Résumé
OBJECTIVES@#To examine the changes of intestinal flora in children newly diagnosed with acute lymphoblastic leukemia (ALL) and the influence of chemotherapy on intestinal flora.@*METHODS@#Fecal samples were collected from 40 children newly diagnosed with ALL before chemotherapy and at 2 weeks, 1 month, and 2 months after chemotherapy. Ten healthy children served as the control group. 16S rDNA sequencing and analysis were performed to compare the differences in intestinal flora between the ALL and control groups and children with ALL before and after chemotherapy.@*RESULTS@#The ALL group had a significant reduction in the abundance of intestinal flora at 1 and 2 months after chemotherapy, with a significant reduction compared with the control group (P<0.05). Compared with the control group, the ALL group had a significant reduction in the diversity of intestinal flora before and after chemotherapy (P<0.05). At the phylum level, compared with the control group, the ALL group had a significant reduction in the relative abundance of Actinobacteria at 2 weeks, 1 month, and 2 months after chemotherapy (P<0.05) and a significant increase in the relative abundance of Proteobacteria at 1 and 2 months after chemotherapy (P<0.05). At the genus level, compared with the control group, the ALL group had a significant reduction in the relative abundance of Bifidobacterium at 2 weeks, 1 month, and 2 months after chemotherapy (P<0.05); the relative abundance of Klebsiella in the ALL group was significantly higher than that in the control group at 1 and 2 months after chemotherapy and showed a significant increase at 1 month after chemotherapy (P<0.05); the relative abundance of Faecalibacterium in the ALL group was significantly lower than that in the control group before and after chemotherapy and showed a significant reduction at 2 weeks and 1 month after chemotherapy (P<0.05). The relative abundance of Enterococcus increased significantly at 1 and 2 months after chemotherapy in the ALL group (P<0.05), and was significantly higher than that in the control group (P<0.05).@*CONCLUSIONS@#The diversity of intestinal flora in children with ALL is significantly lower than that in healthy children. Chemotherapy significantly reduces the abundance of intestinal flora and can reduce the abundance of some probiotic bacteria (Bifidobacterium and Faecalibacterium) and increase the abundance of pathogenic bacteria (Klebsiella and Enterococcus) in children with ALL.