ORIGINAL ARTICLE Low Serum Vitamin D Levels Are Associated with Severe Histological Features and Poor Response to Therapy in Patients with Autoimmune Hepatitis Cumali Efe • Taylan Kav • Cisel Aydin • Mustafa Cengiz • Narin Nasıroglu Imga • Tugrul Purnak • Daniel S. Smyk • Murat Torgutalp • Turan Turhan • Seren Ozenirler • Ersan Ozaslan • Dimitrios P. Bogdanos Received: 9 May 2014 / Accepted: 23 June 2014 Ó Springer Science+Business Media New York 2014 Abstract Background and Aim 25-Hydroxyvitamin D [25(OH)D] has an important role in fibrosis progression and inflam- matory response in patients with various etiologies of chronic liver disease. However, its influence on autoim- mune hepatitis (AIH) has not been investigated. We eval- uated the association of serum 25(OH)D levels with clinical, biochemical and histological features and response to therapy in AIH. Materials and methods Serum 25(OH)D levels were quantified in 68 therapy naı ¨ve AIH patients and 34 healthy controls. Results Mean serum 25(OH)D levels were significantly lower in AIH compared to healthy controls (16.8 ± 9.2 vs. 35.7 ± 13.6, p \ 0.0001). Low levels of 25(OH)D ( \ 30 lg/L) were independently associated with advance fibrosis and severe interface hepatitis in AIH patients [p = 0.014; odds ratio (OR) 0.12, 95 % confidence interval (CI) 0.02–0.65 and p = 0.020; OR 0.17, 95 % CI 0.04–0.76, respectively]. Severe 25(OH)D deficiency ( \ 10 lg/L) was associated with advance fibrosis, severe interface hepatitis, low platelet counts and sampling time in a univariate analysis. Only interface hepatitis and fibrosis scores were independently associated with 25(OH)D defi- ciency in a multiple regression analysis (p = 0.005; OR 0.12, 95 % CI 0.03–0.53 and p = 0.022; OR 0.15, 95 % CI 0.03–0.75, respectively). Mean serum 25(OH)D levels were lower in non-responders compared to responders (9.2 ± 4.8 vs. 17.1 ± 9.4, p = 0.015), and 25(OH)D deficiency was more commonly observed in non-respond- ers than the responders (80 vs. 43 %, p = 0.036). Conclusions Low 25(OH)D levels are associated with advance fibrosis and severe inflammation in AIH. Our study suggests that vitamin D may be a potential biomarker that predicts response to therapy and histological features in AIH. C. Efe Á T. Kav Á M. Torgutalp Department of Gastroenterology, Hacettepe University, Ankara, Turkey C. Efe (&) Eceabat Sokak 21/12 Cebeci, Ankara, Turkey e-mail: drcumi21@hotmail.com C. Aydin Department of Pathology, Hacettepe University, Ankara, Turkey M. Cengiz Á S. Ozenirler Department of Gastroenterology, Gazi University, Ankara, Turkey N. N. Imga Department of Endocrinology and Metabolism, Numune Research and Education Hospital, Ankara, Turkey T. Purnak Á E. Ozaslan Department of Gastroenterology, Numune Research and Education Hospital, Ankara, Turkey D. S. Smyk Á D. P. Bogdanos Division of Transplantation Immunology and Mucosal Biology, Institute of Liver Studies, King’s College London School of Medicine, London, UK T. Turhan Department of Biochemistry, Numune Research and Education Hospital, Ankara, Turkey 123 Dig Dis Sci DOI 10.1007/s10620-014-3267-3