Correlation of ImmuKnow Assay Levels with Rejection and Infection after Heart Transplantation

Abstract

Purpose Cylex Immune Function Test (IFT)(ImmuKnow®) assesses T-cell activity by measuring ATP levels. It is a useful assay that measures global immune response in patients post heart transplantation (HTx). However, its role in guiding medical therapy is still limited. We aim to study the association of IFT with HTx rejection and infection. Methods We investigated all patients who received HTx from 4/2014 - 8/2018. All IFT levels measured were divided into 3 groups: rejection phase (within 1 month before rejection episode, ISHLT 1990 ≥ grade 1B), infection phase (within 1 month of infection requiring admission), other stable phase, and analyzed these IFT values. Rejection episodes within 1 month post-HTx were excluded. Results 156 HTx patients were included (mean age 54 years, 74% male). The mean follow-up period from HTx was 2.1 ± 1.4 years, over which 757 IFT values were collected. 25 IFT levels were assessed in rejection phase, 123 in infection phase and 611 were in stable phase. Mean IFT in infection phase was significantly lower compared to stable phase (166 ± 143 vs 264 ± 180 ng ATP/mL, p Conclusion Infection was associated with lower IFT levels compared to stable post-transplant levels. IFT may be a valuable tool in the detection of infection post-HTx and can guide reduction in immunosuppression. However, its role in predicting rejection needs further evaluation.