Can serum histone H4 levels predict mucosal healing in Crohn's disease?

Introduction: Mucosal healing (MH) has been a treatment target with the introduction of biological agents in Crohn's disease (CD). Histone H4 increases in chronic inflammation. Aim: Our goal was to investigate the role of serum histone H4 in predicting MH. Material and methods: The study included 44 patients who applied to the endoscopy unit for ileocolonoscopic evaluation with the diagnosis of ileocecal CD and 26 healthy controls. After ileocolonoscopic evaluation, we divided the patients into 2 groups: those with and those without MH, according to the presence of endoscopic ulcer or erosion findings. Blood samples were taken from these patients to analyse serum histone H4 before the endoscopic procedure. We first compared serum histone H4 levels between CD patients and the healthy control group and then between those with and those without MH among the CD patients. Finally, we compared CRP, ESR, and serum histone H4 levels in patients with CD according to the presence of MH and symptoms. Results: Serum histone H4 levels were significantly higher in ileocolonic CD patients compared to the healthy control group (p = 0.002). Also, serum histone H4 levels were significantly higher in CD patients with no MH (p = 0.028) or symptomatic patients (p = 0.033). We did not find a significant difference in C-reactive protein and erythrocyte sedimentation rate levels between CD patients in the presence of MH (p = 0.281 and p = 0.203, respectively) or symptoms (0.779 and 0.652, respectively). Conclusions: Serum histone H4 might be a useful biomarker for MH prediction in ileocolonoscopic CD patients. Validation is needed for large numbers of patients.