ABSENCE OF GLUTEN-SPECIFIC T-LYMPHOCYTES IN THE SKIN OF PATIENTS WITH DERMATITIS-HERPETIFORMIS

Dermatitis Herpetiformis (DH) is an immunobullous skin disease with an associated gluten-sensitive enteropathy. Withdrawal of gluten from the diet leads to the resolution of both the skin lesions and the enteropathy. A T cell-mediated immune response to gluten has been implicated in the damage to the gut; the possible gluten specificity of the T cell infiltrate in DH skin lesions has not, however, been investigated, T cell lines (TCL) were therefore established from the skin lesions of eight patients with DH by culturing skin fragments for 11-17 days with a medium supplemented with 20 U/ml of IL-2. In three cases, gliadin (fraction of gluten toxic to the DH gut) and irradiated, autologous peripheral blood mononuclear cells were also added. The TCL were stained for CD3, CD4, CD8, TCR alpha beta and gamma delta expression by indirect immunofluorescence, and their proliferative responses to mitogens and gluten fraction III (a peptic-tryptic digest of gluten) investigated. Of the eight CD3(+) TCL, four were predominantly CD4(+) (82.1-98.8%), three predominantly CD8(+) (92.6-98.6%) and one TCL contained both 87.6% CD4(+) and 95.2% CD8(+) T cells, a substantial proportion of which were presumably double-labelled CD4(+), CD8(+) T cells. All eight TCL, which were almost exclusively TCR alpha beta(+), proliferated in response to PHA whilst six out of the eight were stimulated by Concanavalin A. None of the TCL proliferated to gluten fraction III alone; however, two TCL showed increased proliferation to the antigen in the presence of exogenous IL-2 or IL-4 (10 U/ml) compared to cytokine alone. All eight TCL proliferated strongly in the presence of IL-2 alone, but only two out of seven showed a moderate response to IL-4. These findings suggest that gluten-specific T cells are absent from DH skin lesions.