Work

Age-specific reference intervals for serum IgG, IgA, and IgM in healthy Brazilian children and adolescents

Year: 2026

Type: article

Abstract: Background: Serum immunoglobulin reference intervals vary by age, ethnicity, and environment, limiting the clinical utility of international guidelines for Brazilian pediatric patients. This study established age-specific reference intervals for serum IgG, IgA, and IgM concentrations in healthy Brazilian children and adolescents, focusing on defining precise trajectories across distinct developmental stages. Methods: Serum samples from 2,911 healthy individuals aged 1 month to 17 years were analyzed. Serum IgG, IgA, and IgM concentrations were measured by rate immunoturbidimetry standardized against international reference materials and evaluated using percentile-based analyses and quantile regression modeling across age-stratified cohorts. Results: Immunoglobulin concentrations varied substantially across age groups. Median IgG levels increased from 3.65 g/L (2.5th percentile: 2.25 g/L) at 1-3 months to 11.66 g/L (2.5th percentile: 7.69 g/L) at 13-17 years, with parallel age-related increases observed for IgA and IgM. The most pronounced changes occurred during infancy. Although early-life immunoglobulin dynamics did not entirely align with traditional trajectories, they suggested population-specific variations in humoral immune maturation. Conclusions: This study establishes the first comprehensive, population-specific reference intervals for serum immunoglobulins in Brazilian youth from early infancy through adolescence. By documenting unexpected deviations from traditional early-life trajectories, our study provides a critical benchmark for Brazilian pediatric care and a model framework for Latin American populations.

Source: Frontiers in Immunology

DOI: 10.3389/fimmu.2026.1969584