A new method, chemotaxis under agarose gel, was used to assess the directed motility of polymorphonuclear (PMN) and mononuclear (MN) phagocytes of 21 newborns, 71 infants and children, and 50 adults. This assay requires only small quantities of cells and is rapid, easy, reproducible, and provides a permanent record. The chemotactic substance was zymosan-activated human serum.
Monocyte chemotaxis in the newborn was approximately 50% of adult control values, using the Boyden chamber (8.1 ± 2 cells per high-power field [HPF] [SE] in newborns compared to 17 ± 3 cells per HPF in adults), and 25% of adult control values, using the agarose method (50 ± 10 cells in newborns compared to 216 ± 15 cells in adults). Both are significant differences (P < .005). MN chemotaxis remains extremely low through age 5, and remains moderately reduced until age 10. PMN chemotaxis in the newborn was 82 ± 21 cells compared to adult controls of 300± 42 cells, also a significant difference (P < .05). PMN chemotaxis remains markedly depressed through age 2. Thereafter, PMN chemotaxis increases but remains significantly less than in adults until age 16.
These chemotactic defects may play an important role in depressed delayed hypersensitivity skin tests, diminished inflammatory reactions, and increased susceptibility to infection present in the newborn and young infant.
- Received January 31, 1977.
- Accepted June 13, 1977.
- Copyright © 1977 by the American Academy of Pediatrics