Abstract
Purpose::
Autoimmune anti-retinal antibodies (ARAs) are postulated to play an important role in Cancer Associated Retinopathy (CAR), Melanoma Associated Retinopathy (MAR), and CAR-like syndrome, which includes retinitis pigmentosa (RP) patients with an autoimmune exacerbation of their retinopathy from anti-retinal antibodies. Carbonic anhydrase II (CAII) has been implicated as a causative antigen in our and other investigators’ work. We have initiated investigations of CAII as reported below.
Methods::
Serum samples from 59 patients diagnosed with RP were screened for antiretinal proteins activity by western blotting. Enzyme linked immunosorbent assay (ELISA) were performed to evaluate the titer of anti-CAII antibodies. Patient records were reviewed to ascertain if there was a specific clinical association with CAII antibodies.
Results::
We found ~30 kDa band in 23 (39%) out of 59 patients’ sera. As compared with normal controls (0.08±0.06), there was no significant difference in the CA II antibody titer in RP patients (0.11±0.15) (p=0.52). However, 9 (39%) out of these 23 patients show high titers (A405 > 0.110) of antibodies to CAII (0.24±0.13). No clear associated was seen between antibodies to CAII and electroretinographic dysfunction, presence of cystoid edema, retinal wrinkling, or unique visual field alterations in these 9 patients.
Conclusions::
ARAs at 30 kDa are relatively common when testing for antibody activity in the group of RP patients who have circulating ARAs. We found that 9 out of 23 (39%) patients with high titer CAII antibody but no specific clinical association. This suggests that CA II antibody in RP patients may be less significant diagnostically. The pathogenetic role of anti-CA II antibody remains uncertain.
Keywords: retinal degenerations: hereditary