Fig. 3.

Bone marrow biopsy findings: H&E sections (A–C, from four different decedents) show varying cellularity with frequent hypercellularity, maturing trilineage hematopoiesis with frequent myeloid left shift (A, B), and occasional decreased M:E ratio (C). There may be pronounced dyserythropoiesis (C-inlay) and varying degrees of histiocytosis and hemophagocytosis that may not be readily appreciated on H&E sections but are unearthed with immunohistochemistry for histiocytic markers (eg, CD163) (D, E). Autopsy cases kindly provided by Dr Olga Pozdnyakova.