Reduced numbers of CD8+ T cells and B cell-expression of Leu-8 antigen in peripheral blood of patients with primary biliary cirrhosis.

The presence of Leu-8 antigen, the human homologue of the murine MEL-14 peripheral lymph node homing receptor, defines subsets of peripheral blood mononuclear cells (PBMC) with different functions. Since it has been suggested that abnormal function of Leu-8 subsets may contribute to the immunopathogenesis of primary biliary cirrhosis (PBC), this study was undertaken to define whether abnormal expression of the Leu-8 antigen occurs in this disease. We studied 25 PBC patients, 12 with other chronic liver diseases, and 21 normal controls. PBMC were tested by direct immunofluorescence using monoclonal antibodies and flow cytometry. In PBC the proportion of PBMC that were CD4+ was normal; in contrast, the proportion that were CD8+ was decreased (p < 0.01). A negative correlation was found between absolute numbers of CD8+ T cells and total serum bilirubin levels (r = -0.50, p < 0.05). The distribution of Leu-8 antigen on T cells was normal; however, the proportion of PBMC that were B cells was increased (p < 0.01) and the fraction of these that were Leu-8 negative was also increased (p < 0.01). The expression of antigens of activation on B cells was similar to that for normal controls. These findings suggest that in peripheral blood of PBC patients reduced numbers of T cells may occur due to a selective intrahepatic sequestration of CD8+ T cells, and that the decreased expression of Leu-8 antigen by B cells may be associated with their participation in autoimmune processes.