Immunosuppressive acidic protein in intraocular fluids

The levels of immunosuppressive acidic protein (IAP) in the vitreous fluid or the aqueous humor were measured in patients with ocular diseases. Undiluted samples of vitreous humor were obtained during pars plana vitrectomy in patients with uveitis, proliferative diabetic retinopathy, and premacular fibrosis. In patients with intraocular tumors, vitreous samples were aspirated after enucleation. Aqueous humor was aspirated during cataract surgery, and levels of IAP were measured in patients with secondary cataract due to uveitis and senile cataract. Single radial immunodiffusion assay was used to quantify IAP levels. To determine the intraocular synthesis of IAP, we calculated the percentage of IAP in patients with uveitis. Patients with uveitis, tumors, and diabetic retinopathy had significantly higher levels of vitreous IAP than patients with premacular fibrosis. The percentage of vitreous IAP was higher in patients with uveitis than in those with tumors and diabetic retinopathy. Patients with uveitis also had markedly higher aqueous IAP levels than patients with senile cataract. In one patient with Behçet's disease, the IAP level was higher in the active stage than in the inactive stage. Our results suggest that immunosuppressive acidic protein could be produced in the eye and that it might modulate intraocular inflammatory processes.