Antithymocyte antiserum effects in man

Fourteen nonsurgical patients received goat antithymocyte antiserums (ATG) without other immunosuppressive drugs. A mean dose level of 1.5 g was administered over an average of 39 days. The following observations were made: (1) Serum total protein, gamma globulin, gamma G, C3 complement and the erythrocyte sedimentation rate increased. (2) A weak positive antiglobulin test developed in many and was due to fixation of C3 to the erythrocyte surface. (3) Heterophil agglutinins of a “foreign serum” variety was produced by 92 per cent of patients. (4) Significant peripheral lymphopenia developed. (5) Secondary humoral immune reactions were not inhibited, but a reduction of primary gamma G and gamma M responses was noted. (6) Both primary and secondary cellular immune reactions were depressed. Allogeneic skin graft survival was prolonged to 26 days. (7) Circulating goat proteins at serum levels of 0.02 mg/ml or higher were found in half the patients, and 79 per cent of subjects produced antibody against goat proteins.