Monocytic HLA-DR expression in intensive care patients: Interest for prognosis and secondary infection prediction

Objectives. To test early measurement of human leukocyte antigen-DR expression on circulating monocytes (mHLA-DR) as prognostic marker, and the trend of mHLA-DR recovery for the prediction of late secondary infection risk in a large intensive care unit population. Design: Prospective, observational study over 16 mos. Setting: Intensive care unit in a tertiary teaching hospital. Inclusion criteria: Simplified Acute Physiology Score II >15, age >18 yrs. Measurements and Main Results: The mHLA-DR was measured by flow cytometry within the first 3 days and twice a week until discharge. We used a logistic regression model for outcome prediction, and a competing risk approach to test the relationship between mHLA-DR recovery (log (mHLA-DR) slope) and incidence of secondary infection. A total of 283 consecutive patients suffering from various pathologies were monitored (Simplified Acute Physiology Score II = 39, Sepsis-related Organ Failure Assessment of 5 on day 0). Early mHLA-DR was decreased in the whole population, however, more deeply in sepsis (p < .0001). Low mHLA-DR was associated with mortality in the whole population (p = .003), as in subgroups (nonseptic, neurologic, and septic), but not when adjusted on Simplified Acute Physiology Score II. In patients with a length of stay of >7 days (n = 70), the lower the slope of mHLA-DR recovery, the higher the incidence of the first secondary infection (adjusted on early mHLA-DR, p = .04). Conclusions: For a given severity, mHLA-DR proved not to a predictive marker of outcome, but a weak trend of mHLA-DR recovery was associated with an increased risk of secondary infection. Monitoring immune functions through mHLA-DR in intensive care unit patients therefore could be useful to identity a high risk of secondary infection. (Crit Care Med 2009; 37: 2746-2752)