Comparison of the infectious and immunological safety of a low-bacterial and modified diet in allogeneic hematopoietic stem cell transplantation in adults

Background. Malnutrition is an aggravating factor in hematopoietic stem cell transplantation (HSCT). Due to the need for the intestinal microbiome protection, which is a key element in homeostasis and is under complex negative effects, a theory aimed at liberalizing dietary restrictions is being developed, which creates the basis for improving the patient’s self-feeding and leads to a number of positive outcomes. Aim. To evaluate the infectious and immunological safety of a modified diet in HSCT. Materials and methods. From 2022 to 2023 at the Raisa Gorbacheva Memorial Research Institute 406 allogeneic HSCT recipients over 18 years old, who followed a low-bacterial (LBD) (n = 177) or modified diet (MD) (n = 229) were enrolled to the randomized trial. The concept of LBD included generally accepted anti-infective restrictions in HSCT, the absence of gluten, lactose, and yeast-containing products. Under MD, only the principles of anti-infective measures were maintained in the preparation, storage, transportation and dishes consumption, and the prohibition of a sharply limited list of foods that are difficult to digest and capable of mechanically injuring the oropharynx and gastrointestinal tract mucous membrane. Results. The patient groups were homogeneous in diagnosis, graft source, HLA-compatibility between the recipient and the donor, conditioning regimen intensity and graft-versus-host disease prophylaxis, except for the age: MD group – 42.3 years, LBD group – 38.4 years; p = 0.009. The one-year overall survival was similar in both groups: 72 % for MD and 75 % for LBD; p = 0.6. Relapse-free one-year mortality was comparable between the groups: 8.7 % for MD versus 9.1 % for LBD; p = 0.9. Graft engraftment at day 30 did not differ: 83 and 92 %, respectively; p = 0.2. The incidence of graft-versus-host disease grade 3–4 was 3.4 % in the MD group and 6.8 % in the LBD group, respectively; p = 0.14. The incidence of bloodstream infections at day 30 was lower in the MD group (14.4 %) compared with the LBD group (45.2 %), respectively; p 0.001. Conclusion. Using the example of the presented patient cohort who underwent allogeneic HSCT, the use of MD has potential advantages over LBD in the form of a tendency to reduce bloodstream infections and the severe graft-versus-host disease incidence. Further studies with a large number of participants are needed to confirm these findings.