GZMA and infection: The concurrent increase of IFNγ expression also points towards a cell-mediated immune response in the heart [40] and further, the protease effector molecule granzyme A showed a pronounced increase in expression during the infection with very high expression levels in some fish (one fish having 3100 times upregulation at 10 wpc compared to 4 wpc), indicating a phenotypic profile of a cytotoxic T cell.