Abstract
OBJECTIVE: Inflammatory bowel disease (IBD) is closely related to stress and fatigue. Human herpesvirus 6B (HHV-6B) is reactivated by stress and fatigue and is associated with IBD. This study aimed to clarify the relationship between IBD and HHV-6B. METHODS: Antibody titers to SITH-1, a protein specific to HHV-6B latent infection, were measured in 163 patients with IBD (107 with ulcerative colitis [UC] and 56 with Crohn's disease [CD]); clinical and endoscopic scores and depression scores of UC and CD were analyzed to examine the relationship between SITH-1 and IBD. The SITH-1 cut-off value was set as 1.96, according to known reports. RESULTS: In patients with UC, C-reactive protein (CRP) level was significantly higher (1.5 vs 0.6 mg/L, P = 0.006) and disease exacerbation within 6 months after entry was significantly more common in the SITH-1 (+) group (20% vs 0%, P < 0.001). In the subanalysis comparing with and without UC exacerbation, the optimal cut-off value for SITH-1 to detect UC exacerbation was 3.44 (area under the curve: 0.81; 95% confidence interval: 0.72-0.90). CRP levels, SITH-1 levels, and disease activity scores by the clinical or endoscopic index were significantly higher in the exacerbation group than in the non-exacerbation group (2.6 vs 0.9 mg/L, P = 0.03; 4.90 vs 1.71, P < 0.001; 4 vs 3, P = 0.03; 5 vs 3, P = 0.02; respectively). CONCLUSION: Patients with UC with high titers of SITH-1 have high disease activity and frequent disease exacerbation. SITH-1 can be associated with UC disease activity.