CXCL9 and hemophagocytic syndrome: Some markers like soluble IL2 receptor/ferritin, interferon (IFN)-inducible protein 10/CXCL10, and monokine-induced by IFN-γ/CXCL9 have been proposed to aid in diagnosing lymphoma-associated HLH (LA-HLH), but their accuracy lacks prospective validation [7–9].