Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 11)

Persistent Parvovirus B19 Infection Chronic parvovirus infection is an important, treatable cause of PRCA. This common virus causes a benign exanthem of childhood (fifth disease) and a polyarthralgia/arthritis syndrome in adults. In patients with underlying hemolysis (or any condition that increases demand for red blood cell production), parvovirus infection can cause a transient aplastic crisis and an abrupt but temporary worsening of the anemia due to failed erythropoiesis. In normal individuals, acute infection is resolved by production of neutralizing antibodies to the virus, but in the setting of congenital, acquired, or iatrogenic immunodeficiency, persistent viral infection may occur. ...
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Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 11) Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 11) Persistent Parvovirus B19 Infection Chronic parvovirus infection is an important, treatable cause of PRCA. Thiscommon virus causes a benign exanthem of childhood (fifth disease) and apolyarthralgia/arthritis syndrome in adults. In patients with underlying hemolysis(or any condition that increases demand for red blood cell production), parvovirusinfection can cause a transient aplastic crisis and an abrupt but temporaryworsening of the anemia due to failed erythropoiesis. In normal individuals, acuteinfection is resolved by production of neutralizing antibodies to the virus, but inthe setting of congenital, acquired, or iatrogenic immunodeficiency, persistentviral infection may occur. The bone marrow shows red cell aplasia and thepresence of giant pronormoblasts (Fig. 102-2), which is the cytopathic sign of B19parvovirus infection. Viral tropism for human erythroid progenitor cells is due toits use of erythrocyte P antigen as a cellular receptor for entry. Direct cytotoxicityof virus causes anemia if demands on erythrocyte production are high; in normalindividuals, the temporary cessation of red cell production is not clinicallyapparent, and skin and joint symptoms are mediated by immune complexdeposition. Figure 102-2 Pathognomonic cells in marrow failure syndromes. A. Giantpronormoblast, the cytopathic effect of B19 parvovirus infection of the erythroidprogenitor cell. B. Uninuclear megakaryocyte and microblastic erythroidprecursors typical of the 5q– myelodysplasia syndrome. C. Ringed sideroblastshowing perinuclear iron granules. D. Tumor cells present on a touch preparationmade from the marrow biopsy of a patient with metastatic carcinoma.