Vitamin C seems to stimulate lymphocyte activity, which is one of the reasons that Linus Pauling thought it was effective in the prevention of malignancy. However, when the malignancy is in the lymphocytes, it is not a good idea to stimulate them any further than they already are.

We all need vitamin C to live. The question then is, what amount of vitamin C is appropriate for people with CLL? The consensus seems to be, stick with recommended daily allowances, and do not go too high above that.