Isolation and labelling of human leukocytes with 99mTc

Area of Science:

• Nuclear medicine
• Hematology
• Cell biology

Background:

• Accurate leukocyte labeling with technetium-99m (99mTc) is crucial for diagnostic imaging.
• Different leukocyte isolation procedures may impact cell purity, recovery, and subsequent radiolabeling efficiency.
• Optimizing isolation techniques is essential for reliable in vitro and clinical applications.

Purpose of the Study:

• To evaluate the impact of two distinct leukocyte isolation methods on cell labeling with 99mTc.
• To compare the purity, recovery, and labeling efficiency of leukocytes obtained by each procedure.
• To recommend the optimal isolation method for specific applications, including in vitro studies and clinical use.

Main Methods:

• Leukocyte separation using methyl cellulose sedimentation followed by discontinuous gradient centrifugation (Procedure 1).
• Leukocyte separation using methyl cellulose sedimentation with hypotonic lysis of residual red blood cells (Procedure 2).
• Labeling of isolated leukocytes with 99mTc using a stannous pyrophosphate agent.

Main Results:

• Procedure 1 resulted in higher purity polymorphonuclear leukocytes but lower recovery, with minimal red blood cell contamination.
• Procedure 2 showed a higher recovery of polymorphonuclear leukocytes.
• 99mTc labeling efficiency was slightly higher with Procedure 1, potentially due to residual red blood cells.

Conclusions:

• Procedure 1 is recommended for in vitro studies focusing on cell kinetics due to higher purity.
• Procedure 2 is recommended for clinical use, likely balancing recovery and purity for patient studies.
• The choice of leukocyte isolation method significantly influences cell characteristics and radiolabeling outcomes.