CXCL9 and inclusion body myositis: Previous studies in IBM muscle detected CD8+ T cell‐secreted cytokines and chemokines related to IFN‐ɣ genes (CXCL9, CXCL10, CCL5, and CCL18) and others, including TNF, IL7, IL15, IL16, and IL32,1, 26 some of which were also detected in the sera of IBM patients.26