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Parvovirus B19 infection Infecção por Parvovírus B19 Elvira Deolinda Rodrigues Pereira Velloso1, Denise da Cunha Pasqualin2, Nelson Hamerschlak3
Figure 2. Bone marrow biopsy: giant cells with intranuclear inclusions (HE x 400)
Figure 1. Bone marrow aspirate: presence of giant proerythroblasts with evident intranuclear inclusions (Rosenfeld X 1.000)
A previously healthy 52 year-old male, was evaluated as an outpatient for fever and fatigue for 30 days. The patient had no other symptoms. Four months before he had prostate surgery for benign prostate hyperplasia. The physical examination was normal. Complete blood count showed: Hb: 13.6 g/dl; leucocytes: 3,800/
1
mm3; neutrophils: 912/mm3; lymphocytes: 2,128/mm3, with atypical morphology; platelets: 125,000/mm3; reticulocytes: 15,000/mm3. Bone marrow aspiration showed normal granulocytic (58%) and megakaryocytic cellularity, mild plasmacytosis (4%) and lymphocytosis (24%) with some atypical elements, and the presence of rare erythroid elements (3.6%), with giant proerythroblasts and intranuclear inclusions (Figure 1). These findings were also seen in the bone marrow biopsy (Figure 2), suggesting parvovirus B19 infection. The diagnosis was confirmed by detection of the virus by serum PCR and serology for anti-parvovirus B19 IgM antibodies. Serology for EBV, hepatitis B and C, CMV, HIV, HTLV1 and dengue were negative for recent infections. The patient improved his symptoms, with no need for specific treatment.
PhD, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo – HC-FMUSP, São Paulo (SP), Brazil.
2
PhD, Pathology Laboratory of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
3
PhD, Hematology/Oncology Program of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
Corresponding author: Elvira Deolinda Rodrigues Pereira Velloso – Rua Ministro Ferreira Alves, 1031 – 183A – Pompéia – CEP 05009-060 – São Paulo (SP), Brasil – Tel.: 11 3872-6114 – e-mail:
[email protected] Received on Oct 3, 2007 – Accepted on Nov 8, 2007
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Velloso EDRP, Pasqualin DC, Hamerschlak N
Human parvovirus B19 causes several clinical syndromes, including infectious erythema (exanthematic disease of childhood), non-immune fetal hydrops, transient aplastic anemia and arthropathies(1). The virus has a tropism for erythroid progenitors, binding itself to the P antigen in the erythroid membrane. It is cytotoxic to the erythroid progenitors and inhibits the growth of erythroid colonies (CFU-E). The production of neutralizing antibodies leads to resolution of the pure red cell aplasia caused by the virus. In patients with chronic hemolytic anemia, the virus may cause acute pure red cell aplasia, characterized by a significant worsening of the anemia and reticulocytopenia. This condition is not observed in the population without hemolytic disease, since anemia is self-limited and does not last long. In immunosuppressed patients (HIV-infection, post organ and hematopoietic stem cell transplants), the anemia is also important, because of the failure to produce antibodies, that causes persistent viremia and chronic red cell aplasia. These patients may also develop viral pneumonia, hepatitis, encephalitis and myocarditis(2). In immunosuppressed children, other conditions associated with the presence of anti-parvovirus B19 IgM antibodies are described, such as hepatosplenomegaly, skin rash and arthropathy. In immunocompetent adults, parvovirus-induced arthropathy (polyarthralgia, erythema, dysesthesia and pruritus) is more frequent, but the diagnosis must also be considered in cases of
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fever of unknown origin, arthralgia, chronic cytopenia, hepatitis, edema, vascular purpura, as well as neural and ophthalmologic manifestations(1). The diagnosis of red cell aplasia is made in cases of reticulocytopenia and bone marrow aspiration with less than 5% of mature erythroblasts; the presence of giant erythroid precursors and nuclear inclusions is highly suggestive of parvovirus infection. The diagnosis is confirmed by immunohistochemical study (viral anticapsid monoclonal antibodies), detection of viral DNA by PCR in the bone marrow aspirate (a more sensitive test), or serum viremia by serology (false-negative results in immunosuppressed patients)(3). Immunocompetent individuals with parvovirus infection need only supportive treatment, whereas intravenous immunoglobulin is recommended for immunocompromised patients with pure red cell aplasia.
REFERENCES 1. Cathébras P, Robert F, Guglielminotti C, Bonnevial L, Rousset H. Primary parvovirus B19 infection in immunocompetent adults: clinical and biological manifestations. Retrospective study of 16 patients. Rev Med Interne. 2000;21(4):324-9. 2. Eid AJ, Brown RA, Patel R, Razonable RR. Parvovirus B19 infection after transplantation: a review of 98 cases. Clin Infect Dis. 2006;43(1):40-8. 3. Lundqvist A, Tolfvenstam T, Bostic J, Söderlund M, Broliden K. Clinical and laboratory findings in immunocompetent patients with persistent parvovirus B19 DNA in bone marrow. Scand J Infect Dis. 1999; 31(1):11-6.
