Viremic co-infections in children with allogeneic haematopoietic stem cell transplantation are predominated by human polyomaviruses.

Background: Viral infections remain the cause of key complications following haematopoietic stem cell transplantation (HSCT). The impact of multiple, concurrent viral reactivations/infections remains to be delineated.

Methods: The clinical correlates of single or multiple viremic infections following HSCT and especially the occurrence of respiratory viruses in the bloodstream were investigated.

Polyomaviruses BK, JC, KI, WU, MC, and TS in children with allogeneic hematopoietic stem cell transplantation.

Timely and reliable detection of viruses is of key importance in early diagnosis of infection(s) following allogeneic HSCT. Among the immunocompetent, infections with BKPyV and JCPyV are mostly subclinical, while post-HSCT, the former may cause HC and the latter PML. The epidemiology and clinical impact of the newly identified KIPyV, WUPyV, MCPyV, and TSPyV in this context remain to be defined.

Surveillance cultures in pediatric allogeneic hematopoietic stem cell transplantation.

The value of surveillance cultures in predicting systemic infections and in guiding antimicrobial treatment is controversial. We investigated 57 pediatric allo-SCTs between 2007 and 2009. ALL (34), AML (5), and severe aplastic anemia (4) were the largest patient groups.

[Immune deficiency and infections in children having cancer].

Childhood cancer and its treatment weaken the immune defenses and predispose the patient to infections. The recovery of immune defences depends on the provided cancer therapy and associated complications such as the graft-versus-host reaction. Recovery takes place gradually and the spectrum of infections suffered by the patient reflects the different stages of restoration of the immune defenses.

Merkel cell polyomavirus DNA in tumor-free tonsillar tissues and upper respiratory tract samples: implications for respiratory transmission and latency.

Background: Merkel cell polyomavirus (MCPyV) was discovered recently. It is considered a potential causative agent of Merkel cell carcinoma, a life-threatening skin cancer.

Objectives: To study the prevalence of MCPyV in a large number of clinical samples of various types.

Respiratory viral infections in children with leukemia.

Background: Respiratory viruses occur frequently in the community and are a common cause of fever in children. Data on respiratory viral infections in children with cancer are limited.

Methods: A long-term, prospective, multicenter study was carried out in Finland searching for respiratory viruses in febrile children with leukemia.

Mixed bacterial-viral infections in septic children with leukemia.

Background: Febrile infections in children with leukemia are common. The occurrence of possible mixed bacterial-viral infections is unknown.

Methods: We searched for viruses in leukemic children with blood culture-positive bacterial infections.