Intracellular ATP Levels in CD4+ Lymphocytes Are a Risk Marker of Rejection and Infection in Renal Graft Recipients

Abstract Objective The immune monitoring of transplant patients may allow us to minimize adverse events of immunosuppression and predict risks of rejection. Herein we have evaluated the capacity of an immune cell function assay to predict episodes of rejection and infections as well as its correlation with immunosuppressive drug trough levels and CD4, CD8, CD25, and DR cell counts. Patients and Methods This prospective study of 38 kidney transplant patients was performed from January to June 2008. Blood samples were obtained at several times posttransplantation until the sixth month. We measured intracellular adenosine triphosphate (iATP) levels following CD4 cell activation for comparison with the clinical courses. Results Patients with ≥525 ng/mL levels of iATP in the first week posttransplantation were 6.6 times more likely to develop an acute rejection episode (ARE) than those with lower immune response values ( P = .014). Those who had an ARE with iATP < 525 ng/mL were generally highly sensitized (4/5). Statistically significant variations in iATP levels were observed among patients who had an ARE ( P = .006). There was a relationship between infections and iATP levels also. Infections were more frequent with iATP ≤ 225 ng/mL ( P = .048); patients with severe infections displayed lower iATP levels (180 ± 143 vs 416 ± 180 ng/mL; P = .01). There were no associations with CD4, CD8, CD25, or DR cell counts or with immunosuppressive drug trough levels. Conclusion iATP levels may be considered to be a reliable marker of cellular immune status among renal graft recipients possibly identifying patients with a high risk of infection or rejection.