Frequency of Vα24 +Vβ11 + NKT cells in peripheral blood of human kidney transplantation recipients

Abstract

There are still lacking data supporting a role for natural killer T (NKT) cells in the maintenance of human tissue-specific tolerance. We are interested to study NKT cell frequency in kidney transplant recipients and its correlation with graft function. Peripheral blood T cell receptors (TCR) Vα24 +Vβ11 + NKT cells were phenotyped according to CD4 and CD8 expression in normal controls (NC), in 10 years rejection-free cadaver kidney allografts maintained with minimal immunosuppression (long-term rejection free [LTRF]), in patients with acute rejection (AR) and in patients with acute tubular necrosis (ATN). Results were expressed as percentages of CD4 +CD8 − (CD4 + NKT) or CD4 −CD8 − (double negative—DN NKT) Vα24 +Vβ11 + cells. The percentages of Vα24 +Vβ11 + cells were 0.09%, 0.14%, 0.02% and 0.09% on gated lymphocytes respectively in AR, ATN, LTRF and NC groups ( p=0.263). DN NKT cells were more frequent in NC patients (52.11%) and less present in ATN patients (11.04%). In contrast, CD4 + NKT (IL-4-producing NKT cells subset) was more frequent in AR (42.86%), and corresponded to almost 3 to 7 folds more what we obtained in the other groups. Although total Vα24 +Vβ11 + cells did not significantly differ among the groups, the lowest frequency was observed in the LTRF group. In conclusion, we observed that total number of NKT cells did not differ significantly among transplant patients when compared to normal controls, although specific-subsets seem to be more frequent in determined events.