HLA-DR Expression on Monocyte Subsets in Critically Ill Children.

Area of Science:

• Immunology
• Pediatric Critical Care

Background:

• Sepsis, surgery, and trauma impact children's immune responses.
• Monocyte subsets and human leukocyte antigen-DR (HLA-DR) expression are key immune indicators.

Purpose of the Study:

• To longitudinally assess blood monocyte subset distribution and HLA-DR expression in critically ill children.
• To correlate these immune markers with outcomes like nosocomial infections and mortality.

Main Methods:

• Flow cytometry was used to analyze monocyte subsets and HLA-DR expression.
• Measurements were taken upon admission and on days 2, 3, and 4 in the pediatric intensive care unit (PICU).
• Comparison was made between critically ill children and healthy controls.

Main Results:

• Critically ill children showed a higher proportion of classical monocytes (CD14++CD16-) upon PICU admission compared to controls.
• HLA-DR expression was significantly decreased in all monocyte subsets, most notably on classical monocytes and in sepsis patients.
• Lower HLA-DR expression on classical monocytes at days 2 and 3 was associated with subsequent nosocomial infections and mortality.

Conclusions:

• Monocytic HLA-DR expression decreases during PICU stay, especially in sepsis.
• Reduced HLA-DR on classical monocytes serves as a potential biomarker for adverse outcomes in critically ill children.