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'-dichlorofluorescein (DCF) assay in screening for alterations in polymorphonuclear cell (PMN) and monocyte (MC) oxidative burst of cystic fibrosis (CF) patients. STUDY
DESIGN: 56 CF patients aged between 2 and 20 years were investigated. 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 oxidative burst was detected in a total of 14 CF patients caused by abnormally high mean fluorescence intensity (MFI) of resting cells. Enhanced oxidative burst 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 significantly (p<0.05) enhanced oxidative burst after stimulation with PMA compared to healthy controls, but no differences could be observed after stimulation with ZX. Serum concentrations of interleukin-6 were elevated in all CF patients, 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.