The Characteristics Of Intestinal Microbiota In Patients With Type 1 Autoimmune Pancreatitis

Background/Objectives:Autoimmune Pancreatitis?AIP?is a special form of pancreatitis that is characterized clinically by frequent presentation with obstructive jaundice or abdominal discomfort,and the pathogenesis of AIP is still not clear.The clinical symptoms of AIP is similar to Pancreatic Head Cancers?PCH?.It is difficult to disagnose the two disease clinically and PCH has a poor prognosis,rapid progress,and often requires surgical resection.In order to improve the prognosis of patients with PCH and reduce unnecessary surgery in patients with AIP,it is important to find a biomarker to distinguish AIP from PCH.There are rare studies on gut microbiota alterations in autoimmune pancreatitis?AIP?and there are also less studies on gut microbiota alterations betweenn AIP with PCH or Chronic Pancreatitis?CP?.We designed this cross-sectional study to elucidate the characteristics of the gut microbiome in patients with AIP and its correlation with other pancreatic diseases such as CP and PCH.Methods:23 patients with type 1 AIP?AIP group?,30 patients with CP?CP group?,and 17 patients with PCH?PCH group?were enrolled from inpatient department in the department of gastroenterology of Changhai Hospital from September 2018 to September 2019.Thirty macthed healthy controls were recruited from nearby communities as the HC group?HC group?.Fecal microbiomes were analyzed through 16S ribosomal RNA gene profiling,based on next-generation sequencing.Serum 20 cytokines were detected in AIP group and PCH group using Quantibody???Array Glass Chip.Data analysing include microbiota diversity and richness,significantly different species,metabolic pathways and correlation between microbiome and inflammatory cytokines.Results:There was no significant difference in sex,age and body mass index?BMI?between AIP with the other three groups?P>0.05?.There was no significant difference in gut microbiota richness and diversity between AIP with the other three groups.PCoA showed significant taxa-composition change in patients with AIP?R=0.2720,P=0.001,weighted unifrac test;R=0.2720,P=0.001,unweighted unifrac test?.PCoA showed significant taxa-composition change in patients between AIP with CP?R=0.0690,P=0.025,weighted unifrac test;R=0.1100,P=0.008,unweighted unifrac test?.And there were no significant taxa-composition change in patients between AIP with PCH?R=0.0216,P=0.260,weighted unifrac test;R=0.0454,P=0.124,unweighted unifrac test?.On the phylum level,the gut microbiome of the AIP group showed higher p_Proteobacteria abundances than the HC group.Comparing with HC group,the abundances of g_Streptococcus,g_Veillonella,g_Prevotella₇ were significantly higher in AIP group,while g_Bacteroides,g_Eubacterium_rectale_group,g_Roseburia were significantly lower in AIP group.The abundance of g_Streptococcus in the AIP group was significantly higher than that in PCH group,while the abundance of g_Phascolarctobacterium was significantly lower than that in PCH group.The abundance levels of g_Streptococcus,g_Veillonella and g_Lactobacillus in the AIP group were significantly higher than those in the CP group,while the abundance of g_Lachnoclostridium were significantly lower than those in the CP group.Correlation analysis showed that g_Streptococcus correlated positively with serum macrophage inflammatory proteins?MIP?-3??r=0.56?.Conclusions:The current findings of this study suggest that the gut microbiota of patients with type 1 AIP has no significant difference in diversity and abundance compared with PCH patients,CP patients and healthy controls.However,there is an imbalance in the structure of the intestinal flora.The structure of the gut microbiota is not significantly different from that of patients with PCH,but is significantly different from that of CP patients and healthy controls.This study also found that g_Streptococus was significantly enriched in AIP patients,and there were significant differences compared with PCH,CP,and healthy controls,suggesting its possibility as a biomarker for AIP diagnosis or differential diagnosis.