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

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. 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. 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. 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.