JUN 15, 2021
This study evaluates the associations between tuberculosis (TB) infection and risk of Behçet disease.
This study is a mendelian randomization and observational analysis of genetic data from 999 Chinese and 611 Japanese patients with uveitis associated with Behçet disease, and 5,154 control patients. Researchers tested for 5 single nucleotide variants (SNPs) that were previously linked to TB infection in genome-wide association studies of Chinese patients. They also tested for TB using T-SPOT.TB immunoassays. The primary outcome was the odds ratio for Behçet disease, estimated by an inverse variance weighted mean of associations with genetically determined TB susceptibility. The T-SPOT.TB immunoassay positivity rate was examined in patients with Behçet disease and control participants.
The analysis revealed that TB susceptibility was associated with an increased risk for Behçet disease. The odds ratio for Behçet disease per 2-fold increase in TB incidence was 1.26 in the Chinese cohort and 1.16 in the Japanese cohort. In addition, a positive T-SPOT.TB immunoassay was an independent risk factor for Behçet disease (OR 2.26).
This study describes an association but did not directly link TB infection and the development of Behçet disease, although the presence of SNPs previously linked to TB infection in patients with Behçet disease provides some indirect support for this hypothesis. A 2-sample mendelian randomization was performed, meaning that there may still be confounding factors in the analysis. The data on T-SPOT positivity, however, does provide some additional indirect support for this association. The link between TB and Behçet disease was weaker in the Japanese cohort, suggesting that additional research in other populations is necessary.
Active or latent TB infection should be evaluated in patients with a diagnosis of Behçet disease, especially when an ophthalmologist is helping guide immunosuppressive therapy. Clinicians should be aware of possible reactivation or progression of TB in patients who are being treated for Behçet disease.