Automated, Point-of-Care mobile flow cytometry: Bringing the laboratory to the sample

B N Jukema; T C Pelgrim; M Spoelder; C C W G Bongers; M T E Hopman; K Smit; M H Rijk; R P Venekamp; N Vrisekoop; L Koenderman

doi:10.1016/j.heliyon.2024.e28883

Automated, Point-of-Care mobile flow cytometry: Bringing the laboratory to the sample

Heliyon. 2024 Apr 3;10(8):e28883. doi: 10.1016/j.heliyon.2024.e28883. eCollection 2024 Apr 30.

Authors

B N Jukema^{1

2}, T C Pelgrim^{1

2}, M Spoelder³, C C W G Bongers³, M T E Hopman³, K Smit⁴, M H Rijk⁴, R P Venekamp⁴, N Vrisekoop^{1

2}, L Koenderman^{1

2}

Affiliations

¹ Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands.
² Center for Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands.
³ Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, Netherlands.
⁴ Department of General Practice and Nursing Science, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands.

Abstract

Background: Innate effector cells are very responsive to infectious and inflammatory cues found in damaged and inflamed tissues. Their activation is a potential target to assess the state of the immune system. Unfortunately, these cells are very susceptible for ex-vivo activation, hampering accurate interpretation of flow cytometry data. Whether a brief window exists before ex-vivo activation starts to occur is currently unknown.

Aims: 1) This study extensively investigated ex-vivo activation of innate effector cells over time. 2) We tested the feasibility of applying a mobile, automated, flow cytometry laboratory for out-of-hospital Point-of-Care analyses to minimize ex-vivo activation bias.

Methods: 1) Ex-vivo neutrophil, eosinophil and monocyte activation in a blood collection tube over time and the reactivity to a formyl-peptide was investigated in a healthy cohort. 2) To facilitate fast, out-of-hospital analysis, application of the mobile flow cytometry was tested by placing an automated flow cytometer into a van. The stability of the setup was assessed by repetitively measuring laser alignment and fluorescence verification beads.

Findings: 1) Immediately after venipuncture activation marker expression on neutrophils, eosinophils and monocyte subsets started to change in a time-dependent manner. 2) The mobile flow cytometry laboratory travelled over 3000 km, performing measurements at 19 locations with a median single-person-set-up time of 14 min. The laser alignment and fluorescence were stable during all experiments.

Conclusions: Accurate flow data of innate immune cells are only obtained when ex-vivo activation is kept to minimum. The use of a mobile, fast, automated, flow cytometry laboratory for out-of-hospital Point-of-Care analyses provides new investigational and diagnostic possibilities outside major hospital flow cytometry laboratories.

Keywords: Eosinophil; First line care; Innate immune activation; Mobile flow cytometry; Monocyte; Monocyte subsets; Near patient; Neutrophil; Point-of-Care; Systemic inflammation.