What counts in cytometric analysis to document vaccine immunogenicity?

Area of Science:

• Immunology
• Vaccinology
• Infectious Diseases

Background:

• Immune cytometry (e.g., flow cytometry, ELISPOT) is increasingly used alongside antibody titers to assess vaccine and infectious disease immunogenicity.
• Current reporting often relies on percentages of immune cells, which can be misleading.
• Peripheral blood mononuclear cell (PBMC) concentrations vary significantly between individuals and over time within individuals.

Purpose of the Study:

• To advocate for the inclusion of absolute cell counts per ml in reporting immune cytometry data.
• To demonstrate the limitations of percentage-based reporting for immunogenicity assessments.
• To highlight the necessity of absolute cell counts for accurate inter- and intra-individual comparisons.

Main Methods:

• Discussion of a hypothetical example.
• Analysis of data presentation in immune cytometry.
• Focus on the impact of peripheral blood mononuclear cell concentration variability.

Main Results:

• Percentage-based reporting of immune cytometry data can lead to incorrect comparisons.
• Without absolute cell counts per ml, detection competition renders comparisons impossible when PBMC concentrations differ.
• Inter-individual and longitudinal variations in PBMC counts necessitate absolute cell count reporting.

Conclusions:

• Absolute cell counts per ml are essential for accurate interpretation of immune cytometry data in immunogenicity studies.
• Supplementing percentage data with absolute counts ensures reliable comparisons of immune responses.
• This approach is critical for vaccine development and infectious disease research.