Tibetans are one of the oldest ethnic groups in China and South Asia. Based on the analysis of 1,059 Tibetans in the Minjiang River basin at an altitude of 500–4,001 m, we found that the dominant phyla of the Tibetan population were Bacteroidota and Firmicutes, and the main genera were Prevotella and Bacteroides, which were mostly in consistent with other nationalities. We further evaluated in total 115 parameters of seven categories, and results showed that altitude was the most important factor affecting the variation in the microbial community. In the process of emigration from high altitudes to the plain, the gut microbial composition of late emigrants was similar to that of plateau aborigines. In addition, regarding immigration from low altitude to high altitude, the microbial community became more similar to that of high altitude population with the increase of immigration time. Changes in these microbes are related to the metabolism, disease incidence and cell functions of the Tibetan population. The results of other two cohorts (AGP and Z208) also showed the impact of altitude on the microbial community. Our study demonstrated that altitude of habitation is an important factor affecting the enterotype of the microflora in the Tibetan population and the study also provided a basis to explore the interaction of impact parameters with gut microbiome for host health and diseases.

Background: Tibetans are one of the oldest ethnic groups in China and South Asia. Tibetan has a unique lifestyle and a long history, which leads to the particularity of their gut microflora in composition and function. Different from the Tibetan population on the Qinghai-Tibet Plateau, Tibetans in Minjiang River Basin have gradually increased their migration to Chengdu Plain in recent years. Based on the analysis of 1059 Tibetans in the Minjiang River Basin at an altitude of 500-4001m, we found that the dominant phylum of Tibetan population is Bacteroidea and Firmicum, and the main genera are Prevotella and Bacteroides. These findings reflect the characteristics of Tibetan population. Results: In order to further study the factors affecting gut microbial composition of Tibetan population, 115 total parameters of 7 categories were evaluated. The results showed that altitude was the most important factor affecting the variation of microbial community in Tibetan population, and the change of altitude promoted the succession of gut microbial community. In the process of migration from high altitude to plain, the intestinal microbial composition of late immigrants was similar to that of plateau aborigines, while that of early immigrants was similar to that of plain aborigines. Migration to Tibet is related to the loss of indigenous gut microbial community species. In addition, from low altitude to high altitude, the similarity of microbial community with high altitude population increased with the reproduction of offspring after marriage. And the change of these flora will affect the metabolism, disease and cell function of Tibetan population. The other two sets (AGP and Z208) of altitude data also show the impact of altitude on the microbial community. Conclusions: This is the first large-scale study on the influencing factors of gut microflora in Tibetan population. Our study confirmed that altitude change is the most important factor affecting the distribution of Tibetan population flora, and provided abundant and unique data to explore the interaction of impact parameter-gut microbiome-host function and disease.

Background: Interleukin-4 (IL-4) is an important cytokine in the Th2 differentiation of CD4 + T cells, which modulates immune responses and participates in host defense against Mycobacterium tuberculosis. The present study aimed to evaluate the significance of IL-4 concentration in patients with tuberculosis. Data from this study will be helpful in understanding the immunological mechanisms of tuberculosis and in clinical practice.Method: A data search was conducted from January 1995 to October 2022 in electronic bibliographic databases such as China National Knowledge Infrastructure, Wan Fang, Embase, Web of Science, and PubMed. The Newcastle-Ottawa Scale was used to assess the quality of the included studies. Heterogeneity between the studies was assessed using I 2 statistics. Publication bias was determined by funnel plot, and Egger's test was used to confirm the presence of publication bias. All qualified studies and statistical analyses were performed using Stata 11.0.Results: Fifty-one eligible studies comprising 4317 subjects were included in the meta-analysis. The results depicted a considerably increased level of serum IL-4 in patients with tuberculosis than in the controls (standard mean difference [SMD] = 0.630, [95% confidence interval (CI), 0.162-1.092]). However, there was no significant difference in plasma IL-4 levels between patients with TB and controls (SMD = 0.290, [95% CI, −0.430 to 1.010]). In addition, the infection status, TB focus location, drug resistance, race, research design type, and detection method divided the subjects into different subgroups for the meta-analysis. The results of the comparison of healthy controls and TB subjects showed that in the Asian population, the serum IL-4 level in patients with TB was higher than that in controls (SMD = 0.887, [95% CI, 0.202 to −1.573]) and patients with active TB as well as people with pulmonary TB showed increased serum IL-4 levels compared to controls (SMD = 0.689, [95% CI, 0.152-1.226]). In the case of the control group with latent TB, the active TB group had higher serum IL-4 levels than the control group (SMD = 0.920, [95% CI, 0.387-1.452]). Conclusion:The present meta-analysis showed that serum IL-4 varied in healthy individuals and patients with TB. Patients with active TB may also exhibit higher IL-4 concentrations.

Background: Tibetans are one of the oldest ethnic groups in China and South Asia. Tibetans have a unique lifestyle and a long history, which leads to the particularity of the composition and function of their gut microflora. Tibetans in the Minjiang River basin have gradually increased their migration to the Chengdu Plain in recent years. Based on the analysis of 1059 Tibetans in the Minjiang River basin at an altitude of 500-4001 m, we analyzed the characteristics of the gut microbiome and further elaborated the main factors affecting the succession of the gut microbiome in the Tibetan population.Results: Our study found that the dominant phyla of the Tibetan population were Bacteroidetes and Firmicutes, and the main genera were Prevotella and Bacteroides. To further study the factors affecting the gut microbial composition of the Tibetan population, 115 total parameters of 7 categories were evaluated. The results showed that altitude was the most important factor affecting the variation in the microbial community in the Tibetan population, and the change in altitude promoted the succession of the gut microbial community. In the process of migration from high altitudes to the plain, the gut microbial composition of late immigrants was similar to that of plateau aborigines, while that of early immigrants was similar to that of plain aborigines. Migration to Tibet is related to the loss of indigenous gut microbial community species. In addition, from low altitude to high altitude, the similarity of the microbial community with the high-altitude population increased with the reproduction of offspring after marriage. Changes in these microbials will affect the metabolism, disease incidence and cell function of the Tibetan population. The other two sets (AGP and Z208) of altitude data also showed the impact of altitude on the microbial community.Conclusions: This is the first large-scale study on the factors influencing the gut microflora in a Tibetan population. Our study confirmed that altitude change is the most important factor affecting the distribution of the microflora in the Tibetan population and provided abundant and unique data to explore the interaction of impact parameter-gut microbiome-host function and disease.