What is the immediate precursor of the band polymorphonuclear neutrophil?

The immediate precursor of the band polymorphonuclear neutrophil is the metamyelocyte. In the process of myeloid cell differentiation within the bone marrow, neutrophil precursors undergo several stages: the myeloblast develops into the promyelocyte, then progresses to the myelocyte, followed by the metamyelocyte.

The band neutrophil, also known as a band cell, represents a more mature stage prior to the fully segmented neutrophil. The unique feature of the metamyelocyte is its kidney-shaped nucleus, which is a critical transition point before the further maturation into the band form. Once the metamyelocyte further matures and the nuclear changes occur, it develops into the band cell.

This makes the metamyelocyte not just a precursor but the direct preceding stage for band neutrophils in hematopoiesis, thereby establishing its significance in understanding myeloid lineage differentiation.