The Hermansky-Pudlak syndrome: ultrastructure of bone marrow macrophages.

The present investigation has explored the fine structure of the lipid inclusions which fill the bone marrow macrophages of patients with the Hermansky-Pudlak syndrome. Red blood cells are the major substrate of the reticular macrophages, and incomplete digestion of erythrocytes leads to formation of the massive inclusions. Progressive transformation of the macrophages results in an end-stage cell whose damaged cytoplasm is nearly replaced by huge lipid-containing vacuoles surrounded by particulate debris. This type of cell has not been found in bone marrows from patients with hemolytic, thrombocytopenic or lipid storage diseases.