Retinal autoantibody profile in early age-related macular degeneration: preliminary findings from the Blue Mountains Eye Study

To compare the retinal autoantibody profile in individuals with and without early age-related macular degeneration (AMD) and to determine whether baseline autoantibodies are associated with progression to advanced AMD 5 and 10 years later. Western immunoblotting was used to detect the presence of retinal autoantibodies in the baseline serum of 47 individuals with early AMD and 16 healthy controls from the Blue Mountains Eye Study. Autoantibody isotype, IgG subclass distribution and target antigens in the early AMD group were compared with the control group. The association between baseline autoantibodies and progression to advanced AMD 5 and 10 years later was evaluated using the chi-square test. Retinal autoantibodies were found in a higher proportion of the early AMD group compared with controls (57% vs. 25%, chi(2) = 5.028, P = 0.025). Autoantibodies targeted a range of retinal polypeptides in both AMD cases and controls. The commonest polypeptide antigens occurred between 20-35 kDa and 50-60 kDa. More than one IgG subclass was often present in participants with autoantibodies. Over a 10-year period, 11 participants (23.4%) with early AMD progressed to advanced AMD. No association was found between baseline autoantibodies and the development of advanced AMD over 10 years (chi(2) = 0.16, Fisher's exact P = 0.59). The retinal autoantibody profile in early AMD is complex, both in terms of antigenic targets and immunoglobulin isotypes. Detection of potential disease-associated autoantibodies will require a larger sample size and full characterization of the retinal antigens involved.