Bone marrow recovery following fetal liver infusion (FLI) in aplastic anaemia: morphological studies.

Twenty-two of 35 patients with aplastic anaemia who received fetal liver infusion (FLI), responded to this treatment. Detailed review of bone marrow aspirates and biopsies was available in 17. There was a good correlation between clinical improvement and blood counts. The bone marrow cellularity increased to 48 percent in about 18 weeks with repopulation by both erythroid and myeloid cells. The erythroid response was predominant and the earliest to occur (1.5-61 weeks); it lasted for 7.5-100 weeks. Marked dyserythropoiesis was observed. Myeloid response occurred simultaneously in 45 percent of the responders; in the others it was delayed by 1.5 to 4 weeks. Significant dysmyelopoiesis with shift to the left, unrelated to infection, was seen 1.5 to 9.5 weeks after FLI lasting for 9-26 weeks in most cases. Megakaryocytic response either did not occur or was delayed, less marked and often transient.