Chapters authored
Clinical and Pathological Review of Post Transplant Lymphoproliferative Disorders
Posttransplant lymphoproliferative disorder (PTLD) is a rare but potentially serious complication following transplantation with an overall incidence of PTLD of 1–5% in solid organ transplant (SOT) recipients and 1% in hematopoietic stem cell transplant (HSCT) recipients. The clinical and pathological spectrum of PTLD is broad; however, most cases of PTLD occur within the first year after transplantation and are associated with EBV. Clinical features that independently predict rates of response and survival have not been systematically studied for PTLD. Patients whose PTLD expressed CD20 or EBV have shorter intervals to PTLD onset, whereas late-onset cases of PTLD are typically EBV negative. Phenotypic characterization of PTLD reveals potential reliance on EBV or NF-kappaB signaling instead of B-cell receptor signaling, which links PTLD to other subgroups of EBV-related lymphomas, highlighting new potential treatment approaches. PTLD can be a life-threatening post-HSCT complication due to the impact of the patient’s underlying disease (malignant or nonmalignant) as well as the type and intensity of the conditioning regimen. EBV-negative PTLD is more often a delayed phenomenon post-HSCT compared to EBV-positive PTLD. Further investigations are needed to better understand the role of EBV in the pathogenesis of different forms of PTLD in the immunosuppressed patients.
Part of the book: Organ Donation and Transplantation
Immunosuppression and Viral Infections
Immunosuppression is commonly used for prevention of graft rejection in solid organ transplantation (SOT) and prevention of graft versus host disease in hematopoietic allogeneic stem cell transplant (ASCT). In ASCT, immunosuppression is used to control GVHD and can be tapered off within 6–12 months after transplantation. SOT recipients require lifelong immunosuppression to prevent graft rejection, making them susceptible to serious viral infections including EBV PTLD. EBV PTLD occurs within the first 6 months following ASCT prior to effective reconstitution of cytotoxic T lymphocytes (CTL). Our understanding on EBV-related PTLD is mostly extrapolated from SOT-associated PTLD. Features of conditioning and use of serotherapy remain important in development of EBV PTLD. Other viral infections that occur early post-transplant include CMV, HHV6, BK, and adenovirus, and usually correspond to degree of immunosuppression post-transplant. These infections are associated with significant morbidity and mortality. However, the current literature lacks information on outcomes of viral infections related to immunosuppression. Alternative donor ASCT are now more common, and patients are more susceptible to multiple viral infectious complications at the peak of immunosuppression and require monitoring for viral infections in these immunosuppressed patients.
Part of the book: Immunosuppression