Abstract

Quantitative immunohistochemical (IHC) Assessment of Neutrophils (PMNs) in Bronchiolar Wall Compartment of Patients with Fatal Asthma.

A M Mitchell, J Erjefalt, L Dribin and A T Mariassy

Severe asthma presents with diverse clinical signs. We hypothesize that the variation in severity correlates with abundance of inflammatory cells in defined compartments of the lung. In this study we examined the bronchiolar wall lamina propria compartment to assess neutrophils (PMNs) from 14 cases of fatal asthmatic and 6 control subjects. Formalin-fixed, paraffin-processed tissues were immunohistochemically stained, in the DAKOcytomation auto-stainers. IHC EGDD antibodies for myeloperoxidase tagged with winegreen visualized the PMNs green. Aperio ImageScope program was used to assess the number of PMNs in the bronchiolar wall and relate them to 1mm² of lamina propria. The average PMN count per 1mm² in 19 bronchioles of asthmatics with diameter >1mm was 199.09 PMNs/mm², and the cell count in 38 bronchioles <1mm was 472.05 PMNs/mm². In controls, the average PMN count in 11 bronchioles <1mm and 6 bronchioles >1mm were 26.47 PMNs/mm² and 100.95 PMNs/mm² respectively. Statistical analysis of PMN counts/mm² between asthmatics and control bronchioles <1 mm showed statistically significant differences with p < 0.02, and for bronchioles >1mm, p ≈ 0.03. PMNs were three-folds more abundant in asthmatic small airways, while larger bronchioles are nearly two-folds more numerous. Further morphometric assessment is required to determine correlation between other inflammatory cell distribution in the bronchioles and the clinical signs. Funded by: NSU FRG, NIEHS 00628