Elevated serum immunoglobulin G titers against chlamydia pneumoniae in primary open-angle glaucoma patients without systemic disease

Purpose: To determine if Chlamydia pneumoniae infection is associated with primary open-angle glaucoma (POAG). Patients and Methods: Consecutive patients with newly diagnosed primary POAG attending the Glaucoma clinic of Keio University Hospital between June 2007 and January 2008 were considered for inclusion in this prospective case-control study. Forty consecutive POAG patients and 41 normal healthy individuals as a control population met the inclusion criteria. The exclusion criteria for both groups were; taking steroids or immunosuppressive agents, smoking, and history of any acute or chronic systemic disease including stroke, heart attack, diabetes mellitus, hypertension, asthma, and autoimmune diseases. The serum was analyzed for C. pneumoniae and C. trachomatis immunoglobulin G antibody titers by enzyme-linked immunosorbent assay. Seroactivity to each antigen between case and control groups was evaluated by Mann-Whitney U test. Results: The age, male/female ratio, and intraocular pressure of the cases and control groups were not significantly different. Immunoglobulin G titers for C. pneuemoniae was significantly higher in patients with POAG than in controls (P=0.009). The titers to C. trachomatis were not significantly different between the 2 groups (P=0.99). Conclusion: The results suggest that higher C. pneumoniae titers are associated with POAG. If confirmed, this may indicate either a common factor that causes susceptibilities to both glaucoma and C. pneumoniae infection or that C. pneumoniae may be a causal factor for developing POAG.