[Comparative study on in vitro lymphocytotoxicity and mitogenicity of different antilymphocyte globulin (ALG) preparations].

The lymphocytotoxicity and mitogenicity between six different ALG preparations on the clinical use world wide were compared. No significant difference in the lympholytic activity was observed between preparations and 100% cell lysis was achieved at a concentration of 50 micrograms/ml in the presence of complement. On the other hand, four preparations now in use in European countries and USA showed variable mitogenic activities on lymphocytes in the absence of complement, whereas two ALGs used in Japan did not. As the stimulatory effects of ALG on lymphocytes may contribute to the clinical outcome in the treatment of severe aplastic anemia (Kawano et al, 1988), these date can explain the poor clinical results of ALG therapy with those two preparations in Japan. Careful measures should be paid in the construction of treatment protocol and selection of ALG preparations to yield the best results.