Abstract
Purpose: :
In previous studies alterations in IgG and IgM autoantibody patterns have been shown. Hitherto, Immunoglobulin G subclass antibody patterns have not been analyzed. To gain further insight we analyzed the IgG1-4 antibody reactivities in patients with primary open-angle glaucoma (POAG) and healthy subjects (CO). For this purpose we used an advanced protein microarray approach.
Methods: :
Sera of POAG-patients (n=19) and CO subjects (n=19) were used for antibody analysis. Protein microarrays were prepared by spotting 45 antigens onto nitrocellulose-coated slides. These were incubated with diluted sera (1:250) and subsequently with anti-IgG1-4 antibodies. Antibody-antigen-reactions were visualized with a fluorescence labeled tertiary antibody. Emitted fluorescence signals were digitized and spot intensities were compared using diverse statistical techniques (ANOVA, Tukey-Test).
Results: :
Overall we could detect strong immune response to IgG1 and weak response to IgG4. Comparison of subclasses between study groups showed changes in general immunoreactivity distribution (e.g. IgG1: 41% POAG vs 36% CO; IgG3: 25% POAG vs 30% CO). For 24 antigens, e.g. Caspase 3 (P≤0.02) or γ-Synuclein (P≤0.04), significant differences in IgG-subclass autoantibody patterns between study groups were found. Both increased autoantibody reactivities (e.g. anti-NT 3) as well as down-regulations (e.g. anti-HSP 70) appeared in glaucoma group (each with P≤0.05). Only 7 (29%) of these antigens showed differences in reactivity in several subclasses, with none showing differences in all subclasses. The remaining 17 autoreactivity patterns were different in only one subclass (9xIgG1, 2xIgG2, 3xIgG3, 3xIgG4), e.g. anti-VEGF IgG3 (P≤0.02) and anti-NSE IgG4 (P≤0.04).
Conclusions: :
For the first time Immunoglobulin G subclass autoantibody reactivitites in glaucoma patients were analyzed. We could show that the immunoreactivites against specific antigens differ according to particular IgG subclasses. Strong immune response to IgG1/IgG3 and majority of significant group differences in subclass 1 may be a hint of activation of complement cascade in the course of the disease. These findings are further indications for a possible involvement of autoimmunity in glaucoma pathogenesis.
Keywords: proteomics • immunomodulation/immunoregulation