Investigation of relationship between recent chlamydia pneumoniae infection and active ankylosing spondylitis / 中华风湿病学杂志

ABSTRACT

Objective To investigate the relationship between recent chlamydia pneumoniae (Cp)infection and active ankylosing spondylitis (AS). Methods Seventy nine AS outpatients and 73 normal controls (NC) were enrolled into this study. Serum anti-Cp antibodies (CpIg) were tested using the enzymelinked immunosorbent assay (ELISA). Clinical and experimental data were collected. Patients with positive CpIgM or CpIgA were considered as having a recent Cp infection. Wilcoxon test, Student's t test, χ2 test and multivariate logistic regression were used for statistical analysis. Results Both AS patients and normal controls had a high prevalence for sero-positive CpIgG, which was 89％(70/79) vs 92％(67/73) respectively,while AS patients had a higher frequency of CpIgA and CpIgM when compared with NC [52％(41/79) vs 32％(23/73), χ2=6.61, P=0.010 for CpIgA; 80％(63/79) vs 21％(15/73), χ2=44.031, P＜0.01 for CpIgM]. The presence of CpIgM or CpIgA favored AS, the OR was 17.1 (95％CI 7.4～39.5), or 3.1 (95％CI 1.3～7.2),respectively. In addition, CpIgM was associated with disease activity parameters including ESR (χ2=2.56, P=0.021), CRP (χ2=7.28, P=0.007) and BASDAI (χ2=6.79, P=0.009). Furthermore, consecutive positive CpIgM favored the persistent active or relapsed disease, while negative CpIgM favored a reduced disease activity.There was no correlation between CpIgM/CpIgA and peripheral joint disease and enthesitis. Conclusion Recent Cp infection is highly associated with AS and CpIgM antibody relates with active AS, which indicates that Cp infections may be a critical triggering factor for active AS.