Volumetric capillary cytometry: a new method for absolute cell enumeration

Area of Science:

• Biomedical Engineering
• Immunology
• Analytical Chemistry

Background:

• Traditional flow cytometry requires sample lysis and complex preparation.
• Accurate cell counting is crucial for diagnosing and monitoring various health conditions.
• Existing methods can be time-consuming and prone to error.

Purpose of the Study:

• To introduce a novel, imaging-based cytometry system for analyzing unlysed whole blood.
• To demonstrate the system's capability for accurate cell identification, counting, and reaction kinetics monitoring.
• To provide a simplified and precise method for absolute lymphocyte counts.

Main Methods:

• Utilizing a red excitation source (helium-neon laser) to minimize autofluorescence.
• Employing a two-color fluorescence detection system (Cy5 and Cy5.5) for simultaneous antigen analysis.
• Integrating image processing for cellular event identification and fluorescence quantitation within a defined blood volume.

Main Results:

• Achieved high correlation (0.98 coefficient) with traditional flow cytometry for CD3+/CD4+ lymphocyte counts.
• Demonstrated minimal sample preparation with the entire blood sample contained in a disposable cartridge.
• Successfully monitored reaction kinetics, including antibody-antigen association rates.

Conclusions:

• The novel cytometry system provides accurate and efficient absolute cell counts from unlysed whole blood.
• This technique offers a promising alternative to conventional flow cytometry, simplifying sample handling and preparation.
• The system's ability to monitor reaction kinetics opens avenues for studying cellular interactions and drug efficacy.