Polymorphonuclear leucocyte function tests: a comparison of cytochrome C reduction and flow cytometric analysis

Area of Science:

• Immunology
• Cellular Biology

Background:

• Polymorphonuclear leucocytes (PMN) are crucial for innate immunity.
• Assessing PMN phagocytic and killing functions is vital for diagnosing immune deficiencies.
• Cytochrome C reduction and flow cytometry are common methods for evaluating PMN function.

Purpose of the Study:

• To compare the results of the cytochrome C reduction test with flow cytometry methods for assessing PMN phagocytosis and killing capabilities.
• To investigate potential discrepancies between these commonly used PMN function tests.

Main Methods:

• Assayed PMN samples from 20 healthy individuals.
• Utilized cytochrome C reduction test.
• Employed flow cytometry with fluorescent beads for phagocytosis assessment.
• Used DCFH-DA granules with flow cytometry for phagocytosing-killing capacity evaluation.

Main Results:

• No significant correlation was observed between the cytochrome C reduction test and flow cytometry assays (fluorescent beads or DCFH-DA).
• Discrepancies may arise from technical differences, including varied stimulants and phagocytosed substances used in each test.
• Flow cytometry is increasingly favored for PMN function testing over traditional dye reduction tests like cytochrome C or nitroblue tetrazolium (NBT).

Conclusions:

• Results from cytochrome C reduction and flow cytometry tests for PMN function are not directly comparable.
• Caution is advised when interpreting and comparing PMN function test results across different laboratories.
• A combination of multiple assay principles is recommended for comprehensive PMN function testing.