[Toxoplasmosis in pregnancy: new diagnostic techniques]

Area of Science:

• Medical Parasitology
• Immunology
• Infectious Diseases

Background:

• Diagnosing primary Toxoplasma gondii infection in immunocompetent individuals is difficult.
• Persistent detectable IgM levels can complicate diagnosis for extended periods.

Purpose of the Study:

• To assess the prevalence of T. gondii antibodies in pregnant women.
• To evaluate commercial IgM and IgA detection systems and IgG avidity for diagnosing T. gondii primoinfection.
• To develop and validate a laboratory-based IgA detection system and analyze immunoglobulin-binding antigenic patterns.

Main Methods:

• Studied antibody prevalence and incidence of T. gondii primoinfection in pregnant women.
• Assessed commercial IgM, IgA, and IgG avidity assays.
• Developed a novel IgA detection system.
• Utilized Western blot to analyze antigenic targets of different immunoglobulins.

Main Results:

• Antibody prevalence was 56.70%, with a primoinfection incidence of 0.056% in pregnant women.
• All tested systems detected T. gondii primoinfection during seroconversion.
• IgG avidity and IgA detection demonstrated higher correlation with seroconversion compared to other methods when seroconversion was absent.
• Western blot revealed distinct antigenic patterns recognized by different immunoglobulins, with antigen 31 kD recognized by IgM, IgA, and IgG.

Conclusions:

• Despite high T. gondii antibody prevalence, primoinfection incidence during pregnancy is low.
• Except for seroconversion, no single tested serological method reliably diagnoses T. gondii primoinfection independently.
• IgG avidity and IgA detection offer the most promising results among the evaluated methods for diagnosing T. gondii primoinfection.