Viruses other than HIV and non-Hodgkin's lymphoma.

There are several viral infections which are known to cause lymphoma among animals; all establish latency in lymphoid cells. The human T-lymphotropic virus type I is a human virus which causes lymphomas among a subset of carriers. However, this virus is very restricted in its distribution and as such, is unlikely to play a role in the increase of non-Hodgkin's lymphoma (NHL). A highly prevalent infection, the Epstein-Barr virus (EBV) is known to play a role in the etiology of NHL among persons with acquired or inherited immune suppression. However, whether it is involved with "spontaneous" NHL is unknown. We have found evidence that among a group of 104 NHL patients with blood samples taken several years before diagnosis, there was an alteration in the antibody profile against the EBV which is quite similar to that seen for immune-suppressed patients prior to their diagnosis. This pattern is most evident in the oldest patients. This suggests that there may be an age-related subclinical immune suppression leading to chronic activation of EBV. If a viral infection is a major factor in the recent increase in NHL in the world, then we should consider the role of immune-suppressive exposures which have become widespread in recent decades.