Effects of IgG on in vitro megakaryocyte production, CFU-MK, platelet release, and megakaryocyte apoptosis. (A) In the presence of patient IgG from both groups A and B, most cultures showed reduced megakaryocyte yield compared with cultures containing control IgG (3.15 ± 0.93 × 105, 3.02 ± 1.01 × 105 vs 4.90 ± 0.48 × 105, P < .0001). There was no remarkable differences between group C and controls (P = .811). (B) In the presence of IgG from ITP patients or healthy controls, significant difference in CFU-MK was not seen among groups A, B, C, and controls (P = .568). (C) In the presence of IgG, platelet release in groups A and B were significantly lower than controls (5.95 ± 2.27 × 103, 6.15 ± 2.37 × 103 vs 10.97 ± 1.92 × 103, P < .0001). There were no remarkable differences between group C and controls (P = .184). (D) In the presence of IgG from ITP patients or healthy controls, significant differences in megakaryocyte apoptosis were not seen among groups A, B, C, and controls (P = .353). Data are mean ± SD.
