Initial RNA expression in human monocytes after multiple injury: a screening pilot study on potentially trauma-sensitive factors by using the microarray-technique.

BACKGROUND

Pathological affection of the immune system is one of the initiating mechanisms for the induction of multiple organ failure (MOF) in patients suffering from multiple injuries. Potential responsible intracellular mechanisms such as initial monocyte mRNA expression of specific mediators remain poorly studied, so far. Hence, we applied the microarray technique for screening of a wide variety of genes in circulating monocytes of multiple injured patients and compare the molecular results to the clinical course of the patients (MOF-score).

METHODS

In our prospective pilot study 6 patients were enclosed presenting with blunt multiple injuries (Injury Severity Score 16 to 57 points). Monocytes were isolated out of sequentially drawn samples (6, 12, 24 and 48 hours after trauma) using magnetic cell sorting (CD14) and a human microarray system was used (Atlas stress 1.2, Clontech, 1176 genes). Alterations in the sequential samples were identified by calculating ratios to baseline levels on admission and cluster analysis was performed (Spotfire Decision).

RESULTS

Only 86 (ca.5%) genes displayed an obvious signal. The house-keeping genes clustered well together in all patients in contrast to a substantial inter-individual variability of the other signal giving genes. No mediator burst of the classical pro- or anti-inflammatory cascade were detected.

CONCLUSION

We demonstrate for the first time a screening analysis of mRNA expression patterns in circulating monocytes of multiple injured patients indicating that only very few genes appeared to be influenced by the traumatic event. So far, no correlation to the severity of trauma or MOF could be detected.