β-HHVs and HHV-8 in Lymphoproliferative Disorders

Area of Science:

• Virology
• Oncology
• Hematology

Background:

• Human herpesvirus-8 (HHV-8), a gamma-herpesvirus, is associated with rare B cell lymphomas and lymphoproliferations, especially in HIV-infected individuals.
• Human herpesvirus-6 (HHV-6), a beta-herpesvirus, is implicated in non-malignant lymph node disorders like Rosai Dorfman disease and some Hodgkin's lymphoma cases.
• The role of human cytomegalovirus (HCMV), another beta-herpesvirus, in cancer is unproven, but it may contribute to CD4(+) large granular lymphocyte (LGL) lymphocytosis.

Purpose of the Study:

• To review the current understanding of the pathogenetic roles of HHV-8 and human beta-herpesviruses in human lymphoproliferative disorders.
• To explore the association between specific herpesviruses and the development of various hematological malignancies and lymph node abnormalities.

Main Methods:

• Literature review of existing studies on herpesvirus involvement in lymphoproliferative disorders.
• Synthesis of current knowledge regarding the pathogenesis and disease associations of HHV-8, HHV-6, and HCMV.

Main Results:

• HHV-8 is recognized for its association with specific lymphomas and lymphoproliferations, particularly in immunocompromised hosts.
• HHV-6 has a broad cellular tropism, with debated roles in lymph node proliferations and hematological malignancies.
• Evidence suggests a potential role for HCMV in CD4(+) LGL lymphocytosis, though its broader oncogenic role is not yet established.

Conclusions:

• HHV-8 and HHV-6 are implicated in various lymphoproliferative disorders, with varying degrees of certainty and clinical significance.
• The ubiquitous nature of HHV-6 makes definitive disease association challenging, and its role in hematological cancers remains controversial.
• Further research is needed to elucidate the precise pathogenetic mechanisms and clinical implications of beta-herpesviruses, including HCMV, in human lymphoproliferative disorders and cancer development.