Flow cytometric analysis is superior to the Ham test and permits concomitant diagnosis of PNH in about 20% of patients with myelodysplasia (a rate similar to that seen in patients with aplastic anemia). The presence of GPI-anchored protein-deficient cells in myelodysplasia predicts responsiveness to immunosuppressive therapy. Early emergence of GPI-anchored protein-deficient hematopoiesis in a patient with marrow failure may point to an underlying immune pathogenesis.
Goose parvovirus is the etiological agent of Derzsy's disease, a fatal hepatitis of young geese. The virus infects geese and Muscovy ducks and can be propagated in the laboratory in primary embryonic goose fibroblasts. To date the virus has only been classified by morphological, biochemical, and culture characteristics as an autonomous parvovirus. We now report the cloning and partial sequencing of 3434 nucleotides of the viral genome. Three overlapping clones were obtained, encoding regions in the nonstructural and capsid coding region. The nucleotide sequence show little homology to other autonomous parvoviruses but 55% homology to the dependovirus AAV2. The homology to AAV2 was also confirmed at the amino acid level (nonstructural protein 55%, capsid coding region 51%). DNA cross hybridization studies indicate an even closer similarity of goose parvovirus to the yet unsequenced human dependoviruses AAV1 and AAV3 than to AAV2. These findings suggest that goose parvovirus may be genetically related to the dependovirus genus rather than to the other autonomous parvoviruses.
Parvovirus B19 (B19) DNA was detected by dot blot hybridization in sera from 5 (17%) of 30 human immunodeficiency virus (HIV)-infected patients with hematocrits (HCT) of < or =24 and 4 (31%) of 13 HRV-infected patients with HCT of < or =20, suggesting that B19 is a reasonably common cause of severe anemia in HIV infection. The anemia promptly remitted after immunoglobulin therapy in 3 of 4 treated patients. The presence of IgM to B19, the clinical circumstance in which anemia developed, and the marrow morphology were poor predictors of chronic B19 infection. DNA hybridization studies of sera from 191 HIV-infected and 117 HIV-seronegative homosexual males attending a clinic in the Seattle area revealed that 1 (0.5%) and 2 (2%) samples, respectively, from the 2 groups contained B19. However, when assayed by polymerase chain reaction (PCR), 5% of the serum samples from HIV-infected persons and 9% from uninfected persons contained B19, although each had an HCT of > or =40. The data argue that anemia results from chronic high-titer B19 infection. Although a negative PCR assay excludes this diagnosis, DNA hybridization may be the more specific serum test.
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