Infections in Transplantation: Introduction and Overview

Over the last 70 years, a steady growth in population of patients with severe and mostly iatrogenically induced immune suppression while undergoing myeloablative antineoplastic therapy and blood- and marrow-derived stem cell or solid organ transplantation has resulted in a near-explosive growth of opportunistic infections. Furthermore, the advent and now common use of biologic immunosuppressive drugs are given to an increasing number of patients prior to transplantation or for treatment of complications arising during the posttransplant period such as graft-versus-host disease, lymphoproliferative disorders, opportunistic malignancies, cancer recurrences, and rejection of solid organ allograft. These and other recent therapeutic advances in transplantation procedures continue to be fraught with prolonged and often unpredictable period of drug-induced immune dysregulation. The emergence and spread of difficult-to-treat opportunistic bacterial, viral, fungal, and parasitic diseases in transplant population have evolved under the influence of environmental-, host-, disease-, and treatment-specific variance. A diligent diagnostic adjudication is of utmost importance in a population with known proclivity for atypical disease presentation. Inaccurate diagnosis may result in inappropriate and ineffective empiric therapy that may worsen patients’ morbidity and heighten the risk for further complications and death. Advancement in understanding the immunopathogenesis of infectious diseases, hosts’ immunologic vulnerability for infections, emerging molecular diagnostic paradigms, deciphering potential therapeutic impact of immune modulation by existing and new antimicrobial drugs, and active research and development in mitigation strategies to promote immune recovery and immune preservation are encouraging developments in optimizing care for patients in need for lifesaving transplantation procedures.