EBV is associated with a number of malignant diseases harboring latent virus. Burkitt's lymphoma (BL), a monoclonal B cell lymphoma with germinal center markers, is endemic and represents the most prevalent tumor in children in Africa. Chromosomal translocations between the protooncogene c-myc and the loci for the immunoglobulin heavy and light chains are characteristic for BL. Association with EBV is variable and depends on the geographical distribution. Whereas endemic BL is positive for EBV in more than 90% of cases, only about 15% are positive in sporadic BL and 30-40% in AIDS-associated BL.
Hodgkin' s disease (HD) is also variably associated with EBV depending on age, geographical distribution, and on the subtype of the tumor. There are at least four subtypes of HD: the ''mixed cellularity'' and ''nodular sclerosis'' types, which are the most prevalent types that are EBV-positive in 32-96% and 10-50%, respectively. The ''lymphocyte predominant'' type seems to be mostly EBV-negative, but the ''lymphocyte depleted'' type is EBV-positive in approximately 50% of cases. AIDS-related cases of HD are EBV-infected in more than 95% of cases.
Immunosuppression significantly increases the risk to develop EBV-associated malignant diseases because of the immortalizing and transforming properties of the virus. More than 90% of posttransplantation lymphoproliferative disorders (PTLD) are related to EBV. PTLD is variable with respect to morphology and clonality. In general, monoclonal tumors are more aggressive than polyclonal ones, likely because of additionally acquired genetic mutations enabling immune escape. Polyclonal proliferation often progresses to oligoclonality or mono-clonality without intervention.
AIDS-associated non-Hodgkin's lymphoma (AIDSNHL) is usually of B cell origin. In contrast to NHL in the course of iatrogenic immunosuppression, there is no clear association with EBV.
Although T cells are not the primary target of EBV, various T cell lymphomas are clearly associated with the virus including T cell lymphocytosis, nasal T cell lymphomas, T cell lymphomas with angioimmuno-blastic lymphadenopathic appearance, and NK/T cell lymphoma.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.