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Lymphotropic viruses. Nehal Draz. Human Tcell lymphotropic viruses (HTLVs). They include HTLV-1 & HTLV-2 HTLV-1 is a human oncogenic virus Belong to retroviridae family. Large envelopped RNA viruses There are 2 copies of genomic RNA per virus particle . Retroviridae family.
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Lymphotropic viruses NehalDraz
Human Tcelllymphotropic viruses (HTLVs) • They include HTLV-1 & HTLV-2 • HTLV-1 is a human oncogenic virus • Belong to retroviridae family • Large envelopped RNA viruses • There are 2 copies of genomic • RNA per virus particle Retroviridae family Complex life cycle • Conversion of RNA to DNA (………?) • Integration into host DNA (provirus)
Mode of transmition • The virus is cell associated in the host • Transmission will occur when infected cells are transferred Breast milk sexual Blood transfusion
HTLV-1 is associated with 4 diseases Adult Tcell leukemia Non- Hodgkin lymphoma Tropical spastic paraparesis A form of uveitis
Adult Tcell leukemia /lymphoma (ATL) • Was first recognized in Japan • It is an acuteTcell proliferative malignancy affecting males more than females • Characteristic features: • Leukemia • Generalized LN • Hepatosplenomegaly • Other less dramatic forms exist, including a variant that runs a slow course with LN & hepatosplenomegaly
Non – Hodgkin Lymphoma (NHL) • Involvement of the CD4 Tcells • Slowly progressive myelopathy • spastic & ataxic features • Pathologically; areas of demyelination with lymphocytic inflammation & perivascular cuffing Tropical Spastic paraparesis
Laboratory diagnosis of HTLV-1 1- Ab detection 2- Confirmation Immunoblot • ELISA • IF • ….. • ….. 3- Detection of proviral DNA PCR - Confirmatory - Distinguish between HTLV-1 & HTLV-2
No acute disease is apparent at the time of seroconversion • There is a period of latency until ATL appears • This latency may last for years, often decades
During latency: - viral proteins are expressed as there are steady high Ab titers to viral proteins - Virus is present during the latent period as a provirus & is replicated with the cellular DNA as the cell divides
HTLV-2 • Transmitted by the same routes as HTLV-1 • It shares 65% sequence homology with HTLV-1 with significant serological cross-reactivity • It is not linked to a particular disease, although its first isolation was from a patient with a rare T- hairy cell leukemia