Immunohistologic Pattern of the Portal T-Lymphocyte Infiltration in Hepatic Allograft Rejection

Monoclonal antibodies were used to identify helper T cells (T_H) and suppressor/cytotoxic T cells (T_S/C) in liver allograft biopsy specimens obtained 7,21,90,180, and 365 days postoperatively and then annually or during episodes of graft dysfunction and after treatment of rejection episodes. Biopsy specimens were obtained from 70 hepatic allografts from patients treated with cyclosporine and corticosteroids. Rejection was diagnosed by the presence of appropriate laboratory and light microscopic findings and at least 16 weeks of follow-up to exclude other causes of graft dysfunction. Three immunohistologic patterns were noted: no or only a trace of T lymphocytes, predominantly T_H infiltrate with or without a small amount of T_S/C cells (portal T_H), and a mixture of T_H with an equal or greater number of T_S/C infiltrate (portal mix). Of 68 biopsy specimens obtained during quiescent periods, only 3 had a portal tract T-lymphocyte infiltrate. Of 30 protocol biopsy specimens, 24 contained such an infiltrate a mean of 12.4 days before biochemical and routine histologic indications of rejection in the allograft. At the time of the rejection episode, 33 biopsy specimens were immunohistologically labeled; portal tract T-lymphocyte infiltrate was predominantly T_H in 8 and a mixture of T_H and T_S/C in 25. All rejection episodes with a predominantly T_H pattern responded to methylprednisofone. Of the 25 rejection episodes with a portal mix pattern, only 3 responded to methylprednisolone. Eighty-seven biopsy specimens were obtained more than 10 days after treatment of rejection. Of 31 specimens obtained after resolution of rejection, 25 had no cells in the portal tract, and 43 of 56 biopsy specimens contained either portal T_H or portal mix pattern when the rejection episodes were persistent. Thus, the presence of portal T_H or portal mix pattern in biopsy specimens from hepatic allografts may be an early sign of immunologic rejection. By determining the T-lymphocyte pattern in hepatic allograft biopsy specimens during rejection, the proper course of antirejection therapy may be predicted. A portal T-lymphocyte pattern persists in hepatic allograft rejection episodes that do not resolve.