Phenotypical characterization of peripheral blood T cells in patients with coeliac disease: elevation of antigen-primed CD45RO+ T lymphocytes.

Increased numbers of gamma delta T-cell-receptor-bearing (TCR gamma delta +) lymphocytes are present in the small intestinal epithelium of patients with coeliac disease (CoD). In this study the phenotypic characteristics of peripheral blood T cells from 14 untreated CoD patients and 14 healthy age- and sex-matched controls were determined with special emphasis on TCR gamma delta + lymphocytes. We also studied samples taken from 15 CoD patients who were on gluten-free diet (GFD). Two- and three-colour flow cytometry analyses were performed using a whole-blood lysing method. There was no significant difference between the percentages of TCR gamma delta + lymphocytes in patients and controls. However, the amount of delta TCS1+ lymphocytes was significantly lowered in untreated patients (0.48 +/- 0.42% in CoD versus 0.86 +/- 0.57% in controls, P < 0.05). The percentage of CD45RO+ T cells, which are a primed population of T cells including memory cells, was significantly raised in the peripheral blood of untreated patients. This phenomenon was most prominent within the TCR gamma delta + population (83.9 +/- 12.2% in CoD versus 65.5 +/- 14.7% in controls, P < 0.01), but the same applies to CD45RO+ TCR alpha beta + and delta TCS1+ T cells. In patients on GFD these changes seem to be at least partly corrected. Antigen-primed CD45RO+ T cells have been shown to accumulate in the jejunal epithelium of patients with untreated CoD. The enhanced 'memory activity' also found in the peripheral blood of untreated CoD patients may result from a continuous antigenic stimulus and this stimulus could be gluten triggered.