Host Response to Infection by Direct Analysis of Leukocyte Single Cell-type Gene Expression/transcript Abundance, Direct LS-TA

DIRECT LS-TA is a ratio-based biomarker (RBB) for blood gene expression analysis which can be performed in commonly available equipments (e.g. qPCR or digital PCR machines). Using the ratio of TA of prior defined numerator gene and denominator gene, this RBB can quantify gene expression of the specified constitutional single cell-type (e.g. monocytes and granulocytes) inside a cell-mixture sample of Whole blood. DIRECT LS-TA was a method pioneered by the PI \[Tang 2017, https://patents.google.com/patent/US9589099B2/\]. And it has been developed for quantification of early B cell response after vaccination \[DOI: 10.3390/genes12070971\]. Recently, the method is used to develop host response biomarkers after infection to differentiate the type of pathogens (such as viral, bacterial or active tuberculosis). Numerator and denominator genes have been identified by using public gene expression datasets for monocytes and granulocytes. Diagnostic performance was good using these public data. Therefore, these RBBs will be applied in these retrospective samples to evaluate and compare their diagnostic (triage) performance of febrile patients into different pathogen etiologies.