Chronic neutropenia of childhood: frequent association with parvovirus infection and correlations with bone marrow culture studies

Parvovirus b19-Induced Acute Hepatitis With Hepatosplenomegaly and Polyarthropathy

Parvovirus B19 infection can present with myriads of clinical diseases and syndromes; hepatitis and polyarthropathy are a few of these examples. Parvovirus frequently affects children but this condition has also been reported in adults. 

The present case report discusses a case of a 43-year-old female who presented to the outpatient department (OPD) with complaints of high-grade fever and pain in multiple joints of her body for three days.

On examination, stiffness and swelling of the hand, knees, wrist, and ankles were noted. Laboratory investigations showed highly elevated aspartate transaminase (AST), alanine transaminase (ALT), and bilirubin. Electrocardiogram (ECG) and echocardiogram (ECHO) findings were unremarkable. PCR testing showed the presence of parvovirus. Parvovirus B19 infection led to the development of acute hepatitis, which appeared as yellowing of skin (jaundice) and led to hepatosplenomegaly. Parvovirus-induced polyarthropathy was also observed in the patient. The patient was managed with a parenteral course of ceftriaxone, paracetamol, and a normal saline infusion. Anti-viral drugs were also prescribed to the patient including ribavirin and pegylated interferon. This case study will explore how the patient was diagnosed and managed with conventional therapy and anti-viral to relieve parvovirus-induced hepatitis with hepatosplenomegaly and polyarthritis.

Acute hepatitis can be caused by viruses and other noninfectious causes, all of which must be cleared out to avoid chronic disease development. When patients present with joint pain and skin rashes, a thorough workup for viral indicators, medication histories, autoimmune and metabolic illnesses, and parvovirus b19 infection is required.

A Rare Case of Parvovirus B19 Infection Manifesting as Chronic Aplastic Anemia and Neutropenia in a Human Immunodeficiency Virus-Infected Patient

Parvovirus B19 (PVB19) is a deoxyribonucleic acid (DNA) virus, the only member of the Parvoviridae, which has a direct cytopathic effect on erythroid progenitor cells, resulting in an arrest of hematopoiesis and subsequent anemia. Less frequently, neutropenia and thrombocytopenia have been reported with the PVB19 infection. We report a rare case of chronic neutropenia due to PVB19 in a human immunodeficiency virus (HIV) patient. A 51-year-old male with a medical history of HIV presented to the Emergency Department (ED) with complaints of generalized weakness. His laboratory tests were significant for severe anemia and new neutropenia. PVB19 DNA by polymerase chain reaction (PCR) was positive. PVB19 immunoglobulin M (IgM) and IgG were reported negative. He was diagnosed with aplastic anemia from PVB19 and neutropenia. From June 2013 to January 2019, the patient was admitted 23 times with severe neutropenia and anemia, and on each occasion, PVB19 DNA by PCR was positive. During these multiple admissions, he was treated with antibiotics for neutropenic fever, methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, and methicillin-sensitive Staphylococcus aureus (MSSA) skin abscesses. On each occasion, he required multiple blood transfusions, and he received intravenous immunoglobulin (IVIG) that resulted in significant improvement of absolute neutrophil count (ANC) count. He had bone biopsy twice, which showed normal maturation of the myeloid series and reduced erythroid progenitor cells consistent with PVB19 infection. PVB19 DNA by PCR remains positive to date. Immunocompromised individuals usually develop a chronic infection from PVB19, and rarely infection with PVB19 can cause severe neutropenia that can be long-lasting and life-threatening. Early recognition and treatment with IVIG are the key to improve the clinical outcome.

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.

Agranulocytosis under biotherapy in rheumatoid arthritis: three cases hypothesis of parvovirus B19 involvement in agranulocytosis observed under tocilizumab and rituximab for the treatment of rheumatoid arthritis

Leukopenia is a considerably common complication of tocilizumab [TCZ] and rituximab [RTX] therapy. RTX-induced leukopenia typically exhibits delayed onset. While agranulocytosis has been reported linked to RTX treatment of lymphoma, this complication rarely occurs in rheumatoid arthritis (RA) treatment and, to our knowledge, has never been reported in association with TCZ therapy. We herein report four agranulocytosis cases in three patients, with the first two cases suspected to be secondary to human parvovirus B19 (PVB19) infection. Agranulocytosis manifested in the first patient 2 months following a third RTX course. Bone marrow (BM) polymerase chain reaction (PCR) was positive for PVB19. The patient relapsed after three TCZ courses, with her PCR again positive for PVB19. Both episodes resolved under granulocyte-macrophage colony-stimulating factor (GM-CSF). In the second patient, agranulocytosis manifested after the 74th TCZ course. Bone marrow PCR was positive for PVB19, and the evolution was favorable under intravenous immunoglobulin administration. The third case was a 53-year-old female patient with seropositive RA who presented agranulocytosis after the first infusion of her fourth RTX course. Unfortunately, no PCR PVB19 was made on myelogram. Evolution was favorable after 5 days of GM-CSF. PVB19 infection should be investigated in patients suffering from agranulocytosis manifesting during biotherapy. In cases manifesting from the 15th day of RTX treatment onwards, hemogram must be conducted before readministering the infusion.

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.

Three Adult Cases of HPV-B19 Infection with Concomitant Leukopenia and Low Platelet Counts

We encountered three adult patients with flu-like symptoms diagnosed with human parvovirus B19 (HPV-B19) infection. Blood serum analysis also revealed leukopenia, with white blood cell counts (WBCs) of 1,000–2,000/mL and low platelet counts of 89–150 × 10⁹/L. Typical skin rash was absent in one patient. Bone marrow examination of another patient showed hypoplastic marrow with <5% blast cells. All patients recovered without administration of granulocyte colony-stimulating factor (G-CSF). Therefore, HPV-B19 infection with leukopenia should be considered in adult patients with leukopenia during erythema infectiosum epidemics, even if typical clinical findings (ie, skin rash) are absent. Further, the fact that three cases were observed over the stated time period at our hospital, which is located in Nagoya city, showed a transition to a slightly higher level of incidence than the annual average.

Parvovirus B19: the causative agent of dilated cardiomyopathy or a harmless passenger of the human myocard?

Parvovirus B19 infections may cause a widespread benign and self-limiting disease in children and adults known as erythema infectiosum (fifth disease). Several further manifestations are associated with B19 infections, such as arthralgias, arthritis, leucopenia and thrombocytopenia, anaemia and vasculitis and spontaneous abortion and hydrops fetalis in pregnant women. Persistent infections with continuous virus production may occur in immunocompetent as well as in immunosuppressed individuals. Parvovirus B19 infections have been frequently implicated as a cause or trigger of various forms of autoimmune diseases affecting joints, connective tissue and large and small vessels. Autoimmune neutropenia, thrombocytopenia and haemolytic anaemia are known as sequelae of B19 infections. The molecular basis of the autoimmune phenomena is unclear. Many patients with these long-lasting symptoms are not capable of eliminating the virus or controlling its propagation. Furthermore, latent viral genomes have been detected in cells of various organs and tissues by PCR. At present, it is not clear if these cells produce viral proteins and/or infectious B19 particles, if the virus genome can be reactivated to productive replication and if the presence of viral DNA indicates a causative role of parvovirus B19 with distinct diseases.

Agranulocytosis associated with parvovirus B19 infection in otherwise healthy patients

In the course of 6 years, 23 otherwise healthy patients with acute febrile illness and leukopenia were diagnosed as having acute parvovirus B19 infection. Five of these patients had agranulocytosis associated with acute parvovirus B19 infection and one had chronic agranulocytosis due to persistent parvovirus B19 infection. The diagnosis was made after positive anti-parvovirus B19 IgM antibodies were found in all of the patients and viral DNA was detected by PCR in four patients. Neutropenia and agranulocytosis appear to be much more frequently associated with parvovirus B19 infection than previously reported.

Parvovirus B19 capsid protein VP2 inhibits hematopoiesis in vitro and in vivo: implications for therapeutic use

OBJECTIVE

To evaluate the capacity of parvovirus B19 capsid protein VP2 to inhibit hematopoiesis in vitro and in vivo. If effective, a VP2-derived construct may have therapeutic and prophylactic utility in diseases associated to overproduction of hematopoietic cells.

METHODS

The effect on hematopoiesis in vitro of recombinant VP2, intact and enzymatically fragmented, was evaluated in a colony formation assay, using cells from fetal liver and macaque bone marrow. VP2 was also administered intravenously in macaques and hematological parameters as well as the ex vivo colony formation were assayed during a follow-up period of 33 days.

RESULTS

VP2 inhibited BFU-E colony formation by about 55%. CFU-GM and CFU-GEMM colony formation was also affected. Fragmented VP2 retained the inhibitory effect. The ex vivo colony-forming capacity of macaque bone marrow cells was lower in animals that received VP2 injections, and a drop in hematocrit values was noted in one animal.

CONCLUSION

VP2 has an inhibitory effect on hematopoiesis in vitro and in vivo. An active region within VP2 is implied, which would be a strong candidate for use as a medicament in diseases such as polycytemia vera.

Parvovirus B19 infection and autoimmune disease

Human parvovirus B19 infections may cause a widespread benign and self-limiting disease in children and adults, known as erythema infectiosum or fifth disease. A variety of further manifestations are associated with the infection such as arthralgias, arthritis, leukopenia and thrombocytopenia, anemia and vasculitis, spontaneous abortion and hydrops fetalis in pregnant women. Both in children and adults parvovirus B19 infections have been frequently implicated as a cause or trigger of various forms of autoimmune diseases affecting joints, connective tissue and large and small vessels. In addition, autoimmune neutropenia, thrombocytopenia and hemolytic anemia are known as sequelae of B19 infection. The molecular basis of the autoimmune phenomena and resultant pathogenesis is unclear. The involvement of molecular mimicry between cellular and viral proteins, the induction of enhanced cytokine production via the viral transactivator protein NS1 and the phospholipase A2-like activity of the capsid protein VP1 may contribute to the induction of autoimmune reactions. All the known data and the potential mechanisms involved in the pathogenesis will be discussed in this review.

Glycosphingolipid expression in acute nonlymphocytic leukemia: common expression of shiga toxin and parvovirus B19 receptors on early myeloblasts

Glycosphingolipids (GSLs) are complex macromolecules on cell membranes that have been shown to play a role in neutrophil differentiation, activation, phagocytosis, and adhesion to both microorganisms and vascular endothelium. Because GSLs are often cryptic antigens on cell membranes, little is known regarding GSL expression in early myelopoiesis. To study the latter, myeloblasts were collected from patients with acute nonlymphocytic leukemia (ANLL) who required therapeutic leukocytopheresis for hyperleukocytosis. The neutral GSLs were isolated and identified by high-performance thin-layer chromatography (HPTLC), HPTLC immunostaining, gas chromatography, nuclear magnetic resonance, and fast atom bombardment-mass spectrometry. Like mature peripheral blood neutrophils, myeloblasts expressed glucosylceramide, lactosylceramide, and the neolacto-family GSLs, lactotriaosylceramide and neolactotetraosylceramide. Unlike neutrophils and chronic myeloid leukemia, most ANLL samples also expressed the globo-series GSLs, globotriaosylceramide and globotetraosylceramide. Globo GSL expression was strongly associated with a myeloblastic (ANLL M0-M2) and monoblastic phenotype (M5). A weak association was also noted with expression of either lymphoid (P <.10) or early hematopoietic markers (terminal deoxynucleotidyl transferase [TdT], CD34; P <.10). Globo-positive ANLL samples bound both shiga toxin and parvovirus B19 on HPTLC immunostaining. Based on these findings, we propose that neolacto and globo GSLs are expressed during early myeloid differentiation. Globotriaosylceramide expression on myeloblasts, and possibly myeloid stem cells, may have important implications for the use of shiga toxin as an ex vivo purging agent in autologous stem cell transplantation. Expression of globotetraosylceramide, the parvovirus B19 receptor, on myeloblasts may also explain the association between B19 infection, aplastic anemia, and chronic neutropenia of childhood.

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.

Mumps-like syndrome owing to parvovirus B19: a brief report

Major manifestations of acute parvovirus B19 infection are usually erythema infectiosum, transient aplastic crisis and polyarthropathy. We report a case suspected to have mumps-meningo-encephalitis who had IgM and IgG antibodies positive for parvovirus B19.

Chronic autoimmune thrombopenia/neutropenia in a boy with persistent parvovirus B19 infection

OBJECTIVE

We report an 11-year-old boy presenting with splenomegaly, chronic thrombocytopenia and concordant neutropenia.

RESULTS

In contrast to autoantibodies against platelets, there were no detectable neutrophil-specific autoantibodies present in this patient. Extensive serologic investigations revealed increased IgM- and IgG-antibody titers against parvovirus B19. A nested polymerase chain reaction (PCR) showed parvovirus B19-specific sequences in the patient's bone-marrow cells but not in the serum. Specific antibodies against the structural proteins VP1 and VP2 in addition to those against non-structural protein NS1 of parvovirus B19 were detected by Western blot analysis. Thrombocytopenia and neutropenia responded to immunosuppressive therapy and subsequent splenectomy, the latter being necessary due to severe side-effects of steroid medication.

CONCLUSION

Autoimmune thrombocytopenia/neutropenia may have been triggered and/or sustained by a chronic parvovirus B19 infection. Patients with this very rare disorder should be screened for this virus.

Primary phagocytic disorders of childhood

Primary phagocytic disorders are rare and usually first manifest during childhood. A phagocytic disorder should be considered in patients with unusually severe or recurrent infections by common pathogens or an infection by certain opportunistic pathogens. Common manifestations of primary phagocytic disorders include recurrent soft-tissue infections requiring incision and drainage, severe dental infections leading to premature tooth loss, recurrent pneumonias, and perirectal infections. Primary phagocytic disorders are caused by defects of neutrophil number or function, and the latter, in turn, can be divided into disorders of oxidative and nonoxidative pathways. Certain phagocytic disorders have unique characteristics apart from the immune defect that may facilitate diagnosis. Early diagnosis of phagocytic disorders can be life-saving or lead to a significant reduction in morbidity and relies on a compatible clinical (or family) history and appropriate laboratory diagnostic studies. Key principles of management of such patients involve early recognition and aggressive treatment of infections and appropriate surgical débridement of localized disease. Prophylactic antibiotics, BMT, and the use of exogenous cytokines, such as IFN-gamma and G-CSF, are appropriate for specific phagocytic disorders. Gene therapy is a promising strategy for several of the phagocytic disorders.

Neutrophil Antibody Specificity in Different Types of Childhood Autoimmune Neutropenia

Autoimmune neutropenia (AIN) in children can be divided into 2 forms. In primary AIN, neutropenia is the sole abnormality, and although neutrophil counts are generally below 500 μL−1, mild bacterial infections occur. Primary AIN is mostly seen in young children and shows a self-limited course. AIN occurring in association with autoimmune diseases (secondary AIN) often shows more severe infectious complications. We analyzed clinical and serological data from 28 pediatric patients with AIN to evaluate whether there is a possible relationship between specificity of the neutrophil autoantibodies and the clinical course of the disease. Specificity of the circulating antibodies was determined with the indirect granulocyte immunofluorescence test (GIFT) and a panel of phenotyped donor neutrophils. The samples were further analyzed in the monoclonal antibody immobilization of granulocyte antigens assay (MAIGA) for neutrophil antigen (NA)1, NA2, CD11a, and CD11b specificity. With the indirect GIFT, an antibody specificity was deduced in 26 of the 28 analyzed samples. In all but 3 sera from patients with primary AIN, NA1-(76%) or NA2-(10%) specific antibodies were detected with the indirect GIFT. In 2 samples, the reactivity in the indirect GIFT was too weak to draw conclusions, but the MAIGA showed NA1 and/or NA2 specificity of the antibodies. One serum, from a patient with primary AIN with a persistent neutropenia for more than 6 years, contained NA1, possibly pan-FcγRIIIb, and CD11a antibodies. In 4 sera from patients with primary AIN, weak antibodies with CD11a or CD11b specificity were detected with the MAIGA. Sera from 7 patients with secondary AIN contained in all cases antibodies with pan-FcγRIIIb specificity, as deduced from the indirect GIFT results and absorbance/elution experiments performed with 2 sera. The MAIGA confirmed this for only 1 of the 5 tested sera. Furthermore, CD11a antibodies were detected in 1 of the 5 tested sera. In conclusion, our results indicate that primary AIN is usually associated with NA-specific antibodies, whereas secondary AIN seems to be associated with pan-FcγRIIIb antibodies. Thus, characterization of the antibodies in sera from children with AIN discriminates patients with primary AIN from those with secondary AIN.

Neutrophil Antibody Specificity in Different Types of Childhood Autoimmune Neutropenia

Autoimmune neutropenia (AIN) in children can be divided into 2 forms. In primary AIN, neutropenia is the sole abnormality, and although neutrophil counts are generally below 500 μL−1, mild bacterial infections occur. Primary AIN is mostly seen in young children and shows a self-limited course. AIN occurring in association with autoimmune diseases (secondary AIN) often shows more severe infectious complications. We analyzed clinical and serological data from 28 pediatric patients with AIN to evaluate whether there is a possible relationship between specificity of the neutrophil autoantibodies and the clinical course of the disease. Specificity of the circulating antibodies was determined with the indirect granulocyte immunofluorescence test (GIFT) and a panel of phenotyped donor neutrophils. The samples were further analyzed in the monoclonal antibody immobilization of granulocyte antigens assay (MAIGA) for neutrophil antigen (NA)1, NA2, CD11a, and CD11b specificity. With the indirect GIFT, an antibody specificity was deduced in 26 of the 28 analyzed samples. In all but 3 sera from patients with primary AIN, NA1-(76%) or NA2-(10%) specific antibodies were detected with the indirect GIFT. In 2 samples, the reactivity in the indirect GIFT was too weak to draw conclusions, but the MAIGA showed NA1 and/or NA2 specificity of the antibodies. One serum, from a patient with primary AIN with a persistent neutropenia for more than 6 years, contained NA1, possibly pan-FcγRIIIb, and CD11a antibodies. In 4 sera from patients with primary AIN, weak antibodies with CD11a or CD11b specificity were detected with the MAIGA. Sera from 7 patients with secondary AIN contained in all cases antibodies with pan-FcγRIIIb specificity, as deduced from the indirect GIFT results and absorbance/elution experiments performed with 2 sera. The MAIGA confirmed this for only 1 of the 5 tested sera. Furthermore, CD11a antibodies were detected in 1 of the 5 tested sera. In conclusion, our results indicate that primary AIN is usually associated with NA-specific antibodies, whereas secondary AIN seems to be associated with pan-FcγRIIIb antibodies. Thus, characterization of the antibodies in sera from children with AIN discriminates patients with primary AIN from those with secondary AIN.

[Elective phagocytosis of polynuclear neutrophils caused by medullary macrophages and autoimmune neutropenia in children]

Autoimmune neutropenia (AIN) is a frequent cause of chronic neutropenia especially in youngest children. Its diagnosis is established by immunological proof of the autoimmune mechanism. The aim of this study is to better describe this autoimmune process and to show the contribution of bone marrow smears to this diagnosis.

PATIENTS AND METHODS

Ten children, six girls and four boys, were examined between 1990 and 1995. Eight of them had typical AIN, confirmed by the presence of antibodies against neutrophils. Two other patients were included on the basis of bone marrow pictures. Five non-neutropenic children with normal bone marrow smears were chosen as controls. Bone marrow analysis was always performed by the same cytologist according to a reproducible technique.

RESULTS

Six out of ten patients had important features of elective phagocytosis of neutrophils by marrow macrophages (unlike controls) without signs of dysgranulopoiesis or hemophagocytosis. Antibodies against neutrophils were detected in six patients with phagocytosis and in four patients without these cytological features. In two other children presenting the same bone marrow picture and clinical profile, an autoimmune process was probable, even in the absence of antibodies against neutrophils. Some patients had several infections and were given immunoglobulins and/or granulocyte colony-stimulating factor (G-CSF) therapy. The efficacy of Immunoglobulin was not constant, whereas G-CSF was effective at low doses and shortened the duration of infections.

CONCLUSION

Prolonged neutropenia in childhood must lead to look for phagocytosis by marrow macrophages in bone marrow smears, as a possible sign of autoimmunity. Growth factors may temporarily be used associated with antibiotics therapy in severe and prolonged infections.

Human parvovirus B19 and blood products

BACKGROUND AND OBJECTIVES

Human B19 parvovirus (B19), identified in 1975, was only recognised as the causative agent of fifth disease in 1983. The incidence of viraemia is low, around 1 in 1,000, but is sufficient to ensure that most plasma pools for fractionation contain some virus. While infection usually occurs in childhood and is benign, chronic infection sometimes occurs and may be of concern in certain patient groups.

MATERIALS AND METHODS

This review is based on a meeting held in March 1995, and addresses recent concerns regarding the potential transmission of B19 infection by pooled plasma products.

RESULTS

Recent data on the pathophysiology and assay of this virus are summarised along with possible approaches to donor screening, product screening, and virus removal. Only five cases of symptomatic infection have been reported in persons with haemophilia, but no technology for virus removal is established, and infection may be of concern in pregnant women, and in patients with enhanced red cell turnover or who are immunosuppressed, including those infected with human immunodeficiency virus, but only rarely in immunocompetent patients.

CONCLUSIONS

For the future, well-validated assays relevant to virus infectivity are required if blood donations, plasma pools, or plasma products are to be screened, and an in-process virus inactivation step for B19 would be highly desirable. In the interim, non-plasma or recombinant products or a selective transfusion policy might be used in patient groups in which B19 infection is of particular concern. Further clinical data on the prognosis and impact of B19 infection are needed to justify both such policies and the future adoption of new technologies designed to reduce any excess B19 infectivity arising from transfused products.

Diverse hematologic effects of parvovirus B19 infection

Human parvovirus B19 is linked with a broadening spectrum of hematologic disorders, including aplastic crises in the context of hemolytic anemias, neutropenia, thrombocytopenia, and hemophagocytic syndromes. Children with any of these cytopenias should be screened for the presence of B19 because treatment with intravenous gamma globulin may provide resolution of abnormal blood counts if other therapeutic options, such as transfusion, are not adequate or desired.

Diagnosis and management of chronic neutropenia during childhood

The approach to the diagnostic evaluation of a patient with neutropenia can be guided largely by clinical history and physical examination and does not always require an extensive laboratory evaluation. Based on the history and bone marrow morphology, most children with chronic neutropenia can be classified and managed. Most patients with chronic neutropenia are free of infections and are able to maintain a normal lifestyle with no or minimal medical intervention. On the other hand, for patients with recurrent or severe infections, careful follow-up and institution of treatment are mandatory. The Food and Drug Administration has approved the use of rhG-CSF in patients with chronic neutropenia. As mentioned previously, the use of colony-stimulating factors has dramatically improved the outcome for many patients with the more severe neutropenia; however, this cytokine is expensive, so treatment should be reserved for more severely affected patients and not given just because the ANC is low. Although concerns exist regarding leukemogenic effects or eventual loss of the progenitor cell compartment driven by the continuous stimulation of rhG-CSF, at this moment, the long-term data available suggest that the chronic administration of rhG-CSF is safe.

Parvoviruses and bone marrow failure

Parvovirus B19, the only known human pathogenic parvovirus, is highly tropic to human bone marrow and replicates only in erythroid progenitor cells. The basis of this erythroid tropism is the tissue distribution of the B19 cellular receptor, globoside (blood group P antigen). In individuals with underlying hemolytic disorders, infection with parvovirus B19 is the primary cause of transient aplastic crisis. In immunocompromised patients, persistent B19 infection may develop that manifests as pure red cell aplasia and chronic anemia. B19 infection in utero can result in fetal death, hydrops fetalis or congenital anemia. Diagnosis is based on examination of the bone marrow and B19 virological studies. Treatment of persistent infection with immunoglobulin leads to a rapid, marked resolution of the anemia.

[Severe parvovirus B19 infection in an immunocompetent child with hemophilia A]

BACKGROUND

B19 parvovirus is a widespread virus whose typical manifestations in immunocompetent children are erythema infectiosum, acute erythroblastopenia and fetal anemia.

CASE REPORT

An 11 year-old immunocompetent patient with hemophilia A was referred for an hemorrhagic syndrome. Forty days after a pasteurized coagulation factor concentrates treatment, and after 12 days of treatment with solvent/detergent factor VIII concentrates, he developed fever, consciousness disorders, pancytopenia, liver cytolysis and probably minor haemophagocytic syndrome, associated with human parvovirus B19 infection. His clinical state returned to normal within 15 days. A retrospective study revealed that the patient had received every day for 12 days, one parvovirus B19 polymerase chain reaction positive batch before the occurrence of symptoms.

CONCLUSION

This case highlights the possibility of severe parvovirus B19 infection transmitted by clotting factors prepared from large pools of plasma. The use of recombinant factors would allow to reduce human virus contamination, even if immune risk has to be more accurately assessed.

Parvovirus B19 infection infrequently involved in children and adults with myelodysplastic syndrome

Parvovirus B19 infection has occasionally been reported to mimic myelodysplastic syndrome (MDS) or to cause worsening of anemia in MDS. We examined the presence of parvovirus DNA in a series of children (n=19) and adults (n=39) with a diagnosis of MDS. The series of adults included only refractory anemia (RA) and RA with ring sideroblasts (RARS). Investigation for parvovirus B19 DNA in bone marrow cells was performed employing the nested form of the polymerase chain reaction (PCR). Only a 51-year-old male with RA tested positive for parvovirus DNA. Serial examinations demonstrated the disappearance of parvovirus DNA from the bone marrow. We conclude that parvovirus infection may only rarely mimic MDS or be a superimposed infection in childhood MDS or in RA and RARS in adults.

[Human parvovirus B19 infection. Update]

Pathogenicity of parvovirus B19 has been demonstrated. The spectrum of clinical manifestations varies according to the age and immune status of affected patients. Parvovirus B19 is the aetiologic agent of erythema infectiosum in children. In normal adults, it is responsible for acute, bilateral and symmetrical arthritis, although chronic arthritis can develop. Parvovirus B19 has a particular tropism for erythroid precursors: in patients with underlying hemolysis, it induces transient aplastic crisis; in immunosuppressed patients the virus can lead to chronic pure red cell aplasia. Hydrops fetalis is one of the most severe manifestation of the infection. Diagnosis of recent parvovirus B19 infection is based upon serology and PCR, especially in immunosuppressed patients in whom polyvalent intravenous immunoglobulins must be started. The link between parvovirus B19 and systemic vasculitis is questioned.

B19 parvovirus

B19 parvovirus is pathogenic in man and causes a variety of clinical illnesses, among them several haematological diseases. Acute infection of a host with underlying haemolysis produces transient aplastic crisis; of the midtrimester fetus, hydrops fetalis; and of an immunocompromised patient, pure red cell aplasia. The target of B19 parvovirus infection is the human erythroid progenitor cell. Infection is cytotoxic due to expression of the viral nonstructural protein. The virus can be propagated in cultures of human bone marrow, blood, and fetal liver. Humoral immunity normally terminates infection, and commercially available immunoglobulin can be used to treat persistent infection. Recombinant capsids, produced in a baculovirus system, are suitable as a vaccine reagent.

A case of pure red cell aplasia: follow-up on different immunosuppressive regimens

A 66-year-old patient was admitted to our hospital in January 1992 for further evaluation of severe normocytic anemia. Hemoglobin (Hb) was 3.5 g/dl, reticulocyte count 1%. Bone marrow showed a nearly complete lack of red cell precursors, thus favoring the diagnosis of acquired pure red cell aplasia (PRCA). Immunosuppressive therapy with prednisolone was started but had to be supplemented with azathioprine because of a further rapid decrease in Hb to 3.7 g/dl after an initial transfusion of 6 U red blood cells. However, with this regimen a renewed decrease in Hb to 6.6 g/dl was noted, and further transfusions were required. Therefore therapy was switched to cyclosporine A (CyA) while tapering off prednisolone. Four months after the initial diagnosis a positive parvovirus B19 IgM antibody was found. After the failure of hematological remission with three immunosuppressive regimens a course of high-dose intravenous immunoglobulins (IVIG) was administered in July 1992. Six weeks after IVIG therapy a peak hemoglobin concentration of 12.3 g/dl was noted, and further transfusion was not required. CyA was tapered off in October 1992. One month later CyA was reinstituted because of a relapse of PRCA but was unsuccessful until January 1993. At this time immunosuppressive CyA therapy was discontinued because of a periodontal abscess. In February 1993 a second IVIG infusion was given, and a second remission of PRCA was noted, showing an increase in hemoglobin up to 14.5 g/dl by November 1993. At the last follow-up visit in February 1994 our patient was still in complete hematological remission.