Luminol-dependent chemiluminescence microassay for phagocytic function

A luminol-dependent chemiluminescence (CL) microassay was developed to measure phagocytic function of peripheral blood leukocytes. Buffy coats, obtained by centrifugation of only 100 μl of whole blood, provided an enriched population of polymorphonuclear leukocytes (PMNs). The total reaction mixture, consisting of leukocytes-luminol-inducer (opsonized zymosan), was 450 μl. Peak CL activity was seen 5 min after addition of inducer at 37°C with cells tested within 60 min after collection. Tests to determine precision and reproducibility of the microassay gave a coefficient of variation of 8.5% and 11%, respectively. There was no significant difference between the mean peak CL values for 20 healthy adult donors compared to 14 premature neonates, however, the newborns' CL activity declined more rapidly; CL activity was severely depressed in cells obtained from a patient with chronic granulomatous disease. Results suggest that this microassay provides a simple, rapid, and reliable test of phagocytic function in cases where the amount of blood available for testing is limited.