15-deoxyspergualin treatment of graft rejection in man: effect on mononuclear cells

We studied the effects of 15-deoxyspergualin (DSG) on human mononuclear cells in blood when DSG was administered as anti-rejection treatment to kidney-transplant patients in combination with methylprednisolone (MP) in a safety study. The numbers of leucocytes, lymphocytes and monocytes, the percentages of T and B cells and the expression of the interleukin 2 receptor and the human leucocyte antigen DR locus (HLA-DR) were determined in blood from these patients and from patients treated with MP only. We found that the number of lymphocytes and monocytes decreased in all groups, as also did the CD4/CD8 ratio and the HLA-DR expression on monocytes. DSG counteracted the increase in the number of leucocytes observed in patients treated with MP only. Different effects of DSG and MP were also observed on B cells. While the percentage of CD20+ cells increased in the MP group, it remained unaltered in patients given low-dose DSG and/or was decreased in those given higher doses. Since available evidence suggests an effect of DSG on B-cell reactivity, this drug may become an important addition to the arsenal of immunosuppressive drugs in clinical transplantation.