Assessment of bronchial inflammation using an automated cell recognition system based on colour analysis

The aim of this study was to develop an automated system of cell recognitio n based upon colour analysis suitable for microscopic examination of bronch ial inflammation. Human bronchi obtained from 17 patients undergoing thoracotomy were embedde d in glycolmethacrylate to perform immunohistochemistry with antibodies aga inst: neutrophil elastase, tryptase, chymase, eosinophil cationic protein, CD68, CD3 and immunoglobulin E. The image analysis system calculates three independent criteria (optic density, hue density, hue) combined with morpho logical parameters to specifically recognize a positive staining. This auto mated analysis was applied to the study of branchial inflammation in smoker s and nonsmokers in terms of the absolute number of cells and the expressio n of different markers by a single cell. The use of these criteria enabled the characterization of a positive stain on single (intraclass correlation coefficient (ICC)=0.88 or serial (ICC=0.8 4) sections. Cell counts obtained by the automated system were highly repro ducible, Regarding bronchial inflammation, it was found that the number of inflammatory cells was significantly higher in smokers than in nonsmokers, the majority of these cells bearing immunoglobulin E. These results demonstrate that such computerized analysis of colours is a v aluable method for quantifying inflammatory cells in bronchial tissue and f or analysing the expression of different markers by a single cell.