Main proinflammatory cytokines/chemokines increased in the vitreous fluid of diabetic patients (see text for details). Most of them participate also in the angiogenic process, which is essential for developing PDR. Anti-inflammatory/antiangiogenic cytokines also exist in the vitreous fluid of diabetic patients, but their concentration is not sufficient to counterbalance the inflammatory/angiogenic effect of proinflammatory cytokines.