Quantitative flow cytometric analysis of ABO red cell antigens

Area of Science:

• Immunology
• Hematology
• Biochemistry

Background:

• Accurate quantification of red blood cell (RBC) antigen expression is crucial for blood transfusion compatibility and understanding blood group genetics.
• Traditional methods for antigen detection may lack the sensitivity and precision required for detailed cellular analysis.

Purpose of the Study:

• To develop and validate a flow cytometry-based method for the quantitative comparison of A, B, and H antigen expression on individual RBCs.
• To investigate the relationship between A, B, and H antigen expression in different individuals and within cell populations.

Main Methods:

• Utilized flow cytometry with fluorescently labeled lectins and antibodies (anti-H, anti-A, anti-B) for direct and indirect antigen detection.
• Quantified antigen expression by determining the percentage and mean fluorescence intensity of positive subpopulations for each antigen.
• Calculated a compound mean value (percentage x mean fluorescence) to characterize RBC populations for A, B, and H antigen expression.

Main Results:

• Observed significant variations (over tenfold) in fluorescence intensity within individual RBC samples.
• Demonstrated a reciprocal relationship between the expression levels of A or B antigens and H antigen across different individuals.
• Established informative A/H or B/H ratios to distinguish between homozygous and heterozygous individuals for A or B blood groups.
• Successfully differentiated between A1 and A2 phenotypes based on distinct A/H ratios.

Conclusions:

• The developed flow cytometry method provides a sensitive and quantitative approach to analyze RBC antigen expression.
• The reciprocal relationship between A/B and H antigens is a key characteristic of RBCs from different individuals.
• The A/H and B/H ratios are valuable markers for determining blood group genotypes and distinguishing between A1 and A2 phenotypes.