For instance, in the rat model of myocardial infarction, beta-2 microglobulin (B2M) negative UC-MSC lost the ability to induce CD8+ T cell immune rejection response by the B2M-UCMSC exosomes/miR-24/Bcl-2-like protein 11 (Bim) pathway after B2M-UCMSC injection to the heart (43). This evidence concerns the gene B2M and myocardial infarction.