Electron micrographs of erythroblastic inclusions from sections of marrow immunogold-labeled with mouse monoclonal antibody. Inclusions from case no. 1 show positive reactions with antibody against α-globin chains (A) and β-globin chains (B). Inclusions from case no. 2 show positive reactions with antibody against α-globin chains (C) and β-globin chains (D). Magnifications: A, × 32,000; B, × 38,000; C, × 32,000; D, × 37,000.