Failure to down-regulate intragraft cytokine mRNA expression shortly after clinical heart transplantation is associated with high incidence of acute rejection

BACKGROUND: Brain-death, ischemia and reperfusion damage have been implicated as initial factors that lead to a cascade of immunologic events that result in allograft rejection in experimental animals. Cytokines are thought to play a central role in this process. Therefore, we evaluated intragraft cytokine mRNA expression at an early stage after clinical heart transplantation and related these data to ischemia, immunosuppression, and rejection.METHODS: We sampled endomyocardial biopsies at 30 minutes (EMB 0) and at 1 week (EMB 1) after transplantation from 20 cardiac allograft recipients. Intragraft monocyte chemoattractant protein (MCP-1) and basic fibroblast growth factor (bFGF) mRNA expression levels were quantitatively measured using competitive template Reverse-transcriptase polymerase chain reaction (RT-PCR).RESULTS: We measured significantly lower MCP-1 and bFGF mRNA expression levels in EMB 1 compared with EMB 0 (MCP-1, p = 0.006; bFGF, p = 0.019). We found no direct correlation between the cytokine mRNA expression levels in EMB 0 or EMB 1 and ischemic times, induction therapy, or cyclosporine whole-blood trough levels. Patients with a high incidence of acute rejection episodes (>2 in the first year) had higher bFGF mRNA expression levels (p = 0.009) and comparable MCP-1 mRNA expression levels (p = 0.378) at 1 week, compared with patients with a lower rejection incidence. The MCP-1 and bFGF mRNA expression levels in the first week were not associated with the development of graft vascular disease in the first year post-transplant.CONCLUSIONS: We found a significant decrease of intragraft MCP-1 and bFGF mRNA expression levels in the first post-operative week. Patients with a high incidence of acute rejection had higher bFGF mRNA expression levels in their first week biopsy. Therefore, we conclude that patients who fail to down-regulate their bFGF mRNA expression early after transplantation are at higher risk for acute rejection.