PTGDR2 and myocardial infarction: CRTH2 deficiency retarded T‐cell infiltration (CD4+) in peri‐infarct zones (Appendix Fig S5A and B) and reduced the expression of Th2 cytokines (IL‐4, IL‐5, and IL‐13) in the inflamed hearts after MI (Appendix Fig S5C).