H2O2 release from filtration leukapheresis-procured leukocytes

Area of Science:

• Hematology
• Transfusion Medicine
• Cellular Biology

Background:

• Leukapheresis is a method for collecting white blood cells.
• Filtration leukapheresis (FL) is one such method.
• Potential cellular activation and toxicity of FL-procured leukocytes require investigation.

Purpose of the Study:

• To investigate the release of reactive oxygen species (ROS) and myeloperoxidase (MPO) from filtration leukapheresis leukocytes (FL-leukocytes).
• To compare the characteristics of FL-leukocytes with those obtained via dextran sedimentation (DS-leukocytes).
• To assess the potential implications of FL-leukocyte properties on transfusion outcomes.

Main Methods:

• Leukocytes were collected using filtration leukapheresis with varying elution techniques (gentle vs. vigorous tapping).
• Hydrogen peroxide (H2O2) release was measured with and without phagocytic stimuli.
• Myeloperoxidase (MPO) activity was assessed in FL-leukocytes and compared to DS-leukocytes.

Main Results:

• FL-leukocytes released H2O2 spontaneously, even without phagocytic stimulation.
• Marked H2O2 release was observed during phagocytosis for FL-leukocytes, irrespective of elution method.
• FL-leukocytes exhibited lower MPO activity compared to DS-leukocytes.

Conclusions:

• FL-leukocytes demonstrate inherent H2O2 release, indicating cellular activation.
• The reduced MPO activity and observed H2O2 release suggest potential cytotoxic effects.
• These findings may explain adverse transfusion reactions and abnormal post-transfusion kinetics associated with FL-leukocytes.