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Circadian variation in cell-adhesion molecule expression by normal human leukocytes
Gary D Niehaus1, Elyce Ervin, Amit Patel
1Department of Physiology, Northeastern Ohio Universities College of Medicine, 4209 State Route 44, Box 95, Rootstown, OH 44272, USA. gdn@neoucom.edu
Canadian Journal of Physiology and Pharmacology
|November 27, 2002
Summary
Leukocyte cell adhesion molecule expression shows significant daily rhythms, potentially explaining nocturnal disease exacerbations. These findings highlight the importance of circadian biology in immune cell function and disease pathogenesis.
Area of Science:
- Immunology
- Chronobiology
- Cell Biology
Background:
- Leukocyte adhesion molecules (CAMs) mediate critical immune functions like cell adherence and diapedesis.
- Some immune functions intensify nocturnally, suggesting a potential circadian influence on leukocyte behavior.
Purpose of the Study:
- To investigate the hypothesis that cell adhesion molecule expression on leukocytes varies with circadian periodicity.
- To explore the potential clinical relevance of these rhythmic alterations in immune cell function.
Main Methods:
- Blood samples were collected from healthy donors over a 24-hour period.
- Monoclonal antibody binding and flow cytometry were used to evaluate CAM expression on monocytes, neutrophils, and lymphocytes.
Main Results:
- Significant circadian variation was observed in CD62L (L-selectin) expression across all leukocyte types.
- Diurnal variation was noted in monocyte and neutrophil CD54 (ICAM-1) expression.
- Neutrophils also showed circadian-like variation in CD11a (LFA-1a) expression.
Conclusions:
- Leukocyte cell adhesion molecule expression exhibits significant circadian rhythms.
- These rhythmic changes in CAM expression may contribute to the pathogenesis of diseases with nocturnal exacerbations, such as asthma and arthritis.
- Understanding these circadian patterns could inform therapeutic strategies for managing inflammatory and cardiovascular conditions.