THE ROLE OF LYMPHOID-CELLS IN HEMATOPOIETIC REGULATION

The present review has summarized evidence supporting the existence of different lymphoid subsets with opposing effects on hematopoietic cel l growth (Table 1); specifically: a) growth stimulation resulting from the release of interleukins and granulocyte-macrophage colony-stimula ting factor (GM-CSF) by particular subsets of lymphocytes and resting natural killer (NK) cells and b) growth inhibition resulting from the release of interferon (IFN) and tumor necrosis factor (TNF) by stimula ted NK, B and lymphokine-activated killer (W() cells and inhibitory T lymphoid subsets. The systematic examination of the physiologic releva nce of lymphoid subsets would add an important element to a more compr ehensive model of hematopoietic regulation that might hold promise in future clinical applications.