Background: Transplant immune suppression is designed to suppress the adaptive immune response and ensure graft survival, but may have unintended effects on innate immunity. Few studies have investigated the effect of transplant immunosuppression on innate immunity. Susceptibility to nonencapsulated, extracellular bacteria depends largely on innate, rather than adaptive, immune function. Thus, bacteremia occurring after organ transplantation may provide a useful measure of innate immune function. This study examined whether any of four different regimens of induction immunosuppression was associated with altered risk of early bacteremia after transplant, as compared to “no induction.”

Methods: We identified 163 episodes of bacteremia occurring within 90 days of transplantation among 4,012 individuals who received a kidney (n=2,729), liver (n=760), pancreas (n=149), or kidney-pancreas (n=374) transplantation at a large academic center between January 2004 and June 2014. Patients were categorized by the induction regimen that they received: basiliximab (n=1,996), alemtuzumab (n=705), ATG/thymoglobulin (n=343), an institution-specific “desensitization” protocol (induction agent and plasmapheresis, n=276), or “no induction” (n=692).

Results: Early bacteremia occurred in 2.8% of the basiliximab group, 3.4% of the alemtuzumab group, 3.2% of the thymoglobulin group, 4.7% of the desensitization group, and 8.7% of the “no induction” group (p<0.001). After adjustment, desensitization vs. no induction (OR 2.92, 95% CI 1.33-6.40, p=0.008) and alemtuzumab vs. no induction (OR 2.16, 95% CI 1.12-4.17, p=0.021) were associated with bacteremia. Desensitization vs. basiliximab (OR 2.06, 95% CI 1.04-4.06, p=0.038) was also associated with bacteremia. In adjusted models, early bacteremia (HR 2.14, 95% CI 1.52-3.0, p<0.001) was associated with worse long-term survival.

Conclusion: A desensitization protocol consisting of plasmapheresis in addition to an induction agent was associated with increased risk of early bacteremia compared to basiliximab and “no induction.” Alemtuzumab was also associated with increased risk of bacteremia compared to “no induction.” Early bacteremia was associated with significantly worse survival.

CITATION INFORMATION: Misch E., Kelley S., Leverson G., Astor B., Kaufman D. Risk of Bacteremia According to Transplant Induction Immunosuppression Regimen Am J Transplant. 2017;17 (suppl 3).

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