Impact of stem cell graft on early viral infections and immune reconstitution after allogeneic transplantation in adults.

Background: Viral infections are well-known complications after allogeneic stem cell transplant (allo-SCT).

Objectives: We compared prospectively incidences of DNAemia and active infections (AI) for five opportunistic viruses (Human Herpesvirus 6 (HHV-6), Epstein-Barr virus (EBV), BK polyomavirus (BKPyV), Cytomegalovirus (CMV) and Adenovirus (ADV)) and kinetics of immune reconstitution (IR) in adults receiving either double umbilical cord blood (dUCB group) or unrelated peripheral blood stem cell (uPBSC group) allo-SCT after a reduced-intensity conditioning (RIC) regimen.

Study Design: Whole blood samples were collected at transplant, every 15days during the first 3 months and at 4, 5 and 6 months post-transplant.

Human herpesvirus 6 reactivation before engraftment is strongly predictive of graft failure after double umbilical cord blood allogeneic stem cell transplantation in adults.

Our main objective was to determine new factors associated with engraftment and single-unit predominance after double umbilical cord blood (UCB) allogeneic stem-cell transplantation. Engraftment occurred in 78% of cases in this retrospective study including 77 adult patients. Three-year overall survival, disease-free survival, relapse incidence, and nonrelapse mortality were 55 ± 6%, 44 ± 6%, 33 ± 5%, and 23 ± 4%, respectively.

Long-lasting HHV-6 reactivation in long-term adult survivors after double umbilical cord blood allogeneic stem cell transplantation.

Higher incidence of human herpesvirus 6 (HHV-6) infection has been documented after umbilical cord blood allo-transplant in adults. Here we demonstrate that HHV-6 reactivation persists for a very long time in half of the patients after this type of graft. Long-term immune reconstitution does not explain this event, which remains to be explained.

Quantification of two viral transcripts by real time PCR to investigate human herpesvirus type 6 active infection.

Background: Human herpesvirus 6 (HHV-6) causes exanthema subitum and is associated with symptomatic reactivations in immunocompromised patients, particularly after hematopoietic stem cell transplantation. The detection of viral mRNA can help to make the difference between latent, chromosomally integrated and true replicating virus. It can also be a useful tool to investigate viral multiplication in different cell types.

Characterization of various blood and graft sources: a prospective series.

Background: Studies comparing cell components of blood and graft sources are very scarce. We present here a thorough study examining the cellular content of various sources of blood and cell therapy products.

Study Design And Methods: We have prospectively compared by fluorescence-activated cell sorting analyses the cellular composition of three blood sources on the one hand--peripheral blood (PB; n = 10) versus granulocyte-colony-stimulating factor (G-CSF)-mobilized PB (GCSF-PB, n = 10) versus cord blood (CB, n = 10)--and of three graft sources on the other hand--unmanipulated bone marrow (uBM, n = 5) versus leukapheresis product (LP, n = 10) versus thawed CB graft (n = 7).

HHV-6 cell receptor CD46 expression on various cell subsets of six blood and graft sources: a prospective series.

Background: Cord Blood (CB) are increasingly used as an alternative stem cells source in adults for allogeneic Stem Cell Transplantation (allo-SCT). The risk of human herpesvirus (HHV-6) reactivation is significantly higher after CB transplant vs unrelated peripheral blood stem cells (PBSC) allo-SCT. Higher HHV-6 cell receptor CD46 expression on progenitor cells in CB may explain this difference.

Occurrence and molecular characterization of Klebsiella pneumoniae ST37 clinical isolates producing plasmid-mediated AmpC recovered over a 3-year period.

We investigated the clinical and microbiological epidemiology of AmpC plasmidic cephalosporinases (pAmpC) in Klebsiella pneumoniae strains resistant to ceftazidime, during a 3-year period (2007-2009). Among 1505 K. pneumoniae, 7 were pAmpC producers.

In vitro antimicrobial activity of "last-resort" antibiotics against unusual nonfermenting Gram-negative bacilli clinical isolates.

In this prospective multicentric study, we assessed the in vitro antimicrobial activity of carbapenems (imipenem, meropenem, and doripenem), tigecycline, and colistin against 166 unusual nonfermenting Gram-negative bacilli (NF-GNB) clinical isolates collected from nine French hospitals during a 6-month period (from December 1, 2008, to May 31, 2009). All NF-GNB isolates were included, except those phenotypically identified as Pseudomonas aeruginosa or Acinetobacter baumannii. Minimal inhibitory concentrations (MICs) of antimicrobial agents were determined by using the E-test technique.

Stenotrophomonas maltophilia--the most worrisome threat among unusual non-fermentative gram-negative bacilli from hospitalized patients: a prospective multicenter study.

Objectives: Isolation rates of unusual non-fermentative Gram-negative bacilli (i.e. other than Pseudomonas aeruginosa and Acinetobacter baumannii) are increasing but studies are limited to few observations.