Impact on in-depth immunophenotyping of delay to peripheral blood processing

Area of Science:

• Immunology
• Cell Biology
• Clinical Research

Background:

• Peripheral blood mononuclear cell (PBMC) immunophenotyping is vital for monitoring disease and treatment responses.
• Sample processing delays between collection and laboratory analysis can compromise PBMC quality and experimental outcomes.

Purpose of the Study:

• To investigate the effects of processing delays and storage conditions on PBMC immunophenotyping using cytometry by time-of-flight (CyTOF).
• To determine the impact of delayed PBMC processing on cell composition, quality, and marker expression.

Main Methods:

• Utilized an extensive CyTOF immunophenotyping panel on PBMCs from seven adult donors.
• Analyzed samples subjected to varying processing delays (up to 7 days) and distinct storage conditions.
• Employed unbiased clustering analysis to identify granular immune cell subset changes.

Main Results:

• Processing delays exceeding 2 days led to increased red blood cell contamination and cell count variability.
• Monocyte frequencies decreased with 4-day delays, while other immune subsets showed increased variation up to 7 days.
• Specific subsets like monocytes, basophils, plasmacytoid dendritic cells, and T follicular helper cells were impacted at distinct delay times. Activation marker expression changed by Day 2.

Conclusions:

• Existing recommendations to process PBMCs within 36 hours are supported.
• Significant alterations in PBMC composition and quality occur with processing delays beyond 2 days.
• The study provides crucial guidance for designing immunophenotyping experiments with extended sample processing timelines.