GLUTEN STIMULATION OF CELIAC MUCOSA IN-VITRO INDUCES ACTIVATION (CD25) OF LAMINA PROPRIA CD4(-CELLS AND MACROPHAGES BUT NO CRYPT-CELL HYPERPLASIA() T)

Jejunal biopsy specimens from 10 patients with treated coeliac disease and seven non-coeliac controls were challenged in vitro with peptic-t ryptic gluten digest. Mucosal T cells were examined in situ by three-c olour immunofluorescence staining for expression of the activation mar ker CD25 (the p55 alpha-chain of interleukin-2 receptor) and the nucle ar proliferation marker revealed by monoclonal antibody Ki-67. Intraep ithelial T cells expressed CD25 rarely whereas the proportion of activ ated lamina propria T cells increased (P < 0.002) from median 2.8% (cu ltured with 20% fetal calf serum alone for 24-48 h) to 10.0% after 24 h with gluten (n = 10; range 1.1-17.4%) and to 10.4% after 48 h (n = 7 ; range 1.4-17.5%). Such gluten-induced increase of CD25+ T cells was not observed in specimens from non-coeliac control subjects. Crypt-cel l hyperplasia and T-cell proliferation (Ki-67+) were observed neither in the coeliac nor in the control mucosae after gluten stimulation. Th ree-colour staining combining a polyclonal antibody reagent to CD3 and a monoclonal antibody to CD25 with a monoclonal antibody to CD45R0, C D4, CD8, the p75 beta-chain of interleukin-2 receptor, integrin alpha( E)beta7, or HLA-DR showed that most of the CD25+ T cells (> 90%) were CD4+CD8-, co-expressed CD45R0 and the p75 beta-chain, and often also t he integrin alpha(E)beta7 but not HLA-DR. In addition to these activat ed T cells, a dominating population of CD25+ CD3- CD4+ subepithelial p an-HLA-class II + macrophages (CD68+) with variable expression of the p75 beta-chain was often induced by gluten challenge.