[Rejection of a liver allograft. Diagnosis and treatment]

Graft rejection remains a major problem in liver transplantation. The frequency of acute rejection is of the order of 50%. The first episode usually occurs around the 7th day. The diagnosis, suggested by clinical signs and biochemical abnormalities, is confirmed by histology. Three fundamental histological lesions are usually observed: portal infiltrate, biliary lesions and endothelitis. Chronic liver rejection is characterised by progressive reduction in the number of interlobular bile ducts. It affects 5 to 15% of transplant recipients, is refractory or poorly responsive to current immunosuppressant treatments and usually requires retransplantation. Prophylactic immunosuppression usually consists of a triple combination of cyclosporin-azathioprine-corticosteroids. FK 506 has been recently proposed. Corticosteroids inhibit the synthesis of interleukin 1 and reduce the synthesis of mediators of inflammation. Azathioprine is an antimetabolite which inhibits T lymphocyte cell division. Cyclosporin decreases lymphokine secretion. FK 506 can be used to treat acute rejection resistant to other immunosuppressants and may prevent chronic rejection. Cyclosporin is started at low doses and gradually increased until the desired serum concentration is obtained. Regular monitoring of serum cyclosporin levels is essential to reduce the adverse effects of this drug. The doses of corticosteroids are gradually decreased to achieve a maintenance dose (10-30 mg/day). Azathioprine is commenced postoperatively (0.5 to 1.5 mg/kg/day). In the long term, azathioprine should be suspended and the dosage of corticosteroids should be reduced. The initial treatment of rejection consists of bolus injections of corticosteroids: 10 to 15 mg/kg/day of i.v. methylprednisolone for 2 or 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)