Epstein - Barr virus - associated Diseases in Allogeneic Hematopoietic Stem Cell Transplantation

Excerpt

Epstein - Barr virus (EBV) is a gamma - herpes virus that infects more 90% of humans. Most EBV primary infections and reactivations are subclinical and require no therapy in immunocompetent people. However, EBV infection or reactivation may result in life-threatening diseases in immunocompromised people [1‐5]. EBV infection and reactivation might be associated with a spectrum of clinical presentations ranging from fever to post-transplant lymphoproliferative diseases (PTLD), including viremia, pneumonia, encephalitis/ myelitis, PTLD, and so on, in recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT), which arise as a consequence of infected B/T lymphocytes, epithelial cells and neural cells, and they are sustained by EBV latency products [2, 3, 6]. EBV-associated PTLD were only the tip of the iceberg of post-transplant EBV-associated diseases [2], but there is short of large sample data about the incidence of EBV-associated other diseases other than PTLD in recipients of transplants. Kinch et al. reported that 7 of 16 patients with EBV-DNA-emia developed EBV-associated diseases in 39 recipients of allo-HSCT, including 3 PTLD, 1 myelitis, 1 encephalitis and 2 reactivations with fever [7]. In one of our prospective study, 16 of 64 patients with EBV-DNA-emia developed PTLD and 11 patients developed EBV-associated other diseases, including 6 fever, 1 encephalitis, 1 myelitis, 1 pneumonia, 1 encephalitis accompanying pneumonia and 1 enteritis accompanying hepatitis, in 172 recipients of allo-HSCT. The incidence of PTLD in a large study varied from 0.5% to 22% after allo-HSCT, depending on the number of risk factors including T-depleted graft, the use of ATG, unrelated donor, HLA- mismatched, acute / chronic graft versus host disease (GVHD), cytomegavirus (CMV) antigen-emia, and so on [3, 8, 9]. Except for lymph nodes, EBV can also involve nearly all other tissues and organs in recipients of transplants, and isolated central nervous system (CNS) involvement with PTLD is considered to be an exceedingly rare complication after allo-HSCT [10]. But our prospective study showed that 16 of 27 patients with EBV-associated diseases were extranodal involvement and 12 patients developed EBV-associated CNS diseases (6 CNS-PTLD, 5 encephalitis and 1 myelitis). …