Spleen transplantation in a leukaemic individual from his healthy identical twin.

The results of spleen transplantation from a healthy individual to his leukaemic identical twin are reported. The rationale for the procedure and its significance in relation to present hypotheses of tumour growth and spread are reviewed. Although lymphocytes of both the donor and recipient showed specific immune capacity to destroy tumour cells , there was evidence for partial inhibition of the immunological effector process that destroys the tumour cells in the diminished lymphocyte phytoagglutinin stimulation, hypoglobulinaemia, and marked deficiency of IgA in the leukaemic twin. These abnormalities and the final relapse in spite of transplantation of the spleen as a source of immunocompetent cells could also be considered the result of growth potential in the tumour, capable of overriding any immunological control.