Automated bedside flow cytometer for mHLA-DR expression measurement: a comparison study with reference protocol.

Area of Science:

• Immunology
• Critical Care Medicine
• Medical Technology

Background:

• Diminished human leukocyte antigen-DR on monocytes (mHLA-DR) is a marker for immunosuppression in intensive care units (ICUs).
• Low mHLA-DR correlates with increased risk of nosocomial infections and mortality.
• Current flow cytometry methods for mHLA-DR are limited by accessibility and expertise requirements.

Purpose of the Study:

• To evaluate the performance of the Accellix system for measuring mHLA-DR expression.
• Assess Accellix for repeatability and method comparison against a reference protocol.

Main Methods:

• Beta site evaluation of the Accellix automated flow cytometer.
• Repeatability testing at low and high mHLA-DR expression levels.
• Method comparison study with 139 blood samples, including septic shock patients and healthy volunteers.

Main Results:

• Accellix demonstrated repeatability <10% for mHLA-DR measurement, meeting clinical flow cytometry standards.
• Method comparison showed strong correlation (r² 0.71–0.97, p < 0.001) and high intra-class correlation (0.92).

Conclusions:

• The automated Accellix system is a suitable tool for ICU patient monitoring and clinical trials.
• Its ease of use and lack of need for specialized skills make flow cytometry more accessible.
• Further validation in larger cohorts could establish Accellix as a key instrument for critical care settings.