tailieunhanh - 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. . | 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. The bone marrow shows red cell aplasia and the presence of giant pronormoblasts Fig. 102-2 which is the cytopathic sign of B19 parvovirus infection. Viral tropism for human erythroid progenitor cells is due to its use of erythrocyte P antigen as a cellular receptor for entry. Direct cytotoxicity of virus causes anemia if demands on erythrocyte production are high in normal individuals the temporary cessation of red cell production is not clinically apparent and skin and joint symptoms are mediated by immune complex deposition. Figure 102-2 Souk fivci AS Epfpt DL. ftnunvild f 8l Lon s DL- Jpm on JI Locoln Ji Hasnnm s -üjcrir 17th Edition http . www üsrn d -cin .-cprr Cspwrtflhit SI Th Cpmpinbtf Inf All B 5SUÍÍ F UÍI fts. ic p r DL. tr un ld E. Hjuid Si Lôn Si OL. J rr tsn JL. Loic t e Jl MjzzjrwT j e Aevn 17th Êditiom http vwv. iïrTi dkCin .com Cspynflht ö Th Mcûr -H lt Comp rù t Inc Ail rlflhtf rii rv .