ABSTRACT
<p><b>OBJECTIVES</b>To study the expression and distribution of CD4+CD25+ regulatory T cells (Treg) in liver tissues of patients with fibrosing cholestatic hepatitis (FCH) after liver and kidney transplantation and to investigate their roles in the pathogenesis of FCH.</p><p><b>METHODS</b>Liver biopsy specimens from five patients with FCH were studied histopathologically. A specific marker for CD4+CD25+ regulatory T cells in those specimens was detected with anti-FOXP3 monoclonal antibody by immunohistochemistry. Apoptoses of hepatocytes were detected with in situ apoptosis detection TUNEL kit.</p><p><b>RESULTS</b>Fibrosis in portal and around portal areas, cholestasis in some of the hepatocytes and canaliculi, widespread ballooning and ground-glass appearance of liver cells, and positivity of HBsAg and HBcAg and Pre-S1 protein were seen in the livers of all cases. The positive signal of FOXP3 was located in the cytoplasm of lymphocytes and the positive cells were mainly aggregated in the portal areas as well as occasionally appearing in the hepatic sinusoids. There were many more apoptotic hepatocytes near the portal areas.</p><p><b>CONCLUSION</b>Fibrosing cholestatic hepatitis has specific pathological characteristics which might be caused by high expressions of FOXP3 in liver tissues.</p>