Transient pancytopenia preceding acute lymphoblastic leukaemia (pre-ALL) precipitated by parvovirus B19

Transient bone marrow hypoplasia preceding T-Cell acute lymphoblastic leukemia: a case report

Background

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and is characterised by hyperproliferation of malignant lymphocytes in the bone marrow. Rarely, ALL may be preceded by a period of pancytopenia and bone marrow hypoplasia which spontaneously recovers. This phenomenon, which has not before been described in T-cell ALL, is referred to as transient bone marrow hypoplasia.

Case presentation

A 5-year-old boy who presented with high-grade fever and generalised lymphadenopathy, was found to have pancytopenia on peripheral blood count and bone marrow hypoplasia. He was observed over a one-month period during which his bone marrow and peripheral blood counts recovered spontaneously. Symptoms recurred after 4 months and he was found to have blast infiltration of the bone marrow and diagnosed with T-cell ALL.

Conclusion

Cases of transient bone marrow hypoplasia or overt aplastic anemia with spontaneous recovery and then followed by B-cell ALL or Acute Myeloid Leukemia have been described previously in the medical literature. This is the first case of transient bone marrow hypoplasia resulting into ALL of T-cell immunophenotype. While marrow hypoplasia preceding ALL remains poorly understood, it suggests an antecedent environmental insult to lymphoid progenitors or a germline abnormality that predisposes to lymphoid dysplasia. This may provide clues to the hitherto unknown pathophysiological process and etiological factors that precede the majority of childhood ALL cases. This case enlightens pediatricians about the existence of such rare cases so as to periodically follow up children with pancytopenia and/or bone marrow hypoplasia for prolonged periods even after apparent recovery.

Aggressive large B-cell lymphoma triggered by a parvovirus B19 infection in a previously healthy child

In absence of red blood cells disease or immune defect, parvovirus B19 (PVB-19) is usually considered as a benign condition. Here, we report the case of a 10-year-old boy, previously healthy, presenting with a PVB-19 infection revealed by a bicytopenia and a voluminous axillary adenopathy. Pathophysiology examination showed reactional lymphoid population. Nine months later and in the absence of remission, a new biopsy of the same adenopathy revealed a Hodgkin lymphoma with area of T-cell rich aggressive large B-cell lymphoma. This case suggests PVB-19 as potential trigger of this malignant childhood hemopathy. Although no definitive conclusion can be drawn, our clinical case questions the role of PVB-19 in lymphomagenesis.

Molecular Study of Parvovirus B19 Infection in Children with Acute Myeloid Leukemia

Background:

Parvovirus B19 is a common viral infection in children. Nearby evidences are present about its association with acute leukemia, especially acute lymphoblast leukemia. Nevertheless, scanty reports have discussed any role in acute myeloid leukemia (AML).

Purpose:

To evaluate the frequency of virological markers of B19 infection including its DNA along with specific immunoglobulins G (IgG) and M (IgM) among children with newly diagnosed AML. Besides, describing the clinical importance of Parvovirus B19 infection in those patients.

Patients and methods:

A case-control retrospective study was conducted on 48 children recently diagnosed with AML before and during chemotherapy induction and 60 healthy control. Specific serum IgM and IgG levels were determined by enzyme linked immunosorbant assay (ELISA) and DNA detection by polymerase chain reaction (PCR).

Results:

Parvovirus DNA was detected in 20 patients with AML. IgM was found in sera of four patients and one case had positive DNA and IgG (5%). Patients with recent parvovirus B19 infection had a significantly reduced hemoglobin levels, RBCs counts, platelet counts, neutrophil counts and absolute lymphocytosis (p=0.01, p=0.0001, p=0.01, p=0.02, p=0.0003, respectively). There were no clinical findings with statistically significant association to recent infection. Half of the patients with AML had positive PCR and/or IgM for parvovirus B19. Among children with AML under chemotherapy, there were reduced hemoglobin levels (P=0.03), reduced platelet counts (P=0.0001) and absolute neutropenia (mean±SD, 1.200 ±1.00) in those with parvovirus B19 infection. More than half of patients with parvovirus B19 (72.2%) had positive PCR and/or IgM and 36.4% of them had positive IgG.

Conclusion:

This study highlights that parvovirus B19 is common in children with AML either at diagnosis or under chemotherapy. There are no clinical manifestations that can be used as markers for its presence, but hematological laboratory findings can provide evidence for infection in the presence of anemia and neutropenia. Detection of parvovirus B19 by combined molecular and serological markers is required in such patients for 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.

Acute Lymphoblastic Leukemia Presenting With Pancytopenia Followed by a 14-Month-Long Period of Transient Remission Possibly Supporting the Adrenal Hypothesis of Leukemogenesis

A small group of children with acute lymphoblastic leukemia (ALL) have a preleukemic phase of pancytopenia followed by a period of spontaneous remission before the diagnosis (pre-ALL). A 6-year-old girl presented with pancytopenia, fever, and myelodysplasia. Following transient remission pre-B ALL was diagnosed 14 months later. Clonal B-lineage blasts at the period of pancytopenia were identified retrospectively. The interval between pre-ALL and ALL-diagnosis was longer than previously reported. The infection was clinically severe and might have induced a significant endogenous corticosteroids production resulting in the long-lasting remission. The case supports the adrenal and the Coley's toxin hypothesis in leukemogenesis.

Transient pancytopenia preceding adult acute lymphoblastic leukemia with chromosomal abnormalities including the Philadelphia chromosome: A case report and review of the literature

A preleukaemic phase, typified by transient pancytopenia, is a rare occurrence that usually affects children and adolescents. The present study reports the case of a 50-year-old woman with transient pancytopenia, which manifested as a fever, cough and severe anemia. Three weeks following treatment of pancytopenia with antibiotics, red blood cell and platelet transfusion, granulocyte colony-stimulating factor and human γ globulin, the condition of the patient was improved. However, 3 weeks following discharge from hospital, the patient was diagnosed with acute lymphoblastic leukemia (ALL) with complex chromosomal abnormalities, including Philadelphia chromosome and P190 breakpoint cluster region-ABL. Complete remission was achieved following one course of combination chemotherapy. In conclusion, adult ALL with pancytopenia as a preceding symptom is rare, difficult to diagnose early and easily misdiagnosed. In addition, the pathogenesis of ALL and the precipitating factors underlying this disease require further investigation.

Severe systemic infection masking underlying childhood leukemia

Severe childhood infections can occasionally be accompanied by bone marrow suppression. It is unusual for infection induced marrow aplasia to evolve into acute leukemia. We share our experience in managing four children with severe sepsis and pancytopenia which in due course evolved into acute leukemia. This report emphasizes that sepsis related pancytopenia can be a harbinger of evolving hematopoietic disorders.

History of Parvovirus B19 infection is associated with a DNA methylation signature in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) likely has a multistep etiology, with initial genetic aberrations occurring early in life. An abnormal immune response to common infections has emerged as a plausible candidate for triggering the proliferation of pre-leukemic clones and the fixation of secondary genetic mutations and epigenetic alterations. We investigated whether evidence of infection with a specific common myelotropic childhood virus, parvovirus B19 (PVB19), relates to patterns of gene promoter DNA methylation in ALL patients. We serologically tested bone marrow samples at diagnosis of B-cell ALL for PVB19 infection and DNA methylation using a high-throughput bead array and found that 4.2% and 36.7% of samples were seroreactive to PVB19 IgM and IgG, respectively. Leukemia samples were grouped by DNA methylation pattern. Controlling for age and immunophenotype, unsupervised modeling confirmed that the DNA methylation pattern was associated with history of PVB19 (assessed by IgG, p = 0.02), but not recent infection (assessed by IgM). Replication assays on single genes were consistent with the association. The data indicate that a common viral illness may drive specific DNA methylation patterns in susceptible B-precursor cells, contributing to the leukemogenic potential of such cells. Infections may impact childhood leukemia by altering DNA methylation patterns and specific key genes in susceptible cells; these changes may be retained even after the clearance of infection.

Aetiology of childhood leukaemia

The acute leukaemias account for about 30% of all malignancy seen in childhood across the Western world. A peak incidence of precursor B cell ALL has emerged as socio-economic conditions have improved in countries worldwide. From twin studies and the use of neonatal blood spots it has been possible to back track the first initiating genetic events within critical haemopoietic cells to foetal development in utero for most precursor B cell ALL and some cases of AML. These events may occur as part of normal foetal development. Whether other factors (environmental or constitutional) are involved to increase the chance of these first genetic changes happening is unclear. For some leukaemias (e.g. infant MLL positive ALL) the first event appears adequate to create a malignant clone but for the majority of ALL and AML further 'genetic' changes are required, probably postnatal. Many environmental factors have been proposed as causative for leukaemia but only ionising irradiation and certain chemicals, e.g. benzene and cytotoxics (alkylators and topoisomerase II inhibitors) have been confirmed and then principally for acute myeloid leukaemia. It appears increasingly likely that delayed, dysregulated responses to 'common' infectious agents play a major part in the conversion of pre-leukaemic clones into overt precursor B cell ALL, the most common form of childhood leukaemia. Constitutional polymorphic alleleic variants in immune response genes (especially the HLA Class II proteins) and cytokines may play a role in determining the type of immune response. High penetrance germ-line mutations are involved in only about 5% of childhood leukaemias (more in AML than ALL). There is little evidence to support any role of viral transformation in causation, unlike in animals. Other environmental factors for which some evidence exists include non-ionising electromagnetic radiation and electric fields, although their mode of action in leukaemogenesis remains unclear. There is no single cause for childhood leukaemia and for most individuals a combination of factors appears to be necessary; all involving gene-environment interactions. To date few clear preventative measures have emerged, except the complete avoidance of first trimester X-rays in pregnancy; a healthy diet with adequate oral folic acid intake both preconception and early in pregnancy; and the early exposure of children to other children outside the home to facilitate stimulation and maturation of the natural immune system. Here then are clear echoes of the "hygiene hypothesis" regarding the initiation of allergies, autoimmune disease and type I diabetes mellitus in children and young people.

Promoter methylation of P15(INK4B) gene is possibly associated with parvovirus B19 infection in adult acute leukemias

In this study, we examined the P15(INK4B) gene promoter methylation in patients with myelodysplastic syndrome and acute leukemia and its possible relationship with parvovirus B19 and Epstein-Barr virus infections. P15(INK4B) methylation frequency was significantly higher in acute leukemia patients than in that of non-malignant patients (P < 0.05). When the patients with myelodysplastic syndrome were included, no significant difference was found between these groups regarding the methylation status. The possible correlation between P15(INK4B) promoter methylation and parvovirus B19 infection was observed in adult acute leukemia patients (P < 0.05). However, no similar relationship in EBV-infected patients was observed. To the best of our knowledge, this is the first report showing the possible association between P15(INK4B) promoter methylation and parvovirus B19 infection in acute leukemia.

Genetic lesions in a preleukemic aplasia phase in a child with acute lymphoblastic leukemia

In a small fraction ( approximately 2%) of cases of childhood acute lymphoblastic leukemia (ALL) clinical presentation of leukemia is preceded, some 2-9 months earlier, by a transient, remitting phase of nonclassical aplastic anemia, usually in connection with infection. The potential "preleukemic" nature of this prodromal phase has not been fully explored. We have retrospectively analyzed the blood and bone marrow of a child who presented with aplastic anemia 9 months before the development of ETV6-RUNX1 fusion gene positive ALL. High resolution SNP genotyping arrays identified 11 regions of loss of heterozygosity, with and without concurrent copy number changes, at the presentation of ALL. In all cases of copy number change, the deletion or gain identified by single nucleotide polymorphism (SNP) analysis was confirmed in the ALL blasts by FISH. Retrospective analysis of aplastic phase bone marrow showed that the ETV6-RUNX1 fusion was present along with all of the additional genetic changes assessed, albeit subclonal to ETV6-RUNX1. These data identify for the first time the leukemic genotype of an aplasia preceding clinical ALL and indicate that multiple secondary genetic abnormalities can contribute to a dominant subclone several months before a diagnosis of ALL. These data have implications for the biology of ALL and for management of similar patients.

Myeloid sarcoma presenting with bilateral proptosis and kidney infiltration

The authors describe a male infant with a history of transient pancytopenia who developed progressive bilateral proptosis associated with diffuse infiltration of the kidney and normal bone marrow. The histopathological examination of the kidney revealed diffuse infiltration of cells of myeloid origin with monocytic differentiation. Although orbital involvement by myeloid sarcoma, with or without concurrent acute myeloid leukemia, is well known, there are distinctive features in this patient that are not reported in the literature, namely bilateral proptosis and simultaneous presence of bilateral kidney infiltration, which enabled diagnosis.

Infection, immune responses and the aetiology of childhood leukaemia

Childhood leukaemia is the principal subtype of paediatric cancer and, despite success in treatment, its causes remain enigmatic. A plethora of candidate environmental exposures have been proposed, but most lack a biological rationale or consistent epidemiological evidence. Although there might not be a single or exclusive cause, an abnormal immune response to common infection(s) has emerged as a plausible aetiological mechanism.

bcr-abl-positive T-cell acute lymphoblastic leukemia associated with parvovirus B19 infection

The authors report an unusual presentation of a Philadelphia chromosome-positive acute lymphoblastic leukemia with two unusual features: a bcr-abl fusion mRNA coding for p210 protein and a T-cell immunophenotype. The patient was a 16-year-old boy who presented with septic shock and pancytopenia, likely precipitated by an acute parvovirus B19 infection. Management consisted of supportive therapy, followed by chemotherapy for T-cell acute lymphoblastic leukemia and stem cell transplantation. He died 8 months after transplant due to idiopathic pneumonia syndrome, but without evidence of relapsed disease.

Parvovirus B19 Infection Presenting as Pre-B-Cell Acute Lymphoblastic Leukemia: A Transient and Progressive Course in Two Children

Parvovirus B19 is the causative agent of various forms of hematologic diseases such as aplastic crisis in patients with hemolytic anemia, aplastic anemia, hypoplastic anemia, and idiopathic thrombocytopenic purpura. In addition, parvovirus B19 infection may precede or be associated with acute lymphoblastic leukemia (ALL). The authors present two cases of parvovirus B19 infection and bone marrow infiltration with pre-B-cell lymphoblasts; one patients was diagnosed as having ALL, and the other patient, with neurologic findings, showed total resolution of the blastic morphology and phenotype.

Association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia

AIMS

To investigate the association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia.

METHODS

Cerebrospinal fluid (CSF) samples from patients with acute myelogenous leukaemia (AML) at diagnosis (n = 2) and acute lymphoblastic leukaemia (ALL) at diagnosis (n = 14) were analysed for parvovirus B19 DNA by means of nested polymerase chain reaction. In addition, samples from patients with benign intracranial hypertension (BIH) (n = 10) and hydrocephalus (n = 13) were tested as controls.

RESULTS

Four leukaemia cases were positive-common ALL (n = 2), null cell ALL (n =1), and M7 AML (n = 1)-whereas all controls were negative (Yates corrected chi(2) value, 3.97; p = 0.046; odds ratio, 16.92; confidence interval, 1.03 to 77.18). All four patients were significantly anaemic, but none was encephalitic or had evidence of central nervous system leukaemia. In three of these patients, serum tumour necrosis alpha, interferon gamma, interleukin 6, granulocyte-macrophage colony stimulating factor (range, 34.93-3800.06 pg/ml), and macrophage chemoattractant protein 1 were detectable. All of these four patients carried at least one of the HLA-DRB1 alleles, which have been associated with symptomatic parvovirus B19 infection.

CONCLUSION

Erythroid suppression and immune cell proliferation are both associated with B19 infection and may also be important in the pathogenesis of acute leukaemia.

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.

Detection of parvovirus B19 NS1-specific antibodies by ELISA and western blotting employing recombinant NS1 protein as antigen

Human parvovirus B19 (B19) encodes a number of nonstructural proteins, including the major protein, NS1, and two structural proteins, VP1 and VP2. The use of denatured NS1 in enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) assay has provided an opportunity to study some of the immunologic properties of NS1, but the results have been equivocal and the diagnostic sensitivity poor, probably because of the absence of conformational epitopes. Various viral isolates and baculovirus vectors were employed to produce recombinant B19 NS1 under nondenaturing conditions for the first time. To assess the antigenicity of purified B19 NS1, the reaction patterns of 252 samples were compared by B19 NS1 and VP2 ELISA. In sera from individuals with past infection (VP2 IgG-positive), the use of this new antigen increased significantly the sensitivity of ELISA compared with WB (78% vs. 33%, P = 0.001), contradicting perpetuated claims that B19 NS1 IgG is detected primarily in patients with arthralgia or chronic infection. Previous reports of the absence of NS1 IgG during the initial phase of infection (< 6 weeks) were proved incorrect by the detection of NS1 IgG in 60% of samples from patients recently infected by B19. Including conformational epitopes in the ELISA increases the diagnostic sensitivity, although immunologically, a temporal (years) attenuation of NS1 antibodies appears to take place. This novel diagnostic tool may be useful as a supplement in case of borderline results by VP2 ELISA and for monitoring the efficacy of future capsid-based B19 vaccines.

Serologic study on parvovirus b19 infection in childhood acute lymphoblastic leukemia during chemotherapy: clinical and hematologic implications

PURPOSE

To present a first descriptive serologic study on the clinical and hematologic implications of parvovirus B19 (B19) infection in children with acute lymphoblastic leukemia from the time of initial admission until discontinuation of chemotherapy.

PATIENTS AND METHODS

Seventy-five patients were studied by polymerase chain reaction, enzyme-linked immunosorbent assay, sequencing, and immunodiffusion.

RESULTS

During the period of observation, 8% (4/48) of B19-seronegative patients seroconverted and infection triggered profound anemia and thrombocytopenia. B19-specific IgG disappeared in 26% (8/31) of B19-seropositive patients, and these patients were significantly younger and the B19 IgG titers were lower on admission compared with patients who continuously displayed B19 IgG. B19 DNA was detected in the seroconverting patients, and this helped in determining the time of infection, which coincided with a B19 epidemic in 75% (3/4) of patients. Patients typically presented with fever and myalgia; a rash, indicative of B19 infection, was observed in only one patient.

CONCLUSIONS

B19 infection was able to mimic a leukemic relapse or therapy-induced cytopenia and led to hospital admission, frequent blood sampling, renewed bone marrow aspirates, multiple transfusions of red blood cells or platelets, and cessation of maintenance chemotherapy for up to 3 weeks. The peculiar disappearance of B19-specific IgG, which could not be ascribed to a generalized low level of serum immunoglobulins, has not been previously reported. The results indicate that B19 should be assayed at diagnosis of leukemia to avoid subsequent diagnostic uncertainty, and during treatment in B19-seronegative patients exhibiting unexplained cytopenia.