αβ and γδ T cell subsetsin chronic renal failure in children on dialysis treatment

BACKGROUND: Impaired immunity, particularly cell-mediated, is one of the features of chronic renal failure. This also concerns impaired T cell dependent responsiveness. METHODS: The expression of T cell surface antigens (CD3, CD25, TCRalphabeta, TCRgammadelta) was evaluated on peripheral blood (PB) mononuclear cells using two-color flow cytometry in 10 children on continuous ambulatory peritoneal dialysis (CAPD) and in 13 children on maintenance hemodialysis (HD) with polysulfone and cuprophane dialysers. RESULTS: In HD children absolute numbers of leukocytes, lymphocytes, CD3+, alphabeta, gammadelta T cells and a percentage of gammadelta T cells were decreased versus healthy children. Also, we observed a relative increase of CD3+, CD3+/CD25+ and alphabeta T cells after sessions with cuprophane membranes, and an increase of CD3+/CD25+, alphabeta T cell percentages after sessions with the polysulfone membranes. Additionally we found a decrease of both relative and absolute numbers of gammadelta T cells after HD with polysulfone. In CAPD children we found declined absolute numbers of total lymphocytes, CD3+ and alphabeta T cells and higher relative values of CD3+ and alphabeta T cells versus controls. CONCLUSIONS: The T cell depletion in chronic renal failure (CRF) patients primarily results from uremic-related toxicities, rather than from CAPD or HD-related incompatibilities. We showed a significant decrease of gammadelta T cells in CRF patients on HD, that may be partly responsible for impaired T-dependent responsiveness in that group. The intradialytic changes of gammadelta Tcells may result from a different degree of biocompatibility during the application of various dialysis membranes.