Figure 8. Comparison between patient blood samples and in vitro-infected monocytes.

Monocytes from healthy donors were stimulated with O. tsutsugamushi for 8 hours, and Agilent microarrays were used to detect the differential expression of 2,015 genes that corresponded to 1,606 genes in the Illumina microarrays. Among these genes, 184 (250 probes) were altered in patients with scrub typhus with a p value less than 0.01. The hierarchical clustering of these genes demonstrates that the resulting transcriptional signature was specific to scrub typhus.