Finally, the data from previous studies are not readily comparable, owing to differences, from one study to another, in the values studied (mainly ‘percentages considering of positive monocytes’ or ‘mean fluorescence intensity’), which are generally specific for a given laboratory and therefore defy comparability on a wider scale. The European protocol now recommends expression of the results as numbers of antibodies per cell, a recommendation that will facilitate comparison of data obtained by different laboratories.The present study has a number of limitations. First, it is a single-center study. The findings clearly need to be confirmed by a multicenter study. Second, the study enrolled only 105 patients. Though relatively small, the series was very homogeneous in terms of severity and also highly representative of the trauma patient population commonly encountered.
Finally, mHLA-DR expression was measured every 2 days after trauma. However, the mean onset of infection was on day 4; in some patients, this limited the amount of analyzable mHLA-DR expression data available before day 4. In subsequent studies, follow-up of patients should consist of daily monitoring during the early post-trauma period. Indeed, one potentially interesting objective of a future study would be an assessment of the usefulness of daily mHLA-DR measurements to detect patients at an increased risk of infection. To pre-empt development of infection, clinicians could give these patients prophylactic treatment, such as antibiotics [48], immunostimulant by interferon-gamma [62], or granulocyte-macrophage colony-stimulating factor, as used in septic shock [35].
ConclusionsTrauma induces a temporary, relative immunosuppression characterized by diminished mHLA-DR expression. The pattern of progression of mHLA-DR expression over time appears to be a more useful indicator of increased risk of infection than the actual levels of mHLA-DR expression at given points in time. Patients in whom recovery of mHLA-DR expression begins after days 1 Carfilzomib and 2 are likely to have an uneventful outcome, whereas those with persistently lower levels of mHLA-DR expression are more likely to suffer infection. Large, multicenter studies are needed to confirm these promising results.Key messages? Severe trauma patients present with a transient immunosuppression with decreased mHLA-DR expression.? The lack of mHLA-DR recovery between days 3 and 4 and days 1 and 2 is associated with sepsis.? After adjustment for classic confounding risk factors, the lack of mHLA-DR recovery was the sole factor independently and significantly associated with the development of sepsis.