Fecal microbiota transplantation for the treatment of intestinal diseases after allogeneic hematopoietic stem cell transplantation in children

Fecal microbiota transplantation (FMT) is a promising therapy for a variety of diseases involving the gastrointestinal (GI) tract. The purpose of our study is to evaluate the effectiveness of FMT for the treatment of different GI complications after allogenic hematopoietic stem cell transplantation (steroid-refractory and steroid-dependent graft versus host disease (SR/ SD GVHD) and infectious enterocolitis) in children from 1.5 to 18 years old. The study was approved by the Local Ethics Committee of the Morozov Children's Clinical Hospital of the Department of Health of Moscow (No. 176 dated 24.05.2022). The patients' parents gave their informed consent to the participation of their children in the study and the publication of the study results. SR/SD GVHD group included 14 patients and GI infections group – 11 patients. In total, 38 FMTs were performed. Eleven children underwent repeated FMTs due to the lack of effect after the first FMT. The resolution of diarrhea followed by the withdrawal of corticosteroids was recorded in 11 out of 14 patients with SR/SD GVHD. Ten out of 11 patients with GI infections also achieved relief of diarrhea. The clinical effect correlated with changes in the microbiome structure: for both groups of patients, the median proportion of normal microbiota before FMT was 6%, after FMT – 92% (p = 0.043). The median number of different taxa for both groups of patients before and after FMT were 3 and 10 taxa, respectively (p = 0.0016).