Serum antiretinal antibodies (ARA) in patients with exudative age-related macular degeneration (AMD) treated with transpupillary thermotherapy (TTT) alone and with transpupillary thermotherapy (TTT) combined with injection of triamcinolone acetonide (sTTA) under posterior Tenon’s capsule

Introduction
To assess serum level changes of antiretinal antibodies (ARA) in patients with exudative age-related macular degeneration (AMD), treated with transpupillary thermotherapy (TTT) alone and with TTT combined with injection of triamcinolone acetonide (sTTA) under posterior Tenon’s capsule and to compare the efficacy of TTT and TTT+sTTA. The purpose of the study was also to estimate if serum ARA may act as the biomarker of AMD.

Material and methods
This prospective study comprised 46 patients (46 eyes) with exudative AMD. Patients were assigned into: group I (n = 24) received TTT alone and group II (n = 20) received TTT with sTTA. Follow-up was at 3, 6, 9 and 12 months, when best-corrected visual acuity (BCVA), Amsler grid-test, intraocular pressure (IOP), fluorescein angiography (FA) and central retinal thickness (CRT) by optical coherence tomography (OCT) were assessed. In all patients serum ARA was determined using indirect immunofluorescence (IIF) method on normal monkey retina as antigens substrate and FITC – labelled goat’s anti-human IgA, G, M serum as the secondary antibody.

Results
Baseline serum ARA titres in group I ranged from 1: 40 to 1: 5120 and in group II – 1: 40 to 1: 1280 (p = 0.1). In control group serum ARA was present in 46.4% of sera in titres from 1: 10 to 1: 40. These differences were statistcally significant (p<0.001). Nine fluorescence patterns of ARA were detected by IIF method in both groups of AMD patients, while control sera showed only three types of reaction. Statistically significant correlation was found between CNV size, CRT and serum ARA titres in both groups of patients (p<0.01). In a follow-up period decreasing serum ARA titres were noted, specially for subjects treated with combined therapy, however it was not statistically significant at 3, 6 and 9 months while achieved significance (p<0.01) at month 12. BCVA improvement or stabilization was observed in 64 % of eyes in group I and in 75% – in group II (p = 0.1). No leakage on FA was found in 66.7% and 70% of cases, in group I and II, respectively (p = 0.01). CRT reduction was observed in 50% (group I) and in 70% (group II) of eyes (p = 0.01) at month 12.

Conclusions
Our preliminary observations indicate that serum ARA changes may reflect the activity of CNV in a course of AMD and may act as the biomarker of treatment efficacy. The use of sTTA in conjunction with TTT for CNV in AMD showed a tendency towards lower serum ARA titres and better functional results after treatment as compared with eyes treated with TTT alone.