Role of humoral immunity in acute cardiac allograft dysfunction.

To elucidate the pathogenic mechanisms of acute allograft dysfunction that is not caused by acute cellular rejection, we have studied the clinical and immunopathologic characteristics of 11 heart transplant recipients who had acute allograft dysfunction in the absence of interstitial mononuclear cell infiltrates on endomyocardial biopsy samples. Six of eleven patients (54%) had a striking increase in levels of anti-HLA antibodies in close temporal proximity with the episode of acute allograft dysfunction. Cardiac allograft function improved in all patients with intensification of immunosuppression.