The lung as a target organ in patients with hematologic disorders

The lung is one of the organs most severely affected by complications durin g the course of hematologic disorders. In the last years an impressive amou nt of progress has been made in clarifying the pathogenesis of lung disease s, particularly those occurring in conditions of severe immunosuppression s uch as bone marrow transplantion, acquired immunodeficiency syndrome or leu kemia. Peculiar anatomical characteristics render the lung parenchyma highl y susceptible to infections, but the clinical outcome is due not only to th e injury induced by the pathogens I but also to their interactions with inf lammatory cells and particularly to the effects of a wide network of secret ed cytokines. Polymorphonuclear cells, macrophages, lymphocytes and structu ral pulmonary cells (epithelial cells, interstitial cells) generate a varie ty of cytokines and growth factors which, in turn, may be responsible for t he majority of the clinical effects in response to infections, such as thos e of Pneumocystis carinii and cytomegalovirus, but also to certain drugs or to radiation. The pathogenesis of graft-versus-host disease (GVHD) is stil l poorly understood, but I animal models seem to demonstrate the involvemen t I of a number of cytokines and growth factors, together with toxic effect s induced by conditioning regimens. (C)2000, Ferrata Storti Foundation.