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Complement haemolytic activity (classical and alternative pathways), C3, C4 and factor B titres in healthy children
V P Ferriani1, J E Barbosa, I F de Carvalho
1Department of Paediatrics, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil. vplferri@fmrp.usp.br
Acta Paediatrica (Oslo, Norway : 1992)
|November 24, 1999
Summary
Complement component levels (C3, C4, factor B) and lytic activity in children aged 3-14 show age-dependent changes, particularly in C3 and factor B. These findings establish reference ranges for Brazilian children and inform complement system development.
Area of Science:
- Immunology
- Pediatrics
Background:
- The complement system is crucial for innate immunity.
- Understanding complement component levels and activity in children is vital for diagnosing immune deficiencies.
Purpose of the Study:
- To determine normal ranges of complement lytic activity and component concentrations (C3, C4, factor B) in healthy Brazilian children.
- To investigate age-dependent variations in these parameters.
- To explore correlations between complement activity and component levels.
Main Methods:
- Sera from 103 healthy children (3-14 years) were analyzed.
- Complement lytic activity of classical and alternative pathways was measured kinetically.
- Concentrations of complement components C3, C4, and factor B were quantified.
Main Results:
- Age-dependent variations observed in C3 and factor B concentrations, peaking in 5-6-year-olds; C4 showed no significant age variation.
- Classical and alternative pathway lytic activities did not vary significantly with age in this cohort.
- Significant correlations found between alternative pathway activity and C3/factor B levels, and among C3, C4, and factor B concentrations.
Conclusions:
- Established reference ranges for complement parameters in Brazilian children.
- Highlights age-related maturation of the complement system.
- Provides a basis for screening complement system disorders in pediatric populations.