Clinical value of a single determination of intracellular ATP levels in stimulated CD4+ T lymphocytes in pediatric patients with stable liver transplantation. 
In the follow-up of transplanted patients under immunosupression, the functional assessment of CD4+ T cells activation by measuring intracellular ATP levels in vitro, using the Immuknow test give information on how immune system is functioning.  Therefore, it has been reported that low levels of ATP correlate with the risk of opportunistic infection.  Although limited, comprehensive results in adult recipients as well as in pediatric transplanted patients have been reported.  Forty stable liver pediatric transplanted patients (mean age: 11.0 years [SD 5.65]), within at least 1 year of transplant were selected for a scheduled review, and an unique determination of Immuknow was performed.  Average ATP levels were 317 ng/mL (200-400 ng/mL) which were similar to the values observed in adult population.  ATP values among patients with monotherapy Cyclosporin A (CSA) or tacrolimus (TAC) were significantly higher (P = .005) than in patients with double immunosupressive therapy using either CSA/TAC + Mycophenolate Mofetil (MMF).  In CSA treatment, there are significant differences (P = .0003) between monotherapy and double therapy, but in the case of TAC we did not find differences (P > .1).  A single determination of levels of ATP on CD4+ lymphocytes, can provide additional information that could be used as a complementary test to guide immunosuppressive therapy in paediatric liver transplant recipients.