The data demonstrate that during the progression of viral myocarditis into DCM, IL-17A upregulates the expression of ADAMTS-1 and MMP-2 through different mechanisms, causes an imbalance in MMP2/TIMP-1 expression, increases the degradation of type I and type III collagen and eventually prompts the degradation of the extracellular matrix. Here, IL17A is linked to viral myocarditis.