ß-HHVs and HHV-8 in Lymphoproliferative Disorders.

Similarly to Epstein-Barr virus (EBV), the human herpesvirus-8 (HHV-8) is a γ-herpesvirus, recently recognized to be associated with the occurrence of rare B cell lymphomas and atypical lymphoproliferations, especially in the human immunodeficiency virus (HIV) infected subjects. Moreover, the human herpesvirus-6 (HHV-6), a ß-herpesvirus, has been shown to be implicated in some non-malignant lymph node proliferations, such as the Rosai Dorfman disease, and in a proportion of Hodgkin's lymphoma cases. HHV-6 has a wide cellular tropism and it might play a role in the pathogenesis of a wide variety of human diseases, but given its ubiquity, disease associations are difficult to prove and its role in hematological malignancies is still controversial. The involvement of another ß-herpesvirus, the human cytomegalovirus (HCMV), has not yet been proven in human cancer, even though recent findings have suggested its potential role in the development of CD4(+) large granular lymphocyte (LGL) lymphocytosis. Here, we review the current knowledge on the pathogenetic role of HHV-8 and human ß-herpesviruses in human lymphoproliferative disorders.

Prevalence of human herpesvirus-6 chromosomal integration (CIHHV-6) in Italian solid organ and allogeneic stem cell transplant patients.

The unique phenomenon of human herpesvirus-6 (HHV-6) chromosomal integration (CIHHV-6) may account for clinical drawbacks in transplant setting, being misinterpreted as active infection and leading to unnecessary and potentially harmful treatments. We have investigated the prevalence of CIHHV-6 in 205 consecutive solid organ (SO) and allogeneic stem cell transplant (alloSCT) Italian patients. Fifty-two (38.5%) of 135 solid organ transplant (SOT) and 16 (22.8%) of 70 alloSCT patients resulted positive for plasma HHV-6 DNA by real-time polymerase chain reaction. Seven SOT and three alloSCT patients presented HHV-6-related diseases, requiring antivirals. Two further patients (0.9%) were identified, presenting high HHV-6 loads. The quantification of HHV-6 on hair follicles disclosed the integrated state, allowing the discontinuation of antivirals. Before starting specific treatments, CIHHV-6 should be excluded in transplant patients with HHV-6 viremia by the comparison of HHV-6 loads on different fluids and tissues. Pretransplantation screening of donors and recipients may further prevent the misdiagnosis of CIHHV-6.

Fatal hemophagocytic syndrome related to active human herpesvirus-8/Kaposi sarcoma-associated herpesvirus infection in human immunodeficiency virus-negative, non-transplant patients without related malignancies.

Hemophagocytic syndrome (HS) may occur as a consequence of herpes viral infections. Human herpesvirus 8 (HHV-8)/Kaposi sarcoma-associated herpesvirus has so far been recognized as a trigger of HS only in immunosuppressed subjects or in patients with Kaposi sarcoma and/or HHV-8-related lymphoproliferative diseases. We report two Italian human immunodeficiency virus (HIV)-negative elderly men who developed an HS with a rapidly fatal course, following treatment with corticosteroids for autoimmune hemolytic anemia. An overwhelming active infection with HHV-8 was unequivocally documented by molecular and immunohistochemical methods, in the absence of HHV-8-related tumors. The occurrence of HHV-8-associated HS, although rare, may be considered, even out of the HIV or the transplantation settings, at least in areas endemic for HHV-8 infection.