TBX21 and cardiomyopathy: The increased constitutive levels of CD4+pSTAT1+, CD4+pSTAT3+, and CD4+pSTAT5+ or the increased constitutive gene expression of these transcription factors compensated for the signal transduction defects found in cardiomyopathy patients; this was supported by the decreased gene expression of downstream STAT genes coding for T-bet (TBX21) and eomesodermin (EOMES), which are expressed in T cells and mediate T-cell differentiation and several T-cell functions, in response to IL-27 [58].