ALTERATION OF COMPLEMENT REGULATORY PROTEINS (CREG) AFTER MULTIPLE-INJURY IN HUMANS

Abstract

After severe injury or during sepsis, complement as a vital part of the body's immune system is excessively activated and uncontrolled. However, protection against complement-mediated tissue destruction is provided by various soluble and membrane-bound regulatory proteins (Creg). So far, little is known about the cellular profile of the inhibitory Creg after multiple injury. Therefore, the expression of the most relevant Creg was investigated by flowcytometry on neutrophils, monocytes and lymphocytes obtained from either healthy volunteers (n = 10) or age-matched multiple-injured patients (n = 6; injury severity score ISS > 18) at the time of admission (emergency room) and 4, 12, 24, 120 und 240 h after trauma. There was a significantly altered expression profile of CD35 (complement receptor 1, CR1), CD46 (membrane co-factor protein, MCP), CD55 (decay accelerating factor, DAF) and CD59 (MAC inhibitor) in neutrophils, monocytes and lymphocytes. Whereas some of them showed a cell-type dependent reverse expression pattern, others showed a similar cellular expression pattern, indicating different regulation of Creg. The study provides first data on leukocytes from humans after multiple injury showing changes of the Creg expression being associated with multiple injury. Ongoing studies have to elucidate the role of the Creg in the uncontrolled systemic inflammatory response after multiple-injury.