PURPOSE: T cells in the airways are considered to play a key role in orchestrating the inflammatory response of asthma. Though radiological and broncho-alveolar lavage (BAL) changes have been reported in asthma, there are not many studies that have investigated the relationship of BAL cell profile with changes on CT scan (which may suggest airway remodeling).
METHODS: BAL was performed on 21 cases of bronchial asthma and 9 controls. The BAL fluid was evaluated for total and differential cell counts. T lymphocyte subsets (CD4+ and CD8+) were determined using flow cytometry. These cases underwent CT scan for assessment of bronchial dilatation (BD),traction bronchiectasis, hyperinflation etc. The data was analyzed using ANOVA, independent t test and Pearson’s correlation.
RESULTS: There were 10 mild (FEV1 > 80% of predicted) and 11 moderately severe (FEV1 = 60-80% of predicted) asthma patients. There was no significant difference in BAL total cells in both asthmatic groups compared to controls (p>0.05). Absolute and percentage eosinophil count were significantly higher in asthma as compared to controls (p <0.01). CD8+(%) in moderate asthma were significantly lower than mild asthmatics (p < 0.01). BD was significantly correlated (r=0.66, p= 0.02) with increase in total cells in moderate asthma but not in mild asthma (r= 0.38, p= 0.27). The same pattern was noted with absolute lymphocyte (r=0.67, p=0.02), neutrophil (r= 0.64, p=0.03) and eosinophil counts (r=0.63, p=0.007). BD correlated negatively with CD8+ (%) in both mild (r= - 0.68, p=0.03), moderate (r= −0.74, p=0.007) asthmatics. Traction bronchiectasis and hyperinflation were significantly more in moderately severe asthma compared to mild asthma.
CONCLUSION: There is an increase in eosinphils in lower respiratory tracts (LRT) of patients with asthma. The abnormally accumulated inflammatory cells (eosinophils, lymphocytes, and neutrophils) in the LRT may favour the development of bronchial dilatation while CD8+ cells may prevent the development of bronchial dilatation.
CLINICAL IMPLICATIONS: This study emphasizes the need for sustainable suppression of LRT inflammation to prevent changes that may lead to airway remodeling.
DISCLOSURE: Pankaj Sayal, None.