Alternations of surface antigens on leukocytes after severe injury: correlation with infectious complications

To investigate the alternations of surface antigens of leukocytes after severe injury and the correlation with clinical outcome.

Emergency Department and Intensive Care Unit of a university hospital.

Patients with severe trauma (injury severity score > 16) were enrolled. Those who were transferred or had critical injuries were excluded.

Polymorphonuclear cells (PMN) and mononuclear cells (MN) were isolated from patients on the 1st, 3rd and 7th day following injury. The mean fluorescent expressions of CD11b and CD16 of PMN, and CD25 of MN were measured and compared with those obtained from paralleled controls. Sixteen injured patients were included. The CD11b expressions of PMN increased on the 1st day and were still high on the 7th day. The CD16 expressions decreased on the 1st day and CD25 decreased on the 3rd day; both were still low on the 7th day. Six patients developed infectious complications. CD11b expression remained high and CD16 expression remained low on three measurements of the infectious patients, whereas both expressions recovered on the last measurement of non-infectious patients. CD25 expression remained low in both groups. Three infectious patients with pneumonia died from multiple organ failure.

Phenotypic alternations of leukocytes develop early after severe injury. The alternations may represent a state of activation of PMN and subsequent suppression of IL-2 related immunity. Persistent activation of PMN with enhanced CD11b and attenuated CD16 expression indicates the development of infectious complications and a poor prognosis can be anticipated if the infectious sites can not be controlled early.