Abstract 2583: Successful Use Of Immune Monitoring (Cylex) In Heart Trasnplantation For Rejection And Infection Risk
Background: An unmet need in heart transplantation (HTx) has been the lack of a reliable immune monitoring test to indicate recipient immunoresponsiveness (IR). Trough immunosuppression blood levels do not reflect a recipient’s IR state. Recently, immune monitoring with Cylex (measure of ATP levels from activated lymphocytes) has been reported to predict risk of rejection or infection in kidney transplant patients. We now review our experience with immune monitoring and clinical course after HTx.
Methods: Between 2005 and 2007, 41 HTx patients had 82 immune monitoring assays obtained from 12 to 3034 days after HTx. ATP activity was graded as low IR (<225 ng/ml), moderate IR (225–525 ng/ml), or high IR (>525 ng/ml). Immune monitoring scores were correlated to infection and rejection episodes. All patients were treated with triple drug immunosuppression (tacrolimus, mycophenolate, and corticosteroids).
Results: For infectious episodes (n=34), immune monitoring scores <225 were found in 18/25 (72%) samples, compared to 16/57 (28%) samples >225, p < 0.001. The average immune monitoring score during infection compared to those samples without infection was 259 vs. 378, p <0.001. For rejection episodes (n=6), immune monitoring scores <225 were found in 0/24 (0%) samples compared to 6/58 (10%) samples >225, p = 0.101. The average immune monitoring score during rejection compared to those scores without rejection was 454 vs. 318, p = 0.041. There were 34 infections (1 parasitic, 8 viral, 13 bacterial, and 12 fungal infections).
Conclusion: Immune monitoring with Cylex for HTx patients appears to reflect the degree of recipient IR state and risk for rejection and infection.