An improved nitroblue tetrazolium test using phorbol myristate acetate-coated coverslips

Area of Science:

• Immunology
• Hematology
• Clinical Diagnostics

Background:

• The nitroblue tetrazolium (NBT) slide test is a diagnostic tool for chronic granulomatous disease (CGD).
• Traditional NBT tests utilize endotoxin to stimulate polymorphonuclear leukocytes (PMNs).
• Modifications to the NBT test aim to improve its sensitivity and reliability.

Purpose of the Study:

• To evaluate a modified NBT slide test using phorbol myristate acetate (PMA) instead of endotoxin.
• To assess the diagnostic utility of the PMA-NBT test for detecting CGD in patients and carriers.
• To compare the efficacy of PMA-coated coverslips versus endotoxin-coated coverslips in the NBT assay.

Main Methods:

• Modification of the NBT slide test by precoating coverslips with PMA.
• Incubation of coverslips with polymorphonuclear leukocytes (PMNs) from healthy controls, CGD patients, and CGD carriers.
• Quantification of NBT reduction by PMNs as an indicator of oxidative burst activity.

Main Results:

• PMNs from healthy controls showed significantly higher NBT reduction on PMA-coated coverslips (99%) compared to endotoxin-coated coverslips (96%).
• PMNs from CGD patients failed to reduce NBT on both PMA- and endotoxin-coated coverslips.
• NBT reduction in PMNs from heterozygotic carriers was intermediate, with a statistically significant abnormality detected using PMA-coated coverslips in one carrier.

Conclusions:

• The PMA-NBT coverslip technique is a rapid, simple, and reliable method for detecting NBT reduction deficiencies.
• This modified assay effectively identifies individuals with chronic granulomatous disease and its carriers.
• The PMA-NBT test demonstrates superior sensitivity in detecting subtle NBT reduction abnormalities in CGD carriers compared to the endotoxin method.