In addition to the amelioration of symptoms and decrease in mortality, many studies observed a significant decrease in the pathology of the gut (35, 36, 39, 41, 48, 56, 59, 64, 67, 72), liver (35, 36, 39, 41, 48, 56, 59, 67), skin (36, 48, 56, 59, 64, 67), lungs (41, 65), and kidneys (41) of patients treated with hMSCs. In conjunction with this reduction in the pathological state, some studies also described a decrease in the serum concentration of local tissue damage biomarkers such as the markers of epithelial damage elafin (71), ccK18 (50), and K18 (50) and the markers of gastrointestinal damage sCK18f (66), Reg3α (71), and CK18 (66, 71). On the other hand, adverse effects observed after the administration of hMSCs included an increase in the rates of pneumonia (47) and infection-related death (49). Additionally, the occurrence of fatal embolism was also found to be significantly associated with the administration of hMSCs in one study (33) and, in another study (70), the reconstitution of both T and B cell function was found to be worsened after hMSCs administration. However, a study conducted by Guo et al. (43) showed that CD3−CD16+56+(NK) and CD3+CD16+56+(NKT) cells and CD3+CD8+ T cells were upregulated in 1–3 months after transplantation when hMSCs were administered, showing that the administration of hMSCs may be important in reducing leukemia relapse after HSCT.