Epstein-Barr virus and other candidate viruses in the pathogenesis of Hodgkin's disease.

The epidemiologic and clinicopathologic features of Hodgkin's disease (HD) suggest that an infectious agent is involved in the etiology. Over the last 12 years, evidence has accumulated suggesting that Epstein-Barr virus (EBV) is associated with a proportion of cases: EBV genomes are present in Reed-Sternberg (HRS) cells and viral proteins including LMP1, which has oncogenic potential, are expressed. HD has a complex epidemiology and EBV-associated cases are not randomly distributed. Disease occurring in early childhood and older adult age groups is more likely to be EBV-associated than for young adult cases. Paradoxically, there is more evidence supporting an infectious etiology in the latter group of younger patients. Defective EBV genomes and "hit and run" mechanisms involving EBV cannot account for all cases, and the direct involvement of known viral agents, including other lymphotropic herpesviruses, has largely been excluded. Hitherto unknown virus may be responsible for the peak incidence in young adults, which is a feature of HD in developed countries.