Fig. 5: In vitro and ex vivo efficacy of JAK1/JAK2 inhibition.

a EBV-B cells from HCs and from patient A1 were stimulated with IFN-γ (10³IU/ml for 1 h, left) and IL-2 (10⁴IU/ml for 2 h, right) in the presence or absence of ruxolitinib (Ruxo). Lysates were incubated with the indicated anti-P-STAT and anti-STAT antibodies, or anti-actin antibodies as a loading control. Data are representative of two independent experiments. b EBV-B cells from controls (CT) and from patient A1 were preincubated or not with ruxolitinib for 1 h, and stimulated for 6 h with IFN-γ. mRNA expression of the STAT1-regulated gene CXCL9 was determined in a quantitative RT-PCR assay. Results represent the fold-increased expression between stimulated and unstimulated states and are normalized to endogeneous GAPDH. Experiment performed once. c Effect of in vitro treatment with ruxolitinib on T-cell proliferation. T-cell blasts from patient C1 were stimulated with IL-2 (100 IU/ml) or anti-CD3/CD28 beads, in the presence or absence of ruxolitinib. The panel shows the proliferation of all T cells (CD3⁺). Data are representative of two independent experiments with cells from five patients (A1, A2, B1, B2, and C1). d Primary monocytes from healthy control (CT, filled line) and E1 before (blue line) and under treatment by 2 mg (orange line) or 4 mg (red line) of baricitinib were stimulated with IFN-γ for 15 min and STAT1 phosphorylation (P-STAT1) was determined by intracelular flow cytometry.