IL6 and proliferative diabetic retinopathy: Among those cytokines, the frequently reported cytokines such as TNF-α [25], IL-6 [7, 26], and TGF-β [27] were compared between our study and proliferative diabetic retinopathy, and the expressions of the three cytokines in proliferative diabetic retinopathy were found times higher as compared with those in MH/ERM.