<prompt> All cause Reticulocytosis EXCEPT:Aplastic anemiaThalassemiaSickle cell anemiaChronic blood loss  <response>: Ans. a Aplastic anemiaRef: Robbiris pathology 9th ed. 631 Aplastic anemia is characterized by destruction of bone marrow and thereby reduction in pluri-potent stem cells and their progeny.Henceforth the production of reticulocytes is less. Thalassemia and sickle cells are hemolytic anemias having extra-vascular hemolysis and thereby reticulocytosis. In chronic blood loss the loss of RBC provoke the bone marrow to be more aggressive and release reticulocytes in circulation. REMEMBER: Reticulocytopenia may be a result of viral Parvovirus B19 infection, which invades and destroys red blood cell precursors and halts the red cell production. 