Abstract
Purpose:
This study aimed to determine the prevalence of positive serology to Chlamydia in patients with Acute Anterior Uveitis (AAU) and Seronegative Arthritis (SNA) as cross-reactivity between self-peptides and bacterial antigens such as Chlamydia may be a pathogenic mechanism for HLA-B27 disease.
Methods:
Serum was obtained from patients with a past history of AAU and/or SNA (n=188). The patients were further stratified as follows: All patients with AAU (n=176), all HLA-B27 positive patients (n=116), HLA-B27 positive patients with AAU (n=102), HLA-B27 positive patients with SNA (n=49), HLA-B27 positive patients with both AAU and SNA (n=37), HLA-B27 positive patients with AAU but no SNA (n=65), HLA-B27 positive patients with SNA but no AAU (n=12) and HLA-B27-negative patients (all AAU) (n=72). Healthy age and sex-matched HLA-B27 negative controls were recruited (n=13) as well as controls from MEDAC GmbH (Hamburg, Germany) (n=416). Serology was undertaken using a commercially available recombinant ELISA kit that detects IgG, IgM and IgA directed against a Chlamydia-specific lipopolysaccharide (MEDAC GmbH). Statistical analysis was performed using a Fisher exact test.
Results:
The prevalence of IgG positivity to Chlamydia in patients who were HLA-B27 positive with both AAU and SNA (48.65%) was significantly higher compared to healthy controls (15.38%) (p<0.05). In comparison to the healthy controls recruited by MEDAC, the following groups had significantly higher proportions of positive IgA and IgM titers compared to controls from MEDAC (13.0%, 3.0%, respectively): all HLA-B27 positive patients (35.1%, 11.7%), HLAB27 positive patients with AAU (32.4%, 10.8%), HLA-B27 positive patients with SNA (32.7%, 10.2%), HLA-B27 positive patients with both AAU and SNA (35.1%, 10.8%) (p<0.05).
Conclusions:
Patients with HLA-B27 AAU and SNA disease have evidence of exposure to Chlamydia. HLA-B27 patients with both AAU and SNA have a higher rate of seropositivity compared to controls.