ABSTRACT
<p><b>OBJECTIVE</b>To investigate the role of CD4+CD25+high regulatory T cells in the pathogenesis of autoimmune hepatitis.</p><p><b>METHODS</b>CD4+CD25+ high regulatory T cells and CD4+ T cells were measured by using flow cytometry in 16 patients with autoimmune hepatitis, 22 patients with chronic hepatitis B and 20 healthy blood donors. Foxp3 protein was detected by immunohistochemical assay in liver tissues from the patients with autoimmune hepatitis or chronic hepatitis B.</p><p><b>RESULTS</b>The percentage of CD4+CD25+high/CD4+ in patients with autoimmune hepatitis was significantly lower than that in healthy controls and patients with chronic hepatitis B. Meanwhile, the percentage of CD4+CD25+high/CD4+ highly increased in patients with chronic hepatitis B, compared with healthy controls; Foxp3 positive cells were mostly located in the hepatic lobular perisinusoidal spaces and the portal tract, and there was a significant difference in the quantity of Foxp3 positive cells between patients with autoimmune hepatitis and chronic hepatitis B.</p><p><b>CONCLUSION</b>Patients with autoimmune hepatitis harbor a decreased percentage of CD4+CD25+ high regulatory T cells, which may be associated with development of autoimmunity.</p>