Abstract
Purpose: :
To determine whether Chlamydia pneumoniae and complement factors H (FH) and C5 were present in surgically removed choroidal neovascular membranes (CNV) of patients with age-related macular degeneration (AMD). Furthermore, to correlate the findings to associated ophthalmic characteristics.
Methods: :
The study material consisted of 26 CNV membranes of 26 AMD patients with exclusion criteria of prior treatment of the CNV. The excised membranes were embedded in paraffin, and sectioned at 7 µm. Sections were then incubated with monoclonal antibodies CF 2 or RR 402 against the Chlamydia genus and C. pneumoniae, respectively. Complement components C5 and FH were detected using polyclonal antibodies. Additionally, clinically relevant pre- and post-operative data have been analyzed.
Results: :
Eleven membranes showed positive reaction for C. pneumoniae (42%), whereas 15 membranes were negative. All positive membranes were concomitantly positive for CF 2 and RR402, as were all negative membranes concomitantly negative. Staining for FH gave a positive reaction in 13 of 19 membranes (68%). Six membranes of 17 showed a positive reaction for C5 (35%). Eight of the Chlamydia-positive membranes were also positive for at least one factor of the complement system. Patients with C5-positive membranes had significantly larger CNV (14.1 ± 19.8 mm² vs. 9.3 ± 8.7 mm²) and were younger than patients with Factor H positive membranes (mean age 65.4 ± 7.6 years vs. 79.8 ± 7.8 years).
Conclusions: :
C. pneumoniae was detected by immunohistochemistry in nearly half of the studied CNV membranes. The majority of these membranes were also positive for factor(s) of the complement system. The data indicate further a possible connection between chlamydia infection, immune system and retinal degeneration. Additional studies need to be performed to evaluate the significance of this finding in correlation to ARMD pathogenesis.
Keywords: age-related macular degeneration • neovascularization • immunohistochemistry