In vitro bone marrow GM-CFC growth in aplastic patients. Correlation between E rosette forming cells and immunotherapy results.

In vitro bone marrow GM-CFC (granulomonocyte colony forming cell) growth following E rosette (+) cell depletion was studied in 14 aplastic patients to determine whether an autoimmune factor could be involved in the pathophysiological process leading to the decrease in bone marrow colony formation. The increase in GM-CFC growth after E rosette (+) cell depletion was high in 8 cases, suggesting that in these cases an autoimmune mechanism may have been involved. All these patients responded within a month to treatment with antithymocyte globulin (ATG) or corticosteroids. Six patients did not respond to immunotherapy, none showed increased GM-CFC growth. The increase of in vitro GM-CFC growth after E rosette (+) cell depletion in aplastic anemia could therefore be a good indication for the trial of immunotherapy. However this study seems to be useful only in patients with at least a few months evolution after diagnosis.