Molecular Characterization of Strains of Respiratory Syncytial Virus Identified in a Hematopoietic Stem Cell Transplant Outpatient Unit Over 2 Years: Community or Nosocomial Infection?

Respiratory syncytial virus (RSV) is recognized as the leading cause of nosocomial respiratory infection among hematopoietic stem cell transplant (HSCT) recipients, causing considerable morbidity and mortality. RSV is easily transmitted by contact with contaminated surfaces, and in HSCT units, more than 50% of RSV infections have been characterized as of nosocomial origin. From April 2001 to October 2002, RSV was identified by direct immunofluorescent assay in 42 symptomatic HSCT recipients. Seven RSV strains from 2001 and 12 RSV strains from 2002 were sequenced. RNA extraction, cDNA synthesis, and seminested polymerase chain reaction (PCR) with primers complementary to RSV genes G and F were pet-formed. PCR products were analyzed by nucleotide sequencing of the C-terminal region of gene G for typing (in group A or B). Of the 7 strains analyzed in 2001, only 2 belonged to group B; the other 5 belonged to group A. Of these 7 strains, 3 were identical and were from recipients receiving outpatient care. In 2002, of the 12 strains analyzed, 3 belonged to group A and the other 9 belonged to group B. Of these 9 strains, 7 were genetically identical and were also from recipients receiving outpatient care. Therefore, multiple strains of RSV cocirculated in the hematopoietic stem cell transplant units (ward and outpatient units) between 2001 and 2002. Nosocomial transmission was more likely to occur at the HSCT outpatient unit than in the HSCT ward. Infection control practices should also be implemented in the outpatient setting.

The monitoring of hematopoietic stem cell transplant donors and recipients from endemic areas for malaria

Malaria is an unusual complication after hematopoietic stem cell transplantation in non-endemic countries. However, transplant candidates, recipients and donors living in endemic regions frequently report previous episodes of malaria. This fact could represent an important risk for immunosuppressed recipients that could develop severe malaria cases. We report a case of hematopoietic stem cell transplant (HSCT) in which the donor had a history of previous malaria, and close monitoring was performed before and after procedure by parasitological and molecular tests. The donor presented Plasmodium vivax in thick blood smears one month after transplant and was treated according to Brazilian Health Ministry guidelines. The polymerase chain reaction (PCR) was able to detect malaria infection in the donor one week earlier than thick blood film. Even without positive results, the recipient was pre-emptively treated with chloroquine in order to prevent the disease. We highlight the importance of monitoring recipients and donors in transplant procedures with the aim of reducing the risk of malaria transmission.

Management of post-transplant Epstein-Barr virus-related lymphoproliferative disease in solid organ and hematopoietic stem cell recipients

Epstein-Barr virus (EBV)-related post-transplant lymphoproliferative disease (PTLD) is one of the most serious complications associated with solid organ and hematopoietic stem cell transplantation. PTLD is most frequently seen with primary EBV infection post-transplant, a common scenario for pediatric solid organ recipients. Risk factors for infection or reactivation of EBV following solid organ transplant are stronger immunosuppressive therapy regimens, and being seronegative for receptor. For hematopoietic stem cell transplantation, the risk factors relate to the type of transplant, human leukocyte antigen disparity, the use of stronger immunosuppressants, T-cell depletion, and severe graft-versus-host disease. Mortality is high, and most frequent in patients who develop PTLD in the first six months post-transplant. The primary goal of this article is to provide an overview of the clinical manifestations, diagnosis, accepted therapies, and management of EBV infection in transplant recipients, and to suggest that the adoption of monitoring protocols could contribute to a reduction in related complications.

Quantitative real-time polymerase chain reaction for detection of adenovirus after T cell-replete hematopoietic cell transplantation: viral load as a marker for invasive disease.

BACKGROUND: The value of adenovirus plasma DNA detection as an indicator for adenovirus disease is unknown in the context of T cell-replete hematopoietic cell transplantation, of which adenovirus disease is an uncommon but serious complication. METHODS: Three groups of 62 T cell-replete hematopoietic cell transplant recipients were selected and tested for adenovirus in plasma by polymerase chain reaction. RESULTS: Adenovirus was detected in 21 (87.5%) of 24 patients with proven adenovirus disease (group 1), in 4 (21%) of 19 patients who shed adenovirus (group 2), and in 1 (10.5%) of 19 uninfected control patients. The maximum viral load was significantly higher in group 1 (median maximum viral load, 6.3x10(6) copies/mL; range, 0 to 1.0x10(9) copies/mL) than in group 2 (median maximum viral load, 0 copies/mL; range, 0 to 1.7x10(8) copies/mL; P<.001) and in group 3 (median maximum viral load, 0 copies/mL; range 0-40 copies/mL; P<.001). All patients in group 2 who developed adenoviremia had symptoms compatible with adenovirus disease (i.e., possible disease). A minimal plasma viral load of 10(3) copies/mL was detected in all patients with proven or possible disease. Adenoviremia was detectable at a median of 19.5 days (range, 8-48 days) and 24 days (range, 9-41 days) before death for patients with proven and possible adenovirus disease, respectively. CONCLUSION: Sustained or high-level adenoviremia appears to be a specific and sensitive indicator of adenovirus disease after T cell-replete hematopoietic cell transplantation. In the context of low prevalence of adenovirus disease, the use of polymerase chain reaction of plasma specimens to detect virus might be a valuable tool to identify and treat patients at risk for viral invasive disease.

Acute myeloid leukaemia of donor cell origin developing 17 years after allogenic hematopoietic cell transplantation for acute promyelocytic leukaemia.

Donor cell leukaemia (DCL) is a rare complication of allogenic hematopoietic cell transplantation (HCT). We report the case of a female patient with acute promyelocytic leukaemia (APL), FAB type M3, who developed acute myeloid leukaemia (AML) type M5 of donor origin 17 years after allogenic bone marrow transplantation (BMT) from her HLA-matched sister. Morphology and immunophenotyping showed differences with the initial leukaemia, and short tandem repeat (STR) analysis confirmed donor-type haematopoiesis. Interphase fluorescence in situ hybridisation (FISH) showed an 11q23 deletion. Given that the latency period between transplant and development of leukaemia was the longest reported to date, we discuss the mechanisms underlying delayed leukaemia onset.

Classification and clinical behavior of blastic plasmacytoid dendritic cell neoplasms according to their maturation-associated immunophenotypic profile.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare subtype of leukemia/lymphoma, whose diagnosis can be difficult to achieve due to its clinical and biological heterogeneity, as well as its overlapping features with other hematologic malignancies. In this study we investigated whether the association between the maturational stage of tumor cells and the clinico-biological and prognostic features of the disease, based on the analysis of 46 BPDCN cases classified into three maturation-associated subgroups on immunophenotypic grounds. Our results show that blasts from cases with an immature plasmacytoid dendritic cell (pDC) phenotype exhibit an uncommon CD56- phenotype, coexisting with CD34+ non-pDC tumor cells, typically in the absence of extramedullary (e.g. skin) disease at presentation. Conversely, patients with a more mature blast cell phenotype more frequently displayed skin/extramedullary involvement and spread into secondary lymphoid tissues. Despite the dismal outcome, acute lymphoblastic leukemia-type therapy (with central nervous system prophylaxis) and/or allogeneic stem cell transplantation appeared to be the only effective therapies. Overall, our findings indicate that the maturational profile of pDC blasts in BPDCN is highly heterogeneous and translates into a wide clinical spectrum -from acute leukemia to mature lymphoma-like behavior-, which may also lead to variable diagnosis and treatment.

BK virus infection in hematopoietic stem cell transplant recipients: frequency, risk factors, and association with postengraftment hemorrhagic cystitis.

Blood samples from 132 consecutive hematopoietic stem cell transplant recipients were obtained and tested weekly for BK virus DNA by use of quantitative real-time PCR. Forty-four patients (33%) developed BK viremia at a median of 41 days (range, 9-91 days) after transplantation. Patients with hemorrhagic cystitis that occurred after platelet engraftment had higher levels of viremia than did patients without hemorrhagic cystitis (median, 9.7x10(3) vs. 0 copies/mL; P=.008) and patients with hemorrhagic cystitis that occurred before platelet engraftment (median, 9.7x10(3) vs. 0 copies/mL; P=.0006). BK viremia also was strongly associated with postengraftment hemorrhagic cystitis in a time-dependent analysis (P=.004).

Chronic norovirus gastroenteritis in a double hematopoietic stem cell and lung transplant recipient.

N. Boillat Blanco, R. Kuonen, C. Bellini, O. Manuel, C. Estrade, J. Mazza-Stalder, J.D. Aubert, R. Sahli, P. Meylan. Chronic norovirus gastroenteritis in a double hematopoietic stem cell and lung transplant recipient. Transpl Infect Dis 2011: 13: 213-215. All rights reserved.

Hematopoietic stem cell function and survival depend on c-Myc and N-Myc activity.

Myc activity is emerging as a key element in acquisition and maintenance of stem cell properties. We have previously shown that c-Myc deficiency results in accumulation of defective hematopoietic stem cells (HSCs) due to niche-dependent differentiation defects. Here we report that immature HSCs coexpress c-myc and N-myc mRNA at similar levels. Although conditional deletion of N-myc in the bone marrow does not affect hematopoiesis, combined deficiency of c-Myc and N-Myc (dKO) results in pancytopenia and rapid lethality. Interestingly, proliferation of HSCs depends on both myc genes during homeostasis, but is c-Myc/N-Myc independent during bone marrow repair after injury. Strikingly, while most dKO hematopoietic cells undergo apoptosis, only self-renewing HSCs accumulate the cytotoxic molecule Granzyme B, normally employed by the innate immune system, thereby revealing an unexpected mechanism of stem cell apoptosis. Collectively, Myc activity (c-Myc and N-Myc) controls crucial aspects of HSC function including proliferation, differentiation, and survival.

High dose chemotherapy with autologous hematopoietic stem cell support for solid tumors other than breast cancer in adults.

Since the early 1980s high dose chemotherapy with autologous hematopoietic stem cell support was adopted by many oncologists as a potentially curative option for solid tumors, supported by a strong rationale from laboratory studies and apparently convincing results of early phase II studies. As a result, the number and size of randomized trials comparing this approach with conventional chemotherapy initiated (and often abandoned before completion) to prove or disprove its value was largely insufficient. In fact, with the possible exception of breast carcinoma, the benefit of a greater escalation of dose of chemotherapy with stem cell support in solid tumors is still unsettled and many oncologists believe that this approach should cease. In this article, we critically review and comment on the data from studies of high dose chemotherapy so far reported in adult patients with small cell lung cancer, ovarian cancer, germ cell tumors and sarcomas.

European guidelines for antifungal management in leukemia and hematopoietic stem cell transplant recipients: summary of the ECIL 3--2009 update.

In 2005, several groups, including the European Group for Blood and Marrow Transplantation, the European Organization for Treatment and Research of Cancer, the European Leukemia Net and the Immunocompromised Host Society created the European Conference on Infections in Leukemia (ECIL). The main goal of ECIL is to elaborate guidelines, or recommendations, for the management of infections in leukemia and stem cell transplant patients. The first sets of ECIL slides about the management of invasive fungal disease were made available on the web in 2006 and the papers were published in 2007. The third meeting of the group (ECIL 3) was held in September 2009 and the group updated its previous recommendations. The goal of this paper is to summarize the new proposals from ECIL 3, based on the results of studies published after the ECIL 2 meeting: (1) the prophylactic recommendations for hematopoietic stem cell transplant recipients were formulated differently, by splitting the neutropenic and the GVHD phases and taking into account recent data on voriconazole; (2) micafungin was introduced as an alternative drug for empirical antifungal therapy; (3) although several studies were published on preemptive antifungal approaches in neutropenic patients, the group decided not to propose any recommendation, as the only randomized study comparing an empirical versus a preemptive approach showed a significant excess of fungal disease in the preemptive group.

Pegfilgrastim after high-dose chemotherapy and autologous peripheral blood stem cell transplant: phase II study.

Pegfilgrastim is equivalent to daily filgrastim after standard dose chemotherapy in decreasing the duration of neutropenia. Daily filgrastim started within 1-4 days after autologous stem cell transplant (ASCT) leads to significant decrease in time to neutrophil engraftment. We undertook a study of pegfilgrastim after high-dose chemotherapy (HDC) and ASCT. In all, 38 patients with multiple myeloma or lymphoma, eligible to undergo HDC and ASCT, were enrolled. Patients received a single dose of 6 mg pegfilgrastim subcutaneously 24 h after ASCT. There were no adverse events secondary to pegfilgrastim. All patients engrafted neutrophils and platelets with a median of 10 and 18 days, respectively. The incidence of febrile neutropenia was 49% (18/37). Neutrophil engraftment results were compared to a historical cohort of patients who received no growth factors or prophylactic filgrastim after ASCT. Time to neutrophil engraftment using pegfilgrastim was comparable to daily filgrastim and was shorter than in a historical group receiving no filgrastim (10 vs 13.7 days, P<0.001). Pegfilgrastim given as a single fixed dose of 6 mg appears to be safe after HDC and ASCT. It accelerates neutrophil engraftment comparable to daily filgrastim after ASCT. Pegfilgrastim may be convenient to use in outpatient transplant units.

Emerging viral infections after hematopoietic cell transplantation.

This overview summarizes recent data on emerging viruses after hematopoietic cell transplantation (HCT), including adenovirus, BK virus, human metapneumovirus (hMPV), and human herpesvirus (HHV) 6. The increased recognition of these infections is due to improved molecular detection methods, increased surveillance and more profound immunosuppression in the host. Adenovirus can cause serious disease especially in T-cell depleted transplant recipients. Adenovirus viremia is an important risk factor for disease in this setting. BK virus has been associated with hemorrhagic cystitis in HCT recipients. BK viremia is significantly associated with hemorrhagic cystitis. hMPV shows a seasonal distribution and can cause fatal pneumonia in HCT recipients. hMPV may be the etiology of some cases previously categorized as idiopathic pneumonia syndrome. HHV-6 commonly leads to viremia in HCT recipients. HHV-6 has been strongly associated with encephalitis and delayed platelet engraftment. Prospective studies are needed to further examine epidemiology, disease associations, and management strategies for these viruses.

Limited sampling strategies for estimation of cyclosporine exposure in pediatric hematopoietic stem cell transplant recipients : methodological improvement and introduction of sampling time deviation analysis.

Le suivi thérapeutique est recommandé pour l’ajustement de la dose des agents immunosuppresseurs. La pertinence de l’utilisation de la surface sous la courbe (SSC) comme biomarqueur dans l’exercice du suivi thérapeutique de la cyclosporine (CsA) dans la transplantation des cellules souches hématopoïétiques est soutenue par un nombre croissant d’études. Cependant, pour des raisons intrinsèques à la méthode de calcul de la SSC, son utilisation en milieu clinique n’est pas pratique. Les stratégies d’échantillonnage limitées, basées sur des approches de régression (R-LSS) ou des approches Bayésiennes (B-LSS), représentent des alternatives pratiques pour une estimation satisfaisante de la SSC. Cependant, pour une application efficace de ces méthodologies, leur conception doit accommoder la réalité clinique, notamment en requérant un nombre minimal de concentrations échelonnées sur une courte durée d’échantillonnage. De plus, une attention particulière devrait être accordée à assurer leur développement et validation adéquates. Il est aussi important de mentionner que l’irrégularité dans le temps de la collecte des échantillons sanguins peut avoir un impact non-négligeable sur la performance prédictive des R-LSS. Or, à ce jour, cet impact n’a fait l’objet d’aucune étude. Cette thèse de doctorat se penche sur ces problématiques afin de permettre une estimation précise et pratique de la SSC. Ces études ont été effectuées dans le cadre de l’utilisation de la CsA chez des patients pédiatriques ayant subi une greffe de cellules souches hématopoïétiques. D’abord, des approches de régression multiple ainsi que d’analyse pharmacocinétique de population (Pop-PK) ont été utilisées de façon constructive afin de développer et de valider adéquatement des LSS. Ensuite, plusieurs modèles Pop-PK ont été évalués, tout en gardant à l’esprit leur utilisation prévue dans le contexte de l’estimation de la SSC. Aussi, la performance des B-LSS ciblant différentes versions de SSC a également été étudiée. Enfin, l’impact des écarts entre les temps d’échantillonnage sanguins réels et les temps nominaux planifiés, sur la performance de prédiction des R-LSS a été quantifié en utilisant une approche de simulation qui considère des scénarios diversifiés et réalistes représentant des erreurs potentielles dans la cédule des échantillons sanguins. Ainsi, cette étude a d’abord conduit au développement de R-LSS et B-LSS ayant une performance clinique satisfaisante, et qui sont pratiques puisqu’elles impliquent 4 points d’échantillonnage ou moins obtenus dans les 4 heures post-dose. Une fois l’analyse Pop-PK effectuée, un modèle structural à deux compartiments avec un temps de délai a été retenu. Cependant, le modèle final - notamment avec covariables - n’a pas amélioré la performance des B-LSS comparativement aux modèles structuraux (sans covariables). En outre, nous avons démontré que les B-LSS exhibent une meilleure performance pour la SSC dérivée des concentrations simulées qui excluent les erreurs résiduelles, que nous avons nommée « underlying AUC », comparée à la SSC observée qui est directement calculée à partir des concentrations mesurées. Enfin, nos résultats ont prouvé que l’irrégularité des temps de la collecte des échantillons sanguins a un impact important sur la performance prédictive des R-LSS; cet impact est en fonction du nombre des échantillons requis, mais encore davantage en fonction de la durée du processus d’échantillonnage impliqué. Nous avons aussi mis en évidence que les erreurs d’échantillonnage commises aux moments où la concentration change rapidement sont celles qui affectent le plus le pouvoir prédictif des R-LSS. Plus intéressant, nous avons mis en exergue que même si différentes R-LSS peuvent avoir des performances similaires lorsque basées sur des temps nominaux, leurs tolérances aux erreurs des temps d’échantillonnage peuvent largement différer. En fait, une considération adéquate de l'impact de ces erreurs peut conduire à une sélection et une utilisation plus fiables des R-LSS. Par une investigation approfondie de différents aspects sous-jacents aux stratégies d’échantillonnages limités, cette thèse a pu fournir des améliorations méthodologiques notables, et proposer de nouvelles voies pour assurer leur utilisation de façon fiable et informée, tout en favorisant leur adéquation à la pratique clinique.

Germ Cell Transplantation in Felids: A Potential Approach to Preserving Endangered Species

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)