Expression of toll-like receptors 2 and 4 is upregulated during hospital admission in traumatic patients: lack of correlation with blunted innate immune responses.
BACKGROUND
There are reports with conflicting results on the expression of toll-like receptors (TLRs) in trauma patients. In addition, these studies analyzed TLR expression only at patients' hospital admission but not later when complications usually arise.


OBJECTIVE
To analyze the surface expression of TLR2 and TLR4 on circulating monocytes from trauma patients during the hospitalization period and to correlate this with cytokine production after stimulation with TLR2 and TLR4 agonists. The phagocytic capacity of monocytes was analyzed at the same time points of TLR expression analysis; to correlate these molecular findings with the presence or absence of infections.


METHODS
Prospective and observational study from June 2005 to June 2007. In all analysis, a control group composed of healthy subjects was included.


RESULTS
We studied 70 trauma patients admitted to the intensive care unit (ICU) of a tertiary hospital, and 30 healthy volunteers. Blood samples were collected at hospital admission, on day 7 and 14. Forty-four patients (63%) developed at least one episode of infection. Monocytes from trauma patients expressed higher levels of TLR2 and TLR4 than monocytes from control subjects at all time points. Expression of TLR2 and TLR4 in monocytes from those patients who developed any infection was significantly lower than in those patients without infection but still significantly higher than in control subjects. Cellular responses to TLR4 agonist were impaired. Monocytes from traumatic patients phagocytosized less efficiently than monocytes from control subjects.


CONCLUSIONS
These results indicate that trauma patients present a dysregulation of the innate immune system that persists during the first 14 days after hospital admission.
Pérez-Bárcena
Jon
J
Surgical Intensive Care Unit, Son Dureta University Hospital, Palma de Mallorca, Spain. juan.perez@ssib.es
Regueiro
Verónica
V
Crespí
Catalina
C
Pierola
Javier
J
Oliver
Antonio
A
Llompart-Pou
Juan A
JA
Ayestarán
Jose I
JI
Raurich
Joan M
JM
Marsé
Pedro
P
Ibáñez
Jorge
J
Bengoechea
José A
JA
D000328:Adult; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D008297:Male; D010343:Patient Admission; D011446:Prospective Studies; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis*; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis*; D015854:Up-Regulation; D014947:Wounds and Injuries / Q000276:immunology*
D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4