Are paramyxoviruses involved in Paget's disease? A negative view.

We believe that the assembled data are consistent with the presence of mRNA species and/or proteins in pagetic bone that are recognized by some paramyxovirus antibodies and nucleic acid probes. The evidence presented so far is insufficient to substantiate claims for the "unequivocal" presence of paramyxovirus sequences in pagetic bone, because the molecular targets for these probes could be endogenous mRNA's and proteins rather than viruses. Positive reports of a viral presence in Paget's disease have so far been confined to two laboratories, both of which have consistently demonstrated evidence for the virus they have worked on most. We argue that independent replication of the aforementioned findings is necessary to conclude that pagetic bone can be considered a site of chronic paramyxovirus infection. For this to be convincing, we would expect to see colocalization of viral antigens, mRNA, and genomic RNA in cells that also show ultrastructural evidence of viral infection. If virus is indeed present, it should, in addition, be possible to clone and characterize extensive tracts of viral cDNA from samples of pagetic tissue. Although we acknowledge that the absence of evidence for viral mRNA in some RT-PCR studies does not constitute evidence of absence, the data implicating paramyxoviruses as causal agents is conflicting and insufficient to prove a cause-effect relationship. In view of this, we believe that the role of paramyxovirus infection as a cause Paget's disease remains uncertain.