[Herpesviruses mixed infections in allogeneic steam cell recipients (allo-HSCT)]

Assessment of frequency and clinical course of infections with herpesviruses: CMV, EBV, HHV-6 and HHV-7 in patients that underwent non-manipulated allo-HSCT from matched-related donors.

35 recipients of age 31 +/- 8 years. Serological status of donor and recipient against CMV and EBV assessed before transplantation. After transplantation, herpesviruses infection was confirmed based on the presence of viral DNA isolated from peripheral leukocytes, using nested PCR method. Patients were examined repeatedly, during 11.7 +/- 7 months of observation.

mixed infections appeared in 80% of allo-HSCT recipients. Infections with two or three viruses dominated, especially CMV and EBV (65%). We observed specific tendency of appearance of particular herpesviruses in each episode--in the first and the second episodes CMV dominated, EBV or HHV-6 infections were rare, whereas in the successive episodes EBV and HHV-7 were the leading viruses. In correlation with clinical symptoms mixed CMV and EBV infections were characterised by the most severe course. Superinfections with HHV-6 or HHV-7 had no significant influence on the progression of illness. Our observations may suggest that the serious CMV infections in allo-HSCT recipients are the result of not only the pathogenic properties of CMV but of the additive effect of replication of other herpesviruses.