Parvovirus B19 infection

Role of clinical, molecular, and serological features in the diagnosis of parvovirus B19 infection in children

BACKGROUND

Parvovirus B19(B19) is a DNA virus. The most common B19 disease is erythema infectiosum (fifth-disease). PCR and ELISA are sensitive for detecting of acute disease. However, it is not clear which test better and the relationship between laboratory tests and clinical findings.

OBJECTIVE

To discuss the clinical and laboratory characteristics of pediatric patients infected with B19.

STUDY DESIGN

236 children were examined. Children with at least one positive molecular or serological test were included. Positive serum B19-DNA and/or B19-IgM was considered an acute B19 infection.

RESULTS

B19DNA was detected in 80.8 % of acute cases. Serological tests were less positive. Acute B19 infection was observed in 24 patients. Only 17 patients were positive for B19 DNA, 3 for IgM and 4 for both. The sensitivity of B19 DNA is 87.5 %. However, this rate is 29.2 % for B19 IgM.

CONCLUSION

B19-DNA and IgM together provide a better, highly accurate diagnosis.

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

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

Primate Erythroparvovirus 1 Infection in Patients with Hematological Disorders

Primate erythroparvovirus 1, commonly referred to as Parvovirus B19 (B19V), is a DNA virus that normally results in a mild childhood infection called "erythema infectiosum". Besides respiratory spread, B19V can also be transmitted through transfusions, which may result in persistent anemia in immunodeficient hosts. Dialysis patients often face acute or chronic anemia after infection with B19V. Here, we describe the laboratory investigation of 21 patients with hematological disorders for B19V infections. B19V DNA was detected in 13 (62%) of them, with specific IgM antibodies in three of the DNA positives. All 13 patients received treatment and were laboratory-monitored over a period of one year. In only two patients (a 14-year-old child with a kidney transplantation and a 39-year-old patient with aplastic anemia), markers of recent B19V infection were still detectable in follow-up samples. For four B19V DNA positive samples, short sequences could be obtained, which clustered with genotype 1a reference strains. Our findings suggest that all cases of hematological disorders should be examined for specific B19V antibodies and DNA for accurate diagnosis and appropriate patient management.

Severe Refractory Anaemia and Fever of Unknow Origin: Human Parvovirus B19 Reactivation

Reactivation of human parvovirus B19 is exceptional and characteristic of immunosuppression, with anaemia being the predominant manifestation although pancytopenia and thrombotic microangiopathy may also occur. We describe a patient with a history of diffuse large B-cell lymphoma with pure erythrocyte aplasia due to reactivation of parvovirus B19, who was treated with corticosteroids and immunoglobulins.

LEARNING POINTS

Infection with human parvovirus B19 is identified by polymerase chain reaction (PCR) testing of blood and the presence of typical giant proerythroblasts in the bone marrow.Cytomegalovirus infection should be considered in immunosuppressed patients with fever and non-specific symptoms with haematological changes.The treatment of persistent infection in immunosuppressed patients is based on the administration of IV immunoglobulins at high doses.

Extra-haematological manifestations related to human parvovirus B19 infection: retrospective study in 25 adults

Background

To describe extra-haematological manifestations associated with human parvovirus B19 (HPV-B19) infection.

Methods

We conducted a nationwide multicentre study to retrospectively describe the characteristics and outcome of extra-haematological manifestations in French adults.

Results

Data from 25 patients followed from 2001 to 2016 were analysed. Median age was 37.9 years (range: 22.7–83.4), with a female predominance (sex ratio: 4/1). Only 3 patients had an underlying predisposing condition (hemoglobinopathy or pregnancy). The most common manifestations were joint (80%) and skin (60%) involvement. Four patients (16%) had renal involvement (endocapillary proliferative or membranoproliferative glomerulonephritis, focal segmental glomerulosclerosis). Three patients (12%) had peripheral nervous system involvement (mononeuritis, mononeuritis multiplex, Guillain-Barré syndrome) and 2 (8%) presented muscle involvement. Other manifestations included hemophagocytic lymphohistiocytosis (n = 1), myopericarditis and pleural effusion (n = 1), and lymphadenopathy and splenomegaly mimicking lymphoma with spleen infarcts (n = 1). Immunological abnormalities were frequent (56.5%). At 6 months, all patients were alive, and 54.2% were in complete remission. In 2 patients, joint involvement evolved into rheumatoid arthritis. Six patients (24%) received intravenous immunoglobulin (IVIg), with a good response in the 3 patients with peripheral nervous system involvement.

Conclusions

HPV-B19 infection should be considered in a wide range of clinical manifestations. Although the prognosis is good, IVIg therapy should be discussed in patients with peripheral nerve involvement. However, its efficacy should be further investigated in prospective studies.

Harlequin Color Change: Neonatal Case Series and Brief Literature Review

First clinical report of Harlequin color change (HCC) phenomenon came in 1952 from Neligan and Strang. Since then, HCC has been described in a fairly broad number of clinical reports involving neonates, infants, children, and adult patients. We here present a small case series of HCC occurring in neonates, pointing out three of the different possible presentations (hemifacial, patchy scattered across the whole body, and hemiscrotal) of this phenomenon. A brief discussion and literature review encompassing epidemiology, clinical features, physiopathology, associated conditions, and differential diagnoses of HCC is then presented. In most cases, HCC represents a benign, idiopathic, and rapidly autoresolutive phenomenon, with no need for treatment. Some drugs (especially anesthetics and prostaglandin E) are thought to enhance HCC expression through their influence on the capillary tone in the peripheral vascular bed; this effect is anyway promptly reversible with drug withdrawal. Only in rare circumstances, HCC may act as a clue for serious central nervous system disorders (e.g., meningitis; hypothalamic, brain stem, or sympathetic nervous system lesions); anyway, in these rare occurrences HCC always represents an epiphenomenon of the disease, never acting as the sole sign of the underlying disorder.

Antibodies in the pathogenesis of hypertension

It has long been known that circulating levels of IgG and IgM antibodies are elevated in patients with essential and pregnancy-related hypertension. Recent studies indicate these antibodies target, and in many cases activate, G-protein coupled receptors and ion channels. Prominent among these protein targets are AT₁ receptors, α₁-adrenoceptors, β₁-adrenoceptors, and L-type voltage operated Ca²⁺ channels, all of which are known to play key roles in the regulation of blood pressure through modulation of vascular tone, cardiac output, and/or Na⁺/water reabsorption in the kidneys. This suggests that elevated antibody production may be a causal mechanism in at least some cases of hypertension. In this brief review, we will further describe the protein targets of the antibodies that are elevated in individuals with essential and pregnancy-related hypertension and the likely pathophysiological consequences of antibody binding to these targets. We will speculate on the potential mechanisms that underlie elevated antibody levels in hypertensive individuals and, finally, we will outline the therapeutic opportunities that could arise with a better understanding of how and why antibodies are produced in hypertension.

Parvovirus

Name of Virus: Parvovirus

Human parvovirus B19 induced apoptotic bodies contain altered self-antigens that are phagocytosed by antigen presenting cells

Human parvovirus B19 (B19V) from the erythrovirus genus is known to be a pathogenic virus in humans. Prevalence of B19V infection has been reported worldwide in all seasons, with a high incidence in the spring. B19V is responsible for erythema infectiosum (fifth disease) commonly seen in children. Its other clinical presentations include arthralgia, arthritis, transient aplastic crisis, chronic anemia, congenital anemia, and hydrops fetalis. In addition, B19V infection has been reported to trigger autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. However, the mechanisms of B19V participation in autoimmunity are not fully understood. B19V induced chronic disease and persistent infection suggests B19V can serve as a model for viral host interactions and the role of viruses in the pathogenesis of autoimmune diseases. Here we investigate the involvement of B19V in the breakdown of immune tolerance. Previously, we demonstrated that the non-structural protein 1 (NS 1) of B19V induces apoptosis in non-permissive cells lines and that this protein can cleave host DNA as well as form NS1-DNA adducts. Here we provide evidence that through programmed cell death, apoptotic bodies (ApoBods) are generated by B19V NS1 expression in a non-permissive cell line. Characterization of purified ApoBods identified potential self-antigens within them. In particular, signature self-antigens such as Smith, ApoH, DNA, histone H4 and phosphatidylserine associated with autoimmunity were present in these ApoBods. In addition, when purified ApoBods were introduced to differentiated macrophages, recognition, engulfment and uptake occurred. This suggests that B19V can produce a source of self-antigens for immune cell processing. The results support our hypothesis that B19V NS1-DNA adducts, and nucleosomal and lysosomal antigens present in ApoBods created in non-permissive cell lines, are a source of self-antigens.

Viral infection in induction of Hashimoto's thyroiditis: a key player or just a bystander?

PURPOSE OF REVIEW

Viral infection activates both the innate and adaptive immunity and is implicated as a trigger of autoimmune diseases including Hashimoto's thyroiditis. This review summarizes our knowledge respecting the role of viral infection in the cause of Hashimoto's thyroiditis.

RECENT FINDINGS

Components of several viruses such as hepatitis C virus, human parvovirus B19, coxsackie virus and herpes virus are detected in the thyroid of Hashimoto's thyroiditis patients. Bystander activation of autoreactive T cells may be involved in triggering intrathyroidal inflammation. Signaling molecules associated with antiviral responses including Toll-like receptors may participate in Hashimoto's thyroiditis induction. However, studies have provided insufficient direct evidence for the viral hypothesis in Hashimoto's thyroiditis.

SUMMARY

Despite interesting circumstantial evidence, whether viral infection is responsible for Hashimoto's thyroiditis remains unclear. Studies addressing this issue are required to substantiate a contribution from viral infection to Hashimoto's thyroiditis and, consequently, the prospect for developing preventive modalities for Hashimoto's thyroiditis.

Human parvovirus B19 infection and autoimmunity

Human parvovirus B19 infection is responsible for a wide range of human diseases ranging from mild erythema infectiosum in immunocompetent children to fetal loss in primary infected pregnant women and aplastic anemia or lethal cytopenias in adult immunocompromised patients. Since persistent viral infection is responsible for an autoimmune response and clinical symptoms can mimic autoimmune inflammatory disorders, parvovirus B19 is the object of intense efforts to clarify whether it is also able to trigger autoimmune diseases. Indeed the virus has been implicated as the causative or the precipitating agent of several autoimmune disorders including rheumatoid arthritis, systemic lupus, antiphospholipid syndrome, systemic sclerosis and vasculitides. Molecular mimicry between host and viral proteins seems to be the main mechanism involved in the induction of autoimmunity. By means of a random peptide library approach, we have identified a peptide that shares homology with parvovirus VP1 protein and with human cytokeratin. Moreover the VP peptide shares similarity with the transcription factor GATA1 that plays an essential role in megakaryopoiesis and in erythropoiesis. These new data sustain the role played by molecular mimicry in the induction of cross-reactive (auto)antibodies by parvovirus B19 infection.

[Frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and rubella in the State of Pernambuco between 2001 and 2004]

This study had the aim of investigating the frequency of measles, rubella, dengue and erythema infectiosum among suspected cases of measles and/or rubella in the state of Pernambuco, Brazil. A total of 1,161 serum samples collected between 2001 and 2004 were tested for these four viral diseases, using enzyme immunoassays to detect IgM antibodies. Out of this total, 276 (23.8%) samples were positive for one of the four viral diseases analyzed. There were 196 positive cases (16.9%) for dengue, 38 (3.3%) for erythema infectiosum (parvovirus B19), 32 (2.8%) for rubella and 10 (0.9%) for measles. Among the suspected cases of measles and rubella, dengue infection was the most frequent, followed by parvovirus B19. The similarity of the clinical manifestations among rash diseases contributes towards making it difficult to diagnose measles, rubella, dengue and erythema infectiosum on clinical grounds alone. It must be emphasized that the four tests used were insufficient for diagnosing 76.2% of the febrile and rash diseases notified. This is the first study bringing evidence of human parvovirus B19 circulation in Pernambuco.

Gene-environment interactions in multiple sclerosis: innate and adaptive immune responses to human endogenous retrovirus and herpesvirus antigens and the lectin complement activation pathway

Aspects of gene-environment interactions in multiple sclerosis (MS) were analysed in serum samples from 46 MS families (25 sporadic MS cases and 42 familial MS cases): antibodies to the MS-associated human endogenous retrovirus HERV-H, and levels of three components in the innate pathogen-associated molecular pattern recognition: mannan-binding lectin (MBL), and MASP-2 and MASP-3. For representative MS families, we also determined herpesvirus serology for HSV-1, VZV, and EBV; and tissue typed for HLA-B, and HLA DR and DQ. In MS, a significant correlation between elevated immune reactivity to HERV-H Env and disease activity was demonstrated, as were indications of a protective effect of high MBL and MASP-3 levels. The HLA alleles B*07, DRB*02, and DQB1*06 were commonly present together in the MS families, both in MS patients, and in unaffected family members. Our results support that HERV-H and the antiviral immune response may play a role in MS development, and also underline the tenuous nature of specific genetic contributions to this complex disease.

Serologic and molecular detection of human Parvovirus B19 infection

Following its identification by Yvonne Cossart in 1975, human Parvovirus B19 has been recognized as the causative agent of a wide range of diseases. In childhood, the most common disease is a typical exanthema called "fifth disease". In adults, viral infection may be responsible for fetal loss and for aplastic anaemia in immuno-compromised patients. Because persistent viral infection may induce an autoimmune response, Parvovirus B19 is emerging as an environmental factor linked to the pathogenesis of autoimmunity. As a result of its expanding disease spectrum, Parvovirus B19 is the subject of intense efforts to clarify the pathogenesis of virus-related disorders as well as improve diagnostic laboratory testing including standardization of serological and nucleic acid-based detection assays. Enzymatic immunoassays based on conformational antigens have proven to be the most important tools for accurate diagnosis in the majority of cases. In other selected clinical cases, the detection of Parvovirus B19 infection can be complemented by PCR and, more recently, by the real-time PCR.

Protecting the blood supply from emerging pathogens: the role of pathogen inactivation

Although the risk of infection by blood transfusion is relatively low, breakthrough infections still occur, Transfusion-related fatalities caused by infections continue to be reported, and blood is not tested for many potentially dangerous pathogens. The current paradigm for increasing the safety of the blood supply is the development and implementation of laboratory screening methods and restrictive donor criteria. When considering the large number of known pathogens and the fact that pathogens continue to emerge, it is clear that the utility of new tests and donor restrictions will continue to be a challenge when considering the cost of developing and implementing new screening assays, the loss of potential donors, and the risk of testing errors. Despite improving the safety of blood components, testing remains a reactive approach to blood safety. The contaminating organisms must be identified before sensitive tests can be developed. In contrast, pathogen inactivation is a proactive strategy designed to inactivate a pathogen before it enters the blood supply. Almost all pathogen inactivation technologies target nucleic acids, allowing for the inactivation of a variety of nucleic acid-containing pathogens within plasma, platelets, or red blood cells thus providing the potential to reduce transfusion-transmitted diseases. However, widespread use of a pathogen inactivation technology can only be realized when proven safe and efficacious and not cost-prohibitive.

Neurological manifestations of human parvovirus B19 infection

Since its discovery, human parvovirus B19 has been linked with a broad spectrum of clinical syndromes. An aetiological role for the virus has been confirmed in erythema infectiosum, transient aplastic crisis, persistent infection manifesting as pure red cell aplasia in immunocompromised persons, non-immune hydrops fetalis and arthritis. Less commonly recognised, but receiving increasing attention recently, are the neurological manifestations, a variety of which have been described in patients with either clinically diagnosed or laboratory confirmed B19 infection. The purpose of this review is to summarise present knowledge of B19, its known and potential pathogenic mechanisms and its association with human diseases, particularly those with neurological manifestations. The outcome of the review supports an aetiological role of the virus in neurological disease. However, the pathogenesis remains unknown and elucidating this is a priority.

Current molecular epidemiology and human parvovirus B19 infection

Viruses evolve gradually through replication. Therefore, isolates of a virus species can have different genome sequences, albeit slightly, if isolates are epidemiologically unrelated. The difference in virus genome involves difference in virus functions and clinical manifestations of virus infection. Molecular epidemiology of virus infection is a relatively new field directed at infection in humans but not other animals. Analyses are based on genomic differences between virus strains with advances in methodology related to DNA analyses, progress is being made. Classification of virus strains, tracing of transmission of a strain, analyses of outbreaks (including nosocomial infection), and analyses of pathogenesis of virus infection in humans (a natural host) are given attention in molecular epidemiological studies. Human parvovirus B19 is a common human pathogen associated with a wide variety of diseases, including erythema infectiosum, aplastic crisis, hydrops fetalis, and arthritis. B19 is not propagatable in conventional cell lines, hence, molecular cloning of B19 DNA directly from clinical materials has to be done. Events concerning B19 infection were analyzed based on the concept of molecular epidemiology and studies proved to be productive to better understand the pathogenesis of B19 infection.

Painless erythema of the hands associated with non-Hodgkin's lymphoma in a lung transplant recipient

Acral erythema limited to the fingers or the hands has been described in systemic disease. We report the case of a 17-year-old patient who had undergone lung transplantation for cystic fibrosis. Six weeks after transplantation, rapidly growing large-cell immunoblastic non-Hodgkin's lymphoma of the lungs and mediastinum was diagnosed. Sharply demarcated, painless, glovelike erythema was found on both hands. Therapy was reduction of immunosuppression and 12 cycles of extracorporeal photophoresis. After 4 months, lymphoma was in clinical and radiologic remission. Bilateral erythema of the hands also had disappeared. Acral erythema has been reported in association with chemotherapy, collagen vascular disease, infections as with HIV, hepatitis C virus, parvovirus B19, or cytomegalovirus. None of the described associations were detected in this case.

Transfusion transmitted diseases

Transfusion transmitted disease (TTD) is a major challenge to the transfusion services all over the world. The problem of TTD is directly proportionate to the prevalence of the infection in the blood donor community. In India, hepatitis B/C, HIV, malaria, syphilis, cytomegalo virus, parvo-virus B-19 and bacterial infections are important causes of concern. Hepatitis B and C infections are prevalent in India and carrier rate is about 1-5% and 1%, respectively. Post transfusion hepatitis B/C is a major problem in India (about 10%) because of low viraemia and mutant strain undetectable by routine ELISA. HIV prevalence among blood donors is different in various parts of the country. It may not be so alarming as projected by some agencies. In one study from north India, confirmed HIV positivity was found in 0.2/1000 blood donor. Post transfusion CMV is difficult to prevent but use of leukocyte filters may help to reduce it significantly. Parvo virus B-19 infection in blood donors is 39.9% which may increase morbidity in multitransfused or immunocompromised patients. Current symphilis tests may not be sensitive but it should be continued to exclude high-risk donors. Malaria is a real problem for India due to the lack of a simple and sensitive screening test. Incidence of bacterial contamination is greatly reduced due to improved collection/preservation techniques and use of antibiotics in patients. However, proper vigilance and quality control is needed to prevent this problem. Total dependence of altruistic repeat voluntary donors and use of sensitive laboratory tests may help Indian blood transfusion services to reduce incidences of TTDs.

Dermatomyositis associated with the presence of parvovirus B19 DNA in muscle

We report a case of dermatomyositis associated with molecular evidence of parvovirus B19 DNA in two muscle biopsies collected 5 months apart. IgG- but not IgM-specific antibodies were detected in serum. None of four serum samples was positive for parvovirus B19 DNA. The two biopsies contained B19 VP1 sequences and the second one was also positive for NS1. This is the first report of viral parvovirus B19 DNA in muscle of a patient with dermatomyositis. Latent muscle infection may contribute to the clinical picture.

Parvovirus B19 DNA in kidney tissue of patients with focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) represents a clinicopathological syndrome with diverse causes. We examined the possibility that some cases of FSGS are associated with parvovirus B19 infection. We studied renal biopsy tissue from 40 patients, including those with idiopathic FSGS, collapsing FSGS, membranous nephropathy, and minimal change disease, as well as normal renal tissue removed at the time of nephrectomy from 4 patients. DNA was extracted from frozen blocks of kidney tissue and amplified using nested polymerase chain reaction. Parvovirus B19 DNA was amplified from 8 of 10 patients with idiopathic FSGS, 9 of 10 patients with collapsing FSGS, 6 of 10 patients with membranous nephropathy, 5 of 10 patients with minimal change disease, and 2 of 4 cancer nephrectomy samples. The prevalence of parvovirus B19 DNA was greater among patients with idiopathic FSGS and collapsing FSGS compared with patients with other diagnoses (P = 0.05). In situ hybridization studies using digoxigenin-labeled DNA probes failed to detect parvovirus B19 nucleic acid in any of the kidney tissue samples. These results suggest that parvovirus B19 DNA is commonly found in the kidneys of patients with a range of renal diagnoses, possibly representing latent DNA from past infection. The failure to localize parvovirus B19 nucleic acid within kidney argues against ongoing, high-level viral replication. Nevertheless, the increased prevalence of B19 DNA in patients with idiopathic FSGS and collapsing FSGS could indicate a pathogenic role for the virus in the cause of FSGS in certain patients.

An epidemic of parvovirus B19 in a population of 3,596 pregnant women: a study of sociodemographic and medical risk factors

OBJECTIVES

To estimate the incidence of human parvovirus B19 among pregnant women before and during an epidemic, to elucidate possible sociodemographic and medical risk factors during pregnancy and to estimate the association between parvovirus B19 infection and negative pregnancy outcome.

DESIGN

Prospective study among pregnant women followed from their first antenatal visit before 24 full weeks of gestation until delivery.

SETTING

Department of Obstetrics and Gynaecology, Odense University Hospital, Denmark, November 1992 to February 1994.

METHODS

3,596 pregnant women were invited to participate. The women were examined at first antenatal visit in the period from November 1992 to February 1994 and at delivery. The last delivery was in August 1994 and samples were thus collected before and during a large parvovirus B19 epidemic in Denmark January to September 1994. A blood sample for parvovirus B19 serology was taken at enrollment and from the umbilical cord at delivery. Three questionnaires were completed during 2nd and 3rd trimesters and a registration form at delivery. In total, 3,174 (87.6%) were enrolled and 79.5% completed the study.

RESULTS

The prevalence of B19 IgG seropositivity at the first antenatal visit before 24 full weeks of gestation was 66% . The cumulative prevalence proportion of acute parvovirus B19 infection during pregnancy among IgG negative women was found to be 10.3% (IgM seropositivity and/or IgG seroconversion). The IgG seroconversion incidence increased significantly from 1.0% to 13.5% among 932 seronegative pregnant women before and during the epidemic, respectively (P < 0.001). Independent risk factors related to increased risk of B19 infection during pregnancy, adjusted for other sociodemographic and medical factors, were: children at home (adjusted OR 2.1, 95% CI 1.3-3.2); serious medical disease (adjusted OR 3.0, 95% CI 1.0-8.5); and a stressful job (adjusted OR 1.8, 95% CI 1.0-3.3). Parvovirus B 19 IgM seropositivity was associated with events of late spontaneous abortions and stillbirths (crude OR 9.9; 95% CI 3.3-29.4).

CONCLUSION

Before and during an epidemic of acute B19 infection incidences were measured among pregnant women to be 1.0% and 13.5%, respectively. Three factors, significantly increasing the risk of acute B19, were identified as: having children at home; suffering from serious medical diseases; and having a stressful job. IgM positivity for parvovirus B19 was associated with negative outcome of pregnancy.

Fulminant parvovirus infection following erythropoietin treatment in a patient with acquired immunodeficiency syndrome

We report the case of a 41-year-old black man with acquired immunodeficiency syndrome who developed a severe chronic anemia due to parvovirus infection. Bone marrow biopsy revealed erythroid aplasia. The infectious nature of the anemia was not recognized, and the patient was treated with erythropoietin. The patient's reticulocyte response was inadequate, however, and he remained anemic. A second bone marrow biopsy showed erythroid hyperplasia and prominent intranuclear parvovirus inclusions within erythroid progenitors. Erythropoietin was discontinued and was followed by a course of intravenous immunoglobulin, which resulted in rapid correction of anemia. To our knowledge, this is the first reported case of fulminant human parvovirus infection exacerbated by erythropoietin administration and documented by sequential bone marrow histologic examination. This case illustrates the critical importance of considering parvovirus in the etiology of chronic anemia with erythroid aplasia in immunocompromised patients.

Parvovirus B19 is associated with benign testes as well as testicular germ cell tumours

AIMS

Parvovirus B19 has been demonstrated in testes of patients with germ cell tumours but not in controls, raising the possibility that the virus has an aetiological role in these tumours. The aims of this study were to investigate the association of the virus with germ cell tumours and to localise the virus histologically.

METHODS

DNA was extracted from paraffin wax embedded sections of testes from 10 seminomas, eight teratomas, two mixed seminoma/teratomas, and 10 testes showing benign histology. Polymerase chain reaction (PCR) amplification of three regions within the NS and VP1/2 genes was carried out in duplicate on all samples. One PCR positive case (seminoma/teratoma) was examined by microdissection of histologically defined tissue components followed by PCR amplification of parvoviral sequences. Samples from PCR positive patients were immunostained using a B19 specific monoclonal antibody.

RESULTS

Seven cases were PCR positive, these comprised two of 10 seminomas, one of two mixed tumours, none of eight teratomas, and four of 10 benign controls. PCR analysis of the material microdissected from the seminoma/teratoma showed the presence of the virus in regions of seminoma, teratoma, intratubular germ cell neoplasia, normal tubules, and connective tissue. All patient samples studied immunohistochemically were negative.

CONCLUSIONS

This confirms the presence of parvovirus B19 in a proportion of germ cell tumours; however, in one patient, the virus was widespread in the tissue components and not confined to tumour cells. In addition, the virus was present in control benign testes. These data suggest that B19 might not be of aetiological importance in germ cell tumours of testis.

The 1994 human parvovirus B19 epidemic in Denmark: diagnostic and epidemiological experience

In 1994 the first human parvovirus B19 (B19) epidemic to be documented in Denmark was recorded from February 2 to September 30. In total, 10,333 serum samples were tested for specific B19 IgM and IgG antibodies, using IDEIA Parvovirus B19 IgM and IgG kits. The prevalence of B19 IgM positivity was 11% for the whole period and 29% at the peak of the epidemic in week 14, declining from week 39 and onwards to 1-3%. The prevalence of B19 IgG (IgM-negative samples) was 60%, indicating an earlier infection, and the same for men and women. The gender distribution of tested patients was the same at the beginning of the epidemic as at the end of the epidemic and a year after its peak, i.e. 86% of samples were from women and only 14% from men. Age distribution for women was the same for the three periods (median age 34 years). For men the median age was 32 years, 39 years and 31 years, respectively. Only a few samples from children were tested. No change in test pattern was observed during the three periods. Approximately 75% of all samples tested were from women of childbearing age (18-45 years old), suggesting a fear of fetal complications in an actual or future pregnancy, rather than a serological verification of clinical symptoms. From the sparse clinical information that accompanied the serum sample we were not able to demonstrate that women were more likely than men to have a symptomatic B19 infection. With reservations we estimate that 14% of adverse pregnancy outcome is correlated with a B19 infection.

Assessment of the specificity of a commercial human parvovirus B19 IgM assay

BACKGROUND

It is important to investigate a possible cross-reaction of anti-rubella IgM in the IDEIA Parvovirus B19 IgM test because many B19 infections are either asymptomatic or have clinical symptoms similar to those of rubella virus infections. Epstein-Barr virus (EBV) IgM, cytomegalovirus (CMV) IgM, measles IgM and rheumatoid factor (RF) IgM cross-reactions were also studied.

OBJECTIVES

In the period from February to September 1994 (including a parvovirus B19 epidemic) more than 10,000 serum samples were examined for parvovirus B19 IgM in Denmark. This gave an opportunity to evaluate the commercial IDEIA Parvovirus B19 ELISA kit (DAKO A/S, Glostrup, Denmark), which was used routinely at Statens Serum Institut from the beginning of 1994 and onwards.

STUDY DESIGN

A total of 123 parvovirus B19 IgM positive sera were tested for reactivity in rubella IgM EIA. A total of 78 rubella IgM positive sera, 60 EBV VCA-IgM positive sera, 30 CMV IgM positive sera and 24 measles virus IgM positive sera were tested for reaction in IDEIA Parvovirus B19 IgM test. Finally, 25 parvovirus IgM positive sera were tested for specific IgM against measles virus, EBV (VCA), CMV and for RF.

RESULTS

One anti-B19 IgM positive serum sample reacted positively in the rubella IgM test. Of rubella IgM positive serum samples 4% cross-reacted in IDEIA Parvovirus B19 IgM test, as did 17 and 20% of EBV VCA-IgM and CMV IgM positive serum samples respectively. None of measles virus IgM positive serum samples cross-reacted in the IDEIA Parvovirus B19 IgM test. Of 25 initially parvovirus B19 IgM positive sera 20% cross-reacted in EBV VCA IgM test and 8% in the CMV IgM test. None reacted positively in measles virus IgM test; 28% showed weak reactivity in RF IgM test.

CONCLUSIONS

Precautions must be taken when results of IgM assays are interpreted. Epidemiological and clinical observations must be considered.