Human Herpesviruses 8 (HHV8)
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Viruses - DNA Viruses
- Herpesvirus Overview
- Herpes Simplex Virus 1 (HSV1)
- Herpes Simplex Virus 2 (HSV2)
- Varicella-Zoster Virus (HHV3)
- Epstein-Barr Virus (HHV4)
- Cytomegalovirus (HHV5)
- Human Herpesviruses 6 and 7 (HHV6 and HHV7)
- Human Herpesviruses 8 (HHV8)
- Poxvirus
- Hepadnavirus
- Adenovirus
- Papillomavirus (HPV)
- Polyomavirus
- Parvovirus
Key Points
- Human herpesvirus 8 (HHV-8)
- Characteristics
- Member of Herpesvirus family
- Enveloped DNA virus with double-stranded, linear DNA
- Herpesviruses are unique in that they get their envelope by budding from nuclear membrane of host cell
- Enveloped DNA virus with double-stranded, linear DNA
- Member of Herpesvirus family
- Transmission
- Endemic in Africa and Sardinia
- Unclear route of transmission
- Sexual contact and saliva may be modes of transmission
- Pathogenesis
- Infects many cell types (e.g. B cells, endothelial cells, macrophages, and epithelial cells)
- Can cause latent infection (like other herpesviruses)
- Reactivation may lead to some forms of Kaposi’s sarcoma (below)
- HHV-8 inhibits tumor suppression pathways
- Presentation
- Primary infection (viremia) may present as non-specific fever and rash
- Kaposi Sarcoma (KS)
- Seen in immunocompromised patients
- especially AIDS and solid organ transplant recipients
- Cancer of blood vessels
- Discolored skin lesions
- Dark blue/red/purple/violet/brown colored macules, plaques or nodules
- Colors from blood vessels with hemorrhage/hemosiderin deposition
- Variance of color depends on vascularity of lesion
- Affects skin, oral or genital mucous membranes, GI tract, or lung
- Associated with lymphedema
- Dark blue/red/purple/violet/brown colored macules, plaques or nodules
- Seen in immunocompromised patients
- May also present with B symptoms (fever, night sweats, and weight loss)
- Results from chronic inflammation (inflammatory cytokine syndrome)
- Elevated levels of cytokines are seen
- Also linked with Primary effusion lymphoma (PEL) and Castleman disease
- Diagnosis
- PCR can confirm presence of HHV-8
- Histopathology of Kaposi’s Sarcoma
- Whorls of spindle cells
- Vessel proliferation (neovascularization)
- Microhemorrhages with hemosiderin deposition may be seen due to leaky capillaries
- Leukocytic proliferation
- Treatment
- Treatment of HHV-8 is poorly understood
- HAART in AIDS-related disease
- Local or systemic chemotherapy depending on severity of disease
- Interferons may hold some utility
- Treatment of HHV-8 is poorly understood
- Characteristics