2.1. Patient population and follow-up

Autologous HSCT was considered for CD patients fulfilling the previously described inclusion criteria.^2,8 Given that the mobilization and conditioning protocols are intensely immunosuppressive, additional immunosuppression is avoided as it may potentially pose additional risks during the recovery phase. Anti-TNFα treatment and immunosuppressive drugs were stopped at least 4 and 2 weeks, respectively, before mobilization. The protocol was approved by the Catalan Transplantation Organization and by the local ethics committee. All patients provided written informed consent following extensive counselling. A total of 18 patients were recruited between March 2010 and September 2015. Patient characteristics at inclusion are shown in Table 1. After discharge, patients were closely followed-up.^2,8 In brief, Crohn’s Disease Activity Index [CDAI] and laboratory markers were assessed weekly during the first 30 days, and every 6 weeks thereafter. Colonoscopy and/or magnetic resonance imaging were performed at baseline and at weeks 26, 52 and 106 after transplant. The Simple Endoscopic Score for Crohn’s Disease [SES-CD] index was used at baseline and during follow-up to assess endoscopic activity. Mucosal healing was defined as SES-CD < 7. Magnetic Resonance Index of Activity [MaRIA] was used at baseline and during follow-up in those patients in whom lesions could not be assessed by ileocolonoscopy. Data are shown in Supplementary Table 1. None of the patients included in this study received any immunosuppressive or biological treatment during the first year of follow-up, with the exception of patient 15 who continued to experience severe lesions 6 months after transplant and started anti-TNFα treatment at that time.

HSCT cohort: patient characteristics at inclusion

CDAI, Crohn’s Disease Activity Index; SES-CD, Simple Endoscopic Score for Crohn’s Disease.

^aMean ± SEM.

^b n [%].

A second cohort comes from an observational prospective study, including CD patients who began treatment with an anti- TNFα antibody [infliximab or adalimumab] and were followed up for 46 weeks. All patients underwent clinical and endoscopic evaluation at weeks 0, 14 and 46. From April 2013 to September 2016, 22 CD patients were included after obtaining written informed consent [Supplementary Table 2]. This study was approved by the Institutional Ethics Committee of the Hospital Clínic de Barcelona [Spain].

Controls [n = 19] were individuals undergoing colonoscopy for mild gastrointestinal symptoms or for colorectal cancer screening, who had a normal examination and no history of inflammatory bowel disease [IBD]. The mean age of this cohort was 53.25 years, ranging from 27 to 69 years; and 10/19 were males.