HIGH-DOSE INTRAVENOUS GAMMA-GLOBULIN REDUCES MACROPHAGE-COLONY-STIMULATING FACTOR LEVELS IN IDIOPATHIC THROMBOCYTOPENIC PURPURA

We investigated the effect of high-dose intravenous gamma globulin the rapy on the plasma level of macrophage-colony stimulating factor (M-CS F) level in 13 patients with chronic idiopathic thrombocytopenic purpu ra. M-CSF and interleukin-6 levels were determined by enzyme-linked im munosorbent assay. The mean +/- S.D. level of M-CSF in the patients wa s 1235 +/- 439 U/ml, and the level in 8 patients was higher than the m ean + S.D. (903.6 U/ml) in normal controls. All 8 patients had steroid -refractory disease. M-CSF levels were significantly correlated with t he serum levels of interleukin-6 (r = 0.66, P < 0.05). Interleukin-6 l evels were also significantly raised in the high M-CSF group compared with the normal M-CSF group (P < 0.05). In the whole patient populatio n, M-CSF levels decreased, but not significantly, after intravenous ga mma globulin, while interleukin-6 decreased significantly. However, in the patients with high pretreatment M-CSF levels, both M-CSF and inte rleukin-6 decreased significantly after treatment (M-CSF, 4 weeks, P < 0.05; IL-6, 1 week, P < 0.05, 4 weeks, P < 0.01). These findings sugg est that high-dose intravenous gamma globulin causes thrombocytosis by the decrease of M-CSF levels in idiopathic thrombocytopenic purpura.