(a) Bone marrow plasma cells display immunolabeling for the monoclonal gamma chains in the numerous prominent cisternae of endoplasmic reticulum (er) in patient 2. m, mitochondria, N, nucleus. Original magnification ×30,000. (b) Bone marrow immunogold labeling for CD36: Gold particles outline the erythroblast junctions (arrowheads) where immunolabeling is more concentrated compared with the erythroblast plasma membrane (pm) not involved in the junction. Original magnification ×40,000.