Convergent Multistage Evidence Implicates the CCR2-Artemin Immune-Inflammation Axis in Acute Myeloid Leukemia.

BACKGROUND: The immune system and inflammatory proteins influence hematologic malignancies, but causal links with immune cell phenotypes are unclear. METHODS: We applied a prespecified, multistage workflow: two-sample and multivariable Mendelian randomization (MVMR; 731 immune traits across 12 hematologic cancers), two-step mediation Mendelian randomization (MR) of 91 circulating inflammatory proteins, MAGMA/FUMA gene and pathway enrichment, and external validation with trait-specific genetic risk scores (GRSs) in UK Biobank (UKB). We then performed CCR2 perturbation assays in human monocytic leukemia cell line (THP-1) and immortalized bone marrow-derived macrophage (IBMDM) cells with artemin (ARTN) mRNA readouts and examined proteomic correlations for ARTN using the Olink inflammatory panel. RESULTS: Eight immune phenotypes showed FDR-significant causal associations with malignancy, seven of which remained independent in MVMR. In acute myeloid leukemia (AML), CCR2 on CD62L (+) myeloid dendritic cells (DCs) was associated with lower risk, whereas BAFF-R and CD19 on transitional B cells were associated with higher risk, CD19 on IgD(-)CD38^dim B cells was associated with chronic myeloid leukemia (CML), and HLA-DR(+) NK cells were protective in non-Hodgkin lymphoma (NHL). Mediation MR identified three protein mediators-CD40L, IL-33, and ARTN, with ARTN mediating the CCR2-AML association. GRS analyses reproduced risk directions, most prominently the protective CCR2-AML association. In THP-1 and IBMDM models, CCR2 inhibition or knockdown increased ARTN mRNA expression, functionally supporting a CCR2→ARTN regulatory relationship. Proteomic correlations positioned ARTN with immune-metabolic proteins (CLEC6A, SIGLEC6, NPC2, and MTHFD2). Pathway analyses highlighted membrane-proximal processes (external plasma membrane and IgG binding) and a 16p11.2 signal. CONCLUSION: This integrative analysis identified CCR2-ARTN as a mechanistically supported immune-inflammation axis contributing to AML risk, offering a potential therapeutic target and warrants direct validation in primary CD62L (+) myeloid DCs.