1/6. parvovirus B19-related anemia in hiv-infected patients.Persistent infection with parvovirus B19 (B19) is an important treatable cause of anemia in hiv-infected patients. B19 has a tropism for erythroid progenitors and causes pure red cell aplasia (PRCA). The failure to produce neutralizing antibodies to the virus following B19 infection in immunodeficient persons may result in persistent viremia and chronic PRCA (B19-PRCA). The seroprevalence rates for B19 in unselected persons with hiv infection are high, similar to those seen in the general population. Reports of B19-related anemia in hiv infected patients, however, are infrequent. A partial explanation may be that B19-PRCA is predominantly a complication associated with advanced immunodeficiency. The condition is probably underdiagnosed as well. The finding of an unexplained normocytic anemia with absent reticulocytes, in an afebrile hiv-infected patient without renal dysfunction suggests a diagnosis of B19-PRCA. The diagnosis is established when the following criteria are met: (1) bone marrow biopsy showing PRCA, (2) serum or bone marrow positivity for B19 dna by PCR or dot-blot hybridization, and (C) no alternate explanation for the PRCA. Serological methods are unreliable for the diagnosis because these patients often lack IgM and IgG antibodies to B19. Nearly all patients with B19-PRCA respond to treatment with intravenous immunoglobulin (IVIg) with a rise in the hemoglobin to levels appropriate for the clinical condition of the patient. An alternative explanation for the anemia must be sought in patients not responding to IVIg. Most patients with CD4 T-lymphocyte counts of < or = 100 cells/mm3 relapse to anemia, usually within 6 months of IVIg therapy. Such patients must be retreated with IVIg 2 g/kg given over 2 to 5 days. The routine use of maintenance IVIg 0.4 g/kg q 4wk may be considered in these patients to prevent relapse.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/6. polymerase chain reaction with double primer pairs for detection of human parvovirus B19 induced aplastic crises in family outbreaks.parvovirus B19 dna can be detected by polymerase chain reaction with double primer pairs (nested PCR). Recent infection was documented by a retrospective serological study using Parvoscan-B19 enzyme linked immunosorbent assay (EIA) for detection of B19 human parvovirus IgM and IgG antibodies in serum or plasma specimens. In 3 families B19 outbreaks caused aplastic crises necessitating blood transfusion in 5 children and 1 adult with hereditary sphaerocytosis. Four members from 2 of the families had clinically overt haemolytic anaemia prior to the event. Two members in another family presented with an aplastic crisis disclosing the underlying chronic haemolytic disease. All 7 patients were identified as PCR positive in serum samples taken 3-14 days after the onset of symptoms. Comparison with dot blot hybridization revealed detectable dna in only 2/3 PCR positive patients. Thus, nested PCR is more sensitive than the dot blot hybridization method and is therefore a suitable complement to the antibody assay for identifying recent B19 infection.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
3/6. antibodies to the nonstructural protein of parvovirus B19 in persistently infected patients: implications for pathogenesis.Three patients with persistent parvovirus B19 infection, as documented by the prolonged presence of IgM directed to the viral capsid proteins and detection of viral dna in serum by dot-blot hybridization or polymerase chain reaction (PCR), were investigated for the presence of antibodies to the nonstructural protein NS-1 of parvovirus B19. This was done by using an ELISA based on recombinant NS-1 protein. Whereas control sera displayed no reactivity, sera from persistently infected patients showed a strong specific antibody response to NS-1. patients were followed for 3-18 months, during which IgM titers declined but IgG directed to the nonstructural protein remained detectable. The appearance of NS-1-specific antibodies might indicate an altered course of viral infection leading to the establishment of persistently active infection and subsequent destruction of cells of nonerythroid lineage.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/6. Fetal-maternal hydrops syndrome in human parvovirus infection.A case of maternal generalized edema with hyponatremia, hypoosmolality and secondary hyperaldosteronism was associated with pseudomolar plasma human chorionic gonadotropin (hCG) concentrations in a case of fetal and placental hydrops due to parvovirus B19 infection. digoxigenin in situ hybridization techniques were effective in demonstrating parvovirus B19 infection on fixed tissues. Hydropic changes in the placenta may have massively increased the maternal plasma hCG concentration with subsequent fluid imbalance leading to maternal hydrops mimicking molar pregnancy.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/6. Case report: detection of parvovirus B19 in a skin biopsy of a patient with erythema infectiosum.We report the findings on a skin biopsy taken from a child acutely infected with parvovirus B19 showing the typical exanthematous rash. By indirect immunofluorescence with a monoclonal antibody to B19, viral capsid proteins were detected in epidermal cells localized mainly in the stratum basale. Additionally, B19 dna was detected in epidermal cells of the stratum basale by in situ hybridization using a Dig-labelled B19 dna probe. The detection of viral capsid proteins and viral dna suggests the presence of complete viral particles. It is therefore concluded that B19 plays a direct role in the formation of the exanthematous rash in erythema infection.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/6. Retrospective study on the influence of human parvovirus B19 infection among children with malignant diseases.Human parvovirus B19 (B19) is a known cause of erythema infectiosum (fifth disease) and aplastic crisis in patients with hemolytic anemias. When patients with malignant diseases are infected by B19 during chemotherapy, erythroid suppression of bone marrow sometimes occurs. We performed a retrospective investigation of B19 infection among 95 children with malignant diseases in our hospital during the past 14 years. By the method of dot blot hybridization, 9 of 95 patients were found to be positive for B19 dna during chemotherapy. All 9 patients had reticulocytopenia at the time B19 dna was detected in their serum samples. neutropenia and thrombocytopenia were not found. Seven of them had only transient reticulocytopenia. serum samples from 2 other patients were positive for B19 dna for a longer time. They suffered from persistent anemia for about 2 and 13 month, respectively. The years when B19 dna was detected from the 9 patients corresponded to the prevalence of erythema infectiosum in japan.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |