Autocrine/paracrine mechanisms in human hematopoiesis

Autocrine/paracrine regulatory mechanisms are believed to play a role in th e pathophysiology of several hematologic malignancies. Evidence is accumula ting that various growth factors, cytokines, and chemokines are expressed a nd secreted by normal early and differentiated hematopoietic cells and thus could also regulate normal hematopoiesis in an autocrine/paracrine manner. In this review we summarize recent advances in identification and understa nding of the role of autocrine/paracrine axes in the growth of both maligna nt and normal human hematopoietic cells. Better understanding of intercellu lar crosstalk operating in normal and pathological states and the mechanism s regulating synthesis of these endogenously produced factors (potential ta rgets for various pharmacological approaches) may allow us to improve antil eukemia treatments, undertake more efficient ex vivo stem cell expansion, a nd develop other therapeutic strategies.