Microbiota-driven interleukin-17-producing cells and eosinophils synergize to accelerate multiple myeloma progression.

The gut microbiota has been causally linked to cancer, yet how intestinal microbes influence progression of extramucosal tumors is poorly understood. Here we provide evidence implying that Prevotella heparinolytica promotes the differentiation of Th17 cells colonizing the gut and migrating to the bone marrow (BM) of transgenic Vk*MYC mice, where they favor progression of multiple myeloma (MM). Lack of IL-17 in Vk*MYC mice, or disturbance of their microbiome delayed MM appearance. Similarly, in smoldering MM patients, higher levels of BM IL-17 predicted faster disease progression. IL-17 induced STAT3 phosphorylation in murine plasma cells, and activated eosinophils. Treatment of Vk*MYC mice with antibodies blocking IL-17, IL-17RA, and IL-5 reduced BM accumulation of Th17 cells and eosinophils and delayed disease progression. Thus, in Vk*MYC mice, commensal bacteria appear to unleash a paracrine signaling network between adaptive and innate immunity that accelerates progression to MM, and can be targeted by already available therapies.

Testicular microbiome in azoospermic men-first evidence of the impact of an altered microenvironment.

STUDY QUESTION: Given the relevant role of the extracellular microenvironment in regulating tissue homeostasis, is testicular bacterial microbiome (BM) associated with germ cell aplasia in idiopathic non-obstructive azoospermia (iNOA)? SUMMARY ANSWER: A steady increase of dysbiosis was observed among testis with normal spermatogenesis vs. iNOA with positive sperm retrieval and iNOA with complete germ cell aplasia. WHAT IS KNOWN ALREADY: Tissue-associated BM has been reported to be a biologically important extracellular microenvironment component for numerous body habitats, but not yet for the human testis. STUDY DESIGN, SIZE, DURATION: Cross-sectional study, investigating tissue-associated BM in the testis of (i) five men with iNOA and negative sperm retrieval at microdissection testicular sperm extraction (microTESE); (ii) five men with iNOA and positive sperm retrieval at microTESE; and (iii) five normozoospermic men upon orchiectomy. Every testicular specimen was histologically classified and analyzed in terms of bacterial community. PARTICIPANTS/MATERIALS, SETTING, METHODS: Massive ultra-deep pyrosequencing was applied to investigate testis microbiome. Metagenome was analyzed using Quantitative Insights Into Microbial Ecology (QIIME). Tissue-associated bacterial load was quantified by digital droplet PCR. MAIN RESULTS AND THE ROLE OF CHANCE: Normozoospermic men showed small amounts of bacteria in the testis, with Actinobacteria, Bacteroidetes, Firmicutes Proteobacteria as the dominating phyla; iNOA individuals had increased amounts of bacterial DNA (P = 0.02), associated with decreased taxa richness due to the lack of Bacteroidetes and Proteobacteria (P = 2 × 10-5). Specimens with negative sperm retrieval at microTESE depicted complete germ cell aplasia and a further decrease in terms of Firmicutes and Clostridia (P < 0.05), a complete lack of Peptoniphilus asaccharolyticus, but increased amount of Actinobacteria. LIMITATIONS, REASONS FOR CAUTION: The limited number of specimens analyzed in this preliminary study deserves external validation. The paraneoplastic microenvironment could have an impact on the residential bacterial flora. WIDER IMPLICATION OF THE FINDINGS: Human testicular microenvironment is not microbiologically sterile, containing low amounts of Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. A dysbiotic bacterial community was associated with iNOA and complete germ cell aplasia. Novel findings on testicular BM could support future translational therapies of male-factor infertility. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by URI-Urological Research Institute free funds. Authors declared no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

IL28B rs12979860 genotype as a predictor marker of progression to BKVirus Associated nephropathy, after kidney transplantation.

BK virus (BKV) associated nephropathy (BKVAN) is still an important cause of allograft dysfunction after kidney transplantation (KT). Recent data have shown that the new interferon (IFN)-λ family has been ascribed antiviral properties similar to IFNα, and that the response to IFNλ in kidney is restricted to epithelial cells, suggesting that the IFNλ system evolves as specific protection of the epithelia. We aimed to test the hypothesis of correlation between a single nucleotide polymorphism (C/T dimorphism rs12979860) in the genomic region of IL28B and BKVAN, in patients after KT. Fifty kidney-transplanted patients were included as follow: Group 1 (BKV+/BKVAN+): 11 patients with active BKV- replication and biopsy-proven BKVAN; Group 2 (BKV+/BKVAN-): 22 patients with active BKV- replication but without evidence of BKVAN; Group 3 (BKV-/BKVAN-): 17 patients without evidence of BKV- replication (control group). Here we show that the C/C genotype was statistically higher in group 2 than in group 1 and BKVAN was detected significantly more frequently in patients with C/T and T/T genotypes than in patients with C/C genotype. We therefore propose IL28B polymorphism (rs12979860), as a predictor-marker to differentiate between patients with self-limited, even if persistent, BKV- reactivation and patients with a high risk of progression towards BKVAN, and to modulate the clinical management of these patients accordingly.

High frequency of intestinal TH17 cells correlates with microbiota alterations and disease activity in multiple sclerosis.

T helper 17 (TH17) cells are key players in multiple sclerosis (MS), and studies in animal models demonstrated that effector TH17 cells that trigger brain autoimmunity originate in the intestine. We validate in humans the crucial role of the intestinal environment in promoting TH17 cell expansion in MS patients. We found that increased frequency of TH17 cells correlates with high disease activity and with specific alterations of the gut mucosa-associated microbiota in MS patients. By using 16S ribosomal RNA sequencing, we analyzed the microbiota isolated from small intestinal tissues and found that MS patients with high disease activity and increased intestinal TH17 cell frequency showed a higher Firmicutes/Bacteroidetes ratio, increased relative abundance of Streptococcus, and decreased Prevotella strains compared to healthy controls and MS patients with no disease activity. We demonstrated that the intestinal TH17 cell frequency is inversely related to the relative abundance of Prevotella strains in the human small intestine. Our data demonstrate that brain autoimmunity is associated with specific microbiota modifications and excessive TH17 cell expansion in the human intestine.

The Microbiome of the Prostate Tumor Microenvironment.

BACKGROUND: The advent of molecular-based methods of identification and characterization of complex microbial populations has led to a new era of microbial discovery. A detailed and comprehensive analysis of the microbial ecosystem of the pathologic and healthy prostate tissues has not been yet reported. OBJECTIVES: To characterize the microbiome possibly associated to the pathologic prostate microenvironment. DESIGN, SETTING, AND PARTICIPANTS: The microbiome profile of tumor, peri-tumor, and nontumor tissues was assessed on 16 radical prostatectomy-specimens. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Microbiome analysis was assessed by massive ultradeep pyrosequencing. Bacteria load was expressed as a percentage of the total number of bacteria. The statistical significance of differences among specimen-groups was tested with Friedman's test (Dunn posthoc test) and Wilcoxon rank-sum test. RESULTS AND LIMITATIONS: Three phyla, six classes, nine orders, 14 families, and 11 genera were above the set threshold value of 1%, respectively. Significant differences in specific microbial populations among tumor/peri-tumor and nontumor prostate specimens were observed at certain taxonomic levels. Among genera, Propionibacterium spp. were the most abundant. Staphylococcus spp. were more represented in the tumor/peri-tumor tissues (p<0.05). The restricted number of specimens represents a potential limitation. CONCLUSIONS: The prostate contains a plethora of bacteria, which set themselves within the gland with a distribution dependent on the nature of the tissue, thus suggesting a possible pathophysiological correlation between the composition of the local microbial niche and the presence of the tumor itself. Future studies will help to clarify the role of these specific bacteria and their potential to be exploited as new biomarkers. PATIENT SUMMARY: The pathological prostate is populated by specific microbial populations, whose distribution varies according to the nature of the tissue. This finding opens interesting perspectives for the identification of novel therapeutic approaches and biomarkers.

One drug for two targets: Biological evaluation of antiretroviral agents endowed with antiproliferative activity.

AIDS-related cancer diseases are malignancies with low incidence on healthy people that affect mostly subjects already immunocompromised. The connection between HIV/AIDS and these cancers has not been established yet, but a weakened immune system is certainly the main cause. We envisaged the possibility to screen a small library of compounds synthesized in our laboratory against opportunistic tumors mainly due to HIV infection like Burkitt's Lymphoma. From cellular assays and gene expression analysis we identified two promising compounds. These derivatives have the dual action required inhibiting HIV replication in human TZM-bl cells infected with HIV-1 NL4.3 and showing cytotoxic activity on human colon HT-29 and breast adenocarcinoma MCF-7 cells. In addition, preclinical in vitro adsorption, distribution, metabolism, and excretion studies highlighted a satisfactory pharmacokinetic profile.

Duodenal Mucosa of Patients With Type 1 Diabetes Shows Distinctive Inflammatory Profile and Microbiota.

Context: Increasing evidences suggest a correlation between gut and type 1 diabetes (T1D). Objective: The objective of this study is to evaluate the gut inflammatory profile and microbiota in patients with T1D compared with healthy control (CTRL) subjects and patients with celiac disease (CD) as gut inflammatory disease controls. Design/Setting/Participants: The inflammatory status and microbiome composition were evaluated in biopsies of the duodenal mucosa of patients with T1D (n = 19), in patients with CD (n = 19), and CTRL subjects (n = 16) recruited at San Raffaele Scientific Institute, in Milan, Italy, between 2009 and 2015. Main Outcome Measures: Inflammation was evaluated by gene expression study and immunohistochemistry. Microbiome composition was analyzed by 16S ribosomal RNA gene sequencing. Results: An increased expression of CCL13, CCL19, CCL22, CCR2, COX2, IL4R, CD68, PTX3, TNFα, and VEGFA was observed in patients with T1D compared with CTRL subjects and patients with CD. Immunohistochemical analysis confirmed T1D-specific inflammatory status compared with healthy and CD control tissues, mainly characterized by the increase of the monocyte/macrophage lineage infiltration. The T1D duodenal mucosal microbiome results were different from the other groups, with an increase in Firmicutes and Firmicutes/Bacteroidetes ratio and a reduction in Proteobacteria and Bacteroidetes. The expression of genes specific for T1D inflammation was associated with the abundance of specific bacteria in the duodenum. Conclusions: This study shows that duodenal mucosa in T1D presents disease-specific abnormalities in the inflammatory profile and microbiota. Understanding the mechanisms underlying these features is critical to disentangle the complex pathogenesis of T1D and to gain new perspectives for future therapies targeting the intestine.

Adaptive immunity against gut microbiota enhances apoE-mediated immune regulation and reduces atherosclerosis and western-diet-related inflammation.

Common features of immune-metabolic and inflammatory diseases such as metabolic syndrome, diabetes, obesity and cardiovascular diseases are an altered gut microbiota composition and a systemic pro-inflammatory state. We demonstrate that active immunization against the outer membrane protein of bacteria present in the gut enhances local and systemic immune control via apoE-mediated immune-modulation. Reduction of western-diet-associated inflammation was obtained for more than eighteen weeks after immunization. Immunized mice had reduced serum cytokine levels, reduced insulin and fasting glucose concentrations; and gene expression in both liver and visceral adipose tissue confirmed a reduced inflammatory steady-state after immunization. Moreover, both gut and atherosclerotic plaques of immunized mice showed reduced inflammatory cells and an increased M2 macrophage fraction. These results suggest that adaptive responses directed against microbes present in our microbiota have systemic beneficial consequences and demonstrate the key role of apoE in this mechanism that could be exploited to treat immune-metabolic diseases.

Inhibition of HIV-1 Reverse Transcriptase Dimerization by Small Molecules.

Because HIV-1 reverse transcriptase is an enzyme whose catalytic activity depends on its heterodimeric structure, this system could be a target for inhibitors that perturb the interactions between the protein subunits, p51 and p66. We previously demonstrated that the small molecule MAS0 reduced the association of the two RT subunits and simultaneously inhibited both the polymerase and ribonuclease H activities. In this study, some analogues of MAS0 were rationally selected by docking studies and evaluated in vitro for their ability to disrupt dimeric assembly. Two inhibitors were identified with improved activity compared to MAS0. This study lays the basis for the rational design of more potent inhibitors of RT dimerization.

The interplay of extracellular matrix and microbiome in urothelial bladder cancer.

Many pathological changes in solid tumours are caused by the accumulation of genetic mutations and epigenetic molecular alterations. In addition, tumour progression is profoundly influenced by the environment surrounding the transformed cells. The interplay between tumour cells and their microenvironment has been recognized as one of the key determinants of cancer development and is being extensively investigated. Data suggest that both the extracellular matrix and the microbiota represent microenvironments that contribute to the onset and progression of tumours. Through the introduction of omics technologies and pyrosequencing analyses, a detailed investigation of these two microenvironments is now possible. In urological research, assessment of their dysregulation has become increasingly important to provide diagnostic, prognostic and predictive biomarkers for urothelial bladder cancer. Understanding the roles of the extracellular matrix and microbiota, two key components of the urothelial mucosa, in the sequelae of pathogenic events that occur in the development and progression of urothelial carcinomas will be important to overcome the shortcomings in current bladder cancer treatment strategies.

In vitro phenotypes to elvitegravir and dolutegravir in primary macrophages and lymphocytes of clonal recombinant viral variants selected in patients failing raltegravir.

OBJECTIVES: The cross-resistance profiles of elvitegravir and dolutegravir on raltegravir-resistant variants is still controversial or not available in macrophages and lack extensive evaluations on wide panels of clonal variants. Thus, a complete evaluation in parallel with all currently available integrase inhibitors (INIs) was performed. METHODS: The integrase coding region was RT-PCR-amplified from patient-derived plasma samples and cloned into an HIV-1 molecular clone lacking the integrase region. Twenty recombinant viruses bearing mutations to all primary pathways of resistance to raltegravir were phenotypically evaluated with each integrase inhibitor in freshly purified CD4+ T cells or monocyte-derived macrophages. RESULTS: Y143R single mutants conferred a higher level of raltegravir resistance in macrophages [fold change (FC) 47.7-60.24] compared with CD4+ T cells (FC 9.55-11.56). All other combinations had similar effects on viral susceptibility to raltegravir in both cell types. Elvitegravir displayed a similar behaviour both in lymphocytes and macrophages with all the tested patterns. When compared with raltegravir, none to modest increases in resistance were observed for the Y143R/C pathways. Dolutegravir maintained its activity and cross-resistance profile in macrophages. Only Q148H/R variants had a reduced level of susceptibility (FC 5.48-18.64). No variations were observed for the Y143R/C (+/-T97A) or N155H variants. CONCLUSIONS: All INIs showed comparable antiretroviral activity in both cell types even if single mutations were associated with a different level of susceptibility in vitro to raltegravir and elvitegravir in macrophages. In particular, dolutegravir was capable of inhibiting with similar potency infection of raltegravir-resistant variants with Y143 or N155 pathways in both HIV-1 major cell reservoirs.

Infection and coinfection of human rhinovirus C in stem cell transplant recipients.

In 54 adult stem cell transplant recipients, the presence and persistence of human rhinoviruses (including the novel lineage C) were evaluated by molecular detection and phylogenetic analysis, independently from respiratory symptoms. In the same group of patients, the presence of other coinfecting respiratory pathogens, including the novel enterovirus 109, was also evaluated.

The role of infections and coinfections with newly identified and emerging respiratory viruses in children.

Acute respiratory infections are a major cause of morbidity in children both in developed and developing countries. A wide range of respiratory viruses, including respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza viruses (PIVs), adenovirus, rhinovirus (HRV), have repeatedly been detected in acute lower respiratory tract infections (LRTI) in children in the past decades. However, in the last ten years thanks to progress in molecular technologies, newly discovered viruses have been identified including human Metapneumovirus (hMPV), coronaviruses NL63 (HcoV-NL63) and HKU1 (HcoV-HKU1), human Bocavirus (HBoV), new enterovirus (HEV), parechovirus (HpeV) and rhinovirus (HRV) strains, polyomaviruses WU (WUPyV) and KI (KIPyV) and the pandemic H1N1v influenza A virus. These discoveries have heavily modified previous knowledge on respiratory infections mainly highlighting that pediatric population is exposed to a variety of viruses with similar seasonal patterns. In this context establishing a causal link between a newly identified virus and the disease as well as an association between mixed infections and an increase in disease severity can be challenging. This review will present an overview of newly recognized as well as the main emerging respiratory viruses and seek to focus on the their contribution to infection and co-infection in LRTIs in childhood.

Epidemiological, molecular and clinical features of enterovirus 109 infection in children and in adult stem cell transplant recipients.

BACKGROUND: A novel human enterovirus (HEV) type within the species HEV-C, named EV109, was discovered from cases of respiratory illness in Nicaragua in September 2010. The aim of this study, was to retrospectively examine the presence and the role of EV109 in respiratory samples from two patients populations; infants below the age of 2 years, hospitalized for acute respiratory diseases (ARDs) and adult hematopoietic stem cell transplantation recipients. RESULTS: A total of 1149 nasopharingeal aspirates were collected and tested for the presence of EV109 by reverse transcription-PCR (RT-PCR). In positive samples, the presence of the most common respiratory viruses was also assayed and clinical symptoms were evaluated. Samples from 2 of the 974 infants tested positive for EV109 RNA (0.2%) and belonged to patients with lower ARDs; co-infection with other viral pathogens under study was observed in both cases. In transplant recipients, one out of the 175 samples analyzed, from a patients with upper respiratory simptoms tested positive for HEV 109 in the absence of co-infecting viruses. Sequence analysis of amplified EV109 genomic regions, showed only a few nucleotide differences when compared with the Nicaraguan strains. CONCLUSIONS: Overall these results indicate that HEV109 variants have circulated and differentiated in different lineages worldwide. Although more cases and larger studies are needed, HEV109 infection may be associated to ARDs both in infants and in hematopoietic stem cell transplantation recipients. If these preliminary observations will be confirmed, improved molecular methods with a wider panel of potential pathogens will be useful for monitoring these categories of patients.

A phage display vector optimized for the generation of human antibody combinatorial libraries and the molecular cloning of monoclonal antibody fragments.

A novel phagemid vector, named pCM, was optimized for the cloning and display of antibody fragment (Fab) libraries on the surface of filamentous phage. This vector contains two long DNA "stuffer" fragments for easier differentiation of the correctly cut forms of the vector. Moreover, in pCM the fragment at the heavy-chain cloning site contains an acid phosphatase-encoding gene allowing an easy distinction of the Escherichia coli cells containing the unmodified form of the phagemid versus the heavy-chain fragment coding cDNA. In pCM transcription of heavy-chain Fd/gene III and light chain is driven by a single lacZ promoter. The light chain is directed to the periplasm by the ompA signal peptide, whereas the heavy-chain Fd/coat protein III is trafficked by the pelB signal peptide. The phagemid pCM was used to generate a human combinatorial phage display antibody library that allowed the selection of a monoclonal Fab fragment antibody directed against the nucleoprotein (NP) of Influenza A virus.

Raltegravir, maraviroc, etravirine: an effective protease inhibitor and nucleoside reverse transcriptase inhibitor-sparing regimen for salvage therapy in HIV-infected patients with triple-class experience.

We prospectively evaluated 28 triple-class experienced HIV-1-infected patients harbouring R5 virus, who received maraviroc, raltegravir and etravirine. By on-treatment analysis, 26 (92%) had less than 50 copies HIV-RNA/ml at week 48. The median (interquartile range) 48-week increase in CD4 cell counts was 267 (136-355) cells/microl. Three serious adverse events occurred: one recurrence of mycobacterial spondylodiscitis, one anal cancer, one Hodgkin lymphoma. Although long-term safety needs further study, this protease inhibitor and nucleoside analogue-sparing regimen showed sustained efficacy.

Molecular epidemiology of KI and WU polyomaviruses in infants with acute respiratory disease and in adult hematopoietic stem cell transplant recipients.

Polyomaviruses KI (KIPyV) and WU (WUPyV) were described recently in children with acute respiratory disease. The pathogenic potential of these human viruses has not been determined completely, but a correlation between immunosuppression and virus reactivation has been suggested. In the present study, the association between KI/WUPyV infection and immunosuppression was investigated using sequential nasopharyngeal aspirates from asymptomatic adult hematopoietic stem cell transplant recipients. In parallel, an investigation on the WU/KIPyV prevalence in children with acute respiratory disease was also carried out. Two of the 126 samples obtained from the 31 hematopoietic transplant recipients were positive for KIPyV (1 sample, 0.79%) and WUPyV (1 sample, 0.79%). Both samples were obtained 15 days after allogeneic transplantation and virus persistence was not observed in subsequent samples. In symptomatic children, 7 of the 486 nasopharyngeal aspirates were positive for WUPyV (1.4%) and 1 for KIPyV (0.2%). Single polyomavirus infection was detected in four patients, whereas the remaining patients were co-infected with respiratory syncityal virus (three patients) or adenovirus (one patient). The results suggest that WU/KIPyVs have a limited circulation in Italy and a low pathogenic potential in young children. Brief and asymptomatic infection can occur in hematopoietic transplant recipients.

Antigen-driven evolution of B lymphocytes in coronary atherosclerotic plaques.

Recent data indicated that adaptive immunity is involved in the process of atherogenesis. Oligoclonal recruitment of T lymphocytes has been described in coronary plaques of patients with acute coronary syndrome. However, the nature of immune response remains to be determined. In the present study, we examined the Ab response in six coronary plaques obtained by endoluminal directional atherectomy. The IgG1/kappa-coding gene repertoires of B lymphocytes present in circulating blood and in coronary plaques were cloned and analyzed. In all of the six plaques, we observed 1) a skewed usage of heavy and light IgG1/kappa Ab-coding genes, 2) an oligoclonal distribution of V(K), J(K), and V(H), D(H), and J(H) genes with overrepresentation of some rarely used IgG genes, and 3) the unequivocal signs of Ag-driven clonal expansion and evolution of B cells. The data document for the first time the presence of a local Ag-driven clonal evolution of B cells in human atherosclerotic plaques.

Persistent replication of severe acute respiratory syndrome coronavirus in human tubular kidney cells selects for adaptive mutations in the membrane protein.

Severe acute respiratory syndrome (SARS) is a systemic disease characterized by both lung pathology and widespread extrapulmonary virus dissemination causing multiple organ injuries. In this regard, renal dysfunction is an ominous sign in patients with SARS. Indeed, clusters of SARS coronavirus (SARS-CoV) particles have been detected in the cytoplasm of renal tubular epithelial cells in postmortem studies, explaining the presence of infectious virus in the urine of SARS patients. In order to investigate the potential SARS-CoV kidney tropism, we have evaluated the susceptibility of human renal cells of tubular and glomerular origin to in vitro SARS-CoV infection. Immortalized cultures of differentiated proximal tubular epithelial cells (PTEC), glomerular mesangial cells (MC), and glomerular epithelial cells (podocytes) were found to express the SARS-CoV receptor angiotensin-converting enzyme 2 on their surface. Productive infection, however, occurred only in PTEC but not in glomerular cells. A transient infection with poor virus production was observed in MC, whereas podocytes were not permissive to SARS-CoV infection. In contrast to the cytopathic infection of the Vero E6 cell line, SARS-CoV did not cause overt cytopathic effects in PTEC or MC. Of interest, PTEC, but not MC, maintained stable levels of SARS-CoV production in serial subcultures, suggesting a persistent state of infection. In this regard, a SARS-CoV variant with increased replication capacity in PTEC was selected after four serial subculture passages. This SARS-CoV variant acquired a single nonconservative amino acid change from glutamic acid (E) to alanine (A) at position 11 in the viral membrane (M) protein. The E11A point mutation was sufficient for enhanced SARS-CoV replication and persistence in PTEC when introduced in a SARS-CoV recombinant infectious clone. These findings indicate that human PTEC may represent a site of SARS-CoV productive and persistent replication favoring the emergence of viral variants with increased replication capacity, at least in these kidney cells.

Long-term study on symptomless human metapneumovirus infection in hematopoietic stem cell transplant recipients.

From October 2004 through October 2006 a study was performed to evaluate the prevalence of human Metapneumovirus (hMPV) infection in adult hematopoietic stem cell transplant (HSCT) recipients. Sequential nasopharyngeal aspirates (NPA) were collected independently from respiratory symptoms and evaluated for hMPV-RNA by polymerase chain reaction (PCR) and sequence analysis. Results indicate epidemiological and molecular differences between the 2004-2005 and 2005-2006 periods and that hMPV seems not to symptomatically affect HSCT patients or cause late respiratory sequelae. In addition, data collected suggest a hospital origin of hMPV infection in most HSCT patients during the 2004-2005 period.