The production of interferon gamma by natural killer (NK) cells and proportion of NK cells in peripheral blood mononuclear cells in patients with severe bronchial asthma

Chun, Eun Mi; Kim, Mi Sun; Chang, Yoon Hae; Park, Sung Sook; Cho, Young Joo

Abstract

BACKGROUND AND OBJECTIVE
The natural killer (NK) cells which play an important role in defense immune system are supposed to be involved in the pathogenesis of bronchial asthma. The goal of this study is to analyze the role of NK cells in the pathogenesis of bronchial asthma by examining the proportion of NK cells in peripheral blood mononucler cells (PBMCs) and production of interferon gamma (IFN-gamma) in NK cells between normal group and asthmatic group.
METHODS
Ten patients with moderate to severe persistent asthma sensitive to house dust mite were enrolled as asthmatic group. PBMCs were activated by 12-0-tetracanoylphorbol-13-acetate (TPA) and calcium inonophore for 18 hours. Surface CD3 and CD56 antigens with intracytoplasmic IFN-gamma staining were performed simultaneously and the results were analyzed by three color flow cytometer.
RESULTS
The percentage of CD56+ positive NK cells in PBMCs from asthma group was lower compared to control group (15.4+/-3.9% vs 19.8+/-4.5%). However, There was no signficant difference of IFN-gamma production in CD56+ NK cells between two groups (30.3+/-3.9% vs 25.9+/-5.8%, p>0.05). IFN-gammaproducing CD3+ T cells were significantly higher in asthma group compared with normal control group (36.3+/-1.8% vs 28.4+/-5.7%, p<0.05). The ratio of TNK cells expressing both CD56 and CD3 was not different between asthma group and control group (4.7+/-1.4 % vs 5.9+/-1.8%, p<0.05).
CONCLUSION
The results suggest that aggravation of asthma symptoms in severe asthma may be caused partly by decrease in NK cells. The increased production of IFN-gamma in asthma patients suggest that IFN-gammamay function as inflammatory cytokine.