Primary Polyomavirus Infection, Not Reactivation, as the Cause of Trichodysplasia Spinulosa in Immunocompromised Patients.

Classic human polyomaviruses (JC and BK viruses) become pathogenic when reactivating from latency. For the rare skin disease trichodysplasia spinulosa, we show that manifestations of the causative polyomavirus (TSPyV) occur during primary infection of the immunosuppressed host. High TSPyV loads in blood and cerebrospinal fluid, sometimes coinciding with cerebral lesions and neuroendocrine symptoms, marked the acute phase of trichodysplasia spinulosa, whereas initiation and maturation of TSPyV seroresponses occurred in the convalescent phase.

Human polyomavirus 9 infection in kidney transplant patients.

Several human polyomaviruses of unknown prevalence and pathogenicity have been identified, including human polyomavirus 9 (HPyV9). To determine rates of HPyV9 infection among immunosuppressed patients, we screened serum samples from 101 kidney transplant patients in the Netherlands for HPyV9 DNA and seroreactivity. A total of 21 patients had positive results for HPyV9 DNA; positivity rates peaked at 3 months after transplantation, but the highest viral loads were measured just after transplantation.

Persistence and antiviral resistance of varicella zoster virus in hematological patients.

Background: Varicella zoster virus (VZV) infections are a relevant cause of morbidity and mortality in hematological patients and especially in hematopoietic stem cell transplant (HSCT) recipients. The present study aimed to investigate the prevalence and clinical significance of viral persistence and antiviral resistance by systematically analyzing all episodes of VZV diagnosed in our laboratory in pediatric and adult hematological patients between 2007 and 2010.

Methods: Patient charts were reviewed to document patient and disease characteristics.

Rapid susceptibility testing for herpes simplex virus type 1 using real-time PCR.

Background: Susceptibility testing of herpes simplex virus type 1 (HSV-1) is traditionally performed by a plaque reduction assay (PRA), but this is labor intensive, time consuming and has a manual read out.

Objectives: The goal of this study was to develop an internally controlled real time PCR-based phenotypical susceptibility test for HSV-1 that is suitable for use in a clinical diagnostic setting.

Study Design: A DNA reduction assay (DRA) was developed and validated on a test panel of 26 well-characterized isolates of varying susceptibility to aciclovir or foscarnet, including low-level resistant isolates.

Failure of pre-emptive treatment of cytomegalovirus infections and antiviral resistance in stem cell transplant recipients.

Background: Treatment of cytomegalovirus (CMV) infections after stem cell transplantation (SCT) does not always lead to a rapid viral response. The causes of treatment failure may be either viral resistance or immunological failure to control viral replication. This study investigated the response to pre-emptive treatment in CMV infections in order to define risk factors for treatment failure, including the role of antiviral resistance.

Mass spectrometry-based comparative sequencing to detect ganciclovir resistance in the UL97 gene of human cytomegalovirus.

Background: Persistent infections with herpesviruses such as human cytomegalovirus (HCMV) frequently occur after solid organ or stem cell transplantation, and are due to either failure of the host to immunologically control the virus or emerging resistance of the virus to the antiviral drug(s) used. Antiviral therapy can be guided by viral drug susceptibility testing based on screening for known resistance-inducing mutations in the viral genome. Mass spectrometry-based comparative sequence analysis (MSCSA) might be advantageous for this purpose because of its suitability for semi-automation.

Preemptive versus sequential prophylactic-preemptive treatment regimens for cytomegalovirus in renal transplantation: comparison of treatment failure and antiviral resistance.

Background: Cytomegalovirus (CMV) infections after transplantation are commonly treated using a prophylactic or preemptive regimen with (val)ganciclovir. It remains unclear, which approach is most effective in preventing CMV disease in D+R- patients. The aim of this retrospective study was to compare the treatment response and antiviral resistance in CMV infections between two treatment regimens in D+R- renal transplant recipients.