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Lymphocyte subpopulation number and function in infancy
D A Stern1, M J Hicks, F D Martinez
1Respiratory Sciences Center, University of Arizona Health Sciences Center, Tucson 85724.
Insights
This study establishes normal values for infant lymphocyte subpopulations and immune responses. Key findings show changes in T cells, B cells, and immune function from birth to 24 months, aiding clinical evaluations.
Area of Science:
- Immunology
- Pediatric Medicine
- Developmental Biology
Background:
- Normal values for infant lymphocyte subpopulations and immune function are not well-established.
- Understanding immune system maturation in infancy is crucial for identifying immune deficiencies.
Purpose of the Study:
- To establish normal reference ranges for lymphocyte subpopulations and mitogen responses in healthy infants.
- To characterize changes in immune cell percentages and function from birth to 24 months of age.
Main Methods:
- Analysis of lymphocyte subpopulations (CD3, CD4, CD8, CD20) and functional responses (ConA, PWM, PHA) in infant blood samples.
- Cross-sectional (n=271) and longitudinal (n=37) study designs utilizing umbilical cord and peripheral blood samples.
- Inclusion of healthy infants from Tucson, Arizona, with assessment for ethnic- and gender-related differences.
Main Results:
- Significant increases in total T cells (CD3), T-cell subsets (CD4, CD8), and B cells (CD20) from birth to later infancy.
- Significant decreases in the CD4/CD8 ratio and responses to ConA and PWM mitogens.
- No significant changes in PHA responsiveness or detectable ethnic/gender differences.
Conclusions:
- Established normal values provide a critical reference for infant immune system studies and clinical diagnostics.
- The findings highlight dynamic changes in infant immune cell populations and function during the first two years of life.
- These data are valuable for evaluating newborns and infants with suspected acquired or congenital immune deficiencies.
Abstract:
Normal values for percentages of lymphocyte subpopulations and functional responses to mitogen stimulation in infancy are not well established. In the present study, lymphocyte subpopulations were examined in umbilical cord blood samples and in peripheral blood samples drawn before 7 and 24 months of age (mean age 10.4 months) from a healthy population of infants born in Tucson, Arizona. Results indicate significant increases occurred from birth to later infancy in the percentages of total T cells (CD3), T-cell subsets (CD4, CD8) and B cells (CD20). The CD4/CD8 ratio and the functional responses to ConA and PWM mitogens significantly decreased from birth to later infancy. PHA responsiveness did not show a significant change. Results from cross-sectional analyses (n = 271) were supported in a smaller longitudinal subset (n = 37). There were no detectable ethnic- or gender-related differences in cord blood or samples obtained in later infancy. The normal values established in this study will be useful in studies of immune-system maturation and in the clinical evaluation of newborns, infants, and toddlers suspected of either acquired or congenital immune-deficiency states.