Pathogen-specific antibody profiles in patients with severe systemic infections

Area of Science:

• Infectious Diseases
• Immunology
• Microbiology

Background:

• Sepsis can arise from pathobionts, bacteria normally present in the microbiota.
• Trauma and surgery can compromise host defenses, leading to severe infections like sepsis.
• Antibody production is a key immune defense against pathogens.

Purpose of the Study:

• To measure plasma antibodies against nine major pathogens in sepsis patients.
• To assess the host's antibody response as a diagnostic tool for severe infections.
• To investigate potential unrecognised polymicrobial invasions in sepsis.

Main Methods:

• Quantified plasma antibody binding to bacterial extracellular proteins.
• Utilized a semi-automated immunoblot assay for antibody measurement.
• Compared pathogen-specific antibody levels before and after infection in sepsis patients.

Main Results:

• An increase in plasma immunoglobulin G (IgG) was observed in 20 out of 37 sepsis patients.
• A specific antibody response to additional bacteria, beyond the primary pathogen, was frequently detected.
• This indicated frequent unrecognised polymicrobial invasions in the studied sepsis cases.

Conclusions:

• Host-directed antibody measurement can complement pathogen-oriented diagnostics.
• The findings suggest unrecognised polymicrobial infections may contribute to sepsis.
• This approach may explain treatment failures in targeted antibiotic therapies.