DNA binding activity of nuclear factor of activated T cells in mononuclear cells from renal transplant patients with and without BK virus viruria

Objectives: Renal transplant patients receive calcineurin inhibitors to suppress the calcineurin-nuclear factor of activated T cells (NFAT) pathway. The DNA binding activity of NFAT and its relationship to the reactivation of BK virus (BKV) has not been evaluated in renal transplant patients. Patients and Methods: The DNA binding activity of NFAT cytoplasmic 1 (NFATc1) was measured by enzyme-linked immunosorbent assay in peripheral blood mononuclear cells from 26 renal transplant patients and 26 healthy controls. At the same time, their urinary BKV viral load was measured by real-time polymerase chain reaction. Results: The activity of NFATc1 was lower in renal transplant patients without BKV viruria [BKV (-)] than in healthy controls, while it trended to be higher in renal transplant patients with BKV viruria [BKV (+)] than in BKV (-) patients. The tacrolimus blood levels did not differ between BKV (+) and BKV (-) renal transplant patients or correlate with NFATc1 activity. Conclusion: NFATc1 DNA binding activity was lower in renal transplant patients without BKV viruria than in those who were BKV (+). However, there was no relationship between tacrolimus blood levels and NFATc1 activity in renal transplant patients.