Currently, available findings coming mainly from allo-HSCT (hhematopoietic cell transplantation) studies, link particular changes in microbiota with overall survival and post-transplant disorders, especially GvHD. According to limited data, further evaluation of associations between the alterations in microbiome composition and toxicities. Detail investigation of both the microbiome and host immune system may help to find microbiome markers useful for very early identification of patients at risk for major transplant-related complications. This might bring the possibility to modulate the gut microbiota in patient´s specific manner to achieve optimal therapeutic outcome and follow-up, while avoiding severe post-transplant complications.~This is prospective, single center, non-randomized, hypothesis generating study. Patients will be asked to provide a sample of blood, urine and stool. This blood will be used for plasma and serum banking for further analysis, including micro RNA (miR) and chemokine detection. Stool will be used for microbiome studies - isolation of total DNA/RNA and 16S (RNA component of the small subunit of a prokaryotic ribosome) rRNA (ribosomal ribonucleic acid) gene sequencing for bacterial taxonomic classification. Furthermore, metagenomic sequencing and subsequent taxonomic and functional classification of microbial genes will be used including characterization of potentially clinically relevant features of the microbiome such as antibiotic resistance and microbial virulence factors.
Numerous in vitro and animal studies as well as growing number of clinical studies support the important role of microbiome in carcinogenesis and cancer treatment. Detection of changes in patients´ microbiome following hematopoietic cell transplantation/CAR-T cell therapy and correlations with adverse transplant outcomes, mainly infectious complications, acute and chronic GvHD, disease recurrence etc. could serve as predictive markers of immune recovery and treatment response.