CXCL9 and Myalgia: This dissociation between IFN-γ and IFN-γ-induced chemokines was described in other diseases such as patients of polymyalgia rheumatica showed that serum levels CXCL9 and CXCL10 were elevated although the levels of IFN-γ and TNF-α were not increased.37 Therefore, it is not well established whether changes in serum chemokines reflect infiltration of immune cells in the myocardium and what is the exact part of macrophage versus CD8+ T-cell involvement in the production of the serum CXCL9 and 10.