Better detection of Torque teno virus in children with leukemia by metagenomic sequencing than by quantitative PCR.

Torque teno virus (TTV) is a group of chronically persisting viruses with a short circular DNA genome. TTV demonstrates a wide sequence diversity and a large majority of humans are chronically infected by one or more types of TTV. As TTV is ubiquitous, and viral replication correlates with immune status, TTV has been studied as a marker to assess global functional immune competence in transplant recipients. Most studies of the prevalence, amounts, and variation in TTV have been performed using PCR assays. We here present a comparison of the most frequently used quantitative PCR (qPCR) assay for TTV with shotgun metagenomic sequencing for detection and characterization of TTV in a cohort of pediatric cancer patients. The results show that TTV is more common than the qPCR assays indicate, and analysis of the TTV genome sequences indicate that a qPCR with primers and probe designed on a conserved region of the TTV genome may fail to detect some of the TTV strains found in this study.

Co-infections of human herpesviruses (CMV, HHV-6, HHV-7 and EBV) in non-transplant acute leukemia patients undergoing chemotherapy.

BACKGROUND: Human herpesviruses (HHVs) remain latent after primary infection and can be reactivated in response to immunosuppression and chemotherapy. Little is known about their incidence, potential relationships, risk factors and clinical impact in non-transplant leukemia patients. This study investigated prospectively incidence, risk factors, clinical impact and possible association of HHVs-(1-7) infections in patients with newly diagnosed acute leukemia. METHODS: Study design involved longitudinal sampling before chemotherapy and in different phases of chemotherapy: post-induction, post-remission, and post-salvage during 2016-2018. A total of 734 plasma samples from 95 patients were analyzed by a qualitative, multiplex PCR for HHVs detection and a quantitative real-time PCR was used for cytomegalovirus (CMV) quantification. HHVs-(1-6) IgG and IgM antibodies were tested using immunoassays. Risk factors were analyzed by binary logistic regression and relationships between viruses were analyzed using the Chi-square or Fisher's exact test as appropriate. RESULTS: The overall seroprevalences of HHV-(1-6) IgG were high (> 80%). At least one herpes viral agent was detected in 60 patients (63.3%). CMV was the most commonly detected virus in the different phases of chemotherapy (19.4%), followed by HHV-6 (9.7%), HHV-7 (5.2%) and EBV (2.7%). HSV-1/2 and VZV DNA were not detected. Twenty-seven patients (28.4%) had more than one virus detected in the follow-up, with 23 who were co-infected. CMV/HHV-6 was the most frequent co-infection (69.5%, 16/23). HHV-6 infection (p = 0.008) was identified as a risk factor for CMV infection while salvage treatment (p = 0.04) and CMV infection (p = 0.007) were found to be independent risk factors for HHV-6 infection. CMV co-infection was associated with severe lymphopenia with an absolute lymphocyte count (ALC) (< 500/µL) (p = 0.009), rash (p = 0.011), pneumonia (p = 0.016) and opportunistic infections [bacteremia, p < 0.001 and invasive fungal infection, (p = 0.024)] more frequently than CMV mono-viral infections. CONCLUSIONS: Our data suggest that co-infection with HHVs, especially CMV and HHV-6, may contribute to the development of serious clinical manifestations with profound lymphopenia, pneumonia rash and increased risk for bacterial and fungal co-infections. These findings may suggest the synergistic effect of HHVs associated infection.

Leukemic histiocytic sarcoma in a captive common squirrel monkey (Saimiri sciureus) with Saimiriine Gammaherpesvirus 2 (Rhadinovirus), Saimiri sciureus lymphocryptovirus 2 (Lymphocryptovirus) and Squirrel monkey retrovirus (ß-Retrovirus) coinfection.

Hematopoietic neoplasia other than lymphoma and leukemia is uncommon among non-human primates. Herein, we provide the first evidence of occurrence of leukemic histiocytic sarcoma in a captive common squirrel monkey with Saimiriine Gammaherpesvirus 2 (Rhadinovirus), Saimiri sciureus lymphocryptovirus 2 (Lymphocryptovirus), and Squirrel monkey retrovirus (ß-Retrovirus) coinfection.

Restriction factors in human retrovirus infections and the unprecedented case of CIITA as link of intrinsic and adaptive immunity against HTLV-1.

BACKGROUND: Immunity against pathogens evolved through complex mechanisms that only for sake of simplicity are defined as innate immunity and adaptive immunity. Indeed innate and adaptive immunity are strongly intertwined each other during evolution. The complexity is further increased by intrinsic mechanisms of immunity that rely on the action of intracellular molecules defined as restriction factors (RFs) that, particularly in virus infections, counteract the action of pathogen gene products acting at different steps of virus life cycle. MAIN BODY AND CONCLUSION: Here we provide an overview on the nature and the mode of action of restriction factors involved in retrovirus infection, particularly Human T Leukemia/Lymphoma Virus 1 (HTLV-1) infection. As it has been extensively studied by our group, special emphasis is given to the involvement of the MHC class II transactivator CIITA discovered in our laboratory as regulator of adaptive immunity and subsequently as restriction factor against HIV-1 and HTLV-1, a unique example of dual function linking adaptive and intrinsic immunity during evolution. We describe the multiple molecular mechanisms through which CIITA exerts its restriction on retroviruses. Of relevance, we review the unprecedented findings pointing to a concerted action of several restriction factors such as CIITA, TRIM22 and TRIM19/PML in synergizing against retroviral replication. Finally, as CIITA profoundly affects HTLV-1 replication by interacting and inhibiting the function of HTLV-1 Tax-1 molecule, the major viral product associated to the virus oncogenicity, we also put forward the hypothesis of CIITA as counteractor of HTLV-1-mediated cancer initiation.

Virus reactivation and low dose of CD34+ cell, rather than haploidentical transplantation, were associated with secondary poor graft function within the first 100 days after allogeneic stem cell transplantation.

Secondary poor graft function (sPGF) is defined as secondary cytopenia after initial engraftment of allogeneic stem cell transplantation (allo-SCT). It has been shown to be associated with poor prognosis; however, there are very few reports on the incidence, risk factors, and outcomes of sPGF. Between January 2015 and December 2015, 564 patients, who received transplantation at Peking University People's Hospital, were retrospectively reviewed. Among the 490 patients who achieved initial engraftment of both neutrophils and platelets, 28 patients developed sPGF. The cumulative incidence of sPGF on day 100 was 5.7%. The median time of sPGF was 54.5 (34-91) days after transplantation. Low (< median) CD34+ cell dose (p = 0.019, HR 3.07 (95% CI, 1.207-7.813)), Epstein-Barr Virus (EBV) reactivation (p = 0.009, HR 3.648 (95%CI, 1.382-9.629)), and cytomegalovirus (CMV) reactivation (p = 0.003, HR 7.827 (95%CI, 2.002-30.602)) were identified as independent risk factors for sPGF. There was no significant difference in PGF incidence between the matched sibling donor (MSD) group and haploidentical donor (HID) group (p = 0.44). The overall survival of patients with sPGF at 1 year after transplantation was significantly poorer than that of patients with good graft function (GGF) (50.5% versus 87.2%, p < 0.001). In conclusion, sPGF developed in 5.7% patients after allo-SCT, especially in patients with CMV, EBV reactivation, or infusion with a low dose of CD34+ cells. The prognosis of sPGF is still poor owing to a lack of standard treatment.

Resurrection of endogenous retroviruses in antibody-deficient mice.

The mammalian host has developed a long-standing symbiotic relationship with a considerable number of microbial species. These include the microbiota on environmental surfaces, such as the respiratory and gastrointestinal tracts, and also endogenous retroviruses (ERVs), comprising a substantial fraction of the mammalian genome. The long-term consequences for the host of interactions with these microbial species can range from mutualism to parasitism and are not always completely understood. The potential effect of one microbial symbiont on another is even less clear. Here we study the control of ERVs in the commonly used C57BL/6 (B6) mouse strain, which lacks endogenous murine leukaemia viruses (MLVs) able to replicate in murine cells. We demonstrate the spontaneous emergence of fully infectious ecotropic MLV in B6 mice with a range of distinct immune deficiencies affecting antibody production. These recombinant retroviruses establish infection of immunodeficient mouse colonies, and ultimately result in retrovirus-induced lymphomas. Notably, ERV activation in immunodeficient mice is prevented in husbandry conditions associated with reduced or absent intestinal microbiota. Our results shed light onto a previously unappreciated role for immunity in the control of ERVs and provide a potential mechanistic link between immune activation by microbial triggers and a range of pathologies associated with ERVs, including cancer.

Synergistic antitumor activity of triple-regulated oncolytic adenovirus with VSTM1 and daunorubicin in leukemic cells.

V-set and transmembrane domain-containing 1 (VSTM1), which is downregulated in bone marrow cells from leukemia patients, may provide a diagnostic and treatment target. Here, a triple-regulated oncolytic adenovirus was constructed to carry a VSTM1 gene expression cassette, SG611-VSTM1, and contained the E1a gene with a 24-nucleotide deletion within the CR2 region under control of the human telomerase reverse transcriptase promoter, E1b gene directed by the hypoxia response element, and VSTM1 gene controlled by the cytomegalovirus promoter. Real-time quantitative PCR and Western blot analyses showed that SG611-VSTM1 expressed VSTM1 highly efficiently in the human leukemic cell line K562 compared with SG611. In Cell Counting Kit-8 and flow cytometric assays, SG611-VSTM1 exhibited more potent anti-proliferative and pro-apoptotic effects in leukemic cells compared with SG611 and exerted synergistic cytotoxicity with low-dose daunorubicin (DNR) in vitro. In xenograft models, SG611-VSTM1 intratumorally injected at a dose of 1 × 10(9) plaque forming units combined with intraperitoneally injected low-dose DNR displayed significantly stronger antitumor effects than either treatment alone. Histopathologic examination revealed that SG611-VSTM1 induced apoptosis of leukemic cells. These results implicate an important role for VSTM1 in the pathogenesis of leukemia, and SG611-VSTM1 may be a promising agent for enhancing chemosensitivity in leukemia therapy.

Risk of leukaemia in children infected with enterovirus: a nationwide, retrospective, population-based, Taiwanese-registry, cohort study.

BACKGROUND: The association between enterovirus infections in children and risk of leukaemia is unclear. We aimed to assess the risk of leukaemia after enterovirus infection in children. METHODS: We did a nationwide retrospective cohort study by analysing data from the National Health Insurance Research Database (NHIRD) in Taiwan. Children with enterovirus infections aged younger than 18 years were identified. With use of computer-generated random numbers, children not infected with enterovirus were randomly selected and frequency matched (1:1) with children infected with enterovirus by sex, age, urbanisation level, parental occupation, and index year of enterovirus infection. We only included children with complete baseline data for age and sex and who had at least three clinic visits with the diagnosis of enterovirus infection. The diagnosis date of the first clinic visit for the enterovirus infection was defined as the index date for initiation of follow-up person-year measurement and participants. All study patients were followed up until they developed leukaemia, were lost to follow-up, withdrew from the NHI programme, or until the end of the study without leukaemia (censored). Our primary endpoint was a diagnosis of leukaemia during follow-up. FINDINGS: Insurance claims data for 3 054 336 children younger than 18 years were randomly selected from all insured children in the NHIRD. We identified 282 360 children infected with enterovirus and 282 355 children not infected with enterovirus between Jan 1, 2000, and Dec 31, 2007. The incidence density rates of leukaemia were 3·26 per 100 000 person-years for the enterovirus-infected and 5·84 per 100 000 person-years for the non-enterovirus-infected cohorts. The risk of leukaemia was significantly lower in the enterovirus-infected cohort than in the non-enterovirus-infected cohort (adjusted subhazard ratio [SHR] 0·44, 95% CI 0·31-0·60; p<0·0001). Children infected with enterovirus have a reduced risk of both lymphocytic leukaemia (adjusted SHR 0·44, 0·30-0·65; p<0·0001) and acute myeloid leukaemia (adjusted SHR 0·40, 0·17-0·97; p=0·04). Herpangina and hand-foot-and-mouth disease were the main diseases associated with the reduced risk of leukaemia. INTERPRETATION: The association between enterovirus infection and the reduced risk of developing leukaemia supports Greaves' delayed infection hypothesis for the cause of childhood leukaemia.

Combined cytotoxic activity of an infectious, but non-replicative herpes simplex virus type 1 and plasmacytoid dendritic cells against tumour cells.

Malignant melanoma is an aggressive tumour of the skin with increasing incidence, frequent metastasis and poor prognosis. At the same time, it is an immunogenic type of cancer with spontaneous regressions. Most recently, the tumoricidal effect of plasmacytoid dendritic cells (pDC) and their capacity to overcome the immunosuppressive tumour microenvironment are being investigated. In this respect, we studied the effect of the infectious, but replication-deficient, herpes simplex virus 1 (HSV-1) d106S vaccine strain, which lacks essential immediate early genes, in pDC co-cultures with 11 melanoma cell lines. We observed a strong cytotoxic activity, inducing apoptotic and necrotic cell death in most melanoma cell lines. The cytotoxic activity of HSV-1 d106S plus pDC was comparable to the levels of cytotoxicity induced by natural killer cells, but required only a fraction of cells with effector : target ratios of 1 : 20 (P < 0·05). The suppressive activity of cell-free supernatants derived from virus-stimulated pDC was significantly neutralized using antibodies against the interferon-α receptor (P < 0·05). In addition to type I interferons, TRAIL and granzyme B contributed to the inhibitory effect of HSV-1 d106S plus pDC to a minor extent. UV-irradiated viral stocks were significantly less active than infectious particles, both in the absence and presence of pDC (P < 0·05), indicating that residual activity of HSV-1 d106S is a major component and sensitizes the tumour cells to interferon-producing pDC. Three leukaemic cell lines were also susceptible to this treatment, suggesting a general anti-tumour effect. In conclusion, the potential of HSV-1 d106S for therapeutic vaccination should be further evaluated in patients suffering from different malignancies.

EBP1, a novel host factor involved in primer binding site-dependent restriction of moloney murine leukemia virus in embryonic cells.

Mouse embryonic cells are unable to support the replication of Moloney murine leukemia virus (MLV). The integrated viral DNA is transcriptionally silenced, largely due to binding of host transcriptional repressors to the primer binding site (PBS) of the provirus. We have previously shown that a PBS DNA-binding repressor complex contains ZFP809 and TRIM28. Here, we identified ErbB3-binding protein 1 (EBP1) to be a novel component of the ZFP809-TRIM28 silencing complex and show that EBP1 depletion reduces PBS-mediated retroviral silencing.

Evaluation of captive gibbons (Hylobates spp., Nomascus spp., Symphalangus spp.) in North American Zoological Institutions for Gibbon Ape Leukemia Virus (GALV).

This study evaluated 79 captive gibbons (Hylobates, Nomascus, and Symphalangus spp.) within 30 North American zoological institutions for evidence of exposure to and possible infection with gibbon ape leukemia virus (GALV). Enzyme-linked immunosorbent assays (ELISAs) on gibbon serum samples revealed the presence of antibodies against GALV antigens in 28% of animals, indicating previous exposure or possibly protective immunity to GALV. Virus detection in gibbon blood or serum using polymerase chain reaction (PCR) or co-culture of gibbon peripheral blood mononuclear cells with human cells was negative for all samples submitted. The majority (19/27, 70%) of animals with reported health conditions were clinically healthy at the time of sample collection. Historically accrued clinical data were used to assess association of diseases in gibbons antibody positive for GALV. The results suggest captive gibbons could mount an immune response to GALV and show no evidence of infection. There was no association with neoplastic conditions in seropositive animals. The potential role of gibbons as a reservoir for GALV and the role of GALV as an epizoonotic-zoonotic agent or as a contributor to gibbon ape morbidity and mortality are not substantiated by the study findings.

The role of cytomegalovirus serostatus on outcome of hematopoietic stem cell transplantation.

PURPOSE OF REVIEW: The aim of this review is to discuss recent developments regarding the impact of cytomegalovirus (CMV) serological status of hematopoietic stem cell transplantation recipients and their donors on transplant outcome. RECENT FINDINGS: CMV seropositivity of the recipient is still a negative factor for transplant outcome. The use of a CMV seropositive donor has a negative impact on survival in patients receiving unrelated but not human leukocyte antigen-identical sibling grafts. In CMV seropositive patients, the donor serological status influences outcome in patients receiving unrelated donor grafts after myeloablative but not reduced-intensity conditioning. Early CMV replication reduces the risk for leukemia relapse but does not improve survival. The use of leukocyte depleted blood products is sufficient to prevent primary CMV infection. SUMMARY: Despite major advances in management of CMV infections, CMV serologic status remains an important risk factor for transplant-related complications and mortality after allogeneic hematopoietic stem cell transplantation.

Time-varying coefficient proportional hazards model with missing covariates.

Missing covariates often arise in biomedical studies with survival outcomes. Existing approaches for missing covariates generally assume proportional hazards. The proportionality assumption may not hold in practice, as illustrated by data from a mouse leukemia study with covariate effects changing over time. To tackle this restriction, we study the missing data problem under the varying-coefficient proportional hazards model. On the basis of the local partial likelihood approach, we develop inverse selection probability weighted estimators. We consider reweighting and augmentation techniques for possible improvement of efficiency and robustness. The proposed estimators are assessed via simulation studies and illustrated by application to the mouse leukemia data.

Multiplex real-time PCR for prompt diagnosis of an outbreak of human parainfluenza 3 virus in children with acute leukemia.

INTRODUCTION: Human parainfluenza virus type 3 (HPIV-3) causes significant morbimortality in immunocompromised patients. Outbreaks of severe pneumonitis have been previously described in this setting. MATERIALS AND METHODS: Retrospective observational study in children diagnosed with acute leukemia and a documented HPIV-3 infection in the context of a nosocomial outbreak occurred in a single center. RESULT: During summer 2012, an HPIV-3 infection was detected in six hospitalized children with acute leukemia. All the patients had respiratory symptoms and one of them suffered from parotitis. CONCLUSION: Early diagnoses using multiplex real-time polymerase chain reaction (PCR) let us control this outbreak. A phylogenetic analysis confirmed person-to-person transmission of a single HPIV-3 variant.

Human retroviruses in the second decade: a personal perspective.

Human retroviruses have developed novel strategies for their propagation and survival. A consequence of their success has been the induction of an extraordinarily diverse set of human diseases, including AIDS, cancers and neurological and inflammatory disorders. Early research focused on their characterization, linkage to these diseases, and the mechanisms involved. Research should now aim at the eradication of human retroviruses and on treatment of infected people.

[Long-term results of HBV and HCV infection in patients with blood system diseases].

AIM: To specify trends in clinical and laboratory manifestations of virus hepatitis B and C (HBV and HCV) in patients with blood diseases from the moment of the first positive specific tests for HBV and HCV markers; to assess effects of HBV and HCV infection on efficacy of treatment of blood disease treatment, i.e. lifespan of patients with hematological diseases. MATERIAL AND METHODS: The study enrolled 257 patients: 205 with acute leukemia - AL, 40 with lymphoproliferative diseases, 4 - with CML and 8 - others; 8 healthy bone marrow donors. The patients were admitted to Russian Hematological Research Center in 2004-2006 Follow-up median was 253 days. A total of 7800 biological samples were studied, among them about 4000 tests for HBV DNA and HCV RNA. RESULTS: Positive tests for specific markers of HBV and HCV were absent only in 78 (29.4%) patients. Positive markers of coinfection were detected in 57 (32.8%) of 174 patients with HBV infection and in 81.4% of 70 patients with HCV infection. Probability of detection of HCV markers after positive tests for HBV markers and vice versa is about 3 times higher than probability of their isolated detection. Among patients infected with HBVsymptoms of hepatitis B are likely to appear in 56% patients to day 500 of follow-up from the date of the first positive specific test. Median of the interval between the first positive test for HBV markers and probable clinical signs of hepatitis was 30 days. Among patients with HCV infection, 85% develop hepatitis to follow-up day 300 since the date of the first specific positive test. Almost 100% patients infected with two viruses develop hepatitis to follow-up day 600. Median of the interval between the first positive test for HBV and HCV markers and probable hepatitis picture was 47 days. Overall 3-year survival of AL patients was 40%, of patients with lymphoproliferative diseases - 58%. Overall 7-month survival was 75% in AA patients. HBV infection in patients with blood disease is associated with high risk of death, especially in AA and AL. Association between HCV infection and survival is not proved. CONCLUSION: A high rate of clinical realization of viral hepatitis B and C, especially in coinfection, calls for virological and clinical monitoring of patients with any positive test for HBV and HCV markers.