Frequency and function of circulating regulatory T-cells in biliary atresia

Purpose Although the impairment of regulatory T-cells (Tregs) has been shown in the liver or portal area of biliary atresia (BA) the frequency and function of circulating Tregs in BA patients is poorly understood. We aimed to investigate the frequency and function of circulating Tregs in BA patients. Methods Peripheral blood mononuclear cells were collected from 25 BA patients and 24 controls. Treg frequency was measured by flow cytometry; function was determined by T-cell proliferation assay. We also assessed the association between Treg frequency/function and clinical parameters in BA cases. Results There was no significant difference between the two groups in both frequency (BA: 3.4%; control: 3.2%; p = 0.97) and function (BA: 22.0%; control: 7.5%; p = 0.23) of Tregs. We further focused on 13 preoperative BA patients and 14 age-matched controls. Neither Treg frequency nor function were significantly different (frequency: BA: 4.6%; control: 3.4%; p = 0.38, function: BA: 2.7%; control: 7.6%; p = 0.89). There was no association between Treg frequency/function and clinical parameters. Conclusion Neither the frequency nor function of circulating Tregs was affected in BA patients, suggesting the negative role of circulating Tregs in the pathogenesis of BA. Further investigation of local Treg profiles is warranted.