Which term denotes abnormally large, immature, and dysfunctional red blood cells often seen in pernicious anemia?

• A. Megaloblasts
• B. Macrocytes
• C. Microcytic
• D. Morphology

Answer: (A)

In pernicious anemia, defective DNA synthesis due to vitamin B12 deficiency causes erythroid precursors to mature abnormally. The result is abnormally large, immature erythroblasts in the bone marrow that are dysfunctional—these are called megaloblasts. The presence of megaloblasts reflects the ineffective erythropoiesis characteristic of megaloblastic, macrocytic anemia seen in pernicious anemia. Macrocytes refer to large mature red blood cells, not the immature precursors, so they don’t capture the described scenario of immature and dysfunctional cells. Microcytic and morphology describe other concepts (small cells and general cell shape), which don’t fit this specific context. Thus, the correct term is megaloblasts.