Immunomodulatory Effects of Recombinant Interleukin-3 Treatment on Human Alveolar Macrophages and Monocytes

This is the authors' abstract. We don't add key points for this paper.

The purpose of these studies was to examine the effects of in vivo and in vitro recombinant IL-3 treatment on alveolar macrophage and monocyte activities associated with antitumor and antimicrobial properties. Alveolar macrophages and blood monocytes from 6 patients receiving IL-3 (125-500 micrograms/m2/day) subcutaneously were isolated before therapy and at various times during the 15 days of therapy. Results indicated that tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), and interleukin-6 (IL-6) secretion were enhanced from monocytes of all patients and from alveolar macrophages of patients receiving 500 micrograms/m2/day IL-3. Constitutive cytokine gene expression was present before therapy, but further enhancement was not detectable during therapy, suggesting a rapid time course of cytokine gene transcription and translation. Serum neopterin levels were elevated 2-5 fold in all patient compatible with the presence of augmented monocyte/macrophage activity. Peak levels of neopterin did not coincide with peak levels of cytokine secretion. In vitro studies of IL-3-treated normal alveolar macrophage and monocyte population demonstrated that IL-3 significantly augmented TNF and IL-6 secretion in monocytes, but not in alveolar macrophages. These differences in alveolar macrophage cytokine secretion observed after in vivo and in vitro IL-3 treatment may reflect the involvement of other cell populations in IL-3 modulation of alveolar macrophages in vivo. Monocytes, in contrast were comparably activated by IL-3 whether presented in vitro or in vivo.