biopsy specimens and purified intestinal lymphocytes. Results: In the 6 patients with refractory sprue, but not in normal controls or patients with active celiac disease, the intestinal epithelium was massively infiltrated by small lymphocytes that lacked CD8, CD4, and TCR, contained intracytoplasmic but not surface CD3ε chains, and exhibited restricted TCRγ gene rearrangements. Conclusions: Refractory sprue is associated with an abnormal subset of intraepithelial lymphocytes containing CD3ε and restricted rearrangements of the TCRγ chain but lacking surface expression of T-cell receptors.