Human sera obtained from patients with cataract killed lens epithelial cells in culture

Purpose: The broad goal of this study is to assess the importance of autoimmunity in the formation of human cataract. Methods: Patients (N=365) were examined once using LOCSIII. Serum was analyzed for antibody to lens antigens using ELISA and protein blot analysis against human central lens epithelial cell antigens. A subset of these serum samples was analyzed for toxicity to mouse and human lens epithelial cells in vitro. Results: All patients had detectable levels of anti-lens antibody. There was no association between the antibody level and the type or LOCSIII grade for any type of cataract. There was a significant association between the LOCSIII grade of cortical opacification and the presence of a band at approximately 21 kDa on the immune blot. All patients had detectable levels of anti-lens antibody. Ninety six percent of sera from cataractous patients (147/153), and 21 percent of sera from non-cataract individuals (9/43) killed mouse lens epithelial cells in culture. A majority of sera from cataract patients killed 60-100% of mouse lens epithelial cells, and the sera from non-cataract patients killed 0-10% of the lens cells. To isolate the cidal factors, we fractionated sera with high cidal potency by molecular sieve and affinity column chromatographies and found that they were immunoglobulins (IgG and/or IgM). Conclusions: There is also a strong association between the presence of age-related cataract and the cytotoxicity of serum to lens epithelial cells. The cytotoxic antibodies were either IgG or IgM.