Correlation between serum antibody-levels against group B streptococci and gestational age in newborns

Area of Science:

• Neonatal Immunology
• Infectious Diseases
• Maternal-Fetal Medicine

Background:

• Group B streptococci (GBS) are a leading cause of serious infections in newborns.
• Premature infants often exhibit a higher susceptibility to GBS infections compared to full-term infants.
• The role of maternal antibodies in neonatal protection against GBS is not fully understood.

Purpose of the Study:

• To investigate the relationship between gestational age, birthweight, and IgG antibody levels to GBS surface antigens in newborns.
• To determine if antibody levels differ significantly between premature and full-term infants.
• To explore potential immunological explanations for the increased GBS infection rates in premature infants.

Main Methods:

• Sera from 33 newborn infants (27-41 weeks gestational age) were analyzed.
• Radioimmunoassay was used to quantify IgG antibodies against GBS types Ia, Ib, II, and III surface antigens.
• Statistical analysis correlated antibody levels with gestational age and birthweight.

Main Results:

• Positive correlations were observed between GBS antibody levels and infant gestational age and birthweight.
• Significant correlations were found for anti-Ia and anti-II antibody levels.
• Infants <34 weeks gestation had significantly lower mean antibody concentrations for GBS types Ia, II, and III compared to infants ≥34 weeks.

Conclusions:

• Gestational age and birthweight are significant factors influencing neonatal IgG antibody levels against GBS.
• Premature infants (<34 weeks) possess demonstrably lower protective antibody levels against key GBS serotypes.
• These findings suggest that reduced maternal antibody transfer contributes to the heightened risk of GBS infections in premature neonates.