Relationship between immunohistochemical assessment of bronchial mucosa microvascularization and clinical stage in asthma.

Although hardly ever used in current practice, fibrobronchoscopy may provide interesting histopathological-clinical correlations in patients diagnosed with different stages of evolutive asthma. The aim of the study was to evaluate the correlation between semi-quantitative microvascularization features and the asthma severity assessed according to the GINA classification 2006. Our study group consisted in 21 patients diagnosed with asthma of different stages of severity and two-control patients investigated by fibrobronchoscopy with associated biopsy. The tissue fragments underwent standard processing procedures for the immunohistochemical exam, using CD34 as microvascularization marker. The semi-quantitative analysis was based on the "hot spot" method and on a score system that corresponds to the microvessels density. The statistical analysis of the correspondence between CD34 score and clinical parameters was performed using the SPSS 17 software, applying non-parametric correlation tests. The CD34 evaluation showed an increase in blood vessels count in all asthmatic patients in comparison to the control group and a close correlation with the asthma severity, reflected by the FEV1 values. The statistical analysis showed an inverse correlation between FEV1 [%] values and CD34 expression (r=-0.93, p<<0.01). Our data concur to other research reports, supporting the hypothesis that angiogenesis initially facilitates the edema development and later on appears to be involved in the bronchial wall thickening, as a component of the chronic inflammatory response, with concomitant distensibility reduction. The bronchial mucosa microvascularization evaluation opens new perspectives for advanced therapies, with beneficial effects for asthmatic patients' life quality.