Influence of different cytotoxic drugs on T and B lymphocytes in children with all during remission maintenance therapy.

The influence of four different cytotoxic drugs (MTX, CYC, 6MP, and ARA-C) on T, B, and O-lymphocytes was investigated in 20 children with ALL in complete remission during cyclic remission maintenance therapy. Each of the four drugs causes a marked reduction of the absolute number of T and B cells whereas the relative number lies within the normal range with the exception of CYC, which leads to a depression of the percentage of both T and B cells. The percentage of O cells is markedly increased by CYC and slightly increased by MTX, 6MP, and ARA-C. The data are interpreted with care since the function of the immune system and especially tumor rejection depends on the interaction between the different lymphocyte subpopulations.