Increased nitric oxide production by neutrophils in bronchial asthma

ABSTRACT

Nitric oxide [NO] is a major secretory product of mammalian cells that initiates host defense, homeostatic and development functions by either direct effect or intercellular signaling. The aim of this study was to look into the endogenous production of NO by neutrophils and correlate it with the severity of bronchial asthma, based on the postulation that peripheral blood neutrophils would reflect the changes occurring in bronchial tree neutrophils. The study included 30 patients with bronchial asthma selected from Ain Shams University Hospital. The thirty patients were classified into 3 groups according to their clinical manifestations and PEF and FEV[1] as follows Group I[10 patients with mild persistent asthma]; Group 11[10 patients with moderate persistent asthma]; and Group III [10 patients with severe asthma]. Each of these groups was reclassified into subgroup A [those not receiving steroids] and B [those receiving steroids] according to steroid therapy intake. The study included ten apparently healthy age-matched, non-smokers volunteers as control group. Complete blood count [CBC], Peak expiratory flow [PEF] and forced expiratory volume in the first second [FEV[1]] were performed for all subjects included in this study. Also, neutrophils from peripheral venous blood were separated on Ficoll hypaque, stimulated by latex reagent, and the production of total nitrite concentration was assayed. The results of this study showed that Nitrite production by peripheral blood neutrophils was significantly increased [P<0.001] in asthmatic patients in comparison to control subjects. In respect to the severity of bronchial asthma, highly significant increased [P<0.001] levels of nitrate production were encountered between the three studied patients groups. In addition, a highly significant negative correlations were observed between nitrite level and both EFV[1] [r= -0.911; P<0.001] and PEF [r= -0.958; P<0.001]. No significant differences [P >/= 0.05] were encountered on comparison of corticosteroids treated patients versus those not treated with corticosteroids in each asthma grade. NO could be used as a diagnostic marker of bronchial asthma and as a predictor for the severity of asthma. It has no appreciable value as a predictor of the response to corticosteroid therapy