Inflammatory Reaction in Acute Retinal Artery Occlusion: Cytokine Levels in Aqueous Humor and Serum

Purpose: To investigate the role of inflammation in acute retinal artery occlusion (RAO). Methods: Levels of interleukin (IL)-6, IL-8, and tumor necrosis factor alpha (TNF-α) were measured in serum (n = 14) and aqueous humor (AqH) (n = 8) samples from patients with RAO. Findings were compared with 24 age- and disease-matched patients, 10 healthy subjects (serum), and 16 patients undergoing cataract surgery (AqH). Results: Patients who arrived early (within 4-6 hours of occlusion) had higher serum IL-8 and IL-6 levels than controls; the IL-6 level in the AqH was lower than that of controls, while the IL-8 level was higher. In seven patients for whom both serum and AqH samples were available, serum IL-6 levels were higher than their corresponding AqH levels in most patients arriving within 10 hours of occlusion, and AqH IL-8 levels were higher than the corresponding serum levels in all but one. TNF-α levels were consistently higher in the serum than in the AqH at all time points. Conclusions: Serum IL-8 and IL-6 and AqH IL-8 are elevated immediately following acute RAO. The early local suppression of IL-6 may be related to ocular immune mechanisms.