Characteristics Of Intestinal Flora In Patients With Aplastic Anemia

Objective:Explore whether there are differences in intestinal flora composition and function between patients with aplastic anemia（AA）and healthy people.Methods:Fresh feces were collected from the 16 patients with AA before treatment,5 patients with AA after treatment and 9 healthy adults,all of the people meet the inclusion criteria.Total DNA from each stool sample was extracted,amplified and metagenomic sequencing was performed to obtain the biological information of intestinal flora of all samples.Firstly,the difference in the number of genes between groups were analyzed.Secondly,species annotation was performed on the gene fragments to compare species diversity between groups,compare the relative abundance of major species at phylum and genus levels,and perform LEfSe multivariate statistical analysis of significantly different species.Finally,functional annotation of gene fragments was performed,and statistical analysis of relative abundance of function at KEGG-level 1 between groups and Metastat analysis of functions with significant differences were conducted according to the results.Results:The final biological information data obtained by sequencing in this study is of high quality and low error rate,which can completely and accurately reflect the microbial information in all research objects.The comparison of gene number between the two groups showed that:there was no significant difference between the healthy group and the AA group before and after treatment（P>0.05）;however,compared with the AA group before treatment,the gene number of the AA group after treatment was significantly increased（P=0.024）.The comparison of species diversity between groups showed that:compared with the healthy group,the Shannon index of AA group before treatment was significantly decreased（P<0.05）;but the Shannon index of the AA group after treatment was not significantly different from that of the healthy group and the AA group before treatment（P>0.05）.The main bacterial phyla in the three groups include Firmicutes,Bacteroidetes,Proteobacteria and Actinobacteria.the main bacterial genera include Bacteroides,Prevotella,Faecalibacterium,Bifidobacterium,Dialister,Megamonas,Alistipes,Citrobacter,Eubacterium and Roseburia.The results of phylum level analysis showed that the relative abundances of the four main phyla and short chain fatty acidsproducing phyla were not significantly different between the three groups（P>0.05）.The results of major species analysis showed that:compared with the healthy group,the number of Prevotella,Megamonas and Roseburia in AA group before treatment was significantly decreased;the abundance of Alistipes in AA group after group was significantly higher than that in healthy group and the AA group before treatment（P<0.05）.The results of the LEfSe multivariate statistical analysis of significantly different species showed that:the relative abundance of Roseburia and its branch faecis species,intestinalis species,hominis species,inulinivorans species,Prevotella’s branch stercorea species,sp_CAG₂79 species,Haemophilus and its branch Haemophilus parainfluenzae species in the AA group before treatment were significantly reduced than the healthy group;compared with the healthy group,the relative abundance of Alistipes and its branch finegoldii species,Rumenococcus and its branch bicirculans species were significantly increased in the AA group after treatment,however the relative abundance of Roseburia and its branch faecis species,Haldmanella and its branch biformis species were significantly reduced;compared with the AA group before treatment,the relative abundance of Eubacterium’s branch CAG₁80 species,Rumenococcus and its branch callidus species,bicirculans species,Alistipes’branch obesi species,ihumii species were significantly increased in the AA group after treatment,while the relative abundance of Firmicutes_bacterium_CAG₈3 species was significantly reduced.In terms of function annotation results,the relative abundance of functions on KEGG-level 1 among the three groups was not significantly different（P>0.05）.The results of Metastat analysis of significantly different functions showed that:compared with the healthy group,the abundance of functional pathways related to lipid metabolism were significantly increased in the AA group before treatment;while the immune system related functional pathways were significantly decreased（P<0.05）.Conclusions:Compared with healthy people,the diversity of intestinal flora in patients with AA decreased,and the relative abundance of some bacterial genera changed significantly.The abundance of lipid metabolism-related functional pathways increased,and the abundance of immune-related functional pathways decreased.There was no significant difference in these enterobacterial changes in patients with partial hematological reactions after immunosuppressive therapy compared with normal controls.After preliminary exploration of the changes of intestinal flora in patients with AA,it was confirmed that the structure and function of intestinal flora in patients with AA disease had changed to a certain extent,which may be related to the occurrence and development of the disease.