Measuring host immune response status by simultaneous quantitative measurement of activity of signal transduction pathways that coordinate functional activity of immune cells from innate and adaptive immune system

For many diseases, including cancer, viral infections such as COVID-19, bacterial infections, and auto-immune diseases, the immune response is a major determinant of progression, response to therapy, and clinical outcome. Innate and adaptive immune response are controlled by coordinated activity of multiple immune cell types. The functional activity state of immune cells is determined by cellular signal transduction pathways (STPs). A novel mRNA-based signaling pathway assay platform has been developed to quantitatively measure relevant STP activities in all types of immune cells and mixed immune cell samples for experimental and diagnostic purposes. We generated a STP activity profile, termed Immune-Pathway Activity Profile (I-PAP), for a variety of immune cell types in resting and activated state, and provide a first example for use in patient samples. Methods The technology to measure STP activity has been described for androgen and estrogen receptor, PI3K, MAPK, TGFβ, Notch, NFκB, JAK-STAT1/2, and JAK-STAT3 pathways. STP activity was measured on Affymetrix expression microarray data from preclinical studies containing public data from different types of immune cells, resting/naïve or immune-activated in vitro , to establish I-PAPs. Subsequently data from a clinical study on rheumatoid arthritis were analyzed. Results I-PAPs of naïve/resting and immune-activated CD4+ and CD8+ T cells, T helper cells, B cells, NK cells, monocytes, macrophages, and dendritic cells were established and in agreement with known experimental immunobiology. In whole blood samples of rheumatoid arthritis patients TGFβ pathway activity was increased; JAK-STAT3 pathway activity was selectively increased in female patients. In naïve CD4+ Tregs TGFβ pathway activity was increased, while in memory T effector cells JAK-STAT3 pathway activity tended to increase, suggesting that these immune cell types contributed to whole blood analysis results. Conclusion STP assay technology (currently being converted to qPCR-based assays) makes it possible to directly measure functional activity of cells of the innate and adaptive immune response enabling quantitative assessment of the immune response of an individual patient. Envisioned utility lies in (1) prediction and monitoring of response to immunomodulatory treatments for a variety of immune-mediated diseases, including RA; (2) uncovering novel treatment targets; (3) improvement and standardization of in vitro immunology research and drug development. ### Competing Interest Statement Conflict of interest statement All authors are employees of Philips.