Abstract
Purpose :
Diabetic retinopathy (DR) often leads to severe visual impairment, although serum biomarkers remains ill-defined. We identified a serum autoantibody for retinal antigens and to quantify its titer in diabetic retinopathy (DR).
Methods :
Serum specimens were obtained from diabetic patients without DR (DM group) and DR patients (DR group). Lysates of porcine retinas were immunoprecipiated with IgG from DR patients and were subsequently applied to mass spectrometry in order to identify the autoantigen. The titers of IgG in the DM or DR group were quantified using enzyme-linked immunosorbent assay (ELISA).
Results :
The immunoprecipitation and subsequent mass spectrometry allowed us to identify a novel autoantigen, citrin, which is a mitochondrial aspartate glutamate carrier. It might correspond to approximately 75 kDa band in the screening using Western blot. The serum titer of anti-citrin antibody was significantly higher in the DR group than in the DM group (0.712±0.314[A.U.] vs. 0.530±0.150[A.U.]; P=0.007). In contrast, there were no differences in the titer between individual DR severity grades. Multivariate logistic regression analyses revealed that diabetes duration and anti-citrin antibody were related to DR (odds ratio 1.085[95% CI, 1.024-1.149], P=0.005; odds ratio 17.013[95% CI 2.646-109.373], P=0.003). additionally, the area under the receiver operating characteristic (ROC) curve was 0.658(95% CI, 0.568-0.749; P=0.007).
Conclusions :
We identified anti-citrin antibody as a novel autoantibody in DR serum and statistical analyses suggested that this autoantibody is a novel diagnostic biomarker of DR, independent of diabetes duration.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.