Infection induced by gram-negative and gram-positive bacteria results in an enormous host immune response that has two possible outcomes. One in which the organisms are eliminated and the host returns to normal, and the other in which the battle between host and invader leads to disregulation of innate immunity and the development of septic shock. In inflammatory diseases such as septic shock, gene expression patterns of diverse cell types contribute to the pathology. We are currently in the process of monitoring gene expression during different states of infection using cDNA microarrays. mRNA from cultured human monocytic THP-1 cells and isolated peripheral blood leukocytes stimulated with the endotoxin LPS or gram-negative bacteria are analysed for this study.

Preliminary microarray data support the finding that inflammation is associated with the expression of many different cytokines, such as interleukin-1, TNF, interleukin-8 and an abundance of chemokines. Current efforts aim to identify signature expression patterns associated with different states of infection.