CXCR5 and retinal degeneration: Recently, we showed that aged CXCR5 knockout mice (CXCR5−/−) develop retinal degeneration (RD) (22) with pathophysiological changes, such as disruption of photoreceptors, upregulation of TNFα with the presence of apoptotic cells in the retina, and loss of ZO-1 indicative of impaired blood-retinal barrier function.