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INTERACTIONS BETWEEN HIV AND HPV INFECTION. Dr. T L MSIBI Department of O&G University of Limpopo (Medunsa Campus). Importance of HPV and HIV Co-infection. Cervical cancer and HIV are major public health issues
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INTERACTIONS BETWEEN HIV AND HPV INFECTION Dr. T L MSIBI Department of O&G University of Limpopo (Medunsa Campus)
Importance of HPV and HIV Co-infection • Cervical cancer and HIV are major public health issues • There are significant clinical implications of HPV induced cervical cancer in HIV infected patients
HPV Virology • Non-enveloped dsDNA • Early genes (E6 & E7) are implicated in cancer • Transmitted by direct contact • Infects epithelial cells
HPV Associated Conditions • Epithelia dysplasia and cancer • (genital, anal, oropharynx) • Benign lesions • genitalia (condylomata acuminata) • larynx (recurrent respiratory papillomatosis)
HOST IMMUNITY : • INNATE IMMUNITY (phagocytes, cytokines, complements, & Epithelia barriers). • 1st line • No memory • Activate adaptive immunity via antigen presenting cell ( dendritic/ langerhans cells). • ADAPTIVE IMMUNITY • Cellular (Natural killer cells, Cytotoxic CD8 cells, Macrophages). • Humoral (Memory cells & Plasma cells (secretes antibodies).
HIV • HIV infects CD4+ T-helper cells • Suppress CMI • Favour opportunistic infections especially intracellular organisms
HPV in HIV-Infected Patients • 4x increased risk of HPV infection • multiple subtypes • more oncogenic • multifocal infection in the anogenital area • persists longer
Cervical Cancer in HIV-Infected Patients • Lesions tend to be high grade • a shortened interval between infection and invasive cancer. • High rates of recurrence • poorer prognosis
Cervical Cancer in HIV-Infected Patients • tends to be more advanced • occur in younger women • Tends to spread to unusual sites • Increased incidence of death. Mothshedisi and sebitloane. Best Practice & research clinical Obstetrics and gynaecology. April 2005.
Why HPV Persists? • Replicate in keratinocytes which are “programmed to die” (squames) • Thus viral release does not provoke inflammation. • Inhibits of Interferon synthesis and signaling • delayed activation of adaptive immune response • Compromised immune surveillance (Cell mediated immunity is suppressed in non-regressing cells) [MAGARET STANLEY. IMMUNE RESPONSE TO HPV. VACCINE 24s1 (2006)]
Effect of HIV on HPV • Persistent of HPV is due to immune evasion • Stronger immune response is necessary for HPV clearance • HIV- suppress the immune response thereby increase the risk of HPV infection and persistence
Direct molecular interaction • HIV-1 tat (transactivator protein) enhances E2 dependent HPV 16 transcription. • Implication for pathogenesis not yet clear
Effect of HPV on HIV infection • HPV induces production of immune and inflammatory factors that enhance HIV expression (Julia R Cage. Obstetrics & Gynaecology, December 2000).
Future Perspectives • As long as HIV persists in the community HPV complications will prevail • Further surveillance and research should be enhanced to improve the clinical management of cervical cancer