New-Onset of Crohn’s Disease Is Associated with Antistreptolysin O Positive Titers

Objective Different infectious agents have been presumed to be candidates acting as an etiologic factor or trigger of Crohn's disease (CD). Group A Streptococcus (GAS) is a common human infection agent that can also trigger post-infectious immune-mediated conditions. The current study aimed to examine whether the immunogenic activity induced by GAS may trigger new-onset of CD. Methods Data for antistreptolysin O (ASO) level, throat culture for GAS, and history of streptococcal infection were collected from 91 patients with CD that were divided into three groups including; new-onset CD, CD in remission and active CD. The data were compared with the control group. Results All participants had negative results of throat culture for GAS and had no history of documented streptococcal infection in the past year. Our results indicate that new-onset CD, but not CD in remission or active CD, is associated with significantly increased positive ASO compared to controls. Half of the patients in the new-onset CD group were ASO positive, which was significantly higher compared to the control group in a univariant (OR: 4.00; 95% CI 1.27-12.58; P=0.02) and multivariant analysis (OR: 4.41; 95% CI 1.35-14.37; P=0.014). Conclusion Our study is the first to focus on ASO levels in patients with CD and to demonstrate a significant association between ASO and new-onset of CD. Large prospective randomized controlled studies are needed to confirm the validity of this data and to further clarify the clinical significance of our findings.