Outbreak of aplastic crises in sickle cell anaemia associated with parvovirus-like agent

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)

Human parvovirus infection in pregnancy and hydrops fetalis

Human parvovirus is the causative agent of erythema infectiosum, a mild epidemic illness. In a recent outbreak in northeast Scotland, six women had serologic evidence of having contracted human parvovirus infection during pregnancy. Two of the women had midtrimester abortions, and both abortuses were grossly hydropic with anemia. They had similar microscopical histopathological features--a pronounced leukoerythroblastic reaction, hepatitis, excessive iron pigment in the liver, and eosinophilic changes in the hematopoietic cell nuclei. Dot hybridization with radiolabeled human parvovirus DNA probes revealed viral DNA in several tissues from both fetuses, indicating that they had been infected by the virus in utero. The remaining four women had uncomplicated pregnancies and delivered apparently healthy babies, none of whom had human parvovirus-specific IgM antibody at delivery. We conclude that this common virus may pose a serious risk to the fetus after maternal infection.

Hereditary spherocytosis in sisters unmasked by parvovirus infection

Teenage sisters were found to have hereditary spherocytosis when they presented in aplastic crisis associated with otherwise asymptomatic parvovirus infection. Such patients may present a source of cross-infection to others at risk.

Parvovirus infections in childhood

Human parvovirus (HPV) infections have been associated with several clinical syndromes. The virus is the etiologic agent of erythema infectiosum (fifth disease) and the primary cause of aplastic crises in children with sickle cell disease and other hemolytic anemias. Some individuals with an acute symmetric polyarthritis were found to have a recent HPV infection. Although two stillborn infants with proved HPV infections have been identified, the exact relationship among HPV, intrauterine infection, and subsequent fetal damage requires further research.

Identification of the major structural and nonstructural proteins encoded by human parvovirus B19 and mapping of their genes by procaryotic expression of isolated genomic fragments

Plasma from a child with homozygous sickle-cell disease, sampled during the early phase of an aplastic crisis, contained human parvovirus B19 virions. Plasma taken 10 days later (during the convalescent phase) contained both immunoglobulin M and immunoglobulin G antibodies directed against two viral polypeptides with apparent molecular weights of 83,000 and 58,000 which were present exclusively in the particulate fraction of the plasma taken during the acute phase. These two protein species comigrated at 110S on neutral sucrose velocity gradients with the B19 viral DNA and thus appear to constitute the viral capsid polypeptides. The B19 genome was molecularly cloned into a bacterial plasmid vector. Restriction endonuclease fragments of this cloned B19 genome were treated with BAL 31 and shotgun cloned into the open reading frame expression vector pJS413. Two expression constructs containing B19 sequences from different halves of the viral genome were obtained, which directed the synthesis, in bacteria, of segments of virally encoded protein. These polypeptide fragments were then purified and used to immunize rabbits. Antibodies against a protein sequence specified between nucleotides 2897 and 3749 recognized both the 83- and 58-kilodalton capsid polypeptides in aplastic plasma taken during the acute phase and detected similar proteins in the tissues of a stillborn fetus which had been infected transplacentally with B19. Antibodies against a protein sequence encoded in the other half of the B19 genome (nucleotides 1072 through 2044) did not react specifically with any protein in plasma taken during the acute phase but recognized three nonstructural polypeptides of 71, 63, and 52 kilodaltons present in the liver and, at lower levels, in some other tissues of the transplacentally infected fetus.

Transient erythroblastopenia of adolescence

This case report describes a 16-year-old girl with pure red cell aplasia of 7 months duration. The erythrocyte characteristics and in vitro culture of erythroid progenitors was similar to that found in transient erythroblastopenia of childhood (TEC), a disorder most commonly seen in children 2 to 6 years of age. This case may represent the adolescent equivalent of TEC.

Human parvovirus and aplastic crisis in chronic hemolytic anemias: a study of 24 observations

From March 1984 through November 1985, 24 children and adults with aplastic crises were admitted in several Parisian hospitals. Twelve patients had known hemolytic anemia. Aplastic crisis revealed hemolytic anemia in the remaining patients. The detection of human parvovirus antigen was performed by counter-immunoelectrophoresis, and specific IgM antibodies were detected by IgM-antibody-capture-radioimmunoassay, in order to establish the incidence of human parvovirus infection in the genesis of the aplastic crisis. Twenty-one patients had acute infection with human parvovirus. In the three remaining patients, no marker of human parvovirus infection was found. The features of the human parvovirus linked aplastic crisis are described. We consider that human parvovirus infection, and unknown hemolytic anemia, must be systematically researched in any case of unexplained acute aplastic anemia.

Detection of antibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assay

Acute-phase serum from a patient with aplastic crisis provided sufficient human parvovirus B19 to make a monoclonal antibody against B19 and to develop antigen and immunoglobulin M (IgM) and IgG antibody detection enzyme-linked immunosorbent assays (ELISAs). The indirect capture antibody method was used for all three assays. Antigen was detected in 8 of 29 sera drawn within 2 days of onset of illness from patients with aplastic crisis. These sera had high titers of virus by electron microscopy and DNA hybridization and had no detectable B19 antibody. Antigen was not detected in serum specimens that had low titers of B19 DNA and had B19 antibody. With the IgM ELISA, we detected B19 IgM in over 85% of clinical cases of aplastic crisis and fifth disease and less than 2% of controls. The prevalence of B19 IgG antibodies increased with age. Approximately 2% of children less than 5 years of age and 49% of adults greater than 20 years of age had B19 IgG antibodies. The B19 antibody ELISAs are sensitive and specific tests to detect B19 infections.

Parvovirus infection associated with aplastic crisis in a patient with HEMPAS

An aplastic crisis associated with parvovirus infection occurred in a patient suffering from hereditary erythrocytic multinuclearity associated with a positive acidified (Hams) test (HEMPAS). This case emphasises that any patient who has a shortened red cell survival is susceptible to an aplastic crisis induced by parvovirus.

Mechanisms of lymphocytic choriomeningitis virus-induced hemopoietic dysfunction

Results of this study showed that lymphocytic choriomeningitis virus infection causes a marked activation of natural killer (NK) cells not only in the spleen but also in the bone marrow. This activity reached its peak at about day 3 of infection and declined after days 6 to 7. Enhanced NK cell activity was found to correlate with decreased receptivity for syngeneic stem cells in bone marrow and spleen, with the notable exception that decreased receptivity persisted longer in bone marrow. Treatment of infected recipients with anti-asialo GM1 (ganglio-N-tetraosylceramide) significantly increased the receptivity for syngeneic hemopoietic cells. These findings are consistent with the hypothesis that NK cell activation causes rejection of syngeneic stem cells, thus resulting in hemopoietic depression. To understand the mechanisms behind the prolonged decrease in bone marrow receptivity (and bone marrow function in the intact mouse) mentioned above, we followed the changes in the number of pluripotential stem cells (CFU-S) circulating in the peripheral blood and in endogenous spleen colonies in irradiated mice, the limbs of which were partially shielded. It was found that following a marked early decline, both parameters increased to normal or supranormal levels at about day 9 after infection. Because the bone marrow pool of CFU-S is only about 20% of normal at this time after infection, a marked tendency for CFU-S at this stage in the infection to migrate from the bone marrow to the spleen is suggested. It seems, therefore, that as NK cell activity declines, the spleen regains the ability to support growth of hemopoietic cells and the bone marrow resumes an elevated export of stem cells to the spleen. This diversion of hemopoiesis could explain both the long-standing deficiencies of the bone marrow compartment and the prolonged decrease in the receptivity of this organ.

Nucleotide sequence and genome organization of human parvovirus B19 isolated from the serum of a child during aplastic crisis

The nucleotide sequence of an almost-full-length clone of human parvovirus B19 was determined. Whereas the extreme left and right ends of this genomic clone are incomplete, the sequence clearly indicates that the two ends of viral DNA are related by inverted terminal repeats similar to those of the Dependovirus genus. The coding regions are complete in the cloned DNA, and the two large open reading frames which span almost the entire genome are restricted to one strand, as has been found for all other parvoviruses characterized to date. From the DNA sequence we conclude that the organization of the B19 transcription units is similar although not identical to those of other parvoviruses. In particular, we predict that the B19 genome may utilize a fourth promoter to transcribe mRNA encoding the major structural polypeptide, VP2. Analysis of the putative polypeptides confirms that B19 is only distantly related to the other parvoviruses but reveals that there is a small region in the gene probably encoding the major nonstructural protein of B19, which is closely conserved between all of the parvovirus genomes for which sequence information is currently available.

Six cases of hereditary spherocytosis revealed by human parvovirus infection

Recent research has shown that the human parvovirus is a causative agent of aplastic crisis in hereditary haemolytic anaemias. We report six cases--four children and two adults--of hereditary spherocytosis revealed by aplastic crisis due to human parvovirus infection.

Comparison of 17 isolates of the human parvovirus B 19 by restriction enzyme analysis. Brief report

The genomes of 17 isolates of the human parvovirus B 19 were compared by restriction with eight endonucleases. All but four isolates proved indistinguishable. A 3.2 kb B 19 DNA fragment was cloned and used as a molecular probe.

Aplastic and hypoplastic episodes in sickle cell disease and thalassaemia intermedia

Aplastic and hypoplastic crises are well recognised complications of sickle cell disease. Recent evidence has shown that most of these crises are caused by parvovirus infection. Five cases of aplastic or hypoplastic crises in patients born and living in this country were studied. Three patients had clear evidence of parvovirus infection, while in two evidence of parvovirus infection was lacking. One patient had evidence of concurrent parvovirus and Mycoplasma pneumoniae infection. Recurrent crises may occur, and reticulocyte monitoring during infection in patients with chronic haemolytic states is therefore important.

Infectious feline leukaemia virus is erythrosuppressive in vitro

The direct effect of the feline leukaemia virus (FeLV) on erythroid colony formation in vitro was investigated. Bone marrow mononuclear cells (BMMC) from FeLV-naïve, specific-pathogen-free (SPF), adult cats were inoculated with FeLVs of characterized strains and biologically cloned subgroups and the subsequent development of colony forming units-erythroid (CFUE) and burst forming units-erythroid (BFUE) and colony forming units-granulocyte-macrophage (CFUGM) was monitored. Exposure to the anaemia-causing Kawakami-Theilen strain of FeLV (FeLV-KT), a phenotypic mixture of subgroups A, B, and C, caused constant depression of day 2 CFUE (to 47% of sham-inoculated controls), day 4 CFUE (41% of controls), and day 10 BFUE (38% of controls). CFUGM were unaffected. The lymphoma-causing Rickard strain of FeLV (FeLV-R-TL) caused sporadic depression of CFUE and BFUE. In contrast, neither FeLV-R passaged through feline embryonic kidney fibroblasts (FeLV-R-CRFK) nor biologically cloned, subgroup-specific, FeLVs of fibroblast origin, caused decrements in CFUE or BFUE, suggesting that fibroblast passage attenuated the direct erythrosuppressive effect of FeLV. Suppression of CFUE and BFUE by lymphoma cell-origin FeLV was dependent on infectious virus and was associated with FeLV replication by the cultured myelomonocytic precursor cells. Attenuation of infectivity by heat or u.v. restored CFUE and BFUE development. Examination of the relationship between viral infectivity (VI), viral protein concentration, and CFUE suppression showed that the infectious FeLV was 20-fold more effective than u.v.-inactivated FeLV as an inhibitor of erythrogenesis in vitro.

An erythema infectiosum-like illness caused by human parvovirus infection

In the spring of 1980, an epidemic of an illness that resembled erythema infectiosum occurred in Manitoba, Canada. We initiated prospective epidemiologic, clinical, and microbiologic studies of this illness among elementary-school children and their families. Initial microbiologic studies failed to identify the cause of the exanthem. After a similar illness associated with serologic evidence of human parvovirus infection occurred in London, stored specimens of 12 patients with exanthem were investigated for parvovirus infection. Eleven patients had parvovirus-specific IgM antibody, as did two family contacts and a teacher with nonexanthematous illnesses, and two asymptomatic family members. None of 28 children with measles or rubella had serologic evidence of recent parvovirus infection. Human parvovirus was detected by DNA hybridization and immune electron microscopy in the serum of one patient who later had a rash and in one unaffected family contact. Parvovirus DNA was also detected in the pharyngeal specimen of the teacher who was ill but did not have a rash. We conclude that human parvovirus infection can be asymptomatic or cause a variety of clinical manifestations, including nonexanthematous illness and an illness resembling erythema infectiosum.

Human parvovirus (B19) and erythema infectiosum

An outbreak of erythema infectiosum ("fifth disease") was studied in Fukuoka, Japan, in 1980-1981. Human parvovirus (HPV) antigen was not detected in any patients, but anti-HPV, measured by countercurrent immunoelectrophoresis, was found in 33 of 34 affected children and in 21 (15%) of 141 children of the same ages without the disease. Immunoglobulin M class anti-HPV was present in all 25 children with erythema infectiosum tested. In a survey of hospital patients, the prevalence of anti-HPV detected by CIE was 12% in the cohort 5 to 9 years of age, 19% in the cohort 10 to 14 years, and 32 to 55% in the cohorts greater than or equal to 30 years. The antibody reactions in the cases of erythema infectiosum, which were already well established at the onset of disease, indicate that HPV was the cause of the outbreak.

Clinical presentation of homozygous sickle cell disease

The pattern of initial clinical symptoms and signs developing in a representative sample of 305 children with homozygous sickle cell (SS) disease diagnosed at birth was analyzed. Specific symptoms were present by age 6 months in 6% of the group, and had developed by the first to eighth birthdays in 32%, 61%, 78%, 86%, 90%, 92%, 94%, and 96%, respectively. Inclusion of nonspecific symptoms in the analysis led to earlier recognition by a mean of 3 months in the first year and by a mean of approximately 1 year between the ages of 2 and 4 years. Dactylitis was the most common initial symptom, noted in 40% of the group overall and in 50% in the first 2 years. Painful crisis was the first symptom in more than one fourth of the patients and was the most frequent symptom after the age of 2 years. Acute splenic sequestration led to presentation in one-fifth of the group overall and in one third of patients younger than 2 years. The most common nonspecific symptom was pneumonia. There was a significant trend of earlier presentation in children with low fetal hemoglobin levels. The age at presentation did not appear to be affected by alpha-thalassemia status.

Paediatrics among ethnic minorities. Afro-Caribbean and African families

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Hepatic sequestration in sickle cell anaemia

Several episodes of acute hepatic enlargement associated with a dramatic fall in haemoglobin concentration were observed in two patients with sickle cell anaemia. No appreciable disturbances of liver function or signs of cardiac failure were evident. The most likely mechanism was sequestration of sickled erythrocytes in the liver. This complication, which may have a basis similar to that of splenic sequestration and the sickle lung syndrome, may be easily overlooked unless the size of the liver is regularly monitored in patients with sickle cell crisis.

Human parvovirus arthropathy

19 of 153 patients attending an early-synovitis clinic were shown to have been recently infected by the human parvovirus (HPV). 5 other patients had evidence of some other closely preceding infection. HPV-infected patients typically presented with symmetrical peripheral polyarthropathy of sudden onset and moderate severity. Usually there was some improvement within 2 weeks, but in 17 patients symptoms persisted for more than 2 months, and in 3 for more than 4 years. Arthropathy in the absence of the facial rash that characterises HPV infection in children is a common presentation of the infection in adults.

Detection of human parvovirus using a molecularly cloned probe

Half of the genomic DNA of the human parvovirus (B19) was cloned in the plasmid pBR322. The cloned DNA was used as a molecular probe for the detection of parvovirus in serum by means of a dot hybridization test. In an assay of 26 samples, the dot hybridization test was found to be of comparable sensitivity and to be as rapid as radioimmunoassay for viral antigen detection; it is potentially useful as a diagnostic test.

Diagnosis of human parvovirus infection by dot-blot hybridization using cloned viral DNA

The human parvovirus can be detected in serum by the immunological techniques of immune electron microscopy (IEM), counterimmunoelectrophoresis (CIE), and radioimmunoassay (RIA). A portion of the genome of this virus has been cloned in pAT153 and used as a 32P-labelled probe in dot-blot hybridization assays to detect parvovirus DNA in serum specimens. This test proved a highly sensitive means of detecting virus in microlitre volumes of serum, giving positive results for samples containing 0.5 pg viral DNA, equivalent to 10(4) virus particles. Unlike CIE and RIA the test is not affected by the presence of parvovirus-specific antibody in serum specimens, and has permitted virus to be detected in specimens obtained up to 11 days after the onset of clinical symptoms of aplastic crisis.

Direct demonstration of the human parvovirus in erythroid progenitor cells infected in vitro

The human parvovirus (HPV), the cause of transient aplastic crisis of hereditary hemolytic anemia, has been shown to be cytotoxic for erythroid progenitor cells and its presence in these cells demonstrated by morphologic techniques. A relatively pure population of progenitors, isolated by removal of immature erythroid bursts from primary culture, was the target of the virus infection. Infected cells failed to proliferate in secondary culture. Using a monoclonal antibody to HPV, specific fluorescence was demonstrated in a minority of cells 24-48 h after infection with virus. Infected cells examined by electron microscopy showed marked toxic ultrastructural alterations and parvovirus-like particles in crystalline arrays in the nucleus.

Detection of antibodies to human parvovirus in erythema infectiosum (fifth disease)

Two Japanese outbreaks of erythema infectiosum were investigated for evidence of human parvovirus infection by a solid phase antibody capture radioimmunoassay based on a monoclonal antibody to human parvovirus. Specific IgM and high concentrations of specific IgG were detected in 37 sera from 27 children with erythema infectiosum. No anti human parvovirus IgM was detected in a remaining case of erythema infectiosum, in five patients with Kawasaki disease, or in the 17 control children. Seven of the controls were also anti human parvovirus IgG negative, and the 10 who were seropositive had lower concentrations of anti human parvovirus IgG than the patients with erythema infectiosum. These data indicate that human parvovirus is a cause of erythema infectiosum.

Human parvovirus infection and aplastic crisis in hereditary spherocytosis

This report records an episode of parvovirus-induced bone-marrow aplasia in a child with hereditary spherocytosis and arising during a local outbreak of erythema infectiosum (fifth disease or 'slapped-cheek syndrome'). Inapparent infection was found in two haematologically normal family contacts.

Parvovirus infection in a family associated with aplastic crisis in an affected sibling pair with hereditary spherocytosis

There have been many reports of aplastic crisis preceded by a febrile illness in hereditary haemolytic anaemias. Recent research has shown that the human parvovirus may be a causative agent. We report on an adult sibling pair with hereditary spherocytosis who presented in aplastic crisis after a febrile illness. Both had evidence of recent parvovirus infection, shown by the presence of IgM class specific antibody in their sera. The children of one of the sibling pair, one of whom has hereditary spherocytosis but no chronic haemolysis, showed similar evidence of acute parvovirus infection.

Cytomegalovirus pneumonia in sickle cell disease

Cytomegalovirus (CMV) pneumonia frequently occurs in immunocompromised hosts. Unlike encapsulated bacteria and Mycoplasma, CMV pneumonia has not been reported in sickle cell disease. We describe a case of a healthy young man with sickle cell thalassemia who died with CMV pneumonia.

An outbreak of erythema infectiosum associated with human parvovirus infection

Erythema infectiosum (EI) or fifth disease is a mild, acute exanthematous disease, occurring mainly among children, for which a causative virus has long been sought. In May 1983 an outbreak of exanthematous illness was reported in a primary school in North London. Children attending the school were investigated by questionnaire and 162 (43.9%) reported an illness with the features of EI. In each of 36 cases investigated virologically the illness was associated with parvovirus infection. Moreover, pre-existing antibody to parvovirus was correlated with protection from EI in 16 of 17 close family contacts of cases. We propose therefore that EI is the common manifestation of infection with the human parvovirus.

Bone marrow in sickle cell anaemia at time of anaemic crisis

Samples of bone marrow from 33 Ghanaian children with homozygous sickle cell anaemia who presented with profound anaemia (haemoglobin less than 5 g/dl) were studied. The principal finding was depression of erythropoiesis (aplastic crisis) in 14 children and erythroid hyperplasia in 17. A splenic sequestration crisis was clinically diagnosed in the remaining two children. Stainable iron was absent in the marrow of 14 children and reduced in another five. Megaloblastic changes compatible with folate deficiency were present in 8 children. It is suggested that iron and folate deficiencies may complicate sickle cell anaemia in children living in geographical areas where nutritional deficiencies are prevalent.

Characterization of a virus that causes transient aplastic crisis

Transient aplastic crisis in children with congenital hemolytic anemias has been linked epidemiologically to infection with a serum parvovirus-like virus (SPLV). The virus is found in the blood in the early stages of the crisis, and serum containing SPLV inhibits erythroid colony formation in vitro. After sedimentation of virus-containing sera through a sucrose density gradient, colony inhibitory activity is present in the particulate fraction and separate from serum immunoglobulins. No inhibitory activity can be recovered from convalescent-phase sera after similar fractionation procedures. Inhibition of erythroid colony formation in vitro is not a feature of sera from other viral infections. The pattern of resistance of SPLV activity to chemicals and enzymes is compatible with it being a parvovirus. By using replating techniques, a target of SPLV has been identified as a late erythroid progenitor cell. Neither SPLV antigen nor anti-SPLV IgM was present in the sera of patients with other forms of bone marrow failure.