Distinct clinical features of transplanted children with Parvovirus B19 infection.

BACKGROUND: The immature and suppressed immune response makes transplanted children a special susceptible group to Parvovirus B19 (PVB19). However, the clinical features of transplanted children with PVB19 infection haven't been comprehensively described. METHODS: We searched the medical records of all the transplant recipients who attended the Children's Hospital of Fudan University from 1 Oct 2020 to 31 May 2023, and reviewed the medical literature for PVB19 infection cases among transplanted children. RESULTS: A total of 10 cases of PVB19 infection were identified in 201 transplanted children at our hospital, and the medical records of each of these cases were shown. Also, we retrieved 40 cases of PVB19 infection among transplanted children from the literature, thus summarizing a total of 50 unique cases of PVB19 infection. The median time to the first positive PVB19 DNA detection was 14 weeks post-transplantation. PVB19 IgM and IgG were detected in merely 26% and 24% of the children, respectively. The incidence of graft loss/dysfunction was as high as 36%. Hematopoietic stem cell transplant (HSCT) recipients showed higher PVB19 load, lower HGB level, greater platelet damage, lower PVB19 IgM/IgG positive rates, and more graft dysfunction than solid-organ transplant (SOT) recipients, indicating a more incompetent immune system. CONCLUSIONS: Compared with the published data of transplanted adults, transplanted children displayed distinct clinical features upon PVB19 infection, including lower PVB19 IgM/IgG positive rates, more graft dysfunction, and broader damage on hematopoietic cell lines, which was even more prominent in HSCT recipients, thus should be of greater concern.

Parvovirus B19 in Pregnancy.

Importance: Although the risk of parvovirus B19 infection during pregnancy and subsequent risk of adverse fetal outcome are low, understanding management practices is essential for proper treatment of fetuses with nonimmune hydrops fetalis. In addition, continued investigation into delivery management, breastfeeding recommendations, and congenital abnormalities associated with pregnancies complicated by parvovirus B19 infection is needed. Objective: This review describes the risks associated with parvovirus B19 infection during pregnancy and the management strategies for fetuses with vertically transmitted infections. Evidence Acquisition: Original articles were obtained from literature search in PubMed, Medline, and OVID; pertinent articles were reviewed. Results: Parvovirus B19 is a viral infection associated with negative pregnancy outcomes. Up to 50% of people of reproductive age are susceptible to the virus. The incidence of B19 in pregnancy is between 0.61% and 1.24%, and, overall, there is 30% risk of vertical transmission when infection is acquired during pregnancy. Although most pregnancies progress without negative outcomes, viral infection of the fetus may result in severe anemia, congestive heart failure, and hydrops fetalis. In addition, vertical transmission carries a 5% to 10% chance of fetal loss. In pregnancies affected by fetal B19 infection, Doppler examination of the middle cerebral artery peak systolic velocity should be initiated to surveil for fetal anemia. In the case of severe fetal anemia, standard fetal therapy involves an intrauterine transfusion of red blood cells with the goal of raising hematocrit levels to approximately 40% to 50% of total blood volume. One transfusion is usually sufficient, although continued surveillance may indicate the need for subsequent transfusions. There are fewer epidemiologic data concerning neonatal risks of congenital parvovirus, although case reports have shown that fetuses with severe anemia in utero may have persistent anemia, thrombocytopenia, and edema in the neonatal period. Conclusions and Relevance: Parvovirus B19 is a common virus; seropositivity in the geriatric population reportedly reaches 85%. Within the pregnant population, up to 50% of patients have not previously been exposed to the virus and consequently lack protective immunity. Concern for parvovirus B19 infection in pregnancy largely surrounds the consequences of vertical transmission of the virus to the fetus. Should vertical transmission occur, the overall risk of fetal loss is between 5% and 10%. Thus, understanding the incidence, risks, and management strategies of pregnancies complicated by parvovirus B19 is essential to optimizing care and outcomes. Further, there is currently a gap in evidence regarding delivery management, breastfeeding recommendations, and the risks of congenital abnormalities in pregnancies complicated by parvovirus B19. Additional investigations into optimal delivery management, feeding plans, and recommended neonatal surveillance are needed in this cohort of patients.

New atypical epidemiological profile of parvovirus B19 revealed by molecular screening of blood donations, France, winter 2023/24.

In France, blood donations are tested in pools of 96 samples for parvovirus B19 (B19V) DNA to discard plasma for fractionation when it contains high viral loads. Between January 2015 and March 2024, B19V-positive donations decreased during the COVID-19 pandemic, followed by a strong rebound in 2023 and unusually high circulation during winter 2023/24 (ca 10 times higher December 2023-March 2024 vs the pre-pandemic period). Variations over time are probably related to measures implemented to limit SARS-CoV-2 spread.

Changing epidemiology of parvovirus B19 in the Netherlands since 1990, including its re-emergence after the COVID-19 pandemic.

Parvovirus B19V (B19V) infection during pregnancy can be complicated by potentially life-threatening fetal hydrops, which can be managed by intrauterine transfusion (IUT). This study investigates the long-term temporal patterns in the epidemiology of B19V and evaluates the impact on fetal hydrops, by combining data on B19V infections from the Dutch Sentinel Surveillance system in the period 1990 to 2023, Dutch blood banking data and hospital data on fetal hydrops. Using wavelet analysis, we identified annual epidemic cycles in the Netherlands in the period 1990-2019 and we identified superimposed multiannual cycles in the period 1990-2009. After 2009, no multiannual cycle could be identified, although the incidence fluctuated and correlates with number of IUT performed. As of 2020, weekly reports of B19V infection demonstrated a historically low incidence and B19V-DNA positive blood donors were nearly absent. From May 2020 to May 2023, no IUT for B19V-related hydrops was performed. In the spring of 2023, B19V infections re-emerged, reaching pre-pandemic epidemic levels. Due to the changes in B19V epidemiology over the last 30 years and the near-absence of B19V during the COVID-19 pandemic, the resulting low immunity levels may lead to rebound outbreaks. Alertness to severe complications such as fetal hydrops is warranted.

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.

Parvovirus B19 Outbreak in Israel: Retrospective Molecular Analysis from 2010 to 2023.

This study presents an analysis of the epidemiological trends of parvovirus B19 (B19V) in Israel from 2010 to 2023, with particular emphasis on the outbreak in 2023. The analysis utilized molecular diagnostic data from individual patients obtained at the Central Virology Laboratory. Between 2010 and 2022, 8.5% of PCR-tested samples were positive for B19V, whereas in 2023, this percentage surged to 31% of PCR-tested samples. Throughout the study period, annual cycles consistently peaked in early spring/summer, with the most recent prominent outbreak occurring in 2016. Predominantly, diagnoses were made in children and women aged 20-39. Despite the notable surge in 2023, over 80% of positive cases continued to be observed in children and young women, with a decrease in cases during winter months. Furthermore, genotype 1a of the virus remained the predominant strain circulating during the outbreak. In light of these circumstances, consideration should be given to implementing screening measures, particularly among high-risk groups such as pregnant women.

For better or worse: crosstalk of parvovirus and host DNA damage response.

Parvoviruses are a group of non-enveloped DNA viruses that have a broad spectrum of natural infections, making them important in public health. NS1 is the largest and most complex non-structural protein in the parvovirus genome, which is indispensable in the life cycle of parvovirus and is closely related to viral replication, induction of host cell apoptosis, cycle arrest, DNA damage response (DDR), and other processes. Parvovirus activates and utilizes the DDR pathway to promote viral replication through NS1, thereby increasing pathogenicity to the host cells. Here, we review the latest progress of parvovirus in regulating host cell DDR during the parvovirus lifecycle and discuss the potential of cellular consequences of regulating the DDR pathway, targeting to provide the theoretical basis for further elucidation of the pathogenesis of parvovirus and development of new antiviral drugs.

Association between Parvovirus B19 and thyroid/celiac autoantibodies among T1DM pediatric patients.

OBJECTIVE: In recent years, an overwhelming association between Pediatric Type 1 Diabetes Mellitus (T1DM) and autoimmune diseases has been largely reported. The current study was designed to determine a possible association between autoimmune thyroiditis (AIT), celiac disease (CD) - associated autoantibodies, and Parvovirus B19 infection among pediatric T1DM cases in the southwestern region of Saudi Arabia. PATIENTS AND METHODS: Blood samples from age groups 1-18 years attending the Diabetic Clinic were collected over a period of 12 months. Serum anti-thyroid peroxidase (TPO), anti-thyroglobulin (TG), anti-tissue transglutaminase immunoglobulin A (TG-IgA), endomysial IgA (EMA-IgA), Parvovirus B19-IgG and IgM antibodies were detected by standard methods. RESULTS: The results showed the prevalence of autoantibodies against thyroid and CD among pediatric T1DM patients to be 44 (25%) and 25 (14.4%), respectively. The prevalence of antibodies against B19 was 70 (40%). Further determination of the prevalence of Parvovirus B19-IgG antibodies and thyroid antibodies among T1DM pediatric patients revealed that there was a significant association between them with a p<0.0491. CONCLUSIONS: The prevalence of autoantibodies against the thyroid was higher among the seropositive Parvovirus B19 children with T1DM. A positive association between the prevalence of autoantibodies against thyroid disease and the increase in the duration of diabetes was also noted. Hence, periodic screening of T1DM patients for B19 antibodies and autoantibodies for thyroid is crucial.

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.

Parvovirus B19 and Human Parvovirus 4 Encode Similar Proteins in a Reading Frame Overlapping the VP1 Capsid Gene.

Viruses frequently contain overlapping genes, which encode functionally unrelated proteins from the same DNA or RNA region but in different reading frames. Yet, overlapping genes are often overlooked during genome annotation, in particular in DNA viruses. Here we looked for the presence of overlapping genes likely to encode a functional protein in human parvovirus B19 (genus Erythroparvovirus), using an experimentally validated software, Synplot2. Synplot2 detected an open reading frame, X, conserved in all erythroparvoviruses, which overlaps the VP1 capsid gene and is under highly significant selection pressure. In a related virus, human parvovirus 4 (genus Tetraparvovirus), Synplot2 also detected an open reading frame under highly significant selection pressure, ARF1, which overlaps the VP1 gene and is conserved in all tetraparvoviruses. These findings provide compelling evidence that the X and ARF1 proteins must be expressed and functional. X and ARF1 have the exact same location (they overlap the region of the VP1 gene encoding the phospholipase A2 domain), are both in the same frame (+1) with respect to the VP1 frame, and encode proteins with similar predicted properties, including a central transmembrane region. Further studies will be needed to determine whether they have a common origin and similar function. X and ARF1 are probably translated either from a polycistronic mRNA by a non-canonical mechanism, or from an unmapped monocistronic mRNA. Finally, we also discovered proteins predicted to be expressed from a frame overlapping VP1 in other species related to parvovirus B19: porcine parvovirus 2 (Z protein) and bovine parvovirus 3 (X-like protein).

Neonatos con diagnóstico prenatal de hidrops fetal: experiencia durante 10 años en un centro de tercer nivel / Neonates with a prenatal diagnosis of hydrops fetalis: A 10-year experience in a tertiary care center

Introducción: El hidrops fetal (HF) es una condición rara con una alta mortalidad. Este estudio analiza la evolución obstétrica y perinatal de los diagnósticos prenatales de HF, relacionándola con la etiología y el tratamiento intrauterino (TIU) recibido. Pacientes y métodos: Se revisaron 164 gestantes con diagnóstico prenatal de HF entre 2011 y 2021. Se registraron intervenciones prenatales, hallazgos clínicos, etiologías y resultados de los recién nacidos vivos. Resultados: Se realizó un estudio invasivo prenatal en el 79,3% de los pacientes. Las etiologías mayoritarias fueron alteraciones genéticas (31%), infecciones TORCH y por parvovirus B19 (9,7%), y cardiopatías estructurales (9,1%). En el 25,6% se realizó TIU, y entre todas las gestaciones, el 74,4% fueron interrumpidas. Las alteraciones genéticas tuvieron tasas más altas de interrupción legal del embarazo respecto a otras etiologías (p<0,01). Del total, solo nacieron el 25,6% de los fetos, la mayoría pretérmino. Los que recibieron TIU gozaron de mayores tasas de supervivencia perinatal y al año de vida (p<0,001). De entre aquellos nacimientos, las cardiopatías estructurales presentaron las peores tasas de supervivencia, mientras que las causas con mejor pronóstico fueron las taquiarritmias. La supervivencia al año de vida entre aquellos recién nacidos vivos fue del 70%, pero el 58,6% asociaron morbilidad significativa al alta. Conclusiones: A pesar de los avances en el manejo del HF, el mal pronóstico obstétrico, la mortalidad perinatal y la morbilidad de los supervivientes siguen siendo significativos. Estos datos son importantes para asesorar a las familias que reciben un diagnóstico prenatal de HF.(AU)

Introduction: Hydrops fetalis (HF) is a rare condition with a high mortality. This study analysed the obstetric and perinatal outcomes of antenatally diagnosed HF according to its aetiology and the possibility of intrauterine treatment (IUT). Patients and methods: We carried out a retrospective review of the health records of 164 pregnant women with a prenatal diagnosis of HF in a tertiary care centre between 2011 and 2021. We analysed prenatal interventions, clinical findings, aetiologies and obstetric and live-born infant outcomes. Results: An invasive prenatal study had been performed in 79.3% cases. The most common aetiologies were genetic disorders (31%), TORCH and parvovirus B19 infections (9.7%) and structural heart diseases (9.1%). Intrauterine treatment was performed in 25.6%, and 74.4% of pregnancies were terminated. Pregnancies with a prenatal diagnosis of genetic or chromosomal disorders had higher rates of elective termination compared to other aetiologies (P<.01). Among all pregnancies, only 25.6% resulted in live births (LBs), most of them preterm. Perinatal and 1-year survival rates were higher in the group that received IUT (P<.001). Among the LBs, structural heart diseases had the worst survival rates, while the aetiology with the best outcomes was tachyarrhythmia. Survival at 1year of life among those born alive was 70%, but 58.6% of these infants had significant morbidity at discharge. Conclusions: Despite advances in the management of FH, the poor obstetric prognosis, perinatal mortality and morbidity of survivors is still significant. These data are important for the purpose of counselling families when HF is diagnosed antenatally.(AU)

Antiviral alternatives against important members of the subfamily Parvovirinae: a review.

Parvoviruses are responsible for multiple diseases, and there is a critical need for effective antiviral therapies. Specific antiviral treatments for parvovirus infections are currently lacking, and the available options are mostly supportive and symptomatic. In recent years, significant research efforts have been directed toward understanding the molecular mechanisms of parvovirus replication and identifying potential targets for antiviral interventions. This review highlights the structure, pathogenesis, and treatment options for major viruses of the subfamily Parvovirinae, such as parvovirus B19 (B19V), canine parvovirus type 2 (CPV-2), and porcine parvovirus (PPV) and also describes different approaches in the development of antiviral alternatives against parvovirus, including drug repurposing, serendipity, and computational tools (molecular docking and artificial intelligence) in drug discovery. These advances greatly increase the likelihood of discoveries that will lead to potent antiviral strategies against different parvovirus infections.

Viral etiology of measles-like rash in Guinean children during the COVID epidemic in 2022.

Covid-19 in West Africa masked outbreaks of vaccine-preventable diseases such as the measles epidemic in children in Guinea in 2021-2022 characterized by a lack of confirmation of suspected clinical cases. During weeks 13-22 of 2022, saliva samples were collected from 213 children (3-60 months old) with measles-like symptoms within the St Gabriel dispensary in Conakry. Samples were processed in Virus Transport Medium (VTM) and tested on the same day by triplex reverse transcriptase -real-time polymerase chain reaction for Measles, Rubella and RNaseP. Samples were also tested for HHV6 and Parvovirus B19, viruses causing clinical signs similar to measles. We confirmed 146 (68.5%) measles cases, 27 (12.7%) rubella, 5 (2.3%) double-positive measles-rubella, 35 (16.4%) HHV-6 and 8 (3.75%) Parvovirus B19. To test the assay's robustness, 27 samples were kept at 26-30°C. Measles and rubella were still detected after 7 days at 26-30°C, and after 21 days measles and rubella were still detectable in all samples but one. Sequencing indicated the circulation of the B3 measles genotype, as expected in West Africa. This study highlights the robustness of the measles/rubella diagnostic test on saliva samples stored in VTM. The high level of rubella detection questioned the single valence measles vaccination strategy.

On-column refolding and off-column assembly of parvovirus B19 virus-like particles from bacteria-expressed protein.

Virus-like particles (VLPs) are nanometric structures composed of structural components of virions, keeping most of the cellular recognition and internalization properties, but are non-infective as they are deprived of their genetic material. VLPs have been a versatile platform for developing vaccines by carrying their own or heterologous antigenic epitopes. Moreover, VLPs can also be used as nanovessels for encapsulating molecules with therapeutic applications, like enzymes, nucleic acids, and drugs. Parvovirus B19 (B19V) VLPs can be self-assembled in vitro from the denatured major viral particle protein VP2 by equilibrium dialysis. Despite its fair productivity, this process is currently a time-consuming task. Affinity chromatography is used as an efficient step for concentration and purification, but it is only sometimes seen as a method that facilitates the oligomerization of proteins. In this research, we report a novel approach for the in vitro assembly of B19V VLPs through the immobilization of the denatured VP2 into an immobilized metal affinity chromatography (IMAC) column, followed by the on-column folding and the final VLP assembly upon protein elution. This method is suitable for the fast production of B19V VLPs. KEY POINTS: • Biotechnological applications for inclusion bodies • Efficient single-step purification and immobilization strategies • Rapid VLP assembly strategy.

Multiplexed electrical detection of whole viruses from plasma in a microfluidic platform.

The advancement of point-of-care diagnostics is crucial to improving patient outcomes, especially in areas with low access to hospitals or specialized laboratories. In particular, rapid, sensitive, and multiplexed detection of disease biomarkers has great potential to achieve accurate diagnosis and inform high quality care for patients. Our Coulter counting and immunocapture based detection system has previously shown its broad applicability in the detection of cells, proteins, and nucleic acids. This paper expands the capability of the platform by demonstrating multiplexed detection of whole-virus particles using electrically distinguishable hydrogel beads by demonstrating the capability of our platform to achieve simultaneous detection at clinically relevant concentrations of hepatitis A virus (>2 × 103 IU mL-1) and human parvovirus B19 virus like particles (>106 IU mL-1) from plasma samples. The expanded versatility of the differential electrical counting platform allows for more robust and diverse testing capabilities.

Parvovirus in Kidney Transplant Recipients: A Single-Center Experience.

OBJECTIVES: Parvovirus testing is not done in routine clinical practice; thus, it is possible that reported parvovirus cases are just the tip of the iceberg of total prevalence. We present a single-center retrospective analysis of 22 events of parvovirus B19 anemia in 20 renal transplant recipients, among which 2 patients had recurrence. MATERIALS AND METHODS: For this descriptive analytical study, parvovirus B19 disease was defined as parvovirus infection (detection by real-time polymerase chain reaction) in the presence of anemia with clinical symptoms or bone marrow biopsy findings consistent with the diagnosis. Study duration was 18 months, from June 2021 through December 2022, and patients were enrolled from a single center. RESULTS: All patients detected with the virus had received induction with thymocyte globulin and were on standard triple drug immunosuppression. Mean age was 32 ± 12 years with median time to diagnosis of 2 months after transplant. Anemia was observed in all patients with mean hemoglobin level at presentation of 6.02 ± 1.28 g/dL. Creatinine at presentation was 1.49 mg/dL (interquartile range, 0.92-2.69 mg/dL). The most common presentation was asymptomatic patient with evaluation for anemia. During therapy, the highest median creatinine level was 2.0 mg/dL (interquartile range, 1.38-3.2 mg/dL), which was significantly higher than that at presentation (P < .018). After therapy, median creatinine level was 1.3 mg/dL, which was not significantly higher than the baseline level, demonstrating a mostly transient graft dysfunction. CONCLUSIONS: Parvovirus B19 is a relatively underreported disease in renal transplant recipients, with patients presenting with anemia and the disease causing transient graft dysfunction. Parvovirus B19 infection responds well to a decrease in immunosuppression and intravenous immunoglobulin therapy.

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.

Effect of the Functional VP1 Unique Region of Human Parvovirus B19 in Causing Skin Fibrosis of Systemic Sclerosis.

Human parvovirus B19 (B19V) is a single-stranded non-enveloped DNA virus of the family Parvoviridae that has been associated with various autoimmune disorders. Systemic sclerosis (SSc) is an autoimmune connective tissue disorder with high mortality and has been linked to B19V infection. However, the precise mechanism underlying the B19V contribution to the development of SSc remains uncertain. This study investigated the impacts of the functional B19V-VP1 unique region (VP1u) in macrophages and bleomycin (BLE)-induced SSc mice. Cell experimental data showed that significantly decreased viability and migration of both B19V-VP1u-treated U937 and THP-1 macrophages are detected in the presence of celastrol. Significantly increased MMP9 activity and elevated NF-kB, MMP9, IL-6, TNF-α, and IL-1ß expressions were detected in both B19V-VP1u-treated U937 and THP-1 macrophages. Conversely, celastrol revealed an inhibitory effect on these molecules. Notably, celastrol intervened in this pathogenic process by suppressing the sPLA2 activity of B19V-VP1u and subsequently reducing the inflammatory response. Notably, the administration of B19V-VP1u exacerbated BLE-induced skin fibrosis in mice, with augmented expressions of TGF-ß, IL-6, IL-17A, IL-18, and TNF-α, ultimately leading to α-SMA and collagen I deposits in the dermal regions of BLE-induced SSc mice. Altogether, this study sheds light on parvovirus B19 VP1u linked to scleroderma and aggravated dermal fibrosis.