[Fevers of unknown origin: new aspects of an old problem].

Fever is an important component of immune response of the organism to various stimulating effects (trauma, infection, inflammation). This complex process comprises activation of monocytes/ macrophages, their synthesis and secretion of proinflammatory cytokines and realization of multiple biological effects of cytokines including growth stimulation and differentiation of hemopoietic cells. Recently, there has appeared a trend to growing number of cases with uncommon hyperthermia and 2-3 germ cytopenia in the blood. Activation of the macrophage system and hyperproduction of proinflammatory cytokines can be viewed not only as an essential mechanism of hemopoiesis stimulation but also as a potential cause of hemodepression. The paper analyzes the relations between high functional activity of the macrophage system and development of cytopenia in patients with persistent fever. Functional activity of the macrophage system was studied on the model of patients with tumors or reactive proliferations of monocytes-macrophages as the latter are the main sources of IL-1-cytokine--a mediator of human fever. To prove the suggested correlation and its significance, a correlation analysis was made of 29 clinical and laboratory parameters in 184 patients and 100 controls.