Activated T cells in the surface secretion on the adenoid--a flow cytometric study

We previously demonstrated the presence of leucocytes in the adenoid surface secretion with the ability of immunoglobulin A (IgA), IgM and IgG production as well as production of cells with phagocytic capacity. In the present study, we investigated the presence of activated T cells in the secretion. Adenoid surface secretion from 12 children subjected to adenoidectomy was obtained with an imprint method. From six children, peripheral blood was also obtained. By flow cytometry, the number of lymphocytes, granulocytes, epithelial cells and red blood cells was analysed as well as the expression on lymphocyte subsets of the following antigens: CD3, CD4, CD8, CD19, CD25, CD38, CD45RO, CD45RA, HLA-DR, TcRgd, CD161 and l-selectin. The majority of T cells were activated and to a significantly higher degree were CD45RO+, CD161+ and l-selectin-, as compared with the corresponding peripheral blood. The median percentage of B cells and T cells in the secretion were 81 and 13%, respectively. In conclusion, the proportion of B and T cells in the adenoid surface secretion is significantly different as compared with the peripheral blood. The T cells in the adenoid surface secretion are to a high degree activated. The results suggest that the leucocytes in the surface secretion are part of the mucosal defence.