Ethics Approval and Consents
All procedures performed in this study involving human participants were in accordance with the Second Affiliated Hospital of Nanjing Medical University Institutional Ethical Review Board and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all participants included in the study.
Patients, Donors and FMT Procedure
FMT via mid-gut for mild to severe CD with the Harvey Bradshaw Index (HBI) > 4 as a registered trial was performed from October 2012 to December 2016 at the Second Affiliated Hospital of Nanjing Medical University. This study was retrospectively registered with clinicaltrials.gov. Trial registration date: 13/2/2013. Trial registration number: NCT01793831. All patients and donors were informed of the benefits and potential risks of FMT and laboratory screening. All written informed consentd were obtained. Eligible subjects required documentation of definite diagnosis of CD.
Donors were considered to be suitable according to our screening criteria . Healthy donors were selected from patients’ relatives or friends or from our universal stool bank (China fmtBank), and carefully screened using the following exclusion criteria: history of drug use (e.g., antibiotic, laxative or diet pill use within the past 3 months; prior immunomodulator or chemotherapy use) and history of disease (e.g., infectious diseases, obesity, diabetes, IBD, irritable bowel syndrome, chronic diarrhea, constipation, colorectal polyps or malignant neoplasm, immunocompromised states, metabolic syndrome, allergy, history of major gastrointestinal operation or auto-immune diseases, as well as any other diseases or conditions related to the disturbance of intestinal microbiota). All donors accepted laboratory examinations, such as regular blood tests, C-reactive proteins, erythrocyte sedimentation rates, immunoglobulin subtypes, biochemical tests, hepatitis-associated indices, HIV, syphilis, Cytomegalovirus, Epstein–Barr virus, rubella virus, herpes simplex virus, toxoplasma, and stool testing (including stool culture, stool ova and parasites).
Fecal samples were obtained from scanned donors after signing the informed consent, and were processed for enriching microbiota in the laboratory by manual methods (before April 2014) or automatic methods based on the automatic purification machine GenFMTer (FMT Medical, Nanjing, China)  (since April 2014). We followed the “1-h FMT protocol”, which means that the time from the stool coming out of the colon to the patient’s intestine or storing at − 80 °C refrigerator is required to be finished within 1 h . The stored fecal microbiota needed be thawed at 37–39 °C before infusion into the patient’s intestine. However, after we had confirmed that the frozen FMT induced the decreased rate of clinical improvement by 26.7% at 6 months post-FMT compared with the fresh FMT in CD at our earlier phase , the fresh FMT has become the first and even the most important suggestion to patients with CD in our practice. The purified fecal microbiota was delivered into the mid-gut through a naso-jejunal tube or gastroscopic infusion under anesthesia.
The Safety of FMT
All AEs were recorded during the follow-up after FMT. The longest follow-up time was 5 years. All AEs were described using Common Terminology Criteria for Adverse Events (CTCAE) as in our previous study . Grade refers to the severity of the AE. The CTCAE displays Grades 1–5 with clinical descriptions of severity for AE based on the guideline.
The Efficacy of FMT
The efficacy of FMT was evaluated at 1 month after FMT. The activity of disease was assessed by HBI based on abdominal symptoms, examination findings, and the presence of extraintestinal manifestations [6, 7]. Clinical response was defined as the HBI score decreasing to > 3. Clinical remission was defined as HBI ≤ 4 after FMT. All patients who achieved clinical remission were included in the analysis of clinical response.
Data were analyzed by using SPSS 18.0. Analyses included the nonparametric test, Chi square test, Fisher’s exact test and logistic analysis. Two-tailed P value was calculated with each test. P < 0.05 was considered significant.