Bombesin enhances monocyte and macrophage activities: possible role in the modulation of local pulmonary defenses in chronic bronchitis.

Increased lung levels of bombesin-related peptides (BRPs) have been described in smokers and in patients with chronic obstructive pulmonary diseases (COPDs). Moreover, previous studies have shown that BRPs are endowed with immunoregulatory activities. The aim of the present study was to assess the in vitro influence of synthetic bombesin on the activity of mononuclear phagocytes obtained from healthy donors and from COPD patients. Bombesin significantly enhanced in vitro phagocytosis of monocytes and alveolar macrophages in both groups of subjects, restoring deficient phagocytosis in a group of COPD patients. Moreover, bombesin stimulated superoxide anion production and interleukin-8 release by peripheral monocytes.