The effect of a lymphotoxic factor from patients with multiple sclerosis on acute lymphosarcoma cell leukemia and...

Eight patients with acute lymphosarcoma cell leukemia or acute lymphoblastic leukemia received infusions of plasma containing a lymphotoxic factor. The lymphotoxic factor induced a transient fall in the number of "blast" cell forms in the peripheral blood in six of the eight patients but did not produce sustained remissions. Previous investigations have demonstrated that this lymphotoxic factor, found in the plasma of patients with active multiple sclerosis, is of low molecular weight and does not have the properties normally associated with an antibody. This factor appears to selectively interfere with ribonucleic acid synthesis in the thymus-derived lymphocyte. Lymphotoxic factor activity was demonstrated in the serum of one patient during a remission in leukemia induced by a viral illness.