Microbial pathogen primary sequence inversely correlates with blood group antigen immunogenicity.

Area of Science:

• Immunology
• Microbiology
• Transfusion Medicine

Background:

• Individual differences in immune response to red blood cell (RBC) antigens are well-documented.
• Allogeneic RBC antigen exposure is the main driver of alloantibody formation, but other factors are involved.
• Sequence similarities exist between RBC and microbial antigens, suggesting potential cross-reactivity.

Purpose of the Study:

• To investigate the hypothesis that individuals may be primed to form RBC alloantibodies through environmental exposure to cross-reactive microbial epitopes.
• To explore the correlation between RBC antigen immunogenicity and microbial antigen homology.

Main Methods:

• Utilized the BLASTp database to compare 13-residue peptides of common RBC antigens (K, Jk ^a , Lu ^a , E, c, M, C, and S) with microbial peptides.
• Focused analysis on bacteria and fungi, setting a >80% identity threshold.
• Employed linear regression and k-medoids clustering to analyze correlations.

Main Results:

• Identified significant peptide identity between RBC antigens and various pathogenic organisms (e.g., B. fragilis, P. aeruginosa, Candida spp.).
• A statistically significant inverse correlation was observed between RBC antigen immunogenicity and the number of associated microbial genera (b = -0.0017, r ² = 0.624, p = 0.0197).
• Antigens with lower immunogenicity were associated with a greater number of microbial genera.

Conclusions:

• Findings suggest a potential link between microbial exposure and the development of RBC alloantibodies.
• Raises questions about the relationship between the immunogenicity of RBC antigens and the prevalence of specific microbes.
• Highlights the need for further research into environmental priming in alloimmunization.