The proportion of regulatory T cells in peripheral blood of patients with autoimmune hepatitis: A systematic review and meta-analysis

Background: Many researches have reported the impairment of regulatory T cells (Tregs) in autoimmune hepatitis (AIH), whilst the change of Tregs in peripheral blood remains controversial. We performed this systematic review and meta-analysis to clarify the numerical change of circulating Tregs in AIH patients compared with healthy individuals.Methods: Relevant studies were identified from Medline, PubMed, Embase, Web of Science, the Cochrane Library, China National Knowledge Infrastructure, and WanFang Data. Twenty-nine studies involving 968 AIH patients and 583 healthy controls were included. Subgroup analysis stratified by Treg definition or ethnicity was performed, and analysis of active-phase AIH was conducted. Results: The proportions of Tregs among CD4 T cells and PBMCs were generally decreased in AIH patients compared with healthy controls. Subgroup analysis showed that circulating Tregs identified by CD4+CD25+/high, CD4+CD25+Foxp3+, CD4+CD25+/highCD127- /low, and Tregs in Asian population were decreased among CD4 T cells in AIH patients. No significant change of CD4+CD25+/highFoxp3+CD127-/low Tregs and Tregs in Caucasian population among CD4 T cells were found in AIH patients, whereas the number of studies was limited in these subgroups. Moreover, analysis of the active-phase AIH patients showed that Treg proportions were decreased generally, whereas no significant differences in Tregs/CD4 T cells were observed when markers CD4+CD25+Foxp3+, CD4+CD25+/highFoxp3+CD127-/low were used or in Caucasian population.Conclusions: The proportions of Tregs among CD4 T cells and PBMCs were decreased in AIH patients compared with healthy controls generally, whereas Treg definition markers, ethnicity, and disease activity had influence on the results. Further large-scale and rigorous study is warranted.

Automated summary

This systematic review and meta-analysis found that the proportions of regulatory T cells (Tregs) were decreased in autoimmune hepatitis (AIH) patients compared to healthy controls. The results were influenced by Treg definition, ethnicity, and disease activity. Further large-scale and rigorous studies are needed to confirm these findings.