Inhibition of IRAK4 with inhibitor CA-4948 alleviates disease burden. (A) IRAK4 and IL1B messenger RNA expression from the WashU cohort CD34⁺ RNA sequencing encompassing 90 primary samples representative of PV (n = 6), ET (n = 9), MF (n = 30), secondary AML (sAML, n = 34), and NBM (n = 11). Statistics assessed by 2-tailed Student t test. Pearson correlation noted. (B) Relative colony numbers after IRAK4 knockout from additional unique patients with MPN (n = 13) and NBM donors (n = 3). Statistics were assessed by 2-tailed Student t test comparing MPN and NBM after taking an average of each 3 biological replicates per sample. (C) Relative colony numbers after CA-4948 treatment from unique patients with MPN (n = 7-14 across various doses) and NBM donors (n = 3-5). Statistics were assessed by 2-tailed Student t test comparing MPN and NBM after taking an average of each 3 biological replicates per sample. (D-F) Leukemic engraftment in the PB, BM at end point, and normalized spleen weights in the (D) 298191 pMF (n = 4 mice per group), (E) 995962 MF pET (n = 4 mice per group), and (F) NBM3 (n = 5 mice per group) PDX models. PB human CD45⁺ (hCD45⁺) cells statistics assessed by 2-way ANOVA. BM hCD45⁺ and normalized spleen weight statistics assessed by 2-tailed Student t test. (G) qRT-PCR of genes of interest after 6 hours IL-1β (10 ng/mL) and CA-4948 (2 μM) treatment ex vivo in unique CD14⁺ MF monocytes (n = 6-9 patients). (H) Dimensionality plot of cell populations from 652021 MF pET from CyTOF analysis. (I) CD14⁺ monocyte IL-8 expression after ex vivo treatment with IL-1β (10 ng/mL) treatment and CA-4948 (2 μM) by CyTOF analysis. (J) Expression heat map of proinflammatory effectors in CD14⁺ monocytes in additional MPN and NBM samples. Median arcsinh signals are presented and were normalize to the control treatment group.