Unusual bone marrow manifestations of parvovirus B19 infection in immunocompromised patients

Hemophagocytic lymphohistiocytosis associated with parvovirus B19-induced aplastic crisis in a hereditary spherocytosis patient: A case report and literature review

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of pathologic immune activation. It occurs because of severe inflammation due to uncontrolled proliferation of activated lymphocytes and histiocytes, characterized by the production of excessive levels of cytokines. Virus-associated HLH is a well-known entity, and parvovirus B19 is one of the common causes. Parvovirus B19 can also affect blood cell lineages. Therefore, HLH may be accompanied by several diseases such as cytopenia, aplastic anemia, and myelodysplastic syndrome. Herein, we report the case of a patient with hereditary spherocytosis who was diagnosed with parvovirus B19-induced HLH and aplastic crisis. A 7-year-old girl presented to our hospital with fever, pleural effusion, pancytopenia, hepatosplenomegaly, and hypotension. A bone marrow biopsy was performed under the suspicion of HLH, which revealed hemophagocytes. The diagnostic criteria for HLH were met, and prompt chemoimmunotherapy was initiated considering the clinically unstable situation. Her health improved rapidly after initiating treatment. Further study revealed that she had hereditary spherocytosis, and parvovirus B19 had caused aplastic crisis and HLH. The patient's clinical progress was excellent, and chemoimmunotherapy was reduced and discontinued at an early stage. This case shows that aplastic crisis and HLH can coexist with parvovirus B19 infection in patients with hereditary spherocytosis. Although the prognosis was good in this case of HLH caused by parvovirus B19, early detection and active treatment are essential.

[The hematological diversity of human parvovirus B19 infection after allo-hematopoietic stem cell transplantation in pediatric patients]

目的

探讨异基因造血干细胞移植（allo-HSCT）患儿造血重建后人类细小病毒B19（HPV-B19）感染的血液学表现。

方法

对9例allo-HSCT后合并HPV-B19感染的患儿进行回顾性分析。

结果

9例患儿占同期接受allo-HSCT患儿的8.04％（9/112），男8例，女1例，中位年龄9（3～13）岁，均采取清髓性预处理方案。HPV-B19感染中位时间为移植后61（36～114）d。allo-HSCT并发HPV-B19感染患儿血液学表现具有异质性，9例患儿以血红蛋白伴网织红细胞下降为主要特点，7 d内网织红细胞比例、绝对值下降幅度中位数分别为90.4％（24.7％～98.7％）、90.7％（18.6％～99.0％）。除常见红系造血停滞表现外，allo-HSCT后合并HPV-B19感染的患儿还具有非红系的血象及骨髓变化：5例患儿外周血出现中性粒细胞下降，但骨髓涂片未见粒系增生受抑；6例患儿骨髓涂片查见巨核系增生减低，其中5例患儿外周血血小板下降。同时，allo-HSCT造血重建后合并HPV-B19感染的患儿骨髓红系受抑并非必要表现，9例患儿虽然均出现血红蛋白下降，但仅5例患儿骨髓红系增生减低。

结论

血液病患儿allo-HSCT造血重建后合并HPV-B19感染的血液学表现具有异质性，血红蛋白伴网织红细胞下降对HPV-B19感染早期诊断可能具有重要意义。

Surgical Pathologic Diagnosis

Surgical pathology results can play a crucial role in the management of immunocompromised patients. Here we highlight factors that differ between immunocompromised and immunocompetent hosts, such as variation in inflammatory response. Conditions that are covered include drug reactions, disease within solid organ allografts, immune reconstitution inflammatory syndrome, specific immunodeficiency syndromes, neoplasms related to viral infections, and viral, bacterial, fungal, and parasitic infections. Special techniques including immunohistochemistry, in situ hybridization and molecular detection of pathogen nucleic acid from formalin-fixed, paraffin-embedded tissue are discussed.

Parvovirus B19

Primary parvovirus B19 infection is an infrequent, but serious and treatable, cause of chronic anemia in immunocompromised hosts. Many compromised hosts have preexisting antibody to B19 and are not at risk. However, upon primary infection, some patients may be able to mount a sufficient immune response to terminate active parvovirus B19 infection of erythroid precursors. The most common consequence of B19 infection in the compromised host is pure red-cell aplasia, resulting in chronic or recurrent anemia with reticulocytopenia. Anemia persists until neutralizing antibody is either produced by the host or passively administered. Parvovirus B19 should be suspected in compromised hosts with unexplained or severe anemia and reticulocytopenia, or when bone-marrow examination shows either giant pronormoblasts or absence of red-cell precursors. Diagnosis is established by detection of B19 DNA in serum in the absence of IgG antibody to B19. In some cases, IgG antibody is detected but is not neutralizing. Anti-B19 IgM may or may not be present. Therapy includes any or all of the following: red-cell transfusion, adjustment in medications to restore or improve the patient’s immune system, and administration of intravenous immunoglobulin (IVIG). Following treatment, patients should be closely monitored, especially if immunosuppression is unchanged or increased. Should hematocrit trend downward and parvovirus DNA trend upward, the therapeutic options above should be revisited. In a few instances, monthly maintenance IVIG may be indicated. Caregivers should be aware that B19 variants, though rarely encountered, can be missed or under-quantitated by some real-time polymerase-chain reaction methods.

Recurrent severe anaemia: a rare presentation of parvovirus b19 infection

Secondary pure red cell aplasia is usually seen in immunocompromised hosts or patients who have chronic haemolytic anaemia, which is caused by blood transfusion related transmission. The present patient, a 30-year-old immunocompetent female, presented several times with recurrent severe anaemia, over a period of one and half years. Her history, clinical examination and investigations did not reveal any indigenous drug intake, previous blood transfusions, haemolytic disorders, myeloproliferative disorders, pregnancies, autoimmune diseases or thymoma. She was found to have a thalassaemia minor trait, on the basis of which severity and recurrence of anaemia could not be explained, and on further evaluation, she was diagnosed to have acute aplastic crisis caused by Parvovirus B19 induced, acquired pure red cell aplasia. The co- existence of these two haematological disorders in an immunocompetent, non-transfusion dependent individual is rare, which makes our case report unique.

Parvovirus

Name of Virus: Parvovirus

Pediatric Bone Marrow Interpretation

The evaluation of pediatric bone marrow poses specific challenges when compared with the general adult population. These challenges stem in part from the higher likelihood of congenital disorders with hematopoietic manifestations, some of which may give rise to hematologic malignancies. Familiarity with the spectrum of disorders seen in the pediatric age group allows for an appropriate and focused differential diagnosis. This review addresses the diagnostic workup of pediatric bone marrow samples, as directed by the peripheral blood and bone marrow findings in the context of the patient's clinical history. Recommendations for the appropriate use of ancillary studies in various scenarios are provided.

Parvovirus-B19-associated complications in renal transplant recipients

Parvovirus B19 is a common human pathogen, causing erythema infectiosum in children, hydrops fetalis in pregnant women, and transient aplastic crisis in patients with chronic hemolytic anemia. Immunosuppressed patients can fail to mount an effective immune response to B19, resulting in prolonged or persistent viremia. Renal transplant recipients can develop symptomatic B19 infections as a result of primary infection acquired via the usual respiratory route or via the transplanted organ, or because of reactivation of latent or persistent viral infection. The most common manifestations of B19 infection in immunosuppressed patients are pure red cell aplasia and other cytopenias. Thus, this diagnosis should be considered in transplant recipients with unexplained anemia and reticulocytopenia or pancytopenia. Collapsing glomerulopathy and thrombotic microangiopathy have been reported in association with B19 infection in renal transplant recipients, but a causal relationship has not been definitively established. Prompt diagnosis of B19 infection in the renal transplant recipient requires a high index of suspicion and careful selection of diagnostic tests, which include serologies and polymerase chain reaction. Most patients benefit from intravenous immunoglobulin therapy and/or alteration or reduction of immunosuppressive therapy. Conservative therapy might be sufficient in some cases.

Erythrovirus B19 infection in acquired immunodeficiency syndrome: screening by histopathology, immunohistochemistry, and in situ hybridization

Erythrovirus B19 infects erythrocytic progenitors, transiently interrupting erythropoiesis. In AIDS patients it causes chronic anemia amenable to treatment. We looked for evidences of B19 infection in stored bone marrow material from patients with acquired immunodeficiency syndrome. Histological sections were made from stored paraffin blocks from 33 autopsies (39 blocks) and 35 biopsies (45 blocks, 30 patients) performed from 1988 to 2002. They were examined after hematoxylin-eosin (HE) staining, immunohistochemical (IHC), and in situ hybridization. HE revealed intra-nuclear inclusion bodies ("lantern cells") suggesting B19 infection in 19 sections corresponding to 19 of 63 patients examined with this test. Seven of 78 sections subjected to immunohistochemistry were positive, corresponding to 7 of 58 patients examined with this test. Fourteen sections corresponding to 13 of the 20 HE and/or IHC positive patients were subjected to in situ hybridization, with six positives results. Among the 13 patients subjected to the three techniques, only one gave unequivocal positive results in all and was considered a true positive. The frequency of B19 infection (1/63 patients) in the material examined can be deemed low.

Acute parvovirus B19 infection mimicking congenital dyserythropoietic anemia

Infection with human parvovirus B19 is known to cause transient erythroid aplasia in children with hemolytic anemia but has also been associated with bone marrow necrosis and morphologic changes suggesting myelodysplasia. The authors describe a previously healthy child who presented with severe hypoplastic anemia. Initial bone marrow aspiration revealed erythroid hyperplasia, dyserythropoiesis, and multinucleated erythroid cells with nuclear budding and bridging, consistent with the diagnosis of congenital dyserythropoietic anemia. Serologic testing documented acute parvovirus infection, and on recovery the correct diagnosis of unsuspected congenital spherocytosis was established. This case expands the spectrum of hematologic disease associated with acute parvovirus infection.

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.

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.

Fifth (human parvovirus) and sixth (herpesvirus 6) diseases

Fifth (erythema infectiosum) and sixth (roseola infantum) diseases are common rash illnesses of childhood that have long been recognized in clinical medicine. The discovery of the viruses that cause these illnesses has revealed relationships with other syndromes. Primary infection with the agent of erythema infectiosum, human parvovirus B19, is associated with transient aplastic crisis in hemolytic anemia, arthropathy in adults, chronic anemia in immunocompromised patients, and nonimmune fetal hydrops in pregnant women. The only documented illness associated with primary infection with human herpesvirus 6 is roseola or exanthema subitum in young children. However, reactivated infections in adults and immunocompromised patients may be associated with serious illness such as encephalitis/encephalopathy, and bone marrow suppression leading to transplant failure or graft-versus-host disease. Diagnostic studies for both viruses have been limited, although reliable serologic tests for human parvovirus B19 have recently become available. Diagnosis of human herpesvirus 6 remains problematic, because current tests cannot differentiate primary from reactivated disease. This is more of an issue for the putative relationship of these viruses to more chronic conditions, such as rheumatologic disease for human parvovirus B19 and multiple sclerosis for human herpesvirus 6. The relationship between the viruses and these conditions remains controversial, and better diagnostic tests and further information on viral pathogenesis for both viruses are required in order to make a reliable judgment in this regard.

Comparative characteristics of mu chain and alpha chain transcripts expressed by individual tonsil plasma cells

Plasma cells (PCs) are one of the two major cell types generated during germinal center reactions. To test the hypothesis that PCs express a unique repertoire of immunoglobulin (Ig) genes resulting from intensive antigenic stimulation and selection, the mutational pattern and distribution of V(H) gene segments within 178 transcripts amplified from individual IgM and IgA secreting tonsil PCs were analyzed. The results demonstrated that both mu and alpha transcripts expressed repertoires with limited diversity. Moreover, both mu and alpha transcripts were heavily mutated, with a significantly increased mutational frequency noted for alpha compared to mu transcripts (5.0 x 10(-2) vs 1.8 x 10(-2), P<0.001). In addition, both mu and alpha transcripts showed significantly greater targeting of mutations to RGYW motifs (purine/guanine/pyrimidine/A or T) compared to memory B cells. Finally, clonally expanded cells were detected in alpha but not mu PC compartments. These results indicate that antigen driven stimulation and selection shape the entire expressed PC repertoire, but the impact is greater in alpha expressing PCs.

Direct ex vivo measurement of CD8(+) T-lymphocyte responses to human parvovirus B19

Parvovirus B19 is a common human pathogen which can cause severe syndromes, including aplastic anemia and fetal hydrops. The mapping of the first parvovirus B19-derived CD8(+) T-lymphocyte epitope is described. This HLA-B35-restricted peptide derives from the nonstructural (NS1) protein and is strongly immunogenic in B19 virus-seropositive donors.