Characteristics of blood microbiota in high altitude polycythemia patients by 16S rRNA gene sequencing

To investigate the changes in blood microbiota in patients with high altitude polycythemia (HAPC) and the correlation with the risk of HAPC.

A cross-sectional trial was carried out among 41 HAPC patients (HAPC group) and 41 healthy plateau individuals (control group) who took physical examination in the Health Management Department of No. 953 Hospital of PLA Army in 2021. High-throughput sequencing technology was used to detect the V3-V4 variable region of the 16S ribosomal RNA (16S rRNA) gene in the blood smaples, and the composition and difference of the blood microbiota were compared and analyzed between the 2 groups.

All the participants were male and Han people, and there were no significant differences in baseline data such as age, body mass index and plateau migration time between the 2 groups (P>0.05). The α-diversity of blood microbiota in the HAPC group, including the Simpson index (0.931±0.005 vs 0.907±0.008, P < 0.05), Goods Coverage index (0.998±0.001 vs 0.997±0.001, P < 0.001) and Pielou index (0.597±0.011 vs 0.567±0.009, P < 0.05) were significantly higher than those in the control group. Meanwhile, obvious difference was observed in the β diversity between the 2 groups (P < 0.01). The relative abundance analysis of bacteria showed that Pelomonas (0.046±0.004 vs 0.033±0.003, P < 0.05), Azospirillum (0.046±0.006 vs 0.021±0.003, P < 0.01), Acidovorax (0.032±0.003 vs 0.019±0.002, Azospirillum (0.046±0.006 vs 0.021±0.003, P < 0.01) and Acidovorax (0.032±0.003 vs 0.019±0.002, P < 0.05) were statistically higher in the HAPC group than the control group. LEfSe analysis showed that the characteristic blood microbiota of the HAPC group were α-Proteobacteria, and those of control group were Trichospiridae.

Significant changes are found in diversity, relative abundance and characteristic bacteria of the blood microbiota between the HAPC patients and healthy people at the high altitude, which might be closely associated with the occurrence and development of HAPC.