Considering the pathogenic role for cardiac IFNγ+ CD4+ T cells in UCM and the elevated abundance of K. pneumoniae in CKD, we hypothesized that the aberrant gut microbiota, K. pneumoniae in particular, would contribute to development of UCM via the induction of heart-infiltrating IFNγ+ CD4+ T cells expansion. Here, CD4 is linked to chronic kidney disease.