Measurement of serum and vitreous concentrations of anti-type II collagen antibody in diabetic retinopathy

Atsuko Nakaizumi,1 Masanori Fukumoto,1 Teruyo Kida,1 Hiroyuki Suzuki,1 Seita Morishita,1 Takaki Satou,1 Hidehiro Oku,1 Tsunehiko Ikeda,1 Kimitoshi Nakamura2 1Department of Ophthalmology, Osaka Medical College, Takatsuki City, Osaka, 2Nakamura Eye Clinic, Nagano, Japan Background: Autoimmune mechanisms have been postulated as a cause of diabetic retinopathy (DR), as several autoantibodies have reportedly been detected in the serum of DR patients. In this present study, we measured serum and vitreous levels of anti-type II collagen (anti-II-C) antibodies in DR patients and investigated their association with the mechanism of development of DR.Patients and methods: Blood samples were obtained from patients with proliferative DR and from patients with diabetic macular edema who underwent vitrectomy at Osaka Medical College, Takatsuki City, Osaka, Japan. Diabetic patients without DR were also included. The control group consisted of age- and sex-matched patients with noninflammatory eye diseases who underwent eye surgery for retinal detachment or for cataracts. The levels of anti-II-C immunoglobulin (Ig)G antibody in the vitreous and serum were measured using a human/monkey anti-II-C IgG assay kit.Results: The serum levels of anti-II-C IgG antibody were significantly higher in the DR patients than in the patients with noninflammatory eye disease (56.8±33.8 units/mL versus 30.5±13.7 units/mL, respectively; P