Prevalence and Phylogenetic Analysis of Parvovirus (B19V) among Blood Donors with Different Nationalities Residing in Qatar.

Human parvovirus (B19V) is the causative agent of erythema infectiosum in children and is linked to a wide range of clinical manifestations. Studies related to B19V prevalence in the Middle East and North Africa (MENA) region and other parts of Asia are very scarce. The objectives of this study were to estimate the seroprevalence (anti-B19V IgM and IgG), the viremia rate (B19V DNA), and the circulating genotypes of B19V among blood donors in Qatar. METHODS: Donors' blood samples (n = 5026) from different nationalities, mainly from the MENA region and South East Asia, were collected from 2014-2016. Samples were tested for the B19V DNA using RT-PCR. Furthermore, 1000 selected samples were tested to determine the seroprevalence of B19V antibodies using enzyme-linked immunosorbent assay (ELISA). Genotyping was performed on 65 DNA positive samples by sequencing of nested PCR fragments (NS1-VP1u region, 927 nt). RESULTS: Only 1.4% (70/5026) of the samples had detectible B19V DNA in their blood. B19V DNA prevalence statistically decreased with age (p = 0.03). Anti-B19V IgG was detected in 60.3% (561/930) of the tested samples, while only 2.1% (20/930) were IgM-positive and 1.2% (11/930) were both IgM- and IgG-positive. B19V genotyping showed a predominance of Genotype 1 (100%). Sequence analysis of the NS1-VP1u region revealed 139 mutation sites, some of which were amino acid substitutions. CONCLUSION: Our results indicated a relatively high seroprevalence of B19V in Qatar. Most importantly, B19 DNA was detected among Qatari and non-Qatari blood donors. Therefore, blood banks in Qatar might need to consider screening for B19V, especially when transfusion is intended for high-risk populations, including immunocompromised patients.

Flame Figures in Linear Immunoglobulin A Bullous Dermatosis Secondary to Parvovirus B19 Infection.

ABSTRACT: Flame figures represent a characteristic but nondiagnostic histological finding in eosinophilic dermatoses. Some bullous autoimmune diseases with a predominant eosinophilic infiltrate, such as bullous pemphigoid, pemphigoid gestationis, and pemphigus vegetans, may show them. However, it is rare to find them in predominant neutrophilic bullous dermatoses such as linear immunoglobulin A. We present a 60-year-old man with a history of chronic urticaria, which presented a bullous disease after an acute parvovirus B19 infection. The histological findings showed an exceptional linear immunoglobulin A bullous dermatosis with an eosinophilic infiltrate in the dermis forming "flame figures." The clinical and histopathological findings for this entity may be identical to those of other dermatoses. For this reason, combining these findings with direct immunofluorescence analysis is essential for correct diagnosis of this bullous disease.

Healthcare-Associated Transmission of Parvovirus B19 Arthropathy.

Human parvovirus B19 (B19V) is well known for its infectivity. However, the risk for communicability to previously unexposed healthcare professionals is controversial. We report here a small outbreak of B19V infection among physicians and family members in an adult rheumatology practice that occurred after providing care for a patient with B19V arthropathy. As B19V-infected patients who demonstrate findings of erythema infectiosum or viral arthritis are generally beyond the period of transmissability, strict handwashing and droplet precautions remain imperative when there is contact with potentially pre-symptomatic family members.

[Advances in molecular biology research on human parvovirus B19].

Human parvovirus B19 (B19 virus) is one of the two parvoviruses that cause human diseases. As an important pathogen to humans, it causes infectious erythema in children, acute aplastic anemia, fetal edema and death. In this review, we focus on the recent advances in the molecular virology of B19V, such as viral genotypes, viral receptor, genomic features and viral replication, viral transcription and post-transcription regulation, viral nonstructural and structural protein features and functions, viral diagnosis and antiviral agents, to provide reference for further study of B19 pathogenesis mechanisms, treatment and diagnostic strategies.

Pure Red Cell Aplasia and Antibody-Mediated Rejection: Double Trouble in 1 Kidney Transplant Recipient Solved by Intravenous Immunoglobulin Infusion: A Case Report.

Acquired pure red cell aplasia (PRCA) is characterized by severe normocytic (rarely macrocytic) and normochromic anemia, a low reticulocytes count in peripheral blood, and near absence of erythroid precursors in the bone marrow, with a normal level of erythropoietin. We describe a case of the kidney transplant recipient, diagnosed with PRCA induced with parvovirus B19 infection. Our case demonstrates that although this complication is rare, it should be considered in a differential diagnosis of anemia diagnostics in immunocompromised patients. In our case reduced immune response resulted from post-transplant immunosuppressive therapy. In our patient, apart from infection by parvovirus B19, graft dysfunction due to polyomavirus BK virus infection was also detected together with histologic and serologic features of antibody-mediated renal graft rejection. Considering the entire clinical picture, intravenous immunoglobulin therapy (IVIg) was successfully introduced.

A Meta-Analysis on the Seroprevalence of Parvovirus B19 among Patients with Sickle Cell Disease.

BACKGROUND: Parvovirus B19 (B19 V) infection had been reported to be more frequent with serious clinical outcomes in patients with sickle cell disease (SCD) than in the general population. There is a wide variation in data among the existing literature regarding the seroprevalence of B19 V in patients with SCD. These data require further summary and analyses for better accuracy. This systematic review and meta-analysis was done to estimate the seroprevalence of B19 V in patients with SCD. METHODS: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases of MEDLINE/PubMed, Virtual Health Library (VHL), ScienceDirect, Google Scholar, and OpenGrey were used for the systematic search. The random-effects model was used to estimate the pooled prevalence with the corresponding 95% confidence interval (CI) using OpenMeta Analyst software. Publication bias was estimated based on Begg's test, Egger's test, and examination of the funnel plot. Subgroup analyses and metaregression were used to explore the moderators of heterogeneity between studies. RESULTS: A total of 18 studies including 2890 patients were analyzed. The overall IgG seroprevalence of B19 V infection among patients with SCD was found to be 48.8% (95% CI 39.5%-58.0%). Evidence of publication bias was not detected. Evidence of acute viral infection detected by positive IgM antibodies among the screened SCD patients was found in 8.30% (95% CI 5.20%-11.4%) of them. There was a statistically significant association between seroprevalence of B19 V and geographical areas. CONCLUSION: There was a high prevalence of B19 V in patients with SCD. Healthcare providers need to be aware of the magnitude of B19 V infection in patients with SCD to ensure effective management. This review could provide a comprehensive view of B19 V prevalence in this susceptible population.

The Role of Human Parvovirus B19 in the Pediatric Patients with Pancytopenia?

BACKGROUND: Parvoviruses are small DNA viruses causing erythema infectiosum, which is known as the fifth disease. The aim of this study was to investigate the presence of Parvovirus B19 DNA by Real-Time-PCR retrospectively in clinical samples of children diagnosed as acute leukemia and aplastic anemia when investigating the cause of pancytopenia and to investigate its relationship with the clinical manifestations. METHODS: The study samples were collected between March 2014 and March 2018 in Gazi University, Faculty of Medicine, Department of Pediatric Hematology. Sixty pediatric patients; 37 males and 23 females, were included in the study. Nucleic acid isolation was performed by using MagNA-Pure Compact Nucleic Acid Isolation Kit (Roche, Germany). Extracted DNA was studied with LightCycler® 2.0 using the Real-Time PCR method and LightCycler® Parvovirus B19 Quantification Kit (Roche, Germany), and the results were evaluated quantitatively. Parvovirus B19 DNA detection interval of the kit was 101 - 106 copies/mL. RESULTS: Sixty serum samples were investigated and 8.3% (5/60) Parvovirus B19 DNA positivity was determined. Of the five patients with Parvovirus B19 DNA positivity, three had acute lymphoblastic leukemia and two were diagnosed as aplastic anemia. Regarding viral load; 2/5, 1/5, 1/5, and 1/5 of the samples had a viral load of 102, 103, 104, and 105 copies/mL, respectively. Parvovirus B19 DNA positivity was detected in samples from March (2/5), April (2/5), and August (1/5). CONCLUSIONS: Patients with acute leukemia and aplastic anemia in childhood using immunosuppressive drugs, blood, and blood products during chemotherapy, encounter Parvovirus B19 infections in the follow-up period and are diagnosed by serological and molecular methods. As a result of the study, we suggest that the detection of Parvovirus B19 DNA by Real-Time PCR method in children being admitted with pancytopenia and diagnosed as acute leukemia and aplastic anemia is useful in the follow-up and treatment.

Successful re-transplantation in patient with recurrent parvovirus B19 pure red cell aplasia.

Impaired cell-mediated, as well as antibody-mediated immunity predisposes a renal transplant recipient to a wide variety of atypical infection. With an increasing number of re-transplant, the balance between immunosuppression and the risk of recurrent disease poses a clinical and therapeutic challenge. Here, we report a successful re-transplantation in a case of parvovirus B19 infection leading to anaemia and collapsing glomerulopathy in the allograft managed with intravenous immunoglobulin (IVIG) and reduction of immunosuppression. This case emphasizes re-consideration to renal transplant after clearance of the virus in a previous renal allograft lost to PVB19 infection.

Optimized nested PCR enhances biological diagnosis and phylogenetic analysis of human parvovirus B19 infections.

Diagnosis and epidemiological analysis of human parvovirus B19 (hB19V) infections are essential for disease management in severely ill patients. This study aimed to evaluate the performance of an optimized NS1-VP1u nested PCR for detection and sequencing of viruses in clinical samples using 224 clinical and five reference samples. PCR sensitivity, specificity, and positive and negative predictive values were perfect (100%). While phylogenetic analysis of a 615 bp-long fragment demonstrated that the viruses in all of the samples belonged to genotype 1, this study confirmed that this optimized PCR could detect all known hB19V with high performance.

Aggressive large B-cell lymphoma triggered by a parvovirus B19 infection in a previously healthy child.

In absence of red blood cells disease or immune defect, parvovirus B19 (PVB-19) is usually considered as a benign condition. Here, we report the case of a 10-year-old boy, previously healthy, presenting with a PVB-19 infection revealed by a bicytopenia and a voluminous axillary adenopathy. Pathophysiology examination showed reactional lymphoid population. Nine months later and in the absence of remission, a new biopsy of the same adenopathy revealed a Hodgkin lymphoma with area of T-cell rich aggressive large B-cell lymphoma. This case suggests PVB-19 as potential trigger of this malignant childhood hemopathy. Although no definitive conclusion can be drawn, our clinical case questions the role of PVB-19 in lymphomagenesis.

Advances in the Development of Antiviral Strategies against Parvovirus B19.

Parvovirus B19 (B19V) is a human pathogenic virus, responsible for an ample range of clinical manifestations. Infections are usually mild, self-limiting, and controlled by the development of a specific immune response, but in many cases clinical situations can be more complex and require therapy. Presently available treatments are only supportive, symptomatic, or unspecific, such as administration of intravenous immunoglobulins, and often of limited efficacy. The development of antiviral strategies against B19V should be considered of highest relevance for increasing the available options for more specific and effective therapeutic treatments. This field of research has been explored in recent years, registering some achievements as well as interesting future perspectives. In addition to immunoglobulins, some compounds have been shown to possess inhibitory activity against B19V. Hydroxyurea is an antiproliferative drug used in the treatment of sickle-cell disease that also possesses inhibitory activity against B19V. The nucleotide analogues Cidofovir and its lipid conjugate Brincidofovir are broad-range antivirals mostly active against dsDNA viruses, which showed an antiviral activity also against B19V. Newly synthesized coumarin derivatives offer possibilities for the development of molecules with antiviral activity. Identification of some flavonoid molecules, with direct inhibitory activity against the viral non-structural (NS) protein, indicates a possible line of development for direct antiviral agents. Continuing research in the field, leading to better knowledge of the viral lifecycle and a precise understanding of virus-cell interactions, will offer novel opportunities for developing more efficient, targeted antiviral agents, which can be translated into available therapeutic options.

Globoside Is Dispensable for Parvovirus B19 Entry but Essential at a Postentry Step for Productive Infection.

Globoside (Gb4) is considered the primary receptor of parvovirus B19 (B19V); however, its expression does not correlate well with the attachment and restricted tropism of the virus. The N terminus of VP1 (VP1u) of B19V interacts with an as-yet-unknown receptor required for virus internalization. In contrast to Gb4, the VP1u cognate receptor is expressed exclusively in cells that B19V can internalize. With the aim of clarifying the role of Gb4 as a B19V receptor, we knocked out the gene B3GalNT1 coding for the enzyme globoside synthase in UT7/Epo cells. Consequently, B3GalNT1 transcripts and Gb4 became undetectable in the knockout (KO) cells without affecting cell viability and proliferation. Unexpectedly, virus attachment, internalization, and nuclear targeting were not disturbed in the KO cells. However, NS1 transcription failed, and consequently, genome replication and capsid protein expression were abrogated. The block could be circumvented by transfection with a B19V infectious clone, indicating that Gb4 is not required after the generation of viral double-stranded DNA with resolved inverted terminal repeats. While in wild-type (WT) cells, occupation of the VP1u cognate receptor with recombinant VP1u disturbed virus binding and blocked the infection, antibodies against Gb4 had no significant effect. In a mixed population of WT and KO cells, B19V selectively infected WT cells. This study demonstrates that Gb4 does not have the expected receptor function, as it is dispensable for virus entry; however, it is essential for productive infection, explaining the resistance of the rare individuals lacking Gb4 to B19V infection.IMPORTANCE Globoside has long been considered the primary receptor of B19V. However, its expression does not correlate well with B19V binding and uptake and cannot explain the pathogenesis or the remarkable narrow tissue tropism of the virus. By using a knockout cell line, we demonstrate that globoside does not have the expected function as a cell surface receptor required for B19V entry, but it has an essential role at a postentry step for productive infection. This finding explains the natural resistance to infection associated with individuals lacking globoside, contributes to a better understanding of B19V restricted tropism, and offers novel strategies for the development of antiviral therapies.

Clinical Case of Parvovirus B19 Infection in Pregnant Woman with Β-Thalassemia in Bulgaria.

A pregnant 30-year-old female in the 34th gestational week was admitted at University "Maichin Dom" Hospital prior to childbirth. The patient is diagnosed with ß-thalassemia. During laboratory screening hemoglobin of 98 g/L was established. Blood smear shows mild microcytic hypochromic anemia: RBC 5.15 x 1012/L, HGB 98 g/L, MCV 65.8 fL, MCH 19.4 pg, MCHC 295 g/L. Serum iron concentration is 12.9 µmol/L and ferritin 17.5 µg/L. For the delivery process cesium was considered. Two days after procedure a rash presented on face, hands and breasts. Although the mother was positive for parvovirus B19 infection, the baby was negative. This was confirmed by se-rological and molecular investigations. We discovered only the mother's B19V IgG antibodies in the newborn. In connection to the main disease, namely ß-thalassemia, acute virus infection could cause aplastic crisis. After consultation with a hematologist, serum hepcidin concentration (an iron homeostasis regulator) was quantified: 19.4 µg/L. ELISA test was used to prove B19V IgM antibodies in the mother. PCR analysis shows the presence of B19V DNA. During infection, inflammatory cytokines increase hepcidin secretion, leading to iron deposition into cells.

Parvovirus B19 Uncoating Occurs in the Cytoplasm without Capsid Disassembly and It Is Facilitated by Depletion of Capsid-Associated Divalent Cations.

Human parvovirus B19 (B19V) traffics to the cell nucleus where it delivers the genome for replication. The intracellular compartment where uncoating takes place, the required capsid structural rearrangements and the cellular factors involved remain unknown. We explored conditions that trigger uncoating in vitro and found that prolonged exposure of capsids to chelating agents or to buffers with chelating properties induced a structural rearrangement at 4 °C resulting in capsids with lower density. These lighter particles remained intact but were unstable and short exposure to 37 °C or to a freeze-thaw cycle was sufficient to trigger DNA externalization without capsid disassembly. The rearrangement was not observed in the absence of chelating activity or in the presence of MgCl2 or CaCl2, suggesting that depletion of capsid-associated divalent cations facilitates uncoating. The presence of assembled capsids with externalized DNA was also detected during B19V entry in UT7/Epo cells. Following endosomal escape and prior to nuclear entry, a significant proportion of the incoming capsids rearranged and externalized the viral genome without capsid disassembly. The incoming capsids with accessible genomes accumulated in the nuclear fraction, a process that was prevented when endosomal escape or dynein function was disrupted. In their uncoated conformation, capsids immunoprecipitated from cytoplasmic or from nuclear fractions supported in vitro complementary-strand synthesis at 37 °C. This study reveals an uncoating strategy of B19V based on a limited capsid rearrangement prior to nuclear entry, a process that can be mimicked in vitro by depletion of divalent cations.

Quantitative real-time PCR for differential diagnostics of parvovirus B19 infection in acute liver failure patients.

BACKGROUND: Human Parvovirus B19 (B19V) is a common pathogen worldwide. After primary infection, B19V-DNA may permanently persist in non-erythroid tissues, including the liver of patients with acute liver failure (ALF). OBJECTIVE: To validate a real-time PCR (qPCR) for the quantification of B19V-DNA, in order to establish a differential diagnosis for B19V infection in ALF patients. METHODS: The qPCR techniques were based on Sybr Green® and TaqMan® methodologies. To evaluate the quality parameters of both methods, samples from patients with or without B19V infection were tested. The diagnostic utility of qPCR in the detection B19V-DNA in patients with ALF was evaluated by testing archived serum and hepatic tissue explants from 10 patients. RESULTS: The Sybr Green® methodology showed 97% efficiency, the limits of detection and quantification were 62.6 and 53,200 copies/mL, respectively. The TaqMan® methodology showed 95% efficiency, the limits of detection and quantification were 4.48 and 310 copies/mL, respectively. A false positive result was found only with the Sybr Green® methodology. Among ALF patients without defined etiology, three (30%) were positive for B19V DNA in serum and liver. CONCLUSION: The qPCR methods validated here were effective in clarifying uncommon cases of B19V-related ALF and are fit for differential diagnosis of ALF causes.