ANTILYMPHOCYTE serum (ALS) has been shown to be a potent immunosuppressive agent in that animals treated with it maintain allografts of skin, kidney, and other organs for prolonged periods.1-3 Although the mode of action of ALS is unknown, some investigators have suggested that its immunosuppressive ability is related to its ability to produce and maintain a lymphopenia.1,4 Others have reported a reduction in circulating lymphocytes but observed no correlation of this effect with the length of allograft survival.5-7
An important factor which has received little attention is the dose schedule for administering the ALS. It is generally assumed that some period of pretreatment before the application of the allograft is more effective than beginning treatment at the time of, or after, grafting.8 The duration of pretreatment which will give maximum immunosuppression has not been fully determined.
These experiments were not designed to obtain permanent graft survival
Grogan JB, Moynihan PC, Hardy JD. Efficacy of Short-Term in Prolonging Survival Antilymphocyte Serum Treatment of Skin Allografts in Rats. Arch Surg. 1968;97(1):144–148. doi:10.1001/archsurg.1968.01340010174024