Chapter 24: Spleen
Morphologic alterations in erythrocytes seen in individuals after splenectomy include all of the following except
(A) Howell-Jolly’s bodies
(C) Pappenheimer’s bodies
(E) The spleen is responsible for removal of senescent and defective RBCs. In contrast to other organs in which the diameter of the smallest capillaries is slightly larger than that of RBCs, the splenic capillary bed terminates in the red pulp, a sieve-like network of sinuses and cords filled with macrophages through which only the most plastic of cells may pass. Here, the circulation stagnates and permits prolonged contact of the bloodstream with cordal macrophages. Senescent cells are destroyed (culling), and weathered red cells that are salvageable are remodeled and repaired (pitting) as intracellular inclusion bodies are removed.
After splenectomy, leukocytosis and thrombocytosis may develop in some patients, but blood counts usually normalize within the first 3 weeks. Although other macrophage-filled organs continue to remove damaged erythrocytes so that the overall survival of RBCs does not increase, less-damaged cells are not remodeled in the absence of the splenic filter. The result is characteristic differences on peripheral blood smears of splenectomized individuals:
Howell-Jolly bodies are small, spherically shaped nuclear remnants of RBCs. They arise from nuclear fragmentation or incomplete expulsion of the nucleus during normal RBC maturation. They are also seen in patients with megaloblastic anemia and hyposplenic states.
Heinz bodies are composed of denatured proteins—principally hemoglobin—that form in RBCs as a result of chemical injury, hereditary defects of the hexose monophosphate shunt, thalassemia, and inherited syndromes of unstable hemoglobin.
Pappenheimer bodies are a type of siderosome (iron body) commonly found in reticulocytes.
Target cells, also known as codocytes, are characterized by relative membrane excess because of either increased red cell surface area or decreased intracellular hemoglobin. They are seen in obstructive liver disease, hemoglobinopathies (S and C), thalassemia, iron deficiency, the postsplenectomy period, and lecithin cholesterol acetyltransferase deficiency. They are bell-shaped cells that assume a target-like appearance on a laboratory slide.
Spur cells, also known as acanthocytes, result from accumulation of cholesterol in the RBC membrane due to elevated plasma cholesterol/lipoprotein ratios. Acanthocytosis, or spur cell anemia, is most commonly seen in patients with end-stage liver disease.
Basophilic stippling refers to deep blue granules composed of clumped ribosomes, degenerating mitochondria, and siderosomes. They are also seen in lead intoxication and thalassemia.
Dohle’s bodies are cytoplasmic inclusion bodies found in neutrophils in the setting of inflammatory diseases, infections, myelocytic leukemia, burns, cyclophosphamide therapy, and myeloproliferative syndromes.
Beauchamp RD, Holzman MD, Fabian TC. Spleen. In: Townsend CM, Beauchamp RD, Evers BM, et al., eds. Textbook of Surgery: The Biological Basis of ...