Effect of long-term cyclophosphamide treatment on T and B lymphocytes in normal guinea pigs

The effect of long-term repeated cyclophosphamide administration at low doses on T and B lymphocyte levels in the blood, lymph nodes and thymus of the guinea pig has been studied. A significant depletion of B cell levels occurred in the blood and the lymph nodes. Although there was evidence of depression of T cell levels in both blood and thymus, these changes were not statistically significant, except in the case of total T lymphocyte levels in the blood in one experiment. It is suggested that differences in sensitivity of T and B cells to cyclophosphamide may be related to differences in proliferative turnover and in their capacity to repair damage to DNA.