Persistent B19 parvovirus infection in patients infected with human immunodeficiency virus type 1 (HIV-1): a treatable cause of anemia in AIDS

A Retrospective Analysis of Clinical and Epidemiological Aspects of Parvovirus B19 in Brazil: A Hidden and Neglected Virus Among Immunocompetent and Immunocompromised Individuals

Parvovirus B19 (B19V) infection can affect individuals of all ages, both immunocompetent and immunocompromised. This infection is typically acute and self-limiting, most commonly resulting in rash diseases and acute febrile illness. However, its involvement in atypical manifestations such as chronic kidney disease and acute liver failure have also been reported. Diagnosis of B19V is rarely conducted in these populations, and available studies on its prevalence are limited, outdated, and do not accurately depict the current situation. This study describes and discusses retrospective investigations into the role of B19V in cases of rash diseases, acute febrile illness, anemia, occurring in the context of chronic kidney disease and HIV coinfection, and acute liver failure when no identifiable etiological agent was found, focusing on various populations in Brazil. This overview underscores the importance of recognizing the potential for severe B19V infection in all individuals, regardless of perceived immune status, as well as of considering the possibility of B19V concurrent infection, in both high-risk groups and healthy individuals to reduce the risk of serious complications and improve patient outcomes, by considering the inclusion of B19V in the routine of diagnosis and implementing management strategies. This study was limited by the absence of national surveillance data of B19V in Brazil and by the analyses that occurred retrospectively.

Rapid and sensitive detection of methicillin-resistant Staphylococcus aureus through the RPA-PfAgo system

Introduction

Both the incidence and mortality rates associated with methicillin-resistant Staphylococcus aureus (MRSA) have progressively increased worldwide. A nucleic acid testing system was developed in response, enabling swift and precise detection of Staphylococcus aureus (S. aureus) and its MRSA infection status. This facilitates improved prevention and control of MRSA infections.

Methods

In this work, we introduce a novel assay platform developed by integrating Pyrococcus furiosus Argonaute (PfAgo) with recombinase polymerase amplification (RPA), which was designed for the simultaneous detection of the nuc and mecA genes in MRSA.

Results

This innovative approach enables visual MRSA detection within 55 mins, boasting a detection limit of 102 copies/μL. Characterized by its high specificity, the platform accurately identifies MRSA infections without cross-reactivity to other clinical pathogens, highlighting its unique capability for S. aureus infection diagnostics amidst bacterial diversity. Validation of this method was performed on 40 clinical isolates, demonstrating a 95.0% accuracy rate in comparison to the established Vitek2-COMPACT system.

Discussion

The RPA-PfAgo platform has emerged as a superior diagnostic tool, offering enhanced sensitivity, specificity, and identification efficacy for MRSA detection. Our findings underscore the potential of this platform to significantly improve the diagnosis and management of MRSA infection.

New technologies in therapeutic antibody development: The next frontier for treating infectious diseases

Adaptive immunity to viral infections requires time to neutralize and clear viruses to resolve infection. Fast growing and pathogenic viruses are quickly established, are highly transmissible and cause significant disease burden making it difficult to mount effective responses, thereby prolonging infection. Antibody-based passive immunotherapies can provide initial protection during acute infection, assist in mounting an adaptive immune response, or provide protection for those who are immune suppressed or immune deficient. Historically, plasma-derived antibodies have demonstrated some success in treating diseases caused by viral pathogens; nonetheless, limitations in access to product and antibody titer reduce success of this treatment modality. Monoclonal antibodies (mAbs) have proven an effective alternative, as it is possible to manufacture highly potent and specific mAbs against viral targets on an industrial scale. As a result, innovative technologies to discover, engineer and manufacture specific and potent antibodies have become an essential part of the first line of treatment in pathogenic viral infections. However, a mAb targeting a specific epitope will allow escape variants to outgrow, causing new variant strains to become dominant and resistant to treatment with that mAb. Methods to mitigate escape have included combining mAbs into cocktails, creating bi-specific or antibody drug conjugates but these strategies have also been challenged by the potential development of escape mutations. New technologies in developing antibodies made as recombinant polyclonal drugs can integrate the strength of poly-specific antibody responses to prevent mutational escape, while also incorporating antibody engineering to prevent antibody dependent enhancement and direct adaptive immune responses.

Successful use of interferon alfa-2a for persistent parvovirus B19 infection

Human infection with parvovirus B19 causes a range of clinical manifestations, including benign erythema infectiosum in children, arthralgias in adults, aplastic crisis in patients with bone marrow failure, and potentially fatal congenital hydrops fetalis. Persistent parvovirus B19 infection is a rare disease presentation mostly seen in adult women or immunocompromised individuals. Treatment options include corticosteroids and intravenous immunoglobulin; however, viral clearance is difficult to obtain and rarely maintained. In this Grand Round, we report the case of a 43-year-old man with persistent parvovirus B19 infection and anaemia, who was refractory to standard treatment regimens, and whom we successfully treated with pegylated interferon alfa-2a. Initial treatment led to viral clearance and remission of anaemia, although secondary recurrence of virus required treatment extension. Despite extensive genetic and immunological evaluations, no underlying primary or secondary immunodeficiency was identified in the patient. We propose interferon alfa-2a as a treatment option for persistent parvovirus B19 infection and advocate long-term follow-up of patients and potentially repeated treatment.

Parvovirus Infection Leading to Severe Anemia in an Adult Patient With HIV Disease

Individuals with human immunodeficiency virus (HIV) disease frequently suffer from anemia. The causes include anemia of chronic disease, vitamin B12 and iron deficiency, opportunistic infections (Mycobacterium tuberculosis, Pneumocystis jiroveci), HIV-related bone marrow suppression, AIDS-associated malignancies, and antiretroviral therapy (ART), specifically zidovudine. In HIV patients with advanced immunodeficiency, failure to produce neutralizing antibodies can lead to chronic parvovirus B19 (B19) infection. Normally, in persons with intact immunity, the progression of B19 is self-limited. However, in chronic B19 infection, it can lead to pure red cell aplasia (PRCA) and chronic anemia. In human immunodeficiency virus (HIV)-infected patients, B19-related anemia is rare and underdiagnosed. It has a great response to intravenous immunoglobulin (IVIG) therapy. Hence, early diagnosis and prompt treatment can significantly reduce mortality. In this article, we described the case of a 25-year-old male with HIV infection who presented with a headache. He had severe normocytic anemia with a low reticulocyte count. The workup for blood loss, hemolysis, hemoglobinopathy, and iron deficiency was negative. Because of extremely low reticulocytopenia with severe anemia, the investigations favored multiple myeloma, parvovirus infection, and bone marrow aspiration biopsy. He was tested for parvovirus B19 deoxyribonucleic acid (DNA) polymerase chain reaction (PCR) test due to insufficient seroconversion. It turned out to be positive and he was treated with IVIG therapy.

[Parvovirus B19 infections in adults]

Acute Parvovirus B19 (PVB19) infection is responsible for erythema infectiosum in children and non-specific polyarthralgias in immunocompetent adults associated with skin lesions and rarer manifestations (hepatic, neurological, cardiac or nephrological). In immunocompromised patients, cytopenias are more frequent and in some cases, viremia persists and is responsible for PVB19 chronic infection. PVB19 is responsible for pure red cell aplasia during chronic hemolytic diseases. Acute PVB19 infection is a differential diagnosis of some autoimmune diseases and has been suspected to be a trigger for some autoimmune diseases because of its ability to promote the emergence of autoimmune markers. Mechanisms of molecular mimicry, induction of apoptosis and activation of enzymes have been demonstrated, explaining in part the production of autoantibodies during infection. However, the demonstration of a causal relationship in the triggering of autoimmune disease remains to be done. This review provides a synthesis of the PVB19 infection clinical data in adults with a particular focus on these links with autoimmunity.

Aplastic anemia induced by human parvovirus B19 infection in an immunocompetent adult male without prior hematological disorders: A case report

Introduction and importance

Parvovirus B19 (B19V) is a human pathogenic virus of clinical relevance. Human parvovirus B19 infection can be asymptomatic or frequently associated with erythema infectiosum, or joint symptoms in healthy adults. Aplastic anemia as a complication of human parvovirus infection is rare in healthy adults without prior hematological disorders.

Case presentation

We report a case of severe aplastic anemia in a 22-years-old immunocompetent adult male without any hematological dysfunction who presented with periumbilical pain, loose watery stools, and fever with chills and rigor. General examination, laboratory investigation, and peripheral blood smear revealed anemia with leucopenia and relative lymphocytosis, thrombocytopenia, and severe neutropenia. Bone marrow biopsy revealed hypocellular bone marrow with maturation arrest at the proerythroblast stage with intranuclear inclusions and no blast and hematopoietic cells replaced by mature adipocytes in marrow spaces. Parvovirus B19 infection was confirmed by viral serology and polymerase chain reaction.

Clinical discussion

Asymptomatic or mild infection occurs most often when B19 affects immunocompetent adults. However, this is the fourth case reporting severe aplastic anemia in immunocompetent adults and the first case reported in immunocompetent adult males. The patient was admitted for close monitoring and supportive management, which effectively improved the patient's clinical condition, and discharged with a strict follow-up schedule in an outpatient setting.

Conclusion

Thus, acute infection with this virus must be considered a cause of acquired aplastic anemia even in individuals without underlying disease.

•

Erythema infectiosum, often known as the fifth disease is the most common manifestation in children, whereas, in healthy adults, most cases of infection are asymptomatic or associated with arthritis and myalgia.

•The virus causes infections worldwide that vary in severity depending on the age as well as the immunologic and hematologic status of the host.

•Parvovirus infection should be considered as one of the causes of sudden and severe aplastic anemia even in previously hematologically normal individuals with intact immunity.

•Patients should be treated symptomatically until their hematopoiesis restores, and regular follow-up is critical for detecting chronic anemia or recurrence and treating it promptly.

A Persistent Parvovirus Infection Causing Anemia in an HIV Patient Requiring Intravenous Immunoglobulin Maintenance Therapy

Anemia is a common finding in a human immunodeficiency virus (HIV)-positive patient with a wide range of possible causes and is a significant risk factor for mortality in acquired immunodeficiency syndrome (AIDS). Opportunistic parvovirus infection-causing pure red cell aplasia is one of its uncommon causes. It has been suggested that immunocompromised patients with abnormal antibody production are more susceptible to acquiring a chronic parvovirus infection requiring long-term intravenous immunoglobulin (IVIg) treatment; however, there are no specific guidelines for it. Here, we present a case of an HIV patient with persistent parvovirus infection resulting in chronic anemia requiring long-term maintenance immunoglobulin therapy with an excellent therapeutic response.

Algorithm for laboratory diagnostics of parvoviral infection in risk groups

Parvovirus infection (PVI) is widespread, characterized by airborne, bloodborne and vertical transmission routes. Parvovirus B19 (PVB19) exhibits tropism to erythropoietic cells. According to the increased likelihood principle of PVB19 infection and the severity of the consequences, immunocompromised individuals, especially those with hematological manifestations of diseases, are in increased risk group. Based on the own research results and analysis of the published data, we have proposed specific algorithms for PVI laboratory testing in individual risk groups, taking into account the peculiarities of the development and infection manifestation in each group: in HIV-infected patients, in oncohematological patients with to whom allogeneic hematopoietic stem cell transplantation (allo-HSCT) have been prescribed (blood and bone marrow recipients), as well as in patients with chronic anemia of parasitic etiology. For each group, the main clinical or laboratory marker, treatment procedure, or patient physiological parameters have been determined, based on which it was recommended to test for PVI. For HIV-infected patients, the main criterion for PVI testing is persistent anemia. For oncohematological patients, the basis for PVI testing is allo-HSCT procedure, which is planned or performed for this particular patient. For malaria patients, the patient's age was considered as major criterion, since in malaria and PVI coinfected young children can lead to a fatal outcome. The proposed PVI diagnostics algorithms usein risk groups can help to predict the severe course of underlying disease associated with PVB19 infection, and timely correct the therapy used.

[The hematological diversity of human parvovirus B19 infection after allo-hematopoietic stem cell transplantation in pediatric patients]

目的

探讨异基因造血干细胞移植（allo-HSCT）患儿造血重建后人类细小病毒B19（HPV-B19）感染的血液学表现。

方法

对9例allo-HSCT后合并HPV-B19感染的患儿进行回顾性分析。

结果

9例患儿占同期接受allo-HSCT患儿的8.04％（9/112），男8例，女1例，中位年龄9（3～13）岁，均采取清髓性预处理方案。HPV-B19感染中位时间为移植后61（36～114）d。allo-HSCT并发HPV-B19感染患儿血液学表现具有异质性，9例患儿以血红蛋白伴网织红细胞下降为主要特点，7 d内网织红细胞比例、绝对值下降幅度中位数分别为90.4％（24.7％～98.7％）、90.7％（18.6％～99.0％）。除常见红系造血停滞表现外，allo-HSCT后合并HPV-B19感染的患儿还具有非红系的血象及骨髓变化：5例患儿外周血出现中性粒细胞下降，但骨髓涂片未见粒系增生受抑；6例患儿骨髓涂片查见巨核系增生减低，其中5例患儿外周血血小板下降。同时，allo-HSCT造血重建后合并HPV-B19感染的患儿骨髓红系受抑并非必要表现，9例患儿虽然均出现血红蛋白下降，但仅5例患儿骨髓红系增生减低。

结论

血液病患儿allo-HSCT造血重建后合并HPV-B19感染的血液学表现具有异质性，血红蛋白伴网织红细胞下降对HPV-B19感染早期诊断可能具有重要意义。

Parvovirus B19-associated graft failure after allogeneic hematopoietic stem cell transplantation

Background

Parvovirus B19 (PVB19) infection has been implicated in allograft failure or dysfunction in solid organ transplantation (SOT) and allogeneic hematopoietic stem cell transplantation (allo‐HSCT), but the literature is limited.

Case

Two pediatric patients were diagnosed with PVB19 infection around the time of allo‐HSCT graft failure. Both cases were secondary graft failure and required second allo‐HSCT.

Conclusion

There are many risk factors and potential confounders in determining the exact etiology of graft failure after allo‐HSCT. These two cases highlight the importance of including PVB19 in the diagnostic evaluation for graft failure. PVB19 infection may be an important risk factor for allo‐HSCT graft failure.

Integrative overview of antibodies against SARS-CoV-2 and their possible applications in COVID-19 prophylaxis and treatment

SARS-CoV-2 is a novel β-coronavirus that caused the COVID-19 pandemic disease, which spread rapidly, infecting more than 134 million people, and killing almost 2.9 million thus far. Based on the urgent need for therapeutic and prophylactic strategies, the identification and characterization of antibodies has been accelerated, since they have been fundamental in treating other viral diseases. Here, we summarized in an integrative manner the present understanding of the immune response and physiopathology caused by SARS-CoV-2, including the activation of the humoral immune response in SARS-CoV-2 infection and therefore, the synthesis of antibodies. Furthermore, we also discussed about the antibodies that can be generated in COVID-19 convalescent sera and their associated clinical studies, including a detailed characterization of a variety of human antibodies and identification of antibodies from other sources, which have powerful neutralizing capacities. Accordingly, the development of effective treatments to mitigate COVID-19 is expected. Finally, we reviewed the challenges faced in producing potential therapeutic antibodies and nanobodies by cell factories at an industrial level while ensuring their quality, efficacy, and safety.

Tale of two viruses: parvovirus B19 and HIV

We present a HIV-infected patient who developed severe anaemia due to chronic parvovirus B19 infection and subsequently had an unplanned pregnancy. This is in the context of poor adherence to antiretroviral therapy and significant immunosuppression; there was a delay in diagnosis of chronic parvovirus infection due to attribution of anaemia to HIV. She received immunoglobulin therapy and effective antiretroviral therapy, with reduction in parvovirus load and improvement in anaemia. She was counselled regarding the need for monitoring in pregnancy due to risk of intrauterine infection. We review the literature of management of chronic parvovirus infection in the immunosuppressed and the consequences of intrauterine infection.

Human parvovirus B19 infection in an immunocompromised host

Serologic testing may be negative in immunocompromised hosts due to inadequate IgG and IgM response. The classic bone marrow findings of viral inclusions and giant proerythroblasts are pathognomonic for active infection and should prompt initiation of therapy regardless of serologic results.

[Parvovirus B19 infection in HIV-infected patients]

Here we provide a review of the literature and a description of our own clinical case. The patient was a 32-year-old woman who had been infected with HIV for 6 years without antiretroviral therapy. The test results showed CD4 87 cells/l, viral load 3750 copies/ml. Normochromic normocytic anemia and reticulocytopenia developed soon. In the myelogram, all erythroblasts were 0.5%. The viral load of parvovirus B19 DNA according to PCR was more than 9 million IU/ml. Pure red cell aplasia associated with parvovirus B19 was diagnosed. We started antiretroviral therapy with efavirenz, lamevudine and tenofovir. In addition to blood transfusions, we administered intravenous donor immunoglobulin with a dose increase from 5000 mg to 20 000 mg per day. After discontinuing of intravenous immunoglobulins, the laboratory test results were stable over the next 5 months: hemoglobin was more than 115 g/L, reticulocytes more than 3%, in the myelogram all erythroblasts were 21%. However, the elimination of parvovirus B19 wasnt achieved. The maximum decrease in viral load for parvovirus B19 was down to 720 IU/ml. A typical feature of the case was the lack of pure red cell aplasia of the bone marrow with the existing viral load of parvovirus B19. HIV infection progressed: 44 cells/l, viral load not determined. The case ended lethally.

RNA Binding Motif Protein RBM45 Regulates Expression of the 11-Kilodalton Protein of Parvovirus B19 through Binding to Novel Intron Splicing Enhancers

Human parvovirus B19 (B19V) is a human pathogen that causes severe hematological disorders in immunocompromised individuals. B19V infection has a remarkable tropism with respect to human erythroid progenitor cells (EPCs) in human bone marrow and fetal liver. During B19V infection, only one viral precursor mRNA (pre-mRNA) is transcribed by a single promoter of the viral genome and is alternatively spliced and alternatively polyadenylated, a process which plays a key role in expression of viral proteins. Our studies revealed that a cellular RNA binding protein, RBM45, binds to two intron splicing enhancers and is essential for the maturation of the small nonstructural protein 11-kDa-encoding mRNA. The 11-kDa protein plays an important role not only in B19V infection-induced apoptosis but also in viral DNA replication. Thus, the identification of the RBM45 protein and its cognate binding site in B19V pre-mRNA provides a novel target for antiviral development to combat B19V infection-caused severe hematological disorders.

During infection of human parvovirus B19 (B19V), one viral precursor mRNA (pre-mRNA) is transcribed by a single promoter and is alternatively spliced and alternatively polyadenylated. Here, we identified a novel cis-acting sequence (5′-GUA AAG CUA CGG GAC GGU-3′), intronic splicing enhancer 3 (ISE3), which lies 72 nucleotides upstream of the second splice acceptor (A2-2) site of the second intron that defines the exon of the mRNA encoding the 11-kDa viral nonstructural protein. RNA binding motif protein 45 (RBM45) specifically binds to ISE3 with high affinity (equilibrium dissociation constant [K_D] = 33 nM) mediated by its RNA recognition domain and 2-homo-oligomer assembly domain (RRM2-HOA). Knockdown of RBM45 expression or ectopic overexpression of RRM2-HOA in human erythroid progenitor cells (EPCs) expanded ex vivo significantly decreased the level of viral mRNA spliced at the A2-2 acceptor but not that of the mRNA spliced at A2-1 that encodes VP2. Moreover, silent mutations of ISE3 in an infectious DNA of B19V significantly reduced 11-kDa expression. Notably, RBM45 also specifically interacts in vitro with ISE2, which shares the octanucleotide (GGGACGGU) with ISE3. Taken together, our results suggest that RBM45, through binding to both ISE2 and ISE3, is an essential host factor for maturation of 11-kDa-encoding mRNA.

Parvovirus B19 DNA detection in treatment-naïve HIV anemic patients in Lagos, Nigeria: a case control study

BACKGROUND

Parvovirus B19 (B19) has tropism for cells of the erythroid lineage, which may lead to transient inhibition of erythropoiesis. Several studies and case reports suggested that B19 infection may contribute significantly to severe chronic anemia in HIV infected persons.

OBJECTIVE

To detect parvovirus B19 DNA in treatment-naïve HIV patients.

METHODS

This was a case control retrospective study. One hundred nineteen anemic and 81 non-anemic treatment-naïve HIV infected patients participated in the study at the Lagos University Teaching Hospital, Lagos, Nigeria. Polymerase chain reaction was used to detect B19 DNA.

RESULTS

Out of 200 patients analysed, 13(6.5%) had parvovirus B19 DNA. Eight HIV patients with anemia had B19 DNA while five non-anemic HIV patients had B19 DNA. This suggests that the presence of B19 DNA in the blood of HIV positive individuals may contribute to anemia because the majority (61.5%) who were positive for B19 DNA had anemia as compared to the non-anemic control group (38.5%).

CONCLUSION

This study shows that the presence of B19 DNA in anemic HIV infected patients is not associated with chronic anaemia in HIV infection because no significant association exist.

Prevalence of Human Parvovirus B19 in Neurological Patients: Findings from Region of Western Saudi Arabia

Human parvovirus (B19) infection causes Erythema infectiosum in persons with other hematological disorders like aplastic anemia and complications such as hydrops fetalis, spontaneous abortions. This study aimed to determine the prevalence of IgG and IgM antibodies in B19 infected neurological patients and to assess possible transmission related risk factors. This cross-sectional descriptive study comprised 140 neurological patients. Blood samples were screened for both IgG and IgM against B19 by ELISA and nested PCR. IgG and IgM accounted 6.4% and 3.5% prevalence in neurological patients. Both IgG and IgM revealed prevalence of 3.5% simultaneously in different age groups. IgG and IGM Nested PCR displayed 6.42% B19 viral DNA prevalence among samples analyzed. Among B19 risk associated factors, only history of blood transfusion (Odds Ratio=1.9:1, P=0.04) was significantly associated with B19 infection among neurological patients. Neurological patients showed very less prevalence of B19 infection and hence disclose no significant association on risk factors associated with its transmission.

Prevalence and Factors Associated with Human Parvovirus B19 Infection in Sickle Cell Patients Hospitalized in Tanzania

Background

The distribution of human parvovirus B19 (HPV B19) infection is ubiquitous and occurs worldwide. The virus has high tropism to red blood cells progenitor’s cells leading to temporary infection of bone marrow and transient arrest of erythropoiesis. People with frequent episodes of hemolytic anemia including sickle cell disease (SCD) and thalassemia are at increased risk of infection. This study aimed at assessing prevalence and factors associated with HPV B19 infections among hospitalized SCD patients.

Methodology

This was a cross-sectional hospital-based study among SCD patients hospitalized at Muhimbili National Hospital. HPV B19 was detected using RT-PCR. Hematological and Chemistry tests were done using Sysmex XT2000i and Chemistry analyzer respectively.

Results

A total of 329 SCD patients, median age 15 years (interquartile range 7–22 years) were tested for HPV B19. The prevalence of HPV B19 was 29%. In multivariate logistic regression model, HPV B19 infection was associated with pain (OR=4.28, 95%CI: 1.20–15.19; p=0.025), low neutrophil counts (OR=0.57, 95%CI: 0.35–0.92, p=0.022) and MCH (OR=0.92, 95%CI: 0.85–0.99; p=0.033). Individuals infected with HPV B19 had slightly higher prevalence of severe anaemia (30.4% vs. 20.3%, p=0.054) and HIV infection (6.0% vs. 2.1%, p=0.083) in the univariate analysis. Considering the effect of HPV B19 virus on spleen, aplastic anemia and platelet counts in SCD patients, our study did not find any association with these parameters (p=0.244; p= 0.205 and p=0.567 respectively).

Conclusion

The prevalence of HPV B19 among hospitalized SCD patients at MNH was high. SCD patients with HPV B19 were more likely to present with pain, low neutrophils levels, and MCH. HIV infection might be associated with a high risk of HPV infection in SCD patients; however, this requires further investigation.

Structure of Parvovirus B19 Decorated by Fabs from a Human Antibody

Parvovirus B19, one of the most common human pathogens, is a small DNA virus that belongs to the Parvoviridae As a result of previous infections, antibodies to B19 are present in most adults. B19 has a strong tropism to erythroid progenitor cells and is able to cause a series of medical conditions, including fifth disease, arthritis, myocarditis, hydrops fetalis, and aplastic crisis. No approved vaccine is currently available for B19, and there is a lack of structural characterization of any B19 epitopes. Here we present the first cryo-electron microscopy (cryo-EM) structure of a B19 virus-like particle (VLP) complexed with the antigen-binding fragment (Fab) of a human neutralizing antibody, 860-55D. A model was built into the 3.2-Å-resolution map, and the antigenic residues on the surface of the B19 capsid were identified. Antibody 860-55D bridges the capsid of B19 by binding to a quaternary structure epitope formed by residues from three neighboring VP2 capsid proteins.IMPORTANCE Parvovirus B19 is a common human pathogen and a particular threat to children, pregnant women, and patients with sickle cell disease or AIDS. Currently, neutralizing antibody is the most efficient treatment for acute B19 infections. Research on the antigenic properties of B19 will guide the usage of these antibodies and facilitate vaccine development. We have determined and report here the high-resolution structure of B19 virus-like particles (VLPs) complexed with the Fab of a human neutralizing antibody. The structure shows a quaternary structure epitope formed by three VP2 proteins and provides details on host recognition of human B19 virus.

Evolutionary aspects of Parvovirus B-19V associated diseases and their pathogenesis patterns with an emphasis on vaccine development

Parvovirus B-19, a single human pathogenic member of the Parvoviridae family with it's small ssDNA and non-enveloped structure, is known to cause diseases in erythroid progenitor cells. But a wide range of clinical association of this virus with cells of non-erythroid origins has recently been discovered and many of those are being investigated for such association. Higher substitution rates in due course of evolution has been suggested for this cellular tropism and persistence. In this report, we have summarized the different disease manifestations of B-19 virus and have tried to find out a pattern of pathogenesis. Finally, we have focused on the vaccination strategies available against B-19 virus to correlate these with the mechanisms involved in various diseases caused by this virus.

Molecular prevalence of parvovirus B19 among HIV1-infected patients in Iran

Background: Different outcomes of parvovirus B19 (B19V) infection in immunocompromised patients, including HIV1-infected persons, may be life-threatening. Considering the hematologic disorders associated with B19V infection, this study aimed to investigate the prevalence of B19V infection among HIV1-infected individuals in Iran.

Methods: Serum samples from 100 HIV1-infected patients were analyzed for B19 viral DNA using real-time PCR assay. COBAS TaqMan HIV-1 test was performed for quantitative measurements of HIV-1 RNA in the patients’ sera.

Results: Real-time PCR analysis revealed that 10 out of 100 cases (10%) were positive for B19V infection. Across various age groups, the B19V infection was more prevalent among patients within the age range of 21-40 years. Higher prevalence of B19V infection was observed among HIV1-infected patients with a viral load of higher than 400 copies/mL.

Conclusion: Despite limitations, this study may set the stage for further evaluations with larger sample sizes to elucidate the potential role of B19V in hematologic disorders, which may result in exacerbation of the disease in HIV1-infected patients. Moreover, as it has been shown that B19V infection can be treated using intravenous immunoglobulin (IVIG) therapy, available treatments may help improve the quality of life in HIV-infected persons.

Parvoviral disease in childhood cancer: Clinical outcomes and impact on therapy at a tertiary cancer center in India

BACKGROUND AND AIM

Parvovirus-B19 disease in immunocompromised children can cause myelosuppression and therapeutic delays. We studied the clinical profiles of children having symptoms suggestive of parvoviral disease at our institution, a large tertiary cancer center.

METHODS

Children below age 15 years undergoing treatment for malignancies with clinical features suggestive of parvoviral infection, and/or unexplained drop in hemoglobin, and/or prolonged cytopenia were screened for parvovirus infection using DNA-PCR for parvovirus-B19 (PB19) in the peripheral blood. Patients testing positive from September 2014 till February 2017 were studied.

RESULTS

Of the 59 patients (36 patients with hematolymphoid malignancies, 23 with solid tumors) screened for suspected parvoviral infections, 27 tested positive. Median age was 9.6 years (2.25-15 years), 18 (66%) had hematolymphoid malignancies, while 7 (33%) had solid tumors. Six patients (26%) were on intensive phases, 16 (60%) patients developed the symptoms during maintenance chemotherapy, and 4 (15%) after completion of therapy. Isolated anemia was the commonest feature seen in 10 patients (37%) while bicytopenia and pancytopenia were noticed in 8 (30%) and 9 (33%) patients respectively. Fifty percent of patients those who received rituximab (3/6) developed persistent parvoviremia (>4 weeks) as compared with 24% (5/21) of those who did not. Two patients (7%) developed hemophagocytic lymphohistiocytosis (HLH). Treatment delay by more than 14 days was encountered in a majority (62%), with 5 patients requiring treatment modification or even suspension.

CONCLUSIONS

Parvoviral infection in children who are on or have recently completed chemotherapy can lead to multiple cytopenias and significant treatment delays. Rituximab exposure may lead to persistent parvoviral disease (p < 0.05). HLH, though occasional, can be a serious complication.

Uncovering exposures responsible for birth season - disease effects: a global study

Objective

Birth month and climate impact lifetime disease risk, while the underlying exposures remain largely elusive. We seek to uncover distal risk factors underlying these relationships by probing the relationship between global exposure variance and disease risk variance by birth season.

Material and Methods

This study utilizes electronic health record data from 6 sites representing 10.5 million individuals in 3 countries (United States, South Korea, and Taiwan). We obtained birth month–disease risk curves from each site in a case-control manner. Next, we correlated each birth month–disease risk curve with each exposure. A meta-analysis was then performed of correlations across sites. This allowed us to identify the most significant birth month–exposure relationships supported by all 6 sites while adjusting for multiplicity. We also successfully distinguish relative age effects (a cultural effect) from environmental exposures.

Results

Attention deficit hyperactivity disorder was the only identified relative age association. Our methods identified several culprit exposures that correspond well with the literature in the field. These include a link between first-trimester exposure to carbon monoxide and increased risk of depressive disorder (R = 0.725, confidence interval [95% CI], 0.529-0.847), first-trimester exposure to fine air particulates and increased risk of atrial fibrillation (R = 0.564, 95% CI, 0.363-0.715), and decreased exposure to sunlight during the third trimester and increased risk of type 2 diabetes mellitus (R = −0.816, 95% CI, −0.5767, −0.929).

Conclusion

A global study of birth month–disease relationships reveals distal risk factors involved in causal biological pathways that underlie them.

Frequency and Genotype of Human Parvovirus B19 among Iranian Hemodialysis and Peritoneal Dialysis Patients

OBJECTIVES

The aim of this study was to evaluate the frequency and genotype of human parvovirus B19 and its relation with anemia among Iranian patients under dialysis.

METHODS

Fifty hemodialysis (HD) and 33 peritoneal dialysis (PD) patients were enrolled. B19 IgG and IgM antibodies were assessed by ELISA, and the presence of B19 DNA was evaluated by nested PCR. PCR products were sequenced directly and phylogenetic analysis was performed.

RESULTS

In the HD group, the prevalence of B19 antibodies was 54% for IgG and 4% for IgM. B19 DNA was detected in 10% of the cases, and 10% showed B19 IgG and viremia simultaneously. In the PD group, the prevalence of B19 IgG and IgM was 57.6 and 0% respectively, whereas B19 DNA was found in 12.1% of the group. A total of 9.1% showed B19 IgG and viremia concurrently. There was no significant difference regarding anemia and B19 infection in either group. All B19 isolates were clustered in genotype 1A.

CONCLUSION

Our findings indicate that B19 infection plays no role in leading chronic anemia in dialysis patients. However, persistent B19 viremia and the circulation of the same strains in dialysis patients may indicate a potential risk for the contamination of dialysis equipment and nosocomial spread of B19 infection within dialysis units.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.

Parvovirus B19

Primary parvovirus B19 infection is an infrequent, but serious and treatable, cause of chronic anemia in immunocompromised hosts. Many compromised hosts have preexisting antibody to B19 and are not at risk. However, upon primary infection, some patients may be able to mount a sufficient immune response to terminate active parvovirus B19 infection of erythroid precursors. The most common consequence of B19 infection in the compromised host is pure red-cell aplasia, resulting in chronic or recurrent anemia with reticulocytopenia. Anemia persists until neutralizing antibody is either produced by the host or passively administered. Parvovirus B19 should be suspected in compromised hosts with unexplained or severe anemia and reticulocytopenia, or when bone-marrow examination shows either giant pronormoblasts or absence of red-cell precursors. Diagnosis is established by detection of B19 DNA in serum in the absence of IgG antibody to B19. In some cases, IgG antibody is detected but is not neutralizing. Anti-B19 IgM may or may not be present. Therapy includes any or all of the following: red-cell transfusion, adjustment in medications to restore or improve the patient’s immune system, and administration of intravenous immunoglobulin (IVIG). Following treatment, patients should be closely monitored, especially if immunosuppression is unchanged or increased. Should hematocrit trend downward and parvovirus DNA trend upward, the therapeutic options above should be revisited. In a few instances, monthly maintenance IVIG may be indicated. Caregivers should be aware that B19 variants, though rarely encountered, can be missed or under-quantitated by some real-time polymerase-chain reaction methods.

Clinical features and laboratory findings of human parvovirus B19 in human immunodeficiency virus-infected patients

Immunocompromised patients may develop severe chronic anaemia when infected by human parvovirus B19 (B19V). However, this is not the case in human immunodeficiency virus (HIV)-infected patients with good adherence to highly active antiretroviral treatment (HAART). In this study, we investigated the clinical evolution of five HIV-infected patients receiving HAART who had B19V infections confirmed by serum polymerase chain reaction. Four of the patients were infected with genotype 1a strains and the remaining patient was infected with a genotype 3b strain. Anaemia was detected in three of the patients, but all patients recovered without requiring immunoglobulin and/or blood transfusions. In all cases, the attending physicians did not suspect the B19V infections. There was no apparent relationship between the infecting genotype and the clinical course. In the HAART era, B19V infections in HIV-positive patients may be limited, subtle or unapparent.

Anemia of Central Origin

Hypoproliferative anemia results from the inability of bone marrow to produce adequate numbers of red blood cells. The list of conditions that cause hypoproliferative anemia is long, starting from common etiologies as iron deficiency to rarer diagnoses of constitutional bone marrow failure syndromes. There is no perfect diagnostic algorithm, and clinical data may not always clearly distinguish "normal" from "abnormal", yet it is important for practicing clinicians to recognize each condition so that treatment can be initiated promptly. This review describes diagnostic approaches to hypoproliferative anemia, with particular emphasis on bone marrow failure syndromes.

Frequency and genotype of human parvovirus B19 among Iranian patients infected with HIV

The human parvovirus B19 (B19) usually causes a subclinical infection in immunocompetent individuals. Whereas immunocompromised individuals such as patients infected with HIV are at risk of persistent anemia due to B19 infection. Only few studies have been carried out on distribution and molecular epidemiology of B19 in Iran. We aimed to determine the frequency and genotype of B19 among Iranian patients infected with HIV. We conducted a survey on 99 HIV patients and 64 healthy controls. IgG and IgM antibodies against B19 were detected by ELISA and B19 DNA was assessed by nested PCR. PCR products were subjected to direct sequencing and classified after phylogenetic analysis. The prevalence of B19 immunoglobulin was 11.1% for IgG and 1% for IgM. B19 DNA was detected in 13.1% of cases. The prevalence of B19 IgG, IgM, and DNA in control group was 25%, 1.6%, and 9.4%, respectively. B19 IgG was significantly lower in HIV group than in normal controls. There was no significant difference regarding anemia between cases and controls. All sequenced B19 isolates belonged to genotype 1A with low genetic diversity. Our findings indicated that in the HAART era, the importance of B19 infections in HIV patients may be limited whereas persistent B19 viremia in the circulation of healthy controls raises a potential concern in blood donations.

Persistent parvovirus B19 viremia with chronic arthralgia treated with ascorbic acid: a case report

Introduction

According to some studies, ascorbic acid possesses antiviral properties. These studies were mainly focused on the common cold, with very few focusing on other viral infections.

Case presentation

We report the case of a 54-year-old Caucasian woman with chronic arthralgia due to persistent parvovirus B19 viremia. High doses of ascorbic acid treatment were initiated due to the failure of conventional analgesic therapy. Clinical benefit was observed with a simultaneous loss of biological parvovirus B19 viremia.

Conclusions

This observation shows a potential benefit of the use of ascorbic acid against parvovirus B19 infections, even if this case is not sufficient to draw any definite conclusions.

Acute parvovirus B19 infection in adults: a retrospective study of 49 cases

OBJECTIVE

Our aim was to describe the epidemiologic, clinical, and laboratory characteristics of acute parvovirus B19 infection in adults.

MATERIAL AND METHODS

This study describes all cases of acute parvovirus B19 infection in patients older than 18 years of age who were treated at Hospital Universitario La Paz in Madrid, Spain, in 2012.

RESULTS

Forty-nine adults were treated for acute parvovirus B19 infection. Most were young women who were infected in the spring or early summer. In over half the cases skin lesions were key diagnostic signs.We saw the full range of types of rash of purplish exanthems that were fairly generalized; vasculitis was relatively common (in >18%). Mild or moderate abnormalities in blood counts and indicators of liver dysfunction resolved spontaneously in all but 2 immunocompromised patients, who developed chronic anemia.

CONCLUSIONS

This is the largest case series of acute parvovirus B19 infection published to date. This infection should be suspected on observing signs of purplish skin rashes, no matter the location or pattern of distribution, or vasculitis, especially if accompanied by fever and joint pain in young women in the spring. Measures to avoid infection should be recommended to individuals at risk.

Acute parvovirus B19 infection in identical twins unmasking previously unidentified hereditary spherocytosis

Identical Caucasian male twins, previously fit, presented 1 week apart with short histories of fever and lethargy. The twins were febrile at presentation with profound pancytopaenia and evidence of haemolysis. There was no rash or arthralgia. Both required multiple red cell transfusions. The twins had positive IgM serology for Epstein-Barr virus (EBV), cytomegalovirus (CMV) and parvovirus B19. EBV viral capsid antigen and Epstein-Barr nuclear antigen IgGs were also positive however, suggesting past EBV exposure. Parvovirus B19 DNA was detected from peripheral blood PCR; CMV and EBV DNA PCRs were negative. Convalescent serology demonstrated no evolution of the CMV serological response, that is no IgG to CMV developed which implies an initial non-specific polyclonal IgM response. The twins recovered fully over 7 days, the first with a course of prednisolone and the second spontaneously. They were diagnosed with hereditary spherocytosis on convalescent blood films. On further questioning, a family history of hereditary spherocytosis was eventually revealed. The twins' maternal grandmother was known to have the condition asymptomatically. Their mother had prior to this never been tested, but later bloods would reveal a compatible biochemical picture.

Status of immunity against PVB19 in HIV-infected patients according to CD4(+) cell count, and antiretroviral therapy regimen groups

Background:

Human Parvovirus B19 (PVB19) is among the aetiology of aplastic crisis in human immunodeficiency virus (HIV)-infected patients. Several studies have indicated the importance of an infection agent in bringing about complications in immuno-compromised patients. The current study aims to determine the seroprevalence of IgM and IgG antibodies to PVB19 among HIV-positive patients and its association with clinical and epidemiological factors.

Materials and Methods:

In a case control study, 90 HIV-positive patients were compared with 90 sex and age matched healthy controls in terms of anti-PVB19 IgG and IgM along with other primary clinical and laboratory features.

Results:

The overall prevalence of positive anti-PVB19 IgG among HIV patients and controls were 81.1% and 28.9%, respectively (P < 0.001). None of the subjects showed positive results for anti-PVB19 IgM. Patients with CD4⁺ cell count <200 showed higher seroprevalence of positive anti-PVB19 IgG which did not reach statistically significant. However, anti-PVB19 IgG seropositivity differed significantly between HIV patients on different regimens of antiretroviral therapy (ART) (P < 0.05).

Conclusion:

Immunity against PVB19 is more prevalent among HIV-positive patients compared to healthy controls. However, positive HIV status is not associated with acute PVB19 infection. The presence of anti-PVB19 IgG does not necessarily protect the body from further complications like anaemia. Given the results of the study, AIDS patients are recommended to undergo screening for parvovirus antibody in order to prevent complications like aplastic anaemia.

The expanding role of therapeutic antibodies

Therapeutic antibodies have been used since the end of nineteenth century, but their use is progressively increased and recently, with the availability of monoclonal antibodies, they are successfully employed in a large disease spectrum, which transversally covers different fields of medicine. Hyperimmune polyclonal immune globulin has been used against infectious diseases, in a period in which anti-microbial drugs were not yet available, and it still maintains a relevant place in prophylaxis/therapy. Although immune globulin should be considered life-saving as replacement therapy in humoral immunodeficiencies, its place in the immune-modulating treatment is not usually first-choice, but it should be considered as support to standard approved treatments. Despite therapeutic monoclonal antibodies have been lastly introduced in therapy, their extreme potentiality is reflected by the large number of approved molecules, addressed toward different immunological targets and able to heavily influence the prognosis and quality of life of a wide range of different diseases.

Parvovirus b19 infections and blood counts in blood donors

OBJECTIVES

Parvovirus B19 (B19V) is a transfusion-transmissible virus. To obtain data about the prevalence, incidence, the course of B19V infection in blood donors and whether B19V might impair their blood counts, samples from blood donors with B19V infection were investigated.

METHODS

Blood donations were screened for B19V DNA using the Cobas TaqScreen DPX Test® in mini-pools. B19V DNA concentration, anti-B19V IgG antibody titer and blood counts were determined in positive donors.

RESULTS

157/23,889 (0.66%) donors provided 347 B19V DNA-positive samples. Prevalence of B19V infection was 0.45%, incidence 0.20%. B19V DNA concentrations were predominantly low; only in 8 samples were viral loads of ≥10(5) IU B19V DNA/ml plasma detectable. Besides a slight decrease in hemoglobin, hematocrit, mean corpuscular volume, mean cellular hemoglobin and mean hemoglobin concentration, no major differences in blood counts occurred in B19V DNA-positive samples. In samples with a low B19V DNA concentration, anti-B19V IgG titers were rather high. 98 donors provided at least 1 B19V DNA-positive follow-up sample, indicating a prolonged viremia.

CONCLUSIONS

B19V infection induced no major impairment in the blood counts. In donors with low-level viremia, infectivity through their donations is probably reduced by high antibody titers. Low-level viremia is prolonged, probably exceeding 1 year in many cases.

Anemia among HIV-Infected Patients Initiating Antiretroviral Therapy in South Africa: Improvement in Hemoglobin regardless of Degree of Immunosuppression and the Initiating ART Regimen

Among those with HIV, anemia is a strong risk factor for disease progression and death independent of CD4 count and viral load. Understanding the role of anemia in HIV treatment is critical to developing strategies to reduce morbidity and mortality. We conducted a prospective analysis among 10,259 HIV-infected adults initiating first-line ART between April 2004 and August 2009 in Johannesburg, South Africa. The prevalence of anemia at ART initiation was 25.8%. Mean hemoglobin increased independent of baseline CD4. Females, lower BMI, WHO stage III/IV, lower CD4 count, and zidovudine use were associated with increased risk of developing anemia during follow-up. After initiation of ART, hemoglobin improved, regardless of regimen type and the degree of immunosuppression. Between 0 and 6 months on ART, the magnitude of hemoglobin increase was linearly related to CD4 count. However, between 6 and 24 months on ART, hemoglobin levels showed a sustained overall increase, the magnitude of which was similar regardless of baseline CD4 level. This increase in hemoglobin was seen even among patients on zidovudine containing regimens. Since low hemoglobin is an established adverse prognostic marker, prompt identification of anemia may result in improved morbidity and mortality of patients initiating ART.

Prevalence of Anemia and Immunological Markers in HIV-Infected Patients on Highly Active Antiretroviral Therapy in Northeastern Nigeria

BACKGROUND

There are conflicting reports on the impact of highly active antiretroviral therapy (HAART) in resolving hematological complications. Whereas some studies have reported improvements in hemoglobin and other hematological parameters resulting in reduction in morbidity and mortality of HIV patients, others have reported no improvement in hematocrit values of HAART-treated HIV patients compared with HAART-naïve patients.

OBJECTIVE

This current study was designed to assess the impact of HAART in resolving immunological and hematological complications in HIV patients by comparatively analyzing the results (immunological and hematological) of HAART-naive patients and those on HAART in our environment.

METHODS

A total of 500 patients participated, consisting of 315 HAART-naive (119 males and 196 females) patients and 185 HAART-experienced (67 males and 118 females) patients. Hemoglobin (Hb), CD4+ T-cell count, total white blood count (WBC), lymphocyte percentage, plateletes, and plasma HIV RNA were determined.

RESULTS

HAART-experienced patients were older than their HAART-naive counterparts. In HAART-naive patients, the incidence of anemia (packed cell volume [PCV] <30%) was 57.5%, leukopenia (WBC < 2.5), 6.1%, and thrombocytopenia < 150, 9.6%; it was, significantly higher compared with their counterparts on HAART (24.3%, 1.7%, and 1.2%, respectively). The use of HAART was not associated with severe anemia. Of HAART-naive patients, 57.5% had a CD4 count < 200 cells/μL in comparison with 20.4% of HAART-experienced patients (P < 0.001). The mean viral load log10 was significantly higher in HAART-naive than in HAART-experienced patients (P < 0.001). Total lymphocyte count < 1.0 was a significant predictor of <CD4 counts < 200 cells/μL in HAART-naïve patients, but this relationship was not observed in HAART-experienced patients.

CONCLUSION

HAART has the capability of reducing the incidence of anemia, other deranged hematological and immunological parameters associated with disease progression, and death in HIV-infected patients. Total lymphocyte count fails to predict CD4 count < 200 cells/μL in our cohort; thus, its use in the management and monitoring of HIV-infected patients in our settings is not reliable.

[Observations on human parvovirus B19 infection diagnosed in 2011]

INTRODUCTION

The incidence of human parvovirus B19 infection is unknown.

AIM

A retrospective analysis of clinical and laboratory findings was carried out in patients diagnosed with human parvovirus B19 infection in 2011 in a virologic laboratory of a single centre in Hungary.

METHODS

Clinical and laboratory data of patients with proven human parvovirus B19 infection were analysed using in- and out-patient files.

RESULTS

In 2011, 72 patients proved to have human parvovirus B19 infection with the use of enzyme immunoassay. The clinical diagnoses of these patients were as follows: human parvovirus B19 infection (30.6%), transient aplastic crisis (16.7%), arthritis (8.3%) and acute hepatitis (4.1%). Symptoms of each of the four phases of the infection occurred in various combinations with the exception of the monophase of cheek exanthema. This occurred without the presence of other symptoms in some cases. Leading symptoms and signs were exanthema (in 74.6% of cases), haematological disorders (in 69% of cases), fever (in 54.9% of cases) and arthritis (in 33.8% of cases). Several atypical dermatological symptoms were also observed. Acute arthritis without exanthema was noted in 8 patients. Of the 72 patients with proven human parvovirus B19 infection there were 7 pregnant women, and one of them had hydrops foetalis resulting spontaneous abortion. In 16 patients (22.5%) human parvovirus B19 IgG was undetectable despite an optimal time for testing.

CONCLUSION

The observations of this study may contribute to a better recognition of clinical symptoms of human parvovirus B19 infection.

Parvovirus transmission by blood products - a cause for concern?

The introduction of dual viral inactivation of clotting factor concentrates has practically eliminated infections by viruses associated with significant pathogenicity over the last 20 years. Despite this, theoretical concerns about transmission of infection have remained, as it is known that currently available viral inactivation methods are unable to eliminate parvovirus B19 or prions from these products. Recently, concern has been raised following the identification of the new parvoviruses, human parvovirus 4 (PARV4) and new genotypes of parvovirus B19, in blood products. Parvoviruses do not cause chronic pathogenicity similar to human immunodeficiency virus or hepatitis C virus, but nevertheless may cause clinical manifestations, especially in immunosuppressed patients. Manufacturers should institute measures, such as minipool polymerase chain reaction testing, to ensure that their products contain no known viruses. So far, human bocavirus, another new genus of parvovirus, has not been detected in fractionated blood products, and unless their presence can be demonstrated, routine testing during manufacture is not essential. Continued surveillance of the patients and of the safety of blood products remains an important ongoing issue.

Acute diarrhea in West African children: diverse enteric viruses and a novel parvovirus genus

Parvoviruses cause a variety of mild to severe symptoms or asymptomatic infections in humans and animals. During a viral metagenomic analysis of feces from children with acute diarrhea in Burkina Faso, we identified in decreasing prevalence nucleic acids from anelloviruses, dependoviruses, sapoviruses, enteroviruses, bocaviruses, noroviruses, adenoviruses, parechoviruses, rotaviruses, cosavirus, astroviruses, and hepatitis B virus. Sequences from a highly divergent parvovirus, provisionally called bufavirus, were also detected whose NS1 and VP1 proteins showed <39% and <31% identities to those of previously known parvoviruses. Four percent of the fecal samples were PCR positive for this new parvovirus, including a related bufavirus species showing only 72% identity in VP1. The high degree of genetic divergence of these related genomes from those of other parvoviruses indicates the presence of a proposed new Parvoviridae genus containing at least two species. Studies of the tropism and pathogenicity of these novel parvoviruses will be facilitated by the availability of their genome sequences.

Human immunodeficiency virus/human parvovirus B19 co-infection in blood donors and AIDS patients in Sichuan, China

BACKGROUND

Human parvovirus B19 (B19) is a common pathogen which causes a variety of diseases. Persistent B19 infection is related to the degree of host immunodeficiency in patients with human immunodeficiency virus (HIV) infection. However, the existence, loading, virus evolution and distribution of B19 in Chinese HIV-positive patients have not been determined.

MATERIALS AND METHODS

We investigated 573 HIV-positive blood donors and AIDS patients in Sichuan, China in the last two decades. Bl9-specific serology and quantitative polymerase chain reaction were used to determine the prevalence of B19/HIV co-infection. Viral genome fragments were subjected to phylogeny and haplotype analysis.

RESULTS

B19 genomic DNA was found in 26 of 573 (4.5%) HIV-positive individuals, a higher prevalence than in blood donors. DNA levels ranged from 5.3×10(2)-1.1×10(5) copies/mL. The seroprevalence of IgG was significantly lower in HIV-positive samples than in HIV-negative blood donors, indicating deficient production of B19-specific IgG in the former. The B19 isolates were genotype-1 subtype B19-1A which formed a monophyletic group; seven distinct haplotypes were discovered with 60% of the B19/HIV co-infected variants sharing one central haplotype.

DISCUSSION

This study on the prevalence, phylogeny and distribution of human parvovirus B19 in Sichuan, China, demonstrates the persistence of B19 in the circulation of both immunocompetent and immunocompromised subjects, with implications for blood safety.

Study on clinical characteristics and follow-up visit of acquired aplastic anemia associated with parvovirus B19 infection

OBJECTIVE

To investigate clinical characteristics of parvovirus (B19) related aplastic anemia (AA).

METHODS

Of the 28 children with AA included in this study, 24 were treated routinely and received planned follow-up; 15 were subject to B19-DNA re-examination during the treatment and 8 underwent examination for B19-IgM and B19-IgG. Another 39 initially identified AA children were enrolled as the controls and received the treatment same as the above-mentioned group.

RESULTS

There were more patients aged 5-8 y in the B19 infection group than the control group (P < 0.05). The course of AA in the B19 infection group was less than 2 mo and the serious aplastic anemia (SAA) and very serious aplastic anemia (VSAA) were more frequently observed in this group than the controls (P < 0.05). The overall efficacy of the treatments in the B19 infection group was more dismal than that in the controls (P < 0.05). Among 15 patients who were subjected to B19-DNA re-examination, negative findings were found in 6 patients with chronic aplastic anemia (CAA); the B19-DNA was persistently positive in 2 of the SAA and 5 VSAA patients. IgM and IgG were respectively detected in 3 and 2 patients out of the 8 children who received antibody examination.

CONCLUSIONS

Parvovirus B19 infection contributes to the generation of AA, particularly in children aged 5-8 y. The AA induced may be mainly classified as serious and very serious type, with a course of disease less than 2 mo. Patients can be saved if B19-DNA is eliminated and the antibody is produced.

Immunotherapies in infectious diseases

The development of an infection involves interplay between the host's immune system and the virulence of the infecting microorganism. The traditional treatment of an infection involves antimicrobial chemotherapy to kill the organism. The use of immunotherapies in infections includes treatment options that modulate the immune response and can lead to control of infections. These therapies are expected to become more important therapeutic options with the increase in infections due to multidrug-resistant organisms and the increasing number of immunocompromised patients.