Aim: The objective of this study was to evaluate the effects of T4 phage on adsorption and replication of human adenovirus (HAdV). Materials & methods: Experiments were performed on cell lines A549 and HEK-293. Intracellular HAdV virions were released and titrated by Reed–Muench method. Results: T4 significantly (p < 0.05) inhibited both the adsorption of HAdV and viral replication in a dose-dependent manner. Mean reductions in HAdV titer were within the range 0.634–2.12 and 0.238–1.88 log10 TCID50/ml for HAdV adsorption and replication, respectively. Conclusion: T4 phage can inhibit infections by HAdV-5 of target cells. Our results suggest that T4 might be considered a novel agent against HAdV and possibly other pathogenic viruses. Potential antiviral effects of other phages should also be investigated.

Human adenoviruses (HAdV) are important viral pathogens recognized increasingly in immunocompromised hosts, especially in allogeneic haematopoietic stem cell transplant recipients (alloHSCT). The clinical spectrum of HAdV disease ranges from asymptomatic viraemia and mild self-limiting disease to lower respiratory tract infection, multi-organ involvement and even death. Early detection and quantification of HAdV in peripheral blood using real-time PCR (qPCR) assay has been suggested as a useful monitoring tool, but is seldom used for regular surveillance of HAdV in haematology centers. A group of 112 alloHSCT recipients from two hospitals in Warsaw (Poland) was examined in the early post-transplant period using a quantitative qPCR assay. A total of 1,245 serum samples were evaluated for presence of HAdV DNA in patients where 66 (59 %) patients received grafts from unrelated donors whereas the other 46 (41 %) from sibling donors. HAdV sequences were detected in 64 (57 %) of the 112 patients. In 22 of all patients (20 %) HAdV DNA was detected only in a single positive sample, while 42 (37 %) had positive results in two or more subsequent sera. In total, DNAemia was present in 202 sera samples (16 %) with median time to observation of 47 days. Graft-versus-host disease (GvHD) was observed in 18 (28 %) adenovirus-infected transplant recipients and a significant correlation between HAdV infections and GvHD clinical presentation was found (p = 0.018). There is a high prevalence of HAdV infections in HSCT recipients in Poland during early post-transplant period. In consequence, we could only speculate if HAdV DNAemia could be also related to GvHD symptoms, enforcing the important pathogenic role of these viral infections in clinical complications post-alloHSCT.

Human herpesvirus 7 (HHV-7) is widespread around the world and may also be a possible cofactor for cytomegalovirus (CMV) infection in haematopoietic stem cell transplant (HSCT) recipients. In case of viral diseases where specific treatment is available, real-time PCR assays constitute reliable diagnostic tools enabling timely initiation of appropriate therapy and rapid assessment of the efficacy of antiviral treatment strategies. The presence of CMV and HHV-7 was confirmed by the detection of viral DNA isolated from 1,027 plasma samples. A group of 69 allogeneic HSCT (alloHSCT) recipients was examined in early post-transplant period using quantitative real-time PCR methods. Within the study period, 62 % of patients had at least once CMV DNA-emia, while HHV-7 DNA was found in 43 % of subjects. Co-infection between these β-herpesviruses was detected in the plasma samples collected from 18 patients (26 %). Patients with concomitant HHV-7 DNA-emia had significantly higher number of CMV DNA copies compared with those without HHV-7 infection (1986 vs. 432 copies/ml, p < 0.001) but there was no difference in duration of CMV DNA-emia between these groups. On the other hand, while the load of HHV-7 DNA was comparable between patients with CMV DNA-emia and without CMV DNA-emia, the duration of HHV-7 DNA-emia was significantly longer in the first group (38.5 vs. 14 days, p < 0.001). HHV-7 DNA-emia is very frequently detected in Polish alloHSCT recipients. In those, who have subsequent CMV reactivation, the coexistence of the viruses may negatively affect the kinetics of infection with either of them. Therefore the investigation of concomitant HHV-7 DNA-emia could affect the prognosis of post-transplant patients suffering from CMV reactivation.

In patients with immunological disorders, adenovirus infections are associated with significant rates of morbidity and mortality. Only few hematological units use molecular virological methods, such as polymerase chain reaction, for surveillance of adenovirus infection, and treatment strategies have never been evaluated in multicenter clinical trials. This report describes the detection and treatment of human adenovirus (HAdVs) disseminated disease in the case of a 46-year-old immunocompromised female having myelodysplastic syndrome with refractory cytopenia with multilineage dysplasia: International Prognostic Scoring System 1. Serum and urine samples were tested for the presence of adenoviral DNA using the quantitative real-time polymerase chain reaction (PCR) assay. For additional confirmation, sequencing of PCR products was also performed. With real-time PCR, we detected HAdV DNA in both serum and urine samples. The viral level constantly decreased with applied oral ribavirin therapy. As the result of sequencing, HAdVs type 11 was determined. Surveillance of adenovirus by real-time PCR is useful in detecting and monitoring disseminated HAdV infection; it is a potential standard diagnostic approach that could assist clinicians to decide whether antiviral therapy ought to be administered.

Human herpesvirus 6 (HHV-6) has been recognized as a potentially significant pathogen in hemopoietic stem cell transplant (HSCT) recipients. Different clinical manifestations have been described, including fever, skin rash, bone marrow suppression, and encephalitis. A retrospective review of a group of 26 adult recipients of allogeneic HSCTs was conducted. Serum samples taken before transplant were examined for the presence of specific anti-HHV-6 IgM and IgG antibodies. After transplantation, quantitative real-time PCR was used to determine viral load in plasma samples from days 0–80 post-transplant. HHV-6 DNA was detected in plasma samples in 8 (30%) of the 26 recipients between days 18 and 40 after transplantation. All of them developed fever of unknown origin and over 50% had graft-versus-host disease features. Three individuals from this group died during detectable HHV-6 viremia. Another two recipients showed a single positive PCR result at a later time. Infection with HHV-6 was thus confirmed in 10 (38.5%) of the 26 graft recipients. There is a high frequency of detectable HHV-6 viral load in stem cell transplant recipients in Poland. Further investigation to monitor HHV-6 reactivation in graft recipients will be important to improve outcome for these patients.