Antibodies to chlamydial lipopolysaccharides in unstable angina pectoris

Patients with coronary artery disease frequently have elevated antibody tit ers against Chlamydia pneumoniae, but whether antichlamydial antibody titer s are correlated with prognosis in unstable angina remains unclear. We ther efore investigated the sera of 1,096 patients with unstable angina regardin g immunoglobulin (Ig) IgG, IgA, and IgM antibody titers against chlamydial lipopolysaccharides (LPS) and the concentrations of C-reactive protein (CRP ) and troponin T (TnT). Anti-LPS IgG titers were increased in 45% of patien ts at enrollment and in 48% of patients at discharge (p <0.0001). Anti-LPS IgA titers were increased in 27% of patients at enrollment and in 33% of pa tients at discharge (p <0.0001). Patients who subsequently died had signifi cantly lower IgM titers at enrollment than patients without events (p = 0.0 16). IgG, IgA, or IgM titers did not correlate with concentrations of CRP o r TnT. In this large-scale study of patients with unstable angina, we frequ ently found elevated antichlamydial antibody titers. Patients with low IgM anti-LPS titers were at risk for subsequent death. However, there was no co rrelation between antichlamydial antibody titers and CRP or TnT. (C)2001 by Excerpta Medica, Inc.