[Problems of the effectiveness of antihuman lymphocyte globulin corresponding to its in vitro-effect (author's transl)].

The clinical application of antihuman lymphocyte globulin (AHLG) as an immune suppressive drug rises problems concerning a possibly different sensitivity of various subpopulations of immune competent cells. Peripheral lymphocytes of healthy blood donors were studied in vitro. Using AHLG in concentrations between 1:10 and 1:1000 we were able to demonstrate that AHLG works cytotoxically in high doses, has no effect in low doses and partly contrary effect in median doses on cultivated lymphocytes stimulated with different mitogens, on the spontaneous rosette formation and on the unspecific release of migration inhibition factor (leucocyte migration inhibition test). For clinical use it should be claimed out that a sufficient high dose therapy is necessary to obtain a desirable immunosuppression. A possibly changed relation between the lymphoid subpopulation under treatment should be assessed by in vitro testing.