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MARCO expression on pediatric alveolar macrophages
Hazel J Bunn1, Lester Kobzik, Jonathan Grigg
1Department of Child Health, University of Leicester, Leicester, United Kingdom.
Cytometry. Part B, Clinical Cytometry
|June 29, 2004
Summary
Pediatric alveolar macrophages (AM) express the pollutant-clearing receptor MARCO (macrophage receptor with collagenous structure) early in life. This suggests pollutant particle uptake is mature in infants and young children.
Area of Science:
- Immunology
- Pediatric Pulmonology
- Environmental Health
Background:
- Alveolar macrophages (AM) phagocytose unopsonized particles via the macrophage receptor with collagenous structure (MARCO).
- Previous studies showed laser scanning cytometry (LSC) can characterize receptor expression in pediatric AM.
- Ultrafine carbon particles have been found in AM from infants, indicating potential exposure.
Purpose of the Study:
- To determine MARCO expression in pediatric AM using LSC.
- To test the hypothesis that MARCO expression is mature in early infancy.
- To assess the phagocytic capacity for pollutant particles in young children.
Main Methods:
- Bronchoalveolar lavage was used to obtain AM from 17 healthy children (0.1–14.1 years).
- AM were dual immunostained for CD68 (panmacrophage marker) and MARCO or an isotype control.
- MARCO expression was quantified using LSC, adjusted for cell area, and compared to isotype controls.
Main Results:
- MARCO was detected on 98% of pediatric AM.
- No association was found between age and MARCO expression intensity.
- No correlation was observed between age and the proportion of MARCO-expressing cells.
Conclusions:
- Pediatric AM express MARCO, the primary receptor for unopsonized particle uptake, early in life.
- There is no evidence of developmental immaturity in MARCO expression in healthy young children.
- The capacity for phagocytosing pollutant particles appears to be mature in early infancy.