Patchy haemopoiesis in long-term remission of idiopathic aplastic anaemia.

13 patients with idiopathic aplastic anaemia in remission for more than 2 years were examined to define the haemopoietic status by means of bone marrow scintigraphy, ferrokinetics and bone marrow culture for haemopoietic progenitor cells. Haemoglobin levels reached the normal range in all these patients although mild neutropenia and thrombocytopenia were still observed in 5 patients. Bone marrow scintigrams using indium-111 showed normal distribution in 2, diffuse low accumulation in 3, patchy distribution in 7, and expanded distribution with patchy uptake in 1 patient. The defective haemopoiesis was also confirmed by ferrokinetic and bone marrow culture studies. The patchy haemopoiesis appears to characterize the residual marrow damage in remission of idiopathic aplastic anaemia.