Variations in the cell cycle status of lymphopoietic and myelopoietic cells created by zinc deficiency

Zinc deficiency causes thymic atrophy and lymphopenia. It was recently shown that zinc deficiency causes sizable losses among the precursor lymphocytes, such that this compartment was depleted 40%-50% in the marrow of young adult mice. However, the myeloid compartments increased substantially both in proportion and absolute number as zinc deficiency advanced. Zinc deficiency caused no change in the cell cycle status of precursor B cells and only modest changes in cycling pro-B cells. Conversely, cells of the myeloid series, especially monocytes, exhibited as much as a 40% increase in the proportion of cells in S and G(2)/M, while myeloid progenitors had an overall 56% increase in cells in the proliferative phase as zinc deficiency advanced. Whether zinc deficiency alters the rate of production of myeloid and lymphopoietic cells or alters the degree of apoptosis or both awaits further study.