Local administration of interleukin-1beta for the treatment of lung abscesses induces neutrophil activation and changes in proinflammation cytokine production

Interleukin-1 (IL-1) is a potent immunostimulatory molecule with broad range biological activity that limits its systemic application in humans. Alternatively, IL-1 can be applied locally, directly to the inflammatory site for stimulation of local defense mechanisms, without activating an acute phase response. IL-1beta preparations have been successfully used for local therapy of patients with purulent bacterial lung abscesses who were resistant to usual antibiotic treatment. IL-1beta was applied directly to the abscess cavity at a concentration of 10 ng/ml, once a day for 7 days. Before IL-1beta administration, local leukocyte functional activity was significantly reduced compared to the same activity in neutrophils isolated from the peripheral blood of the same patient. Local application of IL-1beta led to increases in adhesion, chemotaxis, oxygen radical production and phagocytosis of abscess fluid neutrophils. After local IL-1beta treatment, the concentration of IL-8 and TNF-alpha in the abscess fluids increased, while in nearly all patients levels of endogenous IL-1beta decreased. Immunocytochemical analysis showed that IL-1beta increased the numbers of cytokine-producing cells and induced proinflammatory cytokine production by neutrophilic granulocytes. According to the results obtained, the mechanism of the local immunostimulatory activity by IL-1beta is associated with the significant activation of neutrophilic granulocyte functions and changes in cytokine production at the inflammatory site. IL-1beta can be used as a highly effective immunotherapeutic drug when applied locally at adequate immunostimulatory dose levels.