[Should mild acute rejection of a cardiac graft be treated?].

With no additional therapy, mild acute cardiac allograft rejection progresses in 30 per cent of the cases towards moderate rejection. Three hundred mild rejections which occurred in 120 patients between May 1987 and May 1989 were studied and divided into 3 groups according to their treatment. Group I rejections (n = 108) were left untreated. In group II rejections (n = 186), the dose of oral corticosteroid therapy was increased, and in group III rejections (n = 6) major immunosuppressive treatment with methylprednisolone and antilymphocyte globulins (or Orthoclone OKT3) were initiated in view of the clinical and echocardiographic severity of the rejection. In the untreated group, 20 per cent of mild rejection progressed to moderate rejection, while 67 per cent are still at a mild stage in control myocardial biopsies. In group II, only 5 per cent of mild rejections have become moderate, and 19 per cent persisted as mild in control biopsies (p less than 0.05). The treatment of group III rejections resulted in complete disappearance of signs of heart failure and improvement of right and left ventricular contractile functions, proving that severe rejection was cured. This study demonstrates the effectiveness of increased oral corticosteroid therapy in minimal acute cardiac allograft rejections, without significant increase in infection or mortality rate. The principal reason for treating mild acute cardiac allograft rejections is to prevent their progression towards moderate rejections which require major immunosuppressive treatments and therefore have higher post-transplantation infection and mortality rates.