A Multiplex Fluorescence of Loop Primer Upon Self-Dequenching Loop-Mediated Isothermal Amplification Assay for the Detection of Epstein-Barr Virus and Human Parvovirus B19 in Clinical Transplant Samples

Viral infections are major causes of mortality in solid-organ and hematopoietic stem cell transplant recipients. Epstein-Barr virus (EBV) and Parvovirus B19 (B19V) are among the common viral infections after transplantation and were recommended for increased screening in relevant guidelines. Therefore, the development of rapid, specific, and cost-effective diagnostic methods for EBV and B19V is of paramount importance. We applied Fluorescence of Loop Primer Upon Self-Dequenching Loop-mediated Isothermal Amplification (FLOS-LAMP) for the first time to develop a novel multiplex assay for the detection of EBV and B19V; the fluorophore attached to the probe are self-quenched in unbound state. After binding to the dumbbell-shaped DNA target, the fluorophore is dequenched, resulting in fluorescence development. The novel multiplex FLOS-LAMP assay was optimized by testing various ratios of primer sets. This novel assay, with great specificity, did not cross-react with the common virus. For the detection of EBV and B19V, the limits of detection could reach 969 and 798 copies/μL, respectively, and the assay could be completed within 25 min. Applying this novel assay to detect 200 clinical transplant individuals indicated that the novel assay had high specificity and good sensitivity. We developed multiplex FLOS-LAMP assay for the detection of EBV and B19V, which has the potential to become an important tool for clinical transplant patient screening.

Seroepidemiology of Human Parvovirus B19 Infection among the Population of Vojvodina, Serbia, over a 16-Year Period (2008-2023)

This study aimed to estimate the serological status and dynamic changes in the prevalence of Parvovirus B19 (PVB19) antibodies within the general population residing in the northern part of the Republic of Serbia (Province of Vojvodina) during a 16-year period. Serum samples were analyzed for Human PVB19-specific IgM and IgG antibodies using enzyme-linked immunosorbent assay (ELISA). Throughout the study period, the overall seroprevalence was 49.51%. Approximately 10% of patients exhibited a serologic profile positive for PVB19 IgM antibodies. Notably, seroprevalence varied significantly, ranging from 9.12% in the pediatric cohort (ages 1-4 years) to 65.50% in the adult demographic (40-59 years old). Seroprevalence was higher (51.88%) among women compared to men (42.50%). Immunologically naive pregnant women in the age groups 26-36 and 36-45 years had 45% (OR = 0.55, 95% CI: 0.31-1.00) and 52% (OR = 0.48; 95% CI: 0.24-0.94) lower odds of having negative IgM and IgG compared to those in age group 16-25 years old. Improved knowledge of the epidemiology of PVB19 may assist clinicians in the differential diagnosis of PVB19 clinical manifestations. The PVB19 detection is particularly important for monitoring individuals in risk groups such as women of reproductive age, medical staff, patients with hematological disorders, and those with immunodeficiency.

An Outbreak of Parvovirus B19 in Israel

Human parvovirus B19 (B19V) has a wide clinical spectrum, ranging from an asymptomatic infection to a life threatening one. During pregnancy, it can lead to fetal loss and hydrops fetalis. This retrospective study examined the incidence rates of B19V in Israel, analyzing anonymized electronic medical records of 2.7 million individuals between January 2015 and September 2023. A generalized linear model with a Poisson distribution was fit to the data, adjusting for potential confounders. A marked increase in B19V was observed in 2023, with an adjusted incidence rate ratio (IRR) of 6.6 (95% CI 6.33-6.89) when comparing 2023 to previous years. When specifically comparing 2023 to COVID-19 years (2020-2022), adjusted IRR climbs to 9.21 (8.66-9.80). Moreover, in 2023, previously existing seasonality has largely disappeared. High SES characterized most infected individuals with a marked discrepancy in social sectors; the Arab population was significantly less likely to be found B19V positive, even when adjusting for SES. Most infections occurred in school-aged children (6-11 years old). Pregnant women experienced the most significant rise in B19V, with an adjusted IRR of 11.47 (9.44-13.97) in 2023 compared to previous years; most cases were diagnosed in the first trimester. This study demonstrates that Israel is currently experiencing the largest and longest reported outbreak of B19V to date. Policymakers should consider setting screening policies in place, at least for populations at risk, while specifically studying and potentially targeting low socioeconomic populations and specific social sectors to avoid health inequalities.

Celastrol attenuates human parvovirus B19 NS1‑induced NLRP3 inflammasome activation in macrophages

Human parvovirus B19 (B19V) has been strongly associated with a variety of inflammatory disorders, such as rheumatoid arthritis (RA), inflammatory bowel disease and systemic lupus erythematosus. Non‑structural protein 1 (NS1) of B19V has been demonstrated to play essential roles in the pathological processes of B19V infection due to its regulatory properties on inflammatory cytokines. Celastrol, a quinone methide isolated from Tripterygium wilfordii, has displayed substantial potential in treating inflammatory diseases, such as psoriasis and RA. However, little is known about the effects of celastrol on B19V NS1‑induced inflammation. Therefore, cell viability assay, migration assay, phagocytosis analysis, zymography assay, ELISA and immunoblotting were conducted to verify the influences of celastrol on macrophages. The present study reported the attenuating effects of celastrol on B19V NS1‑induced inflammatory responses in macrophages derived from human acute monocytic leukemia cell lines, U937 and THP‑1. Although the migration was not significantly decreased by celastrol in both U937 and THP‑1 macrophages, significantly decreased viability, migration and phagocytosis were detected in both B19V NS1‑activated U937 and THP‑1 macrophages in the presence of celastrol. Additionally, celastrol significantly decreased MMP‑9 activity and the levels of inflammatory cytokines, including IL‑6, TNF‑α and IL‑1β, in B19V NS1‑activated U937 and THP‑1 cells. Notably, significantly decreased levels of NLR family pyrin domain‑containing 3, apoptosis‑associated speck‑like, caspase‑1 and IL‑18 proteins were observed in both B19V NS1‑activated U937 and THP‑1 cells in the presence of celastrol, indicating the involvement of the inflammasome pathway. To the best of our knowledge, the present study is the first to report on the attenuating effects of celastrol on B19V NS1‑induced inflammatory responses in macrophages, suggesting a therapeutic role for celastrol in B19V NS1‑related inflammatory diseases.

Encephalopathy Caused by Human Parvovirus B19 Genotype 1 Associated with Haemophilus influenzae Meningitis in a Newborn

Parvovirus B19 infection is associated with a wide range of clinical manifestations, from asymptomatic to severe neurological disorders. Its major clinical symptoms, fever and rash, are common to multiple viruses, and laboratory tests to detect B19 are frequently not available. Thus, the impact of B19 on public health remains unclear. We report the case of a 38-day old girl admitted to São Paulo Clinical Hospital, Brazil, with an initial diagnosis of bacterial meningitis, seizures, and acute hydrocephalus. Antibiotic therapy was maintained for one week after admission and discontinued after negative laboratory results were obtained. Nine days after symptoms onset, a cerebral spinal fluid (CSF) sample revealed persistent pleocytosis. The complete B19 complete genome was subsequently identified in her CSF by a metagenomic next-generation sequencing approach. This report highlights the possible involvement of B19 in the occurrence of acute neurological manifestations and emphasizes that its possible involvement might be better revealed by the use of metagenomic technology to detect viral agents in clinical situations of unknown or uncertain etiology.

[Hemophagocytic Syndrome Secondary to Human Parvovirus B19 Infection in an Acquired Immunodeficiency Syndrome Patient:Report of One Case]

The acquired immunodeficiency syndrome patients with compromised immunity are prone to hemophagocytic syndrome secondary to opportunistic infections.This paper reports a rare case of hemophagocytic syndrome secondary to human parvovirus B19 infection in an acquired immunodeficiency syndrome patient,and analyzes the clinical characteristics,aiming to improve the diagnosis and treatment of the disease and prevent missed diagnosis and misdiagnosis.

Tracking of Human Parvovirus B19 Virus-Like Particles Using Short Peptide Tags Reveals a Membrane-Associated Extracellular Release of These Particles

B19 virus (B19V) is a pathogenic human parvovirus that infects erythroid progenitor cells. Because there are limited in vitro culture systems to propagate this virus, little is known about the molecular mechanisms by which it propagates in cells. In this study, we introduced a HiBiT peptide tag into various loops of VP2 located on the surface of B19V particles and evaluated their ability to form virus-like particles (VLPs). Three independent sites were identified as permissive sites for peptide tag insertion without affecting VLP formation. When the HiBiT tag was introduced into B19V clones (pB19-M20) and transfected into a semipermissive erythroleukemia cell line (UT7/Epo-S1), HiBiT-dependent luciferase activities (HiBiT activities) increased depending on helicase activity of viral NS1. Furthermore, we used a GFP11 tag-split system to visualize VLPs in the GFP1-10-expressing live cells. Time-lapse imaging of green fluorescent protein (GFP)-labeled VLPs revealed that nuclear VLPs were translocated into the cytoplasm only after cell division, suggesting that the breakdown of the nuclear envelope during mitosis contributes to VLP nuclear export. Moreover, HiBiT activities of culture supernatants were dependent on the presence of a detergent, and the released VLPs were associated with extracellular vesicles, as observed under electron microscopy. Treatment with an antimitotic agent (nocodazole) enhanced the release of VLPs. These results suggest that the virions accumulated in the cytoplasm are constitutively released from the cell as membrane-coated vesicles. These properties are likely responsible for viral escape from host immune responses and enhance membrane fusion-mediated transmission. IMPORTANCE Parvovirus particles are expected to be applied as nanoparticles in drug delivery systems. However, little is known about how nuclear-assembled B19 virus (B19V) virions are released from host cells. This study provides evidence of mitosis-dependent nuclear export of B19V and extracellular vesicle-mediated virion release. Moreover, this study provides methods for modifying particle surfaces with various exogenous factors and contributes to the development of fine nanoparticles with novel valuable functions. The pB19-M20 plasmid expressing HiBiT-tagged VP2 is a novel tool to easily quantify VP2 expression. Furthermore, this system can be applied in high-throughput screening of reagents that affect VP2 expression, which might be associated with viral propagation.

Human parvovirus B19 infection in hospitalized patients suspected of infection with pathogenic microorganism

Background

Human parvovirus B19 (HPV B19) is a single-stranded DNA virus. The detection rate of HPV B19 in the blood of healthy blood donors using PCR technology was reported to be 6.323/100000. However, that among hospitalized patients suspected of being infected with a pathogenic microorganism is unknown.

Methods

A retrospective analysis was conducted on 2,182 high-throughput NGS results for 1,484 inpatients admitted to the First Affiliated Hospital of Zhengzhou University from January 2020 to October 2021 who were suspected of being infected with a pathogenic microorganism, as well as on clinical data of some HPV B19-positive patients.

Results

Human parvovirus B19 was detected in 39 samples from 33 patients. The positivity rate was 2.22% among patients and 1.78% among samples. HPV B19 was detected in 20 cerebrospinal fluid samples, 13 blood samples, 3 alveolar lavage fluid samples, 2 tissue samples, and 1 throat swab. Based on clinical symptoms and NGS results, 16 patients were diagnosed with HPV B19 infection. The number of HPV B19 sequences in these patients was greater than 6, and the patients showed common symptoms such as fever (14 cases), anemia (11 cases), and severe nervous system symptoms such as meningoencephalitis (9 cases) and Guillain-Barré syndrome with peripheral motor and sensory nerve axon damage (4 cases). All 16 patients had experienced events likely to lead to decreased immunity (11 had a history of trauma/surgery/major disease, 4 had a history of precursor infection, and 3 had used immunosuppressants) and 7 had a history of blood transfusion during hospitalization. After treatment with antiviral drugs (12 cases) and intravenous human immunoglobulin (3 cases), of the 16 patients, 14 patients improved.

Conclusion

The HPV B19 infection rate in hospitalized patients suspected of microbial infection was 2.22%. Most patients with HPV B19 infection had a history of low immunity and blood transfusion. HPV B19 could be detected in various bodily fluids and tissues (especially cerebrospinal fluid) using NGS. Patients with severe HPV B19 infection may have nervous system damage such as Guillain-Barré syndrome and meningoencephalitis. Early diagnosis using NGS and treatment with antiviral drugs and immunoglobulin can improve prognosis.

[A case of anti-SRP antibody-positive immune-mediated necrotizing myopathy triggered by human parvovirus B19 infection]

We have reported a case of a 44-year-old woman with anti-signal recognition particle (SRP) antibody-positive immune-mediated necrotizing myopathy triggered by human parvovirus B19 (PVB19) infection. She was admitted to the hospital because of lower leg edema and muscle weakness after erythema infectiosum. Magnetic resonance imaging of the lower extremities revealed high signals in the proximal muscles and subcutaneous edema on STIR. Muscle biopsy showed myofiber regenerative changes and variation in fiber size. A myositis-specific autoantibody profile indicated a positive result for anti-SRP antibodies. We diagnosed the patient with immune-mediated necrotizing myopathy (IMNM). Muscle strength and subcutaneous edema improved gradually in 3 months following immunotherapy. This is the first case report of an IMNM associated with PVB19 infection.

High-Resolution Structure of the Nuclease Domain of the Human Parvovirus B19 Main Replication Protein NS1

Two new structures of the N-terminal domain of the main replication protein, NS1, of human parvovirus B19 (B19V) are presented here. This domain (NS1-nuc) plays an important role in the "rolling hairpin" replication of the single-stranded B19V DNA genome, recognizing origin of replication sequences in double-stranded DNA, and cleaving (i.e., nicking) single-stranded DNA at a nearby site known as the terminal resolution site (trs). The three-dimensional structure of NS1-nuc is well conserved between the two forms, as well as with a previously solved structure of a sequence variant of the same domain; however, it is shown here at a significantly higher resolution (2.4 Å). Using structures of NS1-nuc homologues bound to single- and double-stranded DNA, models for DNA recognition and nicking by B19V NS1-nuc are presented that predict residues important for DNA cleavage and for sequence-specific recognition at the viral origin of replication. IMPORTANCE The high-resolution structure of the DNA binding and cleavage domain of the main replicative protein, NS1, from the human-pathogenic virus human parvovirus B19 is presented here. Included also are predictions of how the protein recognizes important sequences in the viral DNA which are required for viral replication. These predictions can be used to further investigate the function of this protein, as well as to predict the effects on viral viability due to mutations in the viral protein and viral DNA sequences. Finally, the high-resolution structure facilitates structure-guided drug design efforts to develop antiviral compounds against this important human pathogen.

Multisystem Involvement Induced by Human Parvovirus B19 Infection in a Non-immunosuppressed Adult: A Case Report

Background

Human parvovirus B19 (B19V) infection is usually symptomless and occurs in the childhood. While in immunocompromised adults, B19V infection also presents various clinical symptoms due to the host's immune status. The classic symptoms include erythema, anemia, arthropathy, and edema, but neurological involvement is rare.

Case Presentation

In this report, we present a case of B19V infection caused multiple organ dysfunction in a non-immunosuppressed adult. Metagenomic next-generation sequencing (mNGS) was used and successfully detected the pathogen in multiple types of samples, including blood, cerebrospinal fluid (CSF), and bronchoalveolar lavage fluid (BALF). The diagnosis was subsequently confirmed by polymerase chain reaction (PCR). He was treated with intravenous gamma globulin, resulting in a significant resolution of symptoms after 1 month.

Conclusion

Multisystem involvement induced by B19V infection was found in this case report. mNGS performed great advantages in rapidly and accurately diagnosing B19V infection in multiple types of samples, which helps the timely adjustment of treatment and improves the prognosis.

Interferon-β Suppresses Transcriptionally Active Parvovirus B19 Infection in Viral Cardiomyopathy: A Subgroup Analysis of the BICC-Trial

Human parvovirus B19 (B19V) is the predominant virus currently detected in endomyocardial biopsies (EMBs). Recent findings indicate that, specifically, transcriptionally active B19V with detectable viral RNA is of prognostic relevance in inflammatory viral cardiomyopathy. We aimed to evaluate B19V replicative status (viral RNA) and beneficial effects in a sub-collective of the prospective randomized placebo-controlled phase II multi-center BICC-Trial (Betaferon In Chronic Viral Cardiomyopathy) after interferon beta-1b (IFN-β) treatment. EMBs of n = 64 patients with B19V mono-infected tissue were retrospectively analyzed. Viral RNA could be detected in n = 18/64 (28.1%) of B19V DNA positive samples (mean age 51.7 years, 12 male), of whom n = 13 had been treated with IFN-ß. Five patients had received placebo. PCR analysis confirmed in follow-up that EMBs significantly reduced viral RNA loads in n = 11/13 (84.6%) of IFN-ß treated patients (p = 0.001), independently from the IFN-ß dose, in contrast to the placebo group, where viral RNA load was not affected or even increased. Consequently, a significant improvement of left ventricular ejection fraction (LVEF) after treatment with IFN-ß was observed (LVEF mean baseline 51.6 ± 14.1% vs. follow-up 61.0 ± 17.5%, p = 0.03). In contrast, in the placebo group, worsening of LVEF was evaluated in n = 4/5 (80.0%) of patients. We could show for the first-time the beneficial effects from treatment with IFN-ß, suppressing B19V viral RNA and improving the hemodynamic course. Our results need further verification in a larger prospective randomized controlled trial.

Donor-Derived Human Parvovirus B19 Infection in Kidney Transplantation

Background

Donor-derived human parvovirus B19 (B19V) infections are rarely reported. Thus, its incidence in kidney transplantation is still unknown due to lack of surveillance studies. Similarly, whether the donor needs to be routinely screened for B19V and whether the kidneys from those with B19V DNAemia could be accepted also remain unknown.

Methods

This retrospective study aims to evaluate the donor-derived B19V infections occurring in 823 living and 1,225 deceased donor kidney transplantations from January 2016 to December 2020. The serum viral load of living donors and their corresponding recipients was evaluated before and after transplantation. Meanwhile, for the deceased donor kidney transplantation, the serum viral load of recipients was only tested after transplantation; if recipients of a deceased donor subsequently developed B19V infection, the serum viral load of recipients and their corresponding donors before transplantation would then be further traced.

Results

A total of 15 living donors were B19V DNAemia positive before the donation, of which B19V DNAemia occurred in three corresponding recipients. In deceased donor kidney transplantation, DNAemia occurred simultaneously in 18 recipients and their corresponding nine donors. A progressive decline in hemoglobin and reticulocyte count could be observed in one living donor recipient and other 11 deceased donor recipients, which were all well controlled by treatment eventually.

Conclusion

The incidence of donor-derived B19V infection was 0.4% and 1.5% in living and deceased kidney transplantations, respectively. B19V was seemingly unnecessary to be routinely screened for the donor. Moreover, kidneys of the donors with B19V infection were acceptable.

Foscarnet Therapy for Pure Red Cell Aplasia Related to Human Parvovirus B19 Infection in Kidney Transplant Recipients: A Preliminary Exploration

Background

Parvovirus B19-associated pure red cell aplasia (PVB19-PRCA) is an uncommon but serious complication after kidney transplantation. Currently, intravenous immunoglobulin (IVIG) is preferred as the first-line treatment for PVB19-PRCA, but presents with disadvantages of disease recurrence and expensive cost. In this context, we propose that foscarnet therapy for kidney transplantation recipients (KTR) with PVB19-PRCA may be an alternative scenario. No related study has been reported, and we performed this study to assess the efficacy and safety of foscarnet for PVB19-associated PRCA in KTR.

Methods

We conducted a retrospective review of PVB19-PRCA in KTR at our center over 9-year period. The data on therapy and outcomes in all cases treated with foscarnet are detailed records and summarized.

Results

Among our 68 patients, PVB19-PRCA was confirmed in 50 based on inclusion/exclusion criteria. All patients presented with refractory anemia and low reticulocyte percentage (<0.5%), the mean hemoglobin of patients was 79.8±12.6g/L at the time of PVB19-PRCA was identified. The median serum genome copy number of parvovirus B19 at diagnosis was 9.6 log₁₀ copies per milliliter. A total of 11 patients received foscarnet therapy, of 10 patients responded well to the treatment and maintained no recurrence. But 1 patient had a poor response to foscarnet therapy. Except for this patient, the mean hemoglobin level gradually increased from 68.5±9.3 g/L to 73.2±8.8 g/L, and the mean percentage of reticulocytes steadily increased from 0.1±0.0% to 7.6±2.9% after foscarnet therapy. The median serum genome copy number of parvovirus B19 decreased from 9.8 log₁₀ to 6.1 log₁₀ copies per milliliter. There was no significant difference (P=0.61, 0.60) in serum creatinine and glomerular filtration rate before and after foscarnet treatment. At the latest follow-up, the mean hemoglobin was 131.5±12.5 g/L and the hemoglobin correction occurred in all patients.

Conclusion

Foscarnet therapy doesn't seem to be worse than IVIG for PVB19-PRCA in KTR, and it can be an alternative option.

Screening for parvovirus B19 antigen through chemiluminescent enzyme immunoassay is equivalent to B19 nucleic acid amplification test-based screening of pooled plasma

BACKGROUND

Human parvovirus B19 (B19) is a pathogen that threatens the quality of plasma products. Therefore, health authorities have mandated measures against B19 contamination of plasma pools. The US FDA has recommended a B19 genome level of 10⁴  IU/ml or lower in pooled plasma lots. Therefore, the B19 nucleic acid amplification test (B19-NAT) has been introduced in many plasma fractionators. However, in the Japanese Red Cross, which is the only approved blood collector in Japan, the B19 antigen test has been introduced for screening donated blood in Japan. Therefore, to clarify whether the antigen test is robust enough to screen blood samples according to the FDA recommendation, we evaluated B19 genome levels in each pooled plasma lot from 2003 to 2020.

STUDY DESIGN AND METHODS

Data of 5576 pooled plasma lots from factories A and B, which were derived from plasma bags and passed the B19 antigen-based tests, receptor-mediated hemagglutination assay (B19-RHA), or chemiluminescent enzyme immunoassay (B19-CLEIA), during 2003 to 2020, were evaluated. The amount of B19 genome in each lot was determined using quantitative or semiquantitative B19-NAT.

RESULTS

The B19 genome levels in pooled plasma lots screened using B19-RHA did not meet the FDA recommendation, whereas the lots derived from B19-CLEIA fulfilled the FDA recommendation, even during the B19 epidemic in Japan.

DISCUSSION

The results suggest that the B19-CLEIA donor screening for plasma pools is also useful in light of the US FDA recommendation.

Acute human parvovirus B19 infection triggers immune-mediated transient bone marrow failure syndrome, extreme direct hyperbilirubinaemia and acute hepatitis in patients with hereditary haemolytic anaemias: multicentre prospective pathophysiological study

A total of 244 patients with hereditary haemolytic anaemias (HHA) were screened for acute symptomatic human parvovirus B19 infection (HPV-B19) in a prospective study. To assess the risks associated with HPV-B19 infection, patients were classified into Group I and Group II according to presence or absence (symptoms, signs and specific serology) of acute HPV-B19 infection respectively. In all, 131 (53·7%) patients had β-thalassaemia, 75 (30·7%) hereditary spherocytosis (HS), 27 (11·1%) sickle cell anaemia (SCA) and 11 (4·5%) glucose-6-phosphate dehydrogenase (G6PD) deficiency. Of 33 (13·5%) patients who presented with symptomatic HPV-B19 infection, 19 (57·5%) had HS, nine (27·3%) had β-thalassaemia and five (15·2%) had SCA. In Group I, there were significant differences in the mean white blood cell, red blood cell and platelet counts, haemoglobin concentration, total bilirubin (TB), alanine aminotransferase, aspartate aminotransferase and serum creatinine (all P < 0·001) compared to Group II. In all, 27 (81·8%) patients had arthropathy and bone marrow failure (BMF); 13 (39·4%) had acute kidney injury (AKI), more in SCA (80%); and 12 (36·4%) patients had hepatitis, more in HS (66·8%). Five (15·2%) patients with HS had BMF, AKI, nervous system involvement and extreme hyperbilirubinaemia (TB range 26·3-84·7 mg/dl). Five (15·2%) patients had haemophagocytic syndrome. Two patients with HS combined with Type-I autoimmune hepatitis presented with transient BMF. Complete recovery or stabilisation was noted at 12 months in every patient except for one patient with SCA who died during the infection. HPV-B19 must be suspected and screened in patients with HHA with typical and atypical presentations with careful follow-up.

Identification of human parvovirus 4 genotypes 1 and 2 in Chinese source plasma pools

Human parvovirus B19 (B19V) and human parvovirus 4 (PARV4) are known to infect humans and transmit through contaminated blood and blood products. Globally, three genotypes of B19V, as well as PARV4, have been identified, respectively. The existence of different B19V genotypes in Chinese plasma donors has been investigated, however, the data regarding PARV4 were not available. The main objective of this study is to identify the genotypes of PARV4 circulating in Chinese plasma donors. By using a duplex quantitative polymerase chain reaction assay adapted for all genotypes of B19V and PARV4, 78 source plasma pools for fractionation were screened and quantified. Results showed that positive rates of B19V and PARV4 DNA in plasma pool samples were 25.64% and 14.10%, respectively. PARV4 sequences in two positive samples were next genotyped, and these two sequences belonged to PARV4 genotypes 1 and 2, respectively. In conclusion, the data present demonstrate the existence of PARV4 genotypes 1 and 2 in Chinese plasma donors for the first time and also show the relatively lower prevalence and level of PARV4 DNA in Chinese plasma donors in comparison with that of B19V DNA.

At least two PARV4 genotypes, 1 and 2, were currently present in China.

The prevalence and level of PARV4 DNA in Chinese plasma donors were relatively lower in comparison with that of B19V DNA.

The rate of B19V and PARV4 coinfection in Chinese source plasma pools was low.

Detection of IgM and IgG Antibodies to Human Parvovirus B19 in Sera of Patients with Thymoma-Associated Myasthenia Gravis

Much uncertainty still exists about the viral etiology of myasthenia gravis (MG). To address this, we explored the relationship between human parvovirus B19 (PVB19) infection and MG by investigating the presence of PVB19-specific antibodies in serum. A total of 131 patients with MG (including 47 with thymoma-associated MG, 14 with hyperplasia-associated MG, and 70 with unknown thymic lesions) and 172 healthy volunteers were enrolled in this study. Enzyme linked immunosorbent assay was conducted to detect virus-specific antibodies in cell-free serum. The data were analyzed using Pearson chi-square (χ²) and Fisher's exact tests. In the 131 patients with MG, there was no significant difference between male (53.41 ± 14.65 years) and female (50.19 ± 15.28 years) groups regarding mean age (p > 0.05). Among all MG subgroups, the largest age group comprised participants aged 30-60 years. We found that the frequency of detecting immunoglobulin G (IgG) antibodies against PVB19 VP1 and VP2 was significantly higher among patients with MG (68.70%) than in healthy controls (41.86%) (p < 0.001). In particular, the positive rate for anti-PVB19 IgG in patients with thymoma-associated MG (35/47, 74.47%) was significantly higher than that in healthy participants (72/172, 41.86%; p < 0.001). The findings of this study indicate that PVB19 infection may play a role in the etiopathogenesis of MG, particularly in patients with thymoma-associated MG. The study protocol was registered at ClinicalTrials.gov with the identifier ChiCTR-1900023338.

Human Parvoviruses May Affect the Development and Clinical Course of Meningitis and Meningoencephalitis

Meningitis and meningoencephalitis are neurological inflammatory diseases, and although routine diagnostics include testing of a wide range of pathogens, still in many cases, no causative agent is detected. Human parvovirus B19 (B19V), human bocaviruses 1–4 (HBoV1–4), and human parvovirus 4 (hPARV4) are members of the Parvoviridae family and are associated with a wide range of clinical manifestations including neurological disorders. The main aim of this study was to determine whether human parvoviruses infection markers are present among patients with meningitis/meningoencephalitis in Latvia as well as to clarify the role of these viruses on the clinical course of the mentioned diseases. Our study revealed HBoV1–4 and B19V genomic sequences in 52.38% and 16.67% of patients, respectively. Furthermore, symptoms such as the presence of a headache and its severity, fatigue, disorientation, and difficulties to concentrate were significantly frequently present in patients with active parvovirus infection in comparison with parvoviruses negative patients, therefore we suggest that HBoV1–4 and B19V infection should be included in the diagnostics to reduce the number of meningitis/meningoencephalitis with unknown/unexplained etiology.

New Insights of Human Parvovirus B19 in Modulating Erythroid Progenitor Cell Differentiation

Human parvovirus B19 (B19), a human pathogen of the erythroparvovirus genus, is responsible for a variety of diseases. B19 cause less symptoms in healthy individuals, also cause acute and chronic anemia in immunodeficiency patients. Transient aplastic crisis and pure red cell aplasia are two kinds of anemic hemogram, respectively, in acute and chronic B19 infection phase, especially occurring in patients with a shortened red cell survival or with immunodeficiency. In addition, B19-infected pregnant women may cause hydrops fetalis or fetal loss. B19 possesses high affinity to bone marrow and fetal liver due to its extremely restricted cytotoxicity to erythroid progenitor cells (EPCs) mediated by viral proteins. The nonstructural protein NS1 is considered to be the major pathogenic factor, which has been shown to inhibit the differentiation and maturation of EPCs through inducing viral DNA damage responses and cell cycle arrest. The time phase property of NS1 activity during DNA replication and conformity to transient change of hemogram are suggestive of its role in regulating differentiation of hematopoietic cells, which is not completely understood. In this review, we summarized the bridge between B19 NS1 and Notch signaling pathway or transcriptional factors GATA, which play an important role in erythroid cell proliferation and differentiation, to provide a new insight of the potential mechanism of B19-induced differential inhibition of EPCs.

Identification of human parvovirus B19 among measles and rubella suspected patients from Cuba

Between September 2014 and December 2015, 298 sera from rash and fever patients from all over Cuba were investigated for specific IgM antibodies against measles, rubella, dengue, human parvovirus B19 (B19V) and human herpesvirus 6 (HHV6) using a commercial enzyme-linked immunosorbent assay kits. B19V IgM positive and equivocal samples were investigated by a polymerase chain reaction and genotyping. No measles, rubella or dengue cases were detected. HHV6-IgM antibodies were confirmed in 5.7% and B19V-IgM antibodies in 10.7% of the patients. A total of 31.3% of the B19V cases were between 5 and 9 years old and 34.4% were 20 years and older. The only B19V sequence obtained belonged to genotype 1a. Diagnosis was established for only 16% of the rash and fever patients, suggesting that other diseases such as Zika or Chikungunya may play a role.

Antibodies against human parvovirus B19 in pregnant women in Ogbomoso, Oyo State Nigeria

Infection caused by Human parvovirus B19 (HPVB19) during pregnancy has been associated with adverse effects on fetus such as intrauterine fetal death but there is dearth information about the seroprevalence and risk factors among pregnant women. This study was carried out to determine the incidence of specific IgM antibodies to HPVB19 among pregnant women attending Bowen University Teaching Hospital, Ogbomoso, Oyo State. A total of 185 participants, in the age range 18-49 years, who consented voluntarily after thorough explanation of the purpose of the study were recruited for the study. Specific IgM antibodies were detected using commercially available third-generation ELISA kits. Data on socio-demographic characteristics and potential risk factors were collected using structured questionnaires. Chi-square (χ²) test was utilized to assess the association between the socio-demographic variables and HPVB19 status (P ˂ 0.05). Logistic regression was done to determine the strength of association between the potential risk factors and HPVB19 status (P ˂ 0.05). The overall incidence of IgM antibody recorded was 2.70% (5/185). Pregnant women in the age group 36-45 (7.7%) years had the highest record. None of the socio-demographic characteristics and risk factor considered were significantly associated with acquiring HPVB19. However, a one-fold risk was observed among those who had previous history of blood transfusion (95% CI = 0.949-0.997, OR = 1.0) The findings in this study confirmed the presence of antibodies to HPVB19 among pregnant women in Ogbomoso. Public awareness, enlightenment, and screening for the virus should be encouraged to prevent fetal complications during pregnancy.

Post-infectious acute glomerulonephritis with podocytopathy induced by parvovirus B19 infection

Human parvovirus B19 infection causes a variety of glomerular diseases such as post-infectious acute glomerulonephritis and collapsing glomerulopathy. Although each of these appears independently, it has not been fully determined why parvovirus B19 provokes such a variety of different glomerular phenotypes. Here, we report a 68-year-old Japanese man who showed endocapillary proliferative glomerulonephritis admixed with podocytopathy in association with parvovirus B19 infection. The patient showed acute onset of heavy proteinuria, microscopic hematuria and kidney dysfunction with arthralgia and oliguria after close contact with a person suffering from erythema infectiosum. In the kidney biopsy specimen, glomeruli revealed diffuse and global endocapillary infiltration of inflammatory cells, with some also showing tuft collapse with aberrant vacuolation, swelling, and hyperplasia of glomerular epithelial cells. Immunofluorescence revealed dense granular C3 deposition that resembled the "starry sky pattern". Intravenous glucocorticoid pulse therapy followed by oral prednisolone and cyclosporine combination therapy resulted in considerable amelioration of the kidney dysfunction and urinary abnormalities. The present case reveals that parvovirus B19 infection can induce different glomerular phenotypes even in the same kidney structure. This finding may provide hints useful for the further elucidation of the pathogenesis of parvovirus B19-induced glomerular lesions.

The Impact of Human Parvovirus B19 Infection on Heart Failure and Anemia with Reference to Iron Metabolism Markers in an Adult Woman

A 35-year-old woman with fever, edema and rash was admitted. Pleural effusion and cardiomegaly were observed. A laboratory analysis revealed anemia with iron deficiency and elevated human parvovirus B19 (B19V) immunoglobulin M. The patient's hepcidin-25 and erythroferrone levels were not elevated compared to those observed later in her clinical course. On the other hand, her growth differentiation factor-15 (GDF-15) levels were elevated. She was diagnosed to have heart failure symptoms and anemia with specific iron metabolism abnormalities due to a B19V infection. After providing supportive treatment, the heart failure symptoms disappeared and her anemia had improved. This case emphasizes the need to include a B19V infection in the differential diagnosis when we encounter cases demonstrating reversible heart failure with anemia.

Insights into epidemiology of human parvovirus B19 and detection of an unusual genotype 2 variant, Bulgaria, 2004 to 2013

The present study aimed to determine the role of human parvovirus В19 (B19V) as an aetiological agent in measles and rubella negative fever/rash patients from Bulgaria between 2004 and 2013. A total of 1,266 sera from all over the country were tested for B19V IgM antibodies and all positives were further investigated by polymerase chain reaction (PCR). Overall, 280 sera (22%) were B19V IgM positive and 227 of these (81%) were also PCR positive. The highest number of IgM positives was found among five to nine year-old children (27%). Eight infected women gave birth to healthy children; one fetus was aborted with hydrops fetalis. Of the 55 genetic sequences obtained, 54 belonged to genotype 1a and one grouped as a genotype 2 outlier. Phylogenetic analysis of all available genotype 2 sequences covering the 994 nucleotide non-structural protein 1(NS1)/capsid viral protein 1 (VP1) unique region junction, showed that only one other sequence grouped with the outlier strain, forming a clearly distinct and well-supported cluster of genotype 2 (between-group genetic distance: 3.32%). In accordance with B19V nomenclature, this cluster may represent a new subgenotype 2b. The study showed that B19V infections may be falsely identified as rubella or measles in ca 22% of cases, emphasising the need for laboratory confirmation.

Genotype 3b of human parvovirus B19 detected from hospitalized children with solid malignancies in a North Indian tertiary care hospital

Human parvovirus B19 (B19V) infection is known to cause serious consequences in immuno-compromized individuals. The present cross sectional study was designed to estimate the prevalence and genotype distribution of B19V in children receiving chemotherapy for solid malignancies at a tertiary care hospital in North India during October 2013 to May 2015. Serum samples from all the patients were tested for anti-B19V IgM and IgG antibodies and for B19V-DNA as soon as received. Samples testing positive for B19V-DNA were subjected to viral load estimation and to genotype determination by sequencing. Total 96 children were enrolled of which 9 (9.3%), 32 (33.3%), and 25 (26%) tested positive for anti-B19V IgM, anti-B19V IgG, and B19V-DNA, respectively. The viral load of B19V-DNA positive children ranged from 5.5 × 10(2) to 3.5 × 10(12) copies/ml. Accordingly children were divided into three groups: group I, with acute infection (n = 25); group II, previously exposed (n = 27), and group III, negative for B19V infection or with inappropriate antibody response (n = 44). B19V positivity was significantly associated (P-value < 0.0001) with a history of blood transfusion in the past 6 months, severe anemia (hemoglobin levels <6 gm%) and thrombocytopenia (platelets <150,000/cu.mm.). Sequence analysis of 21 of 25 DNA positive samples showed that all of them were Genotype 3b that clustered into three groups. All the sequences within each cluster were identical. The nucleotide identity of the sequences suggests a nosocomial outbreak of B19V during the study period. Children on chemotherapy for solid tumors should be routinely screened for B19V infection by both serology and PCR. J. Med. Virol. 88:1922-1929, 2016. © 2016 Wiley Periodicals, Inc.

Focal seizure associated with human parvovirus B19 infection in a non-encephalopathic child

BACKGROUND

The incidence of acute symptomatic (at the time of documented brain insult) seizures and single unprovoked seizures are 29-39 and 23-61 per 100 000 per year, respectively. After stabilization of the patient, finding the etiology of the seizure is of paramount importance. A careful history and physical examination may allow a diagnosis without need for further evaluation.

METHODS

In the literature, severe central nervous system involvement has been reported from human parvovirus B19 infection. We reported a previously healthy 7-year-old girl who presented after an episode of focal seizure. She was afebrile and didn't have any focal neurological abnormalities. She had erythematous malar rash along with reticulating pattern of rash over her both upper extremities.

RESULTS

Parvovirus infection was suspected due to the characteristic erythematous malar rash. Serum human parvovirus B19 DNA polymerase chain reaction was positive which was consistent with acute parvovirus infection. Further confirmation of current infection was done with Sandwich enzyme immunoassays showing positive anti-B19 IgM Index (>1.1). IgG index was equivocal (0.9-1.1).

CONCLUSIONS

We report an extremely rare presentation of non-febrile seizure from acute parvovirus infection in a child without encephalopathy who had an excellent recovery. Timely diagnosis can provide counselling regarding future seizure recurrence risk, curtail expenditure from expensive diagnostic work up and provide additional recommendations about potential risks to a pregnant caregiver.

Spectrum of adult Parvovirus B19 infection according to the underlying predisposing condition and proposals for clinical practice

The virological diagnosis of Parvovirus B19 (PvB19) infection is currently based on sero-diagnosis, molecular methods or both, yet without clear recommendations. We retrospectively identified patients with polymerase chain reaction-positive PvB19 and/or positive serological assay between 2007 and 2013. Eighty-two adults with at least one diagnostic criterion of recent PvB19 infection (IgM antibodies, viral DNA in blood and/or in marrow) were included and classified into three homogeneous groups: 30 patients had no underlying predisposing condition, 25 a hereditary haemolytic anaemia, 27 an underlying immunodeficiency. The classical PvB19-related manifestations were less frequent in immunocompromised than in immunocompetent patients (arthromyalgia: 5 vs. 14; erythema: 4 vs. 17, respectively). Only 41·4% of patients with no underlying disease were anaemic. Bicytopenia and pancytopenia were observed mainly in immunocompromised patients. Classical pure red cell aplasia was observed in only 9 of the 27 marrow smears performed. Specific IgM were found in 93% of immunocompetent patients, whereas only 58% had detectable viral DNA in blood. IgM and DNA were present alone or together in all patients with hereditary haemolytic anaemia. In immunocompromised patients, the diagnosis was confirmed by marrow analysis in 91% of cases. We make some proposals based on this large series of PvB19-infected patients.

Three Adult Cases of HPV-B19 Infection with Concomitant Leukopenia and Low Platelet Counts

We encountered three adult patients with flu-like symptoms diagnosed with human parvovirus B19 (HPV-B19) infection. Blood serum analysis also revealed leukopenia, with white blood cell counts (WBCs) of 1,000–2,000/mL and low platelet counts of 89–150 × 10⁹/L. Typical skin rash was absent in one patient. Bone marrow examination of another patient showed hypoplastic marrow with <5% blast cells. All patients recovered without administration of granulocyte colony-stimulating factor (G-CSF). Therefore, HPV-B19 infection with leukopenia should be considered in adult patients with leukopenia during erythema infectiosum epidemics, even if typical clinical findings (ie, skin rash) are absent. Further, the fact that three cases were observed over the stated time period at our hospital, which is located in Nagoya city, showed a transition to a slightly higher level of incidence than the annual average.

Human parvovirus B19: a mechanistic overview of infection and DNA replication

Human parvovirus B19 (B19V) is a human pathogen that belongs to genus Erythroparvovirus of the Parvoviridae family, which is composed of a group of small DNA viruses with a linear single-stranded DNA genome. B19V mainly infects human erythroid progenitor cells and causes mild to severe hematological disorders in patients. However, recent clinical studies indicate that B19V also infects nonerythroid lineage cells, such as myocardial endothelial cells, and may be associated with other disease outcomes. Several cell culture systems, including permissive and semipermissive erythroid lineage cells, nonpermissive human embryonic kidney 293 cells and recently reported myocardial endothelial cells, have been used to study the mechanisms underlying B19V infection and B19V DNA replication. This review aims to summarize recent advances in B19V studies with a focus on the mechanisms of B19V tropism specific to different cell types and the cellular pathways involved in B19V DNA replication including cellular signaling transduction and cell cycle arrest.

Quantitative analysis of human parvovirus B19 DNA in maternal and fetal serum, and amniotic fluid during an early stage of pregnancy

Simple and accurate diagnosis of vertical transmission of human parvovirus B19 (B19V) infection remains an important issue in pregnancy. There are few reports on quantitative analysis of B19V in amniotic fluids. Quantitative estimation of B19V DNA in amniotic fluids was comparerd with those in maternal or fetal serum obtained at an early stage of pregnancy with possible mother-to-fetus transmission. All pregnant women contracted B19V infection between 13 to 14 weeks gestation. The B19V DNA amount in 3 maternal serum and amniotic fluid sample pairs collected between 16 to 27 weeks gestation was quantified by a real-time polymerase chain reaction assay. Serum from 2 fetuses was included. The B19V DNA concentrations in maternal sera and amniotic fluids ranged from 10(4) to 10(5) copies/ml and from 10(7) to 10(8) copies/ml, respectively. The B19V DNA in the amniotic fluids concentration coincided with those of each fetal serum. The concentrations in amniotic fluids are 100 to 5,000 times higher than in those of maternal sera, and corresponded to the matching fetal serum. Amniotic fluids may substitute for the fetal sera in terms of quantitative estimation of fetal B19V infection at an early stage of pregnancy.

Rhabdomyolysis associated with human parvovirus B19 infection in a patient with Fukuyama-type congenital muscular dystrophy

Patients with Fukuyama-type congenital muscular dystrophy sometimes experience transient exacerbations of muscle weakness. We took care of a 9-year-old boy with Fukuyama-type congenital muscular dystrophy who presented with acute respiratory failure and decreased exercise ability with marked elevation of serum creatine kinase indicating rhabdomyolysis. At that time, his younger sister suffered from erythema infectiosum. Although he had no particular symptoms, he was tested and proven to have acute human parvovirus B19 infection based on detection of anti-B19 IgM and parvovirus B19 DNA in his serum. His acute rhabdomyolysis was possibly triggered by human parvovirus B19 infection.

Quantitation of human parvovirus B19 DNA in erythema infectiosum and aplastic crisis

Several publications concerning the methods of real-time PCR for human parvovirus B19 (B19V) have appeared and some case reports mention B19V DNA loads. However, no large-scale study quantitating levels of B19V DNA in common or representative B19V manifestations such as erythema infectiosum and aplastic crisis has been performed. Consequently, using the TaqMan PCR assay, the B19V load in a large sample of subjects with erythema infectiosum or aplastic crisis was quantitated. Sixty-five subjects in the acute phase of erythema infectiosum were involved, and in addition 22 serum samples from seven subjects with B19V-associated aplastic crisis complicating chronic hemolytic anemia were also analyzed. In the acute phase of erythema infectiosum the median B19V DNA load in the serum samples from the acute phase of erythema infectiosum was 7.63 × 10(5)  genomes/ml, (range from 4.48 × 10(3) to 8.31 × 10(6)  genomes/ml). The serum B19V DNA load during the acute phase of aplastic crisis complicating chronic hemolytic anemia was extremely high, that is 10(10) -10(13)  genomes/ml, and decreased gradually to around 10(5) genomes/ml over 1-2 months. Although all subjects followed an almost uniform and typical clinical course of erythema infectiosum, there was a large individual variation of B19V DNA loads, that is differences of over 1,000 times. Extremely high B19V loads were observed in subjects with aplastic crisis. This study is the first large scale report of studies of the B19V DNA loads in subjects with erythema infectiosum and aplastic crisis, the most common and significant clinical manifestations by B19V infections.

A case of recurrent autoimmune hemolytic anemia during remission associated with acute pure red cell aplasia and hemophagocytic syndrome due to human parvovirus B19 infection successfully treated by steroid pulse therapy with a review of the literature

The patient was a 47-year-old man diagnosed as having autoimmune hemolytic anemia (AIHA) in April 2011. He also had a congenital chromosomal abnormality, a balanced translocation. Treatment with prednisolone (PSL) 60 mg/day resulted in resolution of the AIHA, and the treatment was completed in November 2011. While the patient no longer had anemia, the direct and indirect Coombs tests remained positive. In May 2013, he developed recurrent AIHA associated with acute pure red cell aplasia (PRCA) and hemophagocytic syndrome (HPS) caused by human parvovirus B19 (HPV B19) infection. Tests for anti-erythropoietin and anti-erythropoietin receptor antibodies were positive. Steroid pulse therapy resulted in resolution of the AIHA, PRCA, as well as HPS. The serum test for anti-erythropoietin antibodies also became negative after the treatment. However, although the serum was positive for anti-HPV B19 IgG antibodies, the patient continued to have a low CD4 lymphocyte count (CD4, <300/μL) and persistent HPV B19 infection (HPV B19 DNA remained positive), suggesting the risk of recurrence and bone marrow failure.

Acute transverse myelitis associated with human parvovirus b19 infection

We describe severe acute transverse myelitis in a previously healthy 9-year-old boy in whom primary human parvovirus B19 infection was confirmed serologically and B19 DNA was detected in his serum and cerebrospinal fluid. Besides erythema infectiosum, parvovirus B19 infection has various clinical manifestations; however, central nervous system involvement is rare. Even more unusual is parvovirus B19-associated acute transverse myelitis.

Acquired Pure Red Cell Aplasia caused by Parvovirus B19 Infection following a Renal Transplant

We report a young Omani male who developed severe and persistent anaemia after a kidney transplantation while being on immunosuppression therapy, standard practice to prevent rejection of the transplanted kidney. His bone marrow aspirate showed the classic morphological changes of pure red cell aplasia (PRCA), induced by parvovirus B19 infection which is the presence of giant proerythroblasts with viral inclusions. The virus was also demonstrated by polymerase chain reaction in the blood along with IgM antibodies to parvovirus B19. He responded dramatically to high dose immunoglobulin with a normalisation of his haemoglobin level in two weeks and remained normal until seven months later. Parvovirus B19 induced PRCA can be cured. This aetiology must be kept in mind especially when a chronic anaemia, refractory to treatment, is accompanied by a reticulocytopenia. The latter reflects the lysis of the proerythroblasts, preventing maturation of the erythroid cells causing anaemia. Early recognition and prompt treatment spares the patient unnecessary exposure to blood transfusions, erythropoietin and renal disease caused by the virus. PRCA secondary to parvovirus B19 infection following kidney transplantation is reported in the literature, but not in the Omani population. To the best of our knowledge, this is the first such report in Oman.