USE OF HEMATOPOIETIC GROWTH-FACTORS IN THE NEONATAL INTENSIVE-CARE UNIT

Recombinant hematopoietic growth factors have emerged as valuable trea tments for a variety of medical conditions. Recently, their applicatio ns have reached the neonatal intensive care unit, where they offer new therapeutic options for problems as common as anemia of prematurity, or as catastrophic as neonatal sepsis. When facing bacterial infection , it is known that newborn infants are capable of increasing their ser um G-CSF concentrations. However, their response does not reach the co ncentrations that adults are able to achieve, and frequently neutropen ia complicates the picture of neonatal sepsis, Although Phase III clin ical trials are still in progress, published animal studies, case repo rts, and Phase I trials suggest that neonates with a variety of neutro penias experience a rapid elevation in their blood neutrophil concentr ation following administration of rG-CSF without significant adverse e ffects. Although many factors contribute to the development of the ''a nemia of prematurity,'' one of the major factors is the inability of p reterm infants to generate an erythropoietin (Epo) response appropriat e to their degree of anemia. On the basis of this fact, administration of rEpo to preterm neonates to treat or to prevent the anemia of prem aturity has been the subject of multiple clinical studies, and it is n ow clear that rEpo administration to this population can indeed result in lower transfusion requirements, with only occasional and mild adve rse effects. Neonatal thrombocytopenia is also a frequent clinical pro blem, which in most patients develops without a clear underlying cause . Recent studies, quantifying circulating megakaryocyte progenitors in the peripheral blood of thrombocytopenic neonates, suggest that impai red megakaryocytopoiesis may be the main underlying mechanism of many cases of thrombocytopenia. On the basis of this finding, it is temptin g to speculate that recombinant thrombopoietin, the newly discovered p hysiological stimulator of platelet production, will be of clinical re levance in the treatment of thrombocytopenic neonates.