MRC1 and Granuloma: Our earlier finding, which revealed that the primary cellular constituents of cardiac granulomas are mature macrophages expressing CD68, CD168, and CD206, and with fewer CD3/CD4/CD8 positive T-cells 5, was supported by the expression of various macrophage-associated genes such as RUNX1, MARCO, CD163, and SPI1 (transcription factor PU.1).