Phenotyping of peripheral blood lymphocytes in adult coeliac disease

In coeliac disease immunological abnormalities are not confined to the smal l bowel and it has been suggested that changes in peripheral blood lymphocy tes may predispose to autoimmune or malignant complications. Using dual-col our immunofluorescence with labelled monoclonal antibodies, multiparameter flow cytometry was used to analyse peripheral blood lymphocytes in 32 untre ated coeliacs, 29 treated coeliacs and 20 healthy volunteers. When the abso lute numbers were considered, a decrease of CD3(+), CD4(+), CD8(+) and CD19 (+) lymphocytes was found in untreated coeliacs compared with treated coeli acs and healthy volunteers. The proportion of CD3(+) was significantly high er in untreated coeliacs (P<0.05) than in healthy volunteers. No difference s were observed in CD4+, CD8+ and CD19+ subsets between the three groups st udied. The proportion of CD3(+) CD25(+) and CD3(+) HLA-DR+ cells were highe r in untreated coeliacs (P <0.001 and P > 0.005) and in treated coeliacs (P <0.005 and P < 0.05) than in healthy volunteers. On the contrary, natural killer cells and cytotoxic cells were lower in untreated and treated coelia cs than in healthy volunteers. As regards B-cell subsets, the only differen ce was the increase in Fc epsilon R+ B cells in untreated coeliacs. The abs olute reduction of peripheral lymphocytes in coeliac disease probably refle cts their compartimentalization in intestinal mucosa. The decrease of natur al killer cells and cytotoxic cells may be in keeping with the increased pr evalence of malignancy in this condition. Finally, the phenotypic changes f ound in untreated coeliacs indicate T-cell activation.