Prevention of infections in the solid organ transplantation recipient

Solid organ transplantation (SOT) has transformed the prognosis of many children with organ failure. An estimated 135,860 SOTs were performed worldwide in 2016. A total of 33,610 SOTs were performed in the United States, with children, the majority of whom were younger than 10 years, receiving 1878 of these transplants. ^, Despite advances in the field of transplantation, infections remain an important cause of morbidity and mortality in pediatric SOT recipients. Refinements in immunosuppressive regimens have led to the reduction of graft rejection episodes and prolonged graft and patient survival. However, the evolving armamentarium of immunosuppressive agents with differing mechanisms of actions on distinct components of the immune system has also contributed to the risk for and modified the clinical manifestations of transplant-related infections. Indeed, the clinical diagnosis of infection in an SOT recipient may be complicated by lack of signs of inflammation, and conversely, transplant-associated entities, such as graft rejection, may mimic infection. As the number of pediatric SOTs increases, it is important for pediatric providers to have knowledge of the risk factors for infection after SOT and use optimal prevention strategies.

The risk for infection is determined by the interplay of multiple factors before and after SOT, including the epidemiologic exposures and underlying conditions of both the recipient and donor, the type of transplanted graft and its associated immunosuppressive regimen, and the recipient’s overall “net state of immunosuppression,” which is defined by transplant, host, and pathogen-specific factors. Young age at the time of SOT is an important variable that influences infection risk and type; it follows that younger patients are less likely to have encountered certain pathogens and thus lack immunity, but they are at high risk of developing infection from the donor or acquiring primary infection after SOT while receiving immunosuppression. Furthermore, the extent to which immunosuppressive regimens affect the developing immune system in children who require SOT in infancy has not been fully elucidated. The risk of infection and type of pathogen is also dependent on time elapsed since SOT; the greater the immune dysfunction, the greater the predisposition to infection and to severe disease. In this chapter we review the multiple preventative strategies that may be used to help mitigate the risk of infection after SOT.