Viral Infections in Allogeneic Hematopoietic Stem Cell Transplant Recipients: Literature Review

Abstract

Hematopoietic stem cell transplant (HSCT) recipients are at an increased risk of bacterial, viral, fungal and parasitic infections. Past exposures to infections, the degree of immunosuppression, prolonged neutropenia and presence of graft versus host disease (GVHD) are some of the factors which make HSCT recipients more susceptible to infections. Viral infections have emerged as a major challenge causing high morbidity and mortality in stem cell transplant recipients. Myeloablative conditioning regimens and GVHD prevention strategies which may delay immune reconstitution and serologic status of donors and recipients affect the incidence of viral infections. Community-acquired respiratory and gastrointestinal viral infections like respiratory syncytial virus (RSV), rhinovirus, adenovirus, influenza, norovirus and reactivation of latent viruses like herpes simplex virus (HSV), cytomegalovirus (CMV) are some of the important pathogens increasing the morbidity and mortality in transplant recipients. Clinical manifestations range from asymptomatic carriage to severe disease. Due to lack of effective agents to treat viral infections and emerging resistance patterns, preventive and prophylactic strategies are valuable. Our review article provides an overview of commonly encountered viral infections and their management in an allogeneic stem cell transplant setting in the adult age group. KeywordsViral infections; allogeneic stem cell transplants; hematopoietic stem cell transplants IntroductionViral infections can be asymptomatic or subclinical or even lead to severe disease in allogeneic HSCT recipients. Viral diseases of importance in HSCT include herpes simplex virus (HSV), varicellazoster virus (VZV), human herpesvirus 6 (HHV-6), cytomegalovirus (CMV), Epstein-Barr virus (EBV) and respiratory viruses (eg, respiratory syncytial virus, adenovirus, influenza, parainfluenza). Most of these viral infections are opportunistic in nature and are related to factors influencing engraftment and immune reconstitution [1]. Increase in HLA mismatched donor allogeneic transplants and using anti-thymocyte globulin (ATG) for GVHD prevention are few factors which predispose recipients to viral infections [2,3]. Fortunately, based on molecular diagnostic methods, a polymerase chain reaction can offer an early diagnosis of these infections [4,5]. Early diagnosis facilitates timely intervention controlling infection associated complications. Many prophylactic and pre-emptive treatment strategies are also aimed at decreasing viral infection-related complications [6]. Immunotherapy to restore virus-specific immunity are proven to be effective in treating CMV, EBV and adenovirus infections [7]. In our review article, we have made an attempt to discuss risk factors for post-HSCT viral infections, preventive strategies and treatment options. Risk Factors for Viral Infections Source of Stem CellsPeripheral blood stem cells achieve faster hematopoietic and immune reconstitution compared to bone marrow and cord blood source. Hence, this is asso...

Acute lymphoblastic leukemia complicating with adrenal insufficiency due cytomegalovirus infection

“…contaminated blood or through a donor in transplantations, in this cases the main clinical manifestations are: pneumonia, retinitis and colitis. 6 , 7 …”