Pit cell-hepatocyte contact in autoimmune hepatitis.

This is the first report to document pit cells in the human liver. These cells were identified by characteristic electron-dense granules and rod-cored vesicles. The granules of human pit cells were smaller in number and size than those of the rat. In the present case of autoimmune hepatitis, pit cells and conventional agranular lymphocytes migrated into hepatic parenchyma and contacted degenerating and immature hepatocytes. Pit cells show natural killer activity (Kaneda et al., 1983), and may participate in development of lesions and cellular damage.