Parvovirus infection associated with aplastic crisis in a patient with HEMPAS

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.

Human Parvoviruses

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

Infection Control Measures for Human Parvovirus Bl9 in the Hospital Setting

A human parvovirus was first discovered serendipitously in blood from asymptomatic donors in 1975' and designated B19 because of the location of the original positive serum in a test panel. Subsequently, the newly discovered virus was determined to be the etiologic agent of most cases of transient aplastic crisis in the setting of chronic hemolytic anemia and of the childhood exanthem erythema infectiosum, or fifth disease. While erythema infectiosum with its classic “slapped-cheek” rash is a childhood illness, “fifth disease” in the adult should not be overlooked. At least 40% of adults lack serological evidence of past human parvovirus B19 infection and are at risk. Adults tend to have a more subtle rash, often lacking the “slapped cheeks,” and tend to have a more severe constitutional, flu-like illness with prominent joint symptoms. While the arthralgia and arthritis of adult “fifth disease” are often self-limiting, they may become chronic and lead to an arthropathy that meets American College of Kheumatology criteria for a diagnosis of rheumatoid arthritis. The arthropathy has been reported to persist up to five years, the longest follow-up now available (A. Wolf; MD, personal communication, August 27, 1987).

A review of blood diseases and cytopenias associated with human parvovirus B19 infection

Parvovirus B19 is a single-stranded DNA virus which preferentially targets the erythroblast resulting in red cell aplasia, which is temporary in immunocompetent persons. Since the discovery of B19 virus in 1975, a wide variety of blood diseases and cytopenias affecting several blood cell lineages have been documented during or following B19 infection. These include cytopenias affecting the erythroid, megakaryoblastoid, myeloid and lymphoid lineages, as well as a variety of bicytopenias, pancytopenia, bone marrow necrosis / fat embolism syndrome, myelodysplastic syndrome, leucoerythroblastopenia, and hemophagocytic lymphohistiocytosis. B19 infection may also complicate and precede the course of acute leukemia, the significance of which remains to be determined. This review describes the current state of knowledge of the abnormalities of individual blood cell lineages encountered during parvovirus B19 infection, over the almost 40 years since its discovery, and reveals some very interesting themes, which improve our understanding of the pathogenesis of B19 infection with particular reference to the bone marrow.

The congenital dyserythropoietic anemias

The congenital dyserythropoietic anemias (CDAs) are a heterogeneous group of hereditary disorders that seem to be restricted to the erythroid lineage. They are characterized by morphologic abnormalities of erythroid precursors in the bone marrow, resulting in ineffective erythropoiesis and a suboptimal reticulocyte response. As with many rare disorders, cases of CDA are often misdiagnosed, which may lead to inappropriate management. In this review, the authors highlight the relevant clinical data together with recent molecular advances that should aid decision making in diagnosis and patient management.

Aplastic crisis as a complication of congenital dyserythropoietic anemia type II

A transient aplastic crisis (TAC) is a well-known complication in all types of chronic hemolytic anemia but only 2 cases of such an event were described in congenital dyserythropoietic anemias (CDAs). Here, we report a third case, and by retrospective chart review of 78 cases we found evidence of TAC in 8 further patients with CDA II, with serological evidence of previous human parvovirus B19 (B19V) infection in all but one. Although B19V infection results in TAC in only a minority of patients with CDA, physicians responsible for these patients should be aware of such a potentially life-threatening complication. Testing for B19V-specific IgG is recommended in patients with CDA to estimate the risk of a possible future aplastic crisis.

Advances in the understanding of the congenital dyserythropoietic anaemias

The congenital dyserythropoietic anaemias (CDAs) are a heterogeneous group of diseases in which the anaemia is predominantly caused by dyserythropoiesis and marked ineffective erythropoiesis; three major (types I, II and III) and several minor subgroups have been identified. Additional information on the natural history of these conditions, the beneficial role of splenectomy in CDA type II and efficacy of interferon-alpha in type I have recently been reported. A disease gene has been localised to a chromosomal segment in the three major types and in CDA type I, a disease gene has been identified (CDANI). Mutations have been detected in both familial and sporadic cases but the predicted protein structure gives few clues as to its function. In both type I and II, there are cases unlinked to the identified localisations, suggesting genetic heterogeneity.

Congenital dyserythropoietic anaemia type II (HEMPAS) and haemochromatosis: a report of two cases

We describe two patients with severe iron overload in the context of congenital dyserythropoietic anaemia (CDA) type II, which is characterized by a protein glycosylation defect with impairment of N-glycan synthesis. In both patients a corpuscular, haemolytic anaemia had been diagnosed in early childhood and both patients underwent splenectomy before the age of 9 years. They developed clinical manifestations of haemochromatosis and only re-evaluation during adulthood led to the correct diagnosis. Abnormal glycosylation of proteins involved in iron homeostasis is likely to contribute to the massive hepatic iron accumulation characteristic for CDA type II. Both patients required chelation therapy. This report points out the need to consider CDA in patients presenting with haemochromatosis and anaemia.

Human parvovirus B19

Parvovirus B19 (B19) was discovered in 1974 and is the only member of the family Parvoviridae known to be pathogenic in humans. Despite the inability to propagate the virus in cell cultures, much has been learned about the pathophysiology of this virus, including the identification of the cellular receptor (P antigen), and the control of the virus by the immune system. B19 is widespread, and manifestations of infection vary with the immunologic and hematologic status of the host. In healthy immunocompetent individuals B19 is the cause of erythema infectiosum and, particularly in adults, acute symmetric polyarthropathy. Due to the tropism of B19 to erythroid progenitor cells, infection in individuals with an underlying hemolytic disorder causes transient aplastic crisis. In the immunocompromised host persistent B19 infection is manifested as pure red cell aplasia and chronic anemia. Likewise, the immature immune response of the fetus may render it susceptible to infection, leading to fetal death in utero, hydrops fetalis, or development of congenital anemia. B19 has also been suggested as the causative agent in a variety of clinical syndromes, but given the common nature, causality is often difficult to infer. Diagnosis is primarily based on detection of specific antibodies by enzyme-linked immunosorbent assay or detection of viral DNA by dot blot hybridization or PCR. Treatment of persistent infection with immunoglobulin reduces the viral load and results in a marked resolution of anemia. Vaccine phase I trials show promising results.

The congenital dyserythropoietic anaemias

Congenital dyserythropoietic anaemias (CDA) are a category of rare genetic diseases that affect erythropoiesis. Dyserythropoiesis is associated with abnormal erythroblasts and leads to altered red cells, the amount of which is insufficient. There are three main, well-defined CDAs, CDA I, II and III. Their characterization is based on a careful examination of the bone marrow under light and electron microscopes. In addition, a number of rare or unique forms of dyserythropoiesis have been reported. At least with respect to CDA I to III, the clinical evaluation is reaching an ever increasing refinement: age of discovery, determinants of iron overload and/or biliary complications. Over the past few years, a more promising breakthrough has been the localization of the genes responsible for CDA I, II and III, that is, 15q15.1-q15.3, 20q11.2 and 15q21-q25, respectively. Epidemiological studies have now become possible. The identification of the genes is pending.

HEMPAS. Hereditary erythroblastic multinuclearity with positive acidified serum lysis test

Congenital dyserythropoietic anemia type II or HEMPAS (hereditary erythroblastic multinuclearity with positive acidified serum lysis test) is a genetic anemia in humans caused by a glycosylation deficiency. Erythrocyte membrane glycoproteins, such as band 3 and band 4.5, which are normally glycosylated with polylactosamines lack these carbohydrates in HEMPAS. Polylactosamines accumulate as glycolipids in HEMPAS erythrocytes. Analysis of N-glycans from HEMPAS erythrocyte membranes revealed a series of incompletely processed N-glycan structures, indicating defective glycosylation at N-acetylglucosaminyltransferase II (GnT-II) and/or alpha-mannosidase II (MII) steps. Genetic analysis has identified two cases from England in which the MII gene is defective. Mutant mice in which the MII gene was inactivated by homologous recombination resulted in a HEMPAS-like phenotype. On the other hand, linkage analysis of HEMPAS cases from southern Italy excluded MII and GnT-II as the causative gene, but identified a gene on chromosome 20q11. HEMPAS is therefore genetically heterogeneous. Regardless of which gene is defective, HEMPAS is characterized by incomplete processing of N-glycans. The study of HEMPAS will identify hitherto unknown factors affecting N-glycan synthesis.

Congenital dyserythropoietic anaemias: clinical features, haematological morphology and new biochemical data

Three types of congenital dyserythropoietic anaemia (CDA) were originally identified on the basis of the pattern of dysplastic changes in the erythroblasts and the results of the acidified serum lysis test (Ham test). These were designated CDA types I, II and III. Several other types have been described subsequently and new forms continue to be reported. Some patients with CDA develop iron overload even without repeated blood transfusion and may present with the complications of severe iron overload. Dysmorphic features are seen in some cases, especially of CDA type I. In CDA type II, incomplete processing of N-linked oligosaccharides leads to a marked reduction of polylactosamines associated with band 3 of the red cell membrane. A few cases of CDA type III develop lymphoid neoplasms. Some of the Swedish cases of CDA type III have developed a retinal abnormality characterized by angioid streaks and macular degeneration. The chromosomal localizations of the disease gene in CDA types I and II and in the Swedish family with CDA type III are now known, but the identities of the mutant genes are still unknown. Cases of CDA type I have shown a partial haematological response to interferon-alpha, however the biochemical basis of this response is unclear. An important step in the diagnosis of sporadic cases of CDA is the exclusion of known causes of acquired dyserythropoiesis.

Rheumatic manifestations of parvovirus B19 infection

Human parvovirus B19 is an emerging DNA virus. B19 infection is common and widespread. Major manifestations of B19 infection are transient aplastic crisis, erythema infectiosum, hydrops fetalis, acute and chronic rheumatoid-like arthropathy, and, in the immunocompromised host, chronic or recurrent bone marrow suppression. A number of less common manifestations of B19 infection include various rash illnesses, neuropathies, and acute fulminant liver failure. Of rheumatologic interest, B19 infection must be differentiated from early presentation of more classic erosive rheumatoid arthritis and, in some cases, systemic lupus erythematosus. It is unlikely that B19 plays a role in classic erosive rheumatoid arthritis, but understanding pathogenesis of B19 arthropathy may provide insights into the mechanisms by which rheumatoid arthritis develops. Evidence for persistence of B19 infection suggests that human parvovirus B19 infection may serve as a model for the study of virus-host interactions and the role of viruses in the pathogenesis of rheumatic diseases.

Congenital dyserythropoietic anemias

The congenital dyserythropoietic anemias (CDAs) are a group of relatively rare inherited anemias that share in common ineffective erythropoiesis and morphologic abnormalities of mature red blood cells and their precursors. Three major types of CDA and a number of variants have been described. The diagnosis and categorization of these disorders are facilitated by microscopic examination of the blood and bone marrow and by serologic testing. Management of patients currently consists of observation and supportive care. Because patients with CDAs may be at significant risk for secondary hemochromatosis, they require monitoring for this condition. Splenectomy may be of benefit in certain cases in which the anemia is particularly severe. Over the past few years advances have been made in understanding the pathogenesis of these disorders, and it now appears that CDA II results from enzymatic defects in the cellular glycosylation pathway.

Human parvovirus B19 infection among hospital staff members after contact with infected patients

In the spring and summer of 1988, two separate outbreaks of an illness with a rash resembling erythema infectiosum occurred among members of the nursing staff of the Children's Hospital of Philadelphia. The sources were two adolescent patients with sickle cell disease and aplastic crisis who had unsuspected parvovirus infection. Tests for IgM and IgG antibodies to parvovirus B19 were positive in both patients, and electron microscopical examination showed parvovirus-like particles in the early serum samples. Of 40 health care workers exposed to infected patients, 12 (30 percent) were infected, 2 (5 percent) were possibly infected, 8 (20 percent) had evidence of a past infection with B19, and 18 (45 percent) remained seronegative. Attack rates among the susceptible contacts were 36 percent in the first outbreak and at least 38 percent in the second. Clinical symptoms began a mean of 12.6 days after exposure and included malaise, rash, and joint pain. We conclude that hospital workers are at risk of contracting nosocomial erythema infectiosum from patients with parvovirus-associated aplastic crisis. We recommend that all patients with hereditary hemolytic anemias who are admitted with a febrile illness be evaluated for aplasia and promptly placed in respiratory and contact isolation if aplastic crisis is suspected.

Infection control measures for human parvovirus B19 in the hospital setting

A human parvovirus was first discovered serendipitously in blood from asymptomatic donors in 1975' and designated B19 because of the location of the original positive serum in a test panel. Subsequently, the newly discovered virus was determined to be the etiologic agent of most cases of transient aplastic crisis in the setting of chronic hemolytic anemia and of the childhood exanthem erythema infectiosum, or fifth disease. While erythema infectiosum with its classic “slapped-cheek” rash is a childhood illness, “fifth disease” in the adult should not be overlooked. At least 40% of adults lack serological evidence of past human parvovirus B19 infection and are at risk. Adults tend to have a more subtle rash, often lacking the “slapped cheeks,” and tend to have a more severe constitutional, flu-like illness with prominent joint symptoms. While the arthralgia and arthritis of adult “fifth disease” are often self-limiting, they may become chronic and lead to an arthropathy that meets American College of Kheumatology criteria for a diagnosis of rheumatoid arthritis. The arthropathy has been reported to persist up to five years, the longest follow-up now available (A. Wolf; MD, personal communication, August 27, 1987).

Human parvovirus infections

Discovered by chance in 1974, the human serum parvovirus B19 is at present the only recognized, autonomous, pathogenic human parvovirus. For some years following its discovery, B19 was not associated with any defined clinical syndrome; although a high titre viraemia was often noted in infected individuals they were largely asymptomatic. In 1980 the causal association between B19 infection and aplastic crisis in chronic haemolytic anaemia began to emerge with the discovery of B19 as the agent responsible for aplastic crisis in sickle cell anaemia. This fulfilled the expectation of a disease of tissue comprising a large proportion of dividing cells, namely the erythropoietic elements of the bone marrow, anticipated in autonomous parvovirus infection where viral replication is confined to dividing cells. More recently, erythema infectiosum, an illness sharing many of the clinical features of rubella, has been found to be the common result of B19 infection, although a spectrum of disease is now emerging. Much effort is currently directed toward the elucidation of the effects of maternal B19 infection on the developing fetus.

B19 virus--a pathogenic human parvovirus

B19 virus is the first human virus to be shown to be a member of the parvovirus genus. This review is concerned with the diseases associated with B19 virus, their nature, pathogenesis and diagnosis. The virus was discovered by chance in blood donors but has been shown to be a common infection of childhood. Infection may be asymptomatic or associated with mild, non-specific symptoms. The most common specific clinical manifestation is an erythematous rash illness which often has the classical features of erythema infectiosum. Often, however, it is described simply as rubelliform and only laboratory tests can distinguish B19 and rubella virus infections. Joint involvement is the most common complication of B19 virus infection occurring especially in adult females. It often involves the joints of the hands and wrists, clears rapidly in most patients but may persist for months or years in a few. B19 virus is also the principle cause of the transient aplastic crisis which complicates chronic haemolytic anaemia. This has been demonstrated repeatedly in sickle cell anaemia and hereditary spherocytosis and in individual cases of other haemolytic anaemias. The pathogenesis of the aplastic crisis is related to the ability of B19 virus to infect and damage early erythroid progenitor cells. Volunteer studies in normal individuals have demonstrated that this is a regular event occurring about a week after infection via the respiratory tract. Rash illness and joint involvement occur 7 to 10 days later and are presumably immune mediated. Diagnosis of B19 virus infection can be achieved by detection of the viraemia (aplastic crisis) or by detection of virus specific IgM antibody (all diseases).(ABSTRACT TRUNCATED AT 250 WORDS)