Marina Illiaquer

Characterization of various blood and graft sources: a prospective series

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.

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. Molecular characterization revealed the spread of a ST37 strain producing DHA-1 within intensive care units and the diffusion of the same plasmid among unrelated strains.

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.

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. In multivariate analysis, Human herpesvirus 6 reactivation during aplasia (hazard ratio [HR] = 2.63; 95% confidence interval [CI]: 1.64-4.17; p < 0.001), younger recipient age (<53 years) (HR = 1.97; 95% CI: 1.16-3.35; p = 0.012), and lower human leukocyte antigen matching between the two units (3 of 6 or 4 of 6) (HR = 2.09; 95% confidence interval: 1.22-3.59; p = 0.013) were the three factors independently associated with graft failure. Also, factors independently predicting the losing UCB unit were younger age of the UCB unit (odds ratio [OR] = 1.01; 95% CI: 1-1.02; p = 0.035), lower CD34(+) cell dose contained in the UCB unit (≤ 0.8 × 10(5)/kg) (OR = 2.55; 95% CI: 1.05-6.16; p = 0.04), and presence of an ABO incompatibility between the UCB unit and the recipient (OR = 2.53; 95% CI: 1.15-5.53; p = 0.02). Thus, Human herpesvirus 6 reactivation during aplasia, lower unit-unit human leukocyte antigen matching, and younger UCB unit age, as new unfavorable predictive factors, may represent new parameters to take into account after double UCB allogeneic stem-cell transplantation in adults. These results need to be confirmed prospectively, as they may influence unit selections and patient outcomes.

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. RESULTS Sixty-five patients were enrolled (uPBSC n=34; dUCB n=31). Incidences of HHV-6 and BKPyV DNAemia were significantly higher for dUCB (97% vs 23.5% and 58% vs 32%, respectively) while EBV DNAemia was more frequently detected in uPBSC (71% vs 26%). The incidence of CMV DNAemia was similar between both groups. ADV AI developed only in dUCB. HHV-6 AI were also higher in dUCB (84% vs 21%). In multivariate analysis, dUCB graft was the only independent factor associated with HHV-6 DNAemia (OR: 19.0; 95%CI: 5.2-69.1; p<0.0001) while EBV DNAemia were significantly associated with uPBSC (OR: 29.9; 95%CI: 5.68-158; p <0.0001). dUCB graft was also the only factor associated with HHV-6 AI. Finally, higher counts and faster recoveries of B lymphocytes (p<0.0001) and monocytes (p=0.0007) were observed in the dUCB group. CONCLUSION We demonstrate a strong correlation between sources of graft and patterns of viral DNAemia and AI and IR after RIC allo-SCT.

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. OBJECTIVES To develop molecular tools for the detection and quantification HHV-6 transcripts that can be used in a clinical setting. STUDY-DESIGN Two one-step reverse-transcriptase quantitative real-time PCR (RT-qPCR) were developed for the quantification of the immediate early U90 and the late U100 mRNAs. Viral mRNA loads were compared to viral DNA loads during infection in vitro and in blood samples collected from stem cell transplanted patients. RESULTS Analytical performances of the two quantitative real-time PCR were good. In vitro, kinetics of both transcripts was well correlated with DNA levels. Sixty blood samples from patients with active HHV-6 infection were analyzed. Overall agreement of qualitative results for HHV-6 DNA, U90 RNA and U100 RNA was good. HHV-6 DNA loads were significantly higher than mRNA loads. In clinical samples, the amounts of U100 and U90 mRNAs were low and their detection was mainly associated to viral DNA loads upper than 1000 copies/ml of blood. CONCLUSION The new assays are sensitive and reliable methods for the monitoring of viral transcription in vitro and in vivo. As their detection is associated to high DNA loads in vivo, they can be helpful tools for the diagnosis of active infection.

Longer delay of hematological recovery and increased transfusion needs after haploidentical compared to non-haploidentical stem cell transplantation.

Longer delay of hematological recovery and increased transfusion needs after haploidentical compared to non-haploidentical stem cell transplantation

Lymphocyte expansion after unrelated cord blood allogeneic stem cell transplantation in adults

Limited information is available regarding the incidence and features of lymphocyte expansions after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Large granular lymphocytes (LGL) expansions have been reported after bone marrow or peripheral blood, but not after unrelated cord blood (UCB) allo-HSCT, associated with indolent clinical courses and favorable outcomes. Here, we considered 85 recipients of UCB allo-HSCT to more broadly define the impact of lymphocytosis, not limited to LGL. Sustained lymphocytosis was observed in 21 (25%) patients at a median onset of 12.6 months and with a median duration of 12 months. Immunophenotypic analysis showed predominantly CD8+ T and/or polyclonal B-cell expansions. Three patients only had monoclonal T-cell expansion. CMV reactivation was significantly more frequent in the group of patients with lymphocytosis (76% vs 28%, P=0.0001), but was not associated with survival. Conversely, 2-year disease-free survival and overall survival were significantly higher for lymphocytosis patients (85% vs 55%, P=0.01 and 85% vs 63%, P=0.03, respectively). In conclusion, expansion of T or B lymphocytes after UCB allo-HSCT in adults is not a rare event. Although occurring relatively late after transplant, this feature is predictive of a better outcome for the patients.