“Immuknow” to Measurement of Cell-Mediated Immunity in Renal Transplant Recipients Undergoing Short-Term Evaluation

Abstract

The aim of this preliminary, observational study was to evaluate the value of ImmuKnow (IK), a new tool to measure the net state of immunefunction among renal transplant recipients, in correlation with clinical and laboratory data among unselected renal transplant recipients. Forty-nine recipients of mean age of 51 years were enrolled and followed for 1 year after transplantation. All subjects received the same immunosuppressive strategy with basiliximab induction and tacrolimus, mycophenolate mofetil and steroid maintenance therapy. Samples for IK were collected before transplantation as well as at 7, 14, 21 and 42 days and after 3, 6, and 12 months. There were 54 samples with IK <225 ng/mL, 201 samples with normal IK values, and 135 samples with >525 ng/mL. We divided recipients into 3 groups with respect to their basal IK values: Group 1 (Gr1; IK <225 ng/mL); Group 2 (Gr2; normal values of IK between 226 and 524 ng/mL); and Group 3 (Gr3; IK >525 ng/mL). At 1 year, we observed a significant difference among IK values at the start and the end of the study: Gr1 vs Gr2, P < .0001; Gr2 vs Gr3, P < .06 and Gr 1 vs Gr 3, P < .01). We observed reduced IK values to predict an increased risk of infection, particularly with cytomegalovirus (CMV) replication while higher IK value did not correlate with an increased risk of acute rejection episodes. Reduction of serum creatine levels occurred within 1 year in all groups ( P < .005), but there was a significant difference between Gr 2 versus Grs 1 and 3 ( P < .0001 and P < .0005, respectively). There findings suggested that more stable IK values were associated with clinical quiescence and laboratory stability. In conclusion, our preliminary analysis showed a beneficial capacity of this assay to represent the global depression of the immune system. We noted that reduced IK values, as a sign of excessive immunosuppressive therapy, were associated with an increased risk of infection. We did not confirm the predictive value of higher IK values for an increased risk of an acute rejection episode.