Related Experiment Videos
Longitudinal evaluation of polymorphonuclear leukocyte chemiluminescence in premature infants
M S Driscoll1, V L Thomas, R S Ramamurthy
1Department of Microbiology, Pediatrics, and Pharmacology, University of Texas Health Science Center, San Antonio 78284.
Insights
Premature infants show reduced polymorphonuclear leukocyte (PMN) function for up to two months, impacting their health and increasing infection risk. This defective PMN activity may persist during serious infections.
Area of Science:
- Neonatal immunology
- Infectious disease in newborns
Background:
- Polymorphonuclear leukocytes (PMNs) are critical for host defense.
- Neonates, especially premature infants, may have impaired immune responses.
- Oxidative metabolic activity of PMNs is a key indicator of function.
Purpose of the Study:
- To longitudinally assess polymorphonuclear leukocyte (PMN) function in premature infants.
- To compare PMN function between premature infants and healthy adults.
- To investigate the relationship between PMN function and infant health outcomes.
Main Methods:
- Chemiluminescence (CL) microassay used to measure PMN function.
- Longitudinal study over a 2-month period in premature infants.
- Comparison group of healthy adult subjects.
Main Results:
- Premature infants exhibited significantly lower mean peak CL activity than adults.
- Infants with low CL responses experienced more severe illness, longer hospital stays, and higher infection rates.
- Depressed PMN CL activity was noted during serious infections, suggesting persistent defects.
Conclusions:
- Defective PMN oxidative metabolic responses are common in stressed neonates.
- Impaired PMN function can persist in premature infants for the first two months of life.
- Enhancing PMN host defense may be crucial for managing neonatal sepsis.
Abstract:
A chemiluminescence (CL) microassay was used to evaluate polymorphonuclear leukocyte (PMN) function in premature newborn infants longitudinally during a 2-month period and in healthy adult control subjects. At postnatal ages of 12, 26, 40 and 54 days the infants' mean peak CL activity was significantly lower than that of the adults. Infants with one or more low CL responses were more severely ill than those with normal CL activity. The infants with low CL responses had longer hospital stays and a higher frequency of serious infections, as well as more days of level 3 care, antimicrobial therapy, supplemental oxygen, assisted ventilation, and total parenteral nutrition. The PMN CL activity before, during, and after episodes of serious infection did not differ. In addition, a high frequency of depressed CL activity was observed at the time of infection. Our findings are consistent with previous studies suggesting that defective PMN oxidative metabolic responses are more common in neonates undergoing stress. Our results further suggest that defective PMN function may persist for the first 2 months of life and during the course of serious infection. Enhancement of PMN host defense may be an important strategy in the management of neonatal sepsis.