Chemokines: A novel chronic GVHD target

In this issue of Blood, Du et al demonstrate that not only is chemokine (C-C motif) ligand 15 (CCL15) a diagnostic and prognostic biomarker in patient samples for chronic graft-versus-host disease (GVHD), but antibody inhibition of its homolog, CCL9, reverses established lung GVHD in a mouse model.¹ The median CCL15 concentration was significantly higher in samples from patients with chronic GVHD compared with no chronic-GVHD controls (P 5 .0125), which may aid in diagnosis. Importantly, CCL15 also had prognostic value. Patients with chronic GVHD who have higher than median CCL15 concentrations were at threefold higher risk for nonrelapse mortality than patients with below median CCL15 concentrations.