Leukocyte function assessed via serial microlitre sampling of peripheral blood from sepsis patients correlates with disease severity

Nat Biomed Eng. 2019 Dec;3(12):961-973. doi: 10.1038/s41551-019-0473-5. Epub 2019 Nov 11.


Dysregulated leukocyte responses underlie the pathobiology of sepsis, which is a leading cause of death. However, measures of leukocyte function are not routinely available in clinical care. Here we report the development and testing of an inertial microfluidic system for the label-free isolation and downstream functional assessment of leukocytes from 50 μl of peripheral blood. We used the system to assess leukocyte phenotype and function in serial samples from 18 hospitalized patients with sepsis and 10 healthy subjects. The sepsis samples had significantly higher levels of CD16dim and CD16- neutrophils and CD16+ 'intermediate' monocytes, as well as significantly lower levels of neutrophil-elastase release, O2- production and phagolysosome formation. Repeated sampling of sepsis patients over 7 days showed that leukocyte activation (measured by isodielectric separation) and leukocyte phenotype and function were significantly more predictive of the clinical course than complete-blood-count parameters. We conclude that the serial assessment of leukocyte function in microlitre blood volumes is feasible and that it provides significantly more prognostic information than leukocyte counting.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cross-Sectional Studies
  • Female
  • GPI-Linked Proteins
  • Humans
  • Leukocyte Count
  • Leukocyte Elastase / blood
  • Leukocytes*
  • Male
  • Microfluidic Analytical Techniques / instrumentation
  • Microfluidic Analytical Techniques / methods*
  • Middle Aged
  • Monocytes
  • Neutrophils
  • Phenotype
  • Receptors, IgG
  • Sepsis / blood*
  • Sepsis / diagnosis*
  • Severity of Illness Index*
  • Young Adult


  • FCGR3B protein, human
  • GPI-Linked Proteins
  • Receptors, IgG
  • ELANE protein, human
  • Leukocyte Elastase