[Low monocytic HLA-DR expression and risk of secondary infection]

Objectives: The aim of this bibliographic review is to evaluate the usefulness of the measurement of HLA-DR expression on circulating monocytes (mHLA-DR) in predicting the development of nosocomial infections and unfavourable outcome in critically ill patients.

Data source: References obtained from the medical database PubMed in English and in French were reviewed. The keywords included separately or in combination were: HLA-DR antigens, sepsis, trauma, injuries, wounds, burns, stroke, pancreatitis, postoperative, prognostic, immunity, monocytic.

Data extraction: Data in selected articles were reviewed, clinical and basic science research relevant information were extracted.

Data synthesis: Low mHLA-DR expression appears as a marker for monocytic dysfunctions and immunosuppression, temporarily present in the majority of critically ill patients admitted to the ICU (sepsis, trauma injuries, postoperative, burns, pancreatitis and stroke). The decrease in mHLA-DR expression is a predictor of septic complications in all these clinical conditions. However, no predictive threshold value could be determined regarding unfavourable outcome.

Conclusion: The monitoring of mHLA-DR expression could be a biomarker to detect ICU patients at high risk of developing secondary nosocomial infections. Those patients could probably benefit of preemptive strategies to prevent these infections.