Viral infections associated with the clinical use of monoclonal antibodies

In recent years, immunomodulatory agents, such as monoclonal antibodies (mAbs), have been effectively utilized in the management of several malignancies, in transplant rejection, in autoimmune and inflammatory diseases, and in a range of further indications. However, the administration of mAbs is associated with an increased risk of infections, in particular of viral infections, that is not fully appreciated. The influence of mAbs on viral infections is likely to be relevant, impacting on the incidence, severity and timing of infections. Some of these viral infections may result in treatment delays and may be coupled with increased morbidity and mortality. Although all viral infections presumably play an important role in patients undergoing mAb treatment, and may affect outcome, some are more common than others, e.g. hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus, varicella-zoster virus and Epstein–Barr virus infections. This review focuses on the viral infections of primary clinical relevance, such as HBV, HCV, and herpesvirus infections, that may occur in patients undergoing immunomodulatory treatment.