Discrimination between Seroclearance and Seroconversion in Hepatitis B Using CD4⁺ CD25⁺ CD127^- FoxP3⁺ T Regulatory Cells

Background: Hepatitis B is a viral disease that can be chronic. The Treg population during hepatitis appears to have an important role in controlling disease progression. Objectives: The present study aimed to determine the level of Tregs in patients with chronic hepatitis B (CHB) at different stages of the disease. Methods: This study was carried out on 90 patients with CHB followed-up for an average of 10 years and divided into hepatitis B surface antigen (HBs Ag+), seroconverted (HBs Ag- and hepatitis B surface antibody [HBs Ab+]), and serocleared (HBs Ag- and HBs Ab-) groups. Then, 5 ml of the blood sample was taken, and the peripheral blood mononuclear cells (PBMCs) were separated using Ficoll. The surface markers, including CD4, CD25, and CD127, and FoxP3 intracellular marker were measured in the PBMCs. Isotype was considered the control for each sample. The samples were read by the FACSCalibur 4-color flow cytometer (BD Biosciences, San Jose, CA, USA) and analyzed using FlowJo software (version 7.6.1). The levels of aspartate aminotransferase, alanine transaminase, a-fetoprotein, platelets, white blood cells, and hemoglobin were extracted from the patients' records. Results: The mean age values of the HBs Ag+ (n=35), seroclearance (n=27), and seroconversion (n=28) groups were 43.97 +/- 11.86, 47.26 +/- 12.95, and 47.39 +/- 10.40 years, respectively. The frequency of CD4(+) CD25(+) FoxP3(+) (Treg) was higher in the HBs Ag+ group than that reported for the other two groups. The Treg population demonstrated a significant difference between the serocleared and seroconverted groups; however, the Treg frequency was higher in the seroconverted group in comparison to that of the other two groups. The Treg/T-Activator ratio was significantly higher in the HBs Ag+ group than those reported for the two other groups. Conclusion: CD4(+) CD25(+) FoxP3(+) T cells are the important subgroups of Treg cells affecting immune suppression.