CXCL9 and inclusion body myositis: The top 7 differentially overexpressed genes in IBM also included CD27 (a co-stimulatory protein on T cells), CXCR3 (a TH1/TC1 marker), IL2RG (a common cytokine receptor subunit), the IFN-II-inducible chemokine CXCL9, and IFNG.