Flow-cytometric evaluation of oxidative burst in phagocytic cells of children with cystic fibrosis

Objectives: The objective of this study was to assess the dye 2',7'-dichlor ofluorescein (DCF assay in screening for alterations in polymorphonuclear c ell (PMN) and monocyte (MC) oxidative burst of cystic fibrosis (CF) patient s. Study design: 56 CF patients aged between 2 and 20 years were investigat ed. Purified cells were stimulated with phorbolmyristate acetate: (PMA) and zymosan (ZX). A range for DCF fluorescence for PMA- and ZX-stimulated and non-stimulated cells was established based on data from 60 healthy controls . Results: PMNs showed both enhancement and impairment. A deficient oxidati ve burst was detected in a total of 14 CF patients caused by abnormally hig h mean fluorescence intensity (MFl) of resting cells. Enhanced oxidative bu rst was seen in 6 CF patients. CF patients responded differently to PMA or ZX stimulation. Pseudomonas aeruginosa colonization significantly enhanced (p<0.005) the MFI of resting PMNs. MCs of CF patients showed a significantl y (p<0.05) enhanced oxidative burst after stimulation with PMA compared to healthy controls, but no differences could be observed after stimulation wi th ZX. Serum concentrations of interleukin-6 were elevated in all CF patien ts, in particular in those with activation of both PMNs and MCs. Conclusion : The DCF assay shows for the first time the heterogeneity of the oxidative burst reaction in CF patients. In our opinion, the DCF assay is a reliable method for detecting pathological oxidative burst in CF patients.