IL6 and major depressive disorder: Consistent with the role of IL-6 in depression, the results of the study by Hannestad et al. showed that anti-depressant agents such as SSRIs can reduce serum level of inflammatory cytokine, IL-6 and TNF-α.33 Several studies have showed that increased level of IL-6 can affect the occurrence of complications such as infection, aGVHD, VOD, and rate of hematological recovery.34,35 So, depression can also affect the outcome and survival after transplantation through the increased serum level of pro-inflammatory cytokine such as IL-6.