Assessment of IL17 Producing neutrophiles in Bronchial Asthma Patients with Fungal Allergy

Abstract

Asthma is a heterogeneous chronic inflammatory respiratory disease characterized by overproduction of mucus and airway-wall remodeling that leads to bronchial hyperactivity and airway obstruction. Allergens and some pathogens have been implicated in the worsening of asthma. For many years, allergic asthma has been considered a T helper 2 (TH2)-based disease, characterized by eosinophil infiltration. A TH 17-based response has also been observed in patients that exhibit chronic inflammation and particularly in those with severe asthma who respond poorly to steroids. IL-17 is mainly produced by TH-17 cells, but recent studies have begun to uncover non-CD4 T cells as important sources of IL-17A (the most common form of IL-17), such as CD8+ T cells, γδ T cells, natural killer cells, and granulocytes. In addition, it has been shown that murine neutrophils release IL-17. Our objective in this study is to analyze CD-177% (recently known to express IL-17) in the peripheral blood of asthmatic patients those with fungal allergy and those without, compared to healthy individuals, and if this neutrophil subpopulation could be related to any disease variable. We enrolled 40 asthmatic patients, further classified according to skin prick test results into two groups; group l included l8 asthmatics with positive skin prick test to fungi and group 2 included 22 asthmatics with positive skin test to other allergens. Twenty healthy non smoker volunteers served as control group (age and sex matched). All patients and controls were subjected to full history taking, clinical examination, and laboratory investigations including pulmonary function tests, skin prick test, complete blood picture, serum total IgE levels and flow cytometry for CD177%. Age of the asthmatic patients ranged between 19-60 with Mean ± SD: 42.3 ± l2. 24(60%) were males and 16(40%) were females. Severity was assessed according to GINA 2014 where 14 (35%) patients were mild, 17 (42.5%) were moderate and 9 (22.5%) were severe. We found statistically highly significant differences between cases and controls as regard FEVl%, fungal allergy by skin prick test, CD-l77% and Serum total IgE. On the other hand there were statistically non-significant differences between positive and negative fungal asthmatic cases as regard demographic and all laboratory data. Also, we found statistically non-significant differences between mild, moderate and severe asthmatic cases as regard age, gender, fungal allergy, neutrophils%, Serum total IgE and EOS%. Only a statistically significant difference between mild, moderate and severe asthmatic cases as regard CD-l77% was detected. Correlations between CD177% and different study parameters revealed only a statistically significant positive correlation between CD177% and serum total IgE in asthmatics.