RESUMO
Acute human parvovirus B19 infection is followed by an antibody response to the structural proteins of the viral capsid (VP1 and VP2). We used 80 sera collected from 58 erythema infectiosum and 6 transient aplastic crisis patients to test IgM and IgG antibodies against these two proteins in an immunofluorescence assay (IFA) using Sf9 cells infected with recombinant baculovirus expressing either VP1 or VP2 antigen. Although less sensitive than IgM capture enzyme immunoassay using native antigen (MACEIA), we could detect anti-VP1 or anti-VP2 IgM antibodies by IFA in 49 patients with acute infection (76.6%). Detection of IgG anti-VP1 and anti-VP2 by IFA, however, was as sensitive as IgG detection by indirect enzyme immunoassay. By applying IgG avidity IFA to sera of the 15 IgM IFA negative patients we were able to confirm acute infection in further 12 cases by IFA. Overall, acute infection was confirmed by IFA in 61 (95.3%) of the 64 patients.
Assuntos
Anticorpos Antivirais/análise , Capsídeo/imunologia , Imunoglobulina G/análise , Imunoglobulina M/análise , Infecções por Parvoviridae/imunologia , Parvovirus B19 Humano/imunologia , Adolescente , Adulto , Anticorpos Antivirais/sangue , Afinidade de Anticorpos/imunologia , Capsídeo/sangue , Criança , Eritema Infeccioso/diagnóstico , Eritema Infeccioso/imunologia , Imunofluorescência , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Infecções por Parvoviridae/diagnósticoRESUMO
In view of the scarce references concerning the histological data in congenital parvovirus human B19 infection, we intend to provide a description of the pathological features observed in six autopsies. The virus was detected by DNA hybridization (ISH-DBH), PCR and electronmicroscopy (EM) in paraffin-embedded feto-placentary tissues. These cases constitute a subset from 86 Non Immunologic Hydrops Fetalis (NIHF) cases, in which a systemic complex of inflammatory/degenerative lesions of unknown etiology was visualized by optical microscopy. In one case a syphilitic process was detected, typefying a double infection. All fetuses showed a similar pathology--hydrops, hepato-splenomegaly, lung hypoplasia and erythroblastemia, the specific histological feature being the presence of intranuclear inclusions in the erythroid progenitors, in the erythropoietic visceral tissue and in blood marrow. Complex cardiopathy allied to abnormal lung lobulation and polisplenia were observed once; in 2 cases endocardial fibroelastosis was diagnosed. The pulmonary lesions were represented by dysmaturity allied to interstitial mononuclear infiltration. The hepatic consisted of cholestasis, portal fibrosis, canalicular proliferation, hemossiderosis, focal necroses and giant cell transformation. The central nervous system lesions were predominantly anoxic although the autolysis impaired a correct diagnosis.