In vitro granulocyte-macrophage colony-stimulating factor production by peripheral blood mononuclear cells in aplastic anemia.

We studied the production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by peripheral blood mononuclear cells from 48 patients with aplastic anemia by using an enzyme-linked immunosorbent assay. Detectable concentrations of spontaneous GM-CSF production, ranging from 1.0 to 480 pg/ml (mean +/- SD, 51 +/- 100 pg/ml), were observed in 45 of 48 patients. These concentrations were not significantly different from those observed in normal controls. Phytohemagglutinin-stimulated production of GM-CSF in patients with aplastic anemia, ranged from 1.0 to 2,610 pg/ml (mean +/- SD, 754 +/- 550 pg/ml), which was significantly higher than in normal controls (p < 0.01). The spontaneous production of GM-CSF increased following antilymphocyte globulin (ALG) treatment in 7 of the 11 ALG responders and in 4 of the 14 nonresponders (p = 0.08). The present observations support the hypothesis that ALG functions as an inducer of hematopoietic growth factor in order to restore hematopoiesis.