The Fifth International Cytomegalovirus Conference,
"A multidisciplinary approach towards
controlling cytomegalovirus disease"
Stockholm, May 21-24, 1995
A DNA sequence showing 58% homology to the UL34 gene of human cytomegalovirus was detected in a PCR product amplified from an atypical cytopathic virus repeatedly isolated from a patient with chronic fatigue syndrome (Am. J. Path. 145:440-451, 1994). As described in this reference, the virus was readily distinguishable from CMV (and from other human herpesviruses) on the basis of i) the type of foamy cell cytopathic effect induced in multiple cell types of both human and animal origin; ii) the atypical reactivity patterns seen in PCR and serologic assays using primers and monoclonal antibodies specific for known human herpesviruses; and iii) the lack of significant sequence homologies of a PCR product amplified from another region of the viral genome. DNA sequencing of Eco RI and Sac I clones of the virus has now identified additional regions of partial homology to CMV. The homologous regions extend from the UL31 gene to the US segment of CMV. Much of the cloned viral sequence data, however, cannot be aligned directly to the CMV genome. The results are consistent with the occurrence of widespread mutations and deletions within CMV. Microheterogeneity between closely related clones further suggests continuing instability of the viral genome. In spite of these changes, the virus has retained its cytotoxicity. The findings have implications in terms of pathogenesis and potential recovery from this type of viral infection.