Elevated serum IL-8 levels are associated with disease activity in idiopathic intermediate uveitis

Aim-To find a laboratory indicator for systemic involvement in intermediate uveitis. Methods-Interleukin 8 (IL-8) and C reactive protein (CRP) serum levels were measured in patients with idiopathic intermediate uveitis (n=61), uveitis controls (n=143), and normal controls (n=29). The records of those with intermediate uveitis were reviewed with the emphasis on disease activity and severity as characterised by the presence of cystoid macular oedema, vitreous exudates or snowbank formation, papillitis, and periphlebitis. Results-Increased serum IL-8 (greater than or equal to 20 pg/ mi) was found in 27 out of 61 patients with intermediate uveitis (p< 0.01), 12 of 27 patients with sarcoid uveitis (p<0.05), in 19 of 30 patients with HLA-B27 associated acute anterior uveitis (p<0.05), and in five of 29 healthy controls. Raised IL-8 levels in intermediate uveitis were significantly associated with active disease (p<0.001) and the presence of vitreous exudates (p<0.001), papillitis, and periphlebitis (p<0.01). Elevated CRP levels were found in 12 of the 143 uveitis controls but in none of the intermediate uveitis patients or normal controls. During follow up an associated systemic disease was more frequently noticed in patients with an elevated serum IL-8 at entry into the study. Conclusions-Elevated IL-8 serum levels were found in patients with active intermediate uveitis of unknown origin. An elevated IL-8 level seems to predispose the patient to a later development of associated systemic disease.