Intestinal microbiota dysbiosis play a role in pathogenesis of patients with primary immune thrombocytopenia.

Background: The intestinal microbiota is essential for the maintenance of the physiology of immune homeostasis. Dysbiosis has been described in some autoimmune diseases, however its role is still elusive in primary immune thrombocytopenia (ITP), which is one kind of autoimmune diseases. This study aimed to characterize the phylogenetic diversity of the fecal microbiota and its relationship with the platelet activation status in patients with ITP.

Methods: The platelet activation status was assessed by 2 platelet markers, PAC-1 (antibody that recognizes the activated GPIIb/IIIa complex) and CD62p (Platelet surface P-selectin) by flow cytometry. Total DNA was extracted from fecal samples of ITP patients and healthy controls (HC). Sequencing the V4 hypervariable region of bacterial 16S rRNA genes was used to identify the changes in phylogenetic diversity and composition of the intestinal flora. The obtained sequencing reads were assigned to operational taxonomic units (OTUs, 97% sequence identity) and taxonomically classified to assess composition and diversity.

Results: The percentage of PAC-1+ platelets in ITP patients was higher than that in control group (p < 0.001), The percentage of CD62p+ and PAC-1+CD62p+ platelets in ITP patients both higher than those in control group (p < 0.001). At the phylum level, eight different phyla were identified in ITP individuals, with a majority of Bacteroidetes (45.96%) and Firmicutes (38.59%), followed by Proteobacteria (11.43%), Fusobacteria(1.29%), and Actinobacteria (1.22%). While in the Healthy volunteers, ten phyla were detected, with a predominance of Firmicutes (50.92%) and Bacteroidetes (34.26%), came before Proteobacteria (13.60%), and Actinobacteria (0.90%). The gut microbiota was skewed in ITP, with an increased proportion of Proteobacteria, Bacteroidetes and Bacteroidetes/Firmicutes ratio, a decreased proportion of Firmicutes compared with HC. Disease specific alterations in diversity was also identified, especially the potential markers (Anaerorhabdus, sutterella, Peptostreptococcaceae, Clostridium_XI and carnobacteriaceae, p < 0.05) for ITP.

Conclusions: The results suggested that the distinct microbiota dysbiosis in ITP characterized by alterations in biodiversity and composition, which could provide insights for diet therapy and fecal microbiota transplantation treatment to cure ITP. There might be somehow compensatory enhancement of platelet activation in ITP patients. And there is associate between platelet activation and intestinal microbiota in patients with ITP.