To cater for diverse immune disorders and to augment their therapeutic efficacy, priming and purification of MSC may be required196 as there are marked differences in gene expression of therapeutically effective and ineffective MSC clones, as demonstrated by Lee et al197 Among the genes expressed by effective clones, endothelin-1(EDN-1) significantly increased the efficacy of human UC-MSC against myocardial infarction. The gene discussed is EDN1; the disease is myocardial infarction.