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Updated: Aug 10, 2025
Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels
Published on: August 7, 2017
Correlation of Polymorphonuclear Cell Burden and Microbial Growth to the Inflammatory Cytokines in Tracheal Aspirates
Sophia Baig1, Pragnya Das1, Niharika Podaralla1
1Section of Neonatal-Perinatal Medicine, Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, Pennsylvania.
Objective:
The significance of the presence of microorganisms and polymorphonuclear cells in the tracheal aspirates (TAs) of ventilated preterm infants is not well known. Our aim was to correlate information about the presence of polymorphonuclear cells with microbial growth and the cytokine milieu in the TAs of infants who have been intubated for >7 days.
Study Design:
TAs were collected from infants who had been intubated for 7 days or longer. Respiratory cultures were performed, and infants were stratified based on the presence and abundance of polymorphonuclear cells and microbial growth. Cytokines were measured in the TAs of each of the respective groups.
Results:
In the 19 infants whose TAs were collected, the presence of at least moderate WBC with presence of microbial growth was positively associated with the presence of interleukin (IL)-10, IL-1β, IL-8, and tumor necrosis factor (TNF)-α. The presence of at least moderate WBC, with or without microbial growth, was correlated positively with the presence of IL-8 and TNF-α.
Conclusion:
There are higher levels of proinflammatory cytokines (especially, IL-10, IL-1β, and TNF-α) in TAs with higher cell counts and presence of microbial growth. The findings suggest that the presence of microbial growth correlated with inflammatory burden and warrant a larger study to see if treatment of microbial growth can ameliorate the inflammatory burden.
Key Points:
· Concomitant evaluation of inflammatory cells, microbial growth, and cytokines in tracheal aspirates.. · Moderate TA WBC with presence of microbial growth associated with IL-10, IL-1β, IL-8, and TNF-α.. · Moderate TA WBC, with/without microbial growth, correlated with the presence of IL-8 and TNF-α.. · Higher levels of IL-10, IL-1β, and TNF-α correlated with higher TA cell counts and microbial growth..
Insights
Microbial growth in tracheal aspirates of ventilated preterm infants is linked to increased inflammatory cytokines. This suggests microbial presence contributes to the inflammatory burden in these vulnerable infants.
Area of Science:
- Neonatal Medicine
- Pediatric Critical Care
- Microbiology
Background:
- The role of microorganisms and inflammatory cells in tracheal aspirates (TAs) of ventilated preterm infants remains unclear.
- Understanding these factors is crucial for managing respiratory infections in neonates.
Purpose of the Study:
- To investigate the correlation between polymorphonuclear cells, microbial growth, and cytokine profiles in TAs of preterm infants intubated for over 7 days.
Main Methods:
- Tracheal aspirates were collected from infants intubated for ≥7 days.
- Respiratory cultures were performed to identify microbial growth.
- Infants were categorized based on white blood cell (WBC) counts and microbial presence.
- Cytokine levels (IL-10, IL-1β, IL-8, TNF-α) were measured in TAs.
Main Results:
- Moderate WBCs with microbial growth in TAs were associated with elevated IL-10, IL-1β, IL-8, and TNF-α.
- Moderate WBCs, irrespective of microbial growth, correlated with increased IL-8 and TNF-α.
- Higher WBC counts and microbial presence were linked to increased levels of pro-inflammatory cytokines.
Conclusions:
- Elevated pro-inflammatory cytokines (IL-10, IL-1β, TNF-α) are present in TAs with higher cell counts and microbial growth.
- Microbial presence in TAs correlates with the inflammatory burden in ventilated preterm infants.
- Further research is needed to determine if treating microbial growth can reduce this inflammatory burden.
