Detection of Chlamydia and Complement Factors in Neovascular Membranes of Patients with Age-related Macular Degeneration

Abstract

Purpose: To investigate whether Chlamydia pneumoniae and complement factors were present in surgically removed choroidal neovascular membranes (CNV) of patients with age-related macular degeneration (AMD).

Methods: Paraffin sections of 26 CNV were stained for C. pneumoniae or the complement factors H (CFH) and C5, whereas macrophages were identified by positive CD68 staining. Clinical characteristics have been correlated to the immunohistochemical findings.

Results: C. pneumoniae was found in 68% of the investigated membranes, and 88% of these membranes were also positive for CD68. Staining for CFH and C5 gave a positive reaction in 68 and 41% of the membranes, respectively. Patients with C5-positive membranes had significantly larger CNV mean area and were younger than patients with CFH-positive membranes at the operation time point.

Conclusions: Correlations between clinical symptoms and complement factor C5 could be shown. The results strengthen the hypothesis of an involvement of the complement system in AMD.

KEYWORDS::

• Age-related macular degeneration
• Chlamydia pneumoniae
• Choroidal neovascularization
• Complement C5
• Complement factor H

ACKNOWLEDGEMENTS

The authors would like to thank A. Chrenkowa, A. Olac, and A. Duda for their excellent technical assistance, and A. Kappeler and his team for the support in immunohistochemical matters.

Declaration of interest: The study was supported in part by a grant from the Berne University Research Foundation. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.