Gene expression pattern in human monocytes as a surrogate marker for systemic inflammatory response syndrome (SIRS)

Systemic inflammatory response syndrome (SIRS) is a mild inflammatory episode which, in a minority of patients, may deteriorate into septic shock. In the mouse, injection of bacteria or bacterial endotoxin induces systemic inflammation through the activation of blood monocytes, which leads to lethal shock. A number of intervention strategies have been shown to prevent progression to shock in mouse model systems. However, recent clinical trials of a number of these therapeutic strategies in patients have been uniformly disappointing. In contrast to the situation in the mouse models, there may be many different ways to initiate systemic inflammation in patients and not all of them need necessarily involve activation of blood monocytes. If there is no unifying mechanism behind the induction of systemic inflammation in patients and no common rules governing its development, then it is unlikely that generally applicable therapeutic strategies will be found that can prevent progression into shock.

We used differential display to compare gene expression patterns in monocytes of recent-admission multi-trauma patients with clinically diagnosed SIRS to the patterns in monocytes of healthy controls.

Of seven differentially displayed bands that were recovered and sequenced, five were associated with SIRS and two were preferentially expressed in the monocytes of healthy controls.

The data show that monocytes of SIRS patients are in an activation state that is different from that of monocytes from the healthy controls, that monocytes from many individual patients share similar patterns of differentially expressed sequences, and that by this criterion, the multi-trauma SIRS patients are a remarkably coherent group.