SERUM CYTOKINES IN HUMAN HEART-TRANSPLANT RECIPIENTS - IS THERE A RELATIONSHIP TO REJECTION

Cytokines are important in the pathogenesis of allograft rejection. So me studies have suggested a positive relationship between serum levels of cytokines and rejection, so this study was designed to investigate the presence of a range of cytokines in a large cohort of cardiac tra nsplant recipients. We used enzyme linked immunosorbent assays (ELISA) to examine sequential serum samples hom 28 consecutive heart transpla nt recipients; length of follow up varied between 2 and 566 days (medi an 357 days), Serum levels of IL-2, 4, 6, 10, TNF-alpha, and IFN-gamma were measured. We compared these results with detailed data on patien ts' clinical courses, including histological rejection, infection, and therapeutic use of antithymocyte globulin (ATG). No significant relat ionship was found between rejection and serum cytokine levels for samp les taken more than 30 days after transplantation. Prior to this cytok ine levels were significantly disturbed by the use of cytolytic therap y for induction immunosuppression. Serum cytokine levels sometimes sho wed peaks that appeared to be related to rejection, or occasionally to infection, but these relationships were not consistent. Serum TNF-alp ha and IL-6 were consistently elevated within a few days of administra tion of ATG. We conclude that there is no systematic relationship betw een serum cytokine levels and histological rejection or infection in c ardiac transplant recipients.