Evaluating Pediatric Reference Ranges for Extended Immunophenotyping from a Finnish Cohort against Published...

Area of Science:

• Immunology
• Pediatric Immunology
• Clinical Diagnostics

Background:

• Inborn errors of immunity (IEI) diagnostics in pediatrics rely on flow cytometry and lymphocyte function tests.
• Current diagnostic methods lack sufficient age-matched reference values for pediatric populations.
• Variability in existing literature complicates accurate interpretation of results.

Purpose of the Study:

• To establish age-specific reference values for lymphocyte and dendritic cell subsets in healthy children under 12.
• To compare pediatric and adult lymphocyte mitogen response data.
• To provide a foundation for improved IEI diagnostics in children.

Main Methods:

• Flow cytometric immunophenotyping of lymphocytes and dendritic cells in 68 healthy children.
• Establishment of reference values across four pediatric age groups.
• Comparison of established values with literature data and 46 pediatric IEI patient samples.
• Analysis of lymphocyte mitogen response in 27 children and 177 adults.

Main Results:

• Established novel reference values for pediatric lymphocyte and dendritic cell subsets.
• Identified distinct immunophenotypic profiles in IEI patients (e.g., increased transitional/naïve B cells, decreased memory B cells).
• Observed weaker lymphocyte stimulation in children compared to adults, attributed to a higher proportion of naïve lymphocytes.

Conclusions:

• The established reference values are vital for accurate diagnostics of pediatric immunological conditions.
• Pediatric-specific reference values improve the interpretation of flow cytometry and functional tests for IEI.
• Consideration of lower lymphocyte mitogen response in children is crucial for reliable IEI diagnosis.