Regardless of the initial boost in B1/CLL cell development, in the absence of Blimp-1 (and therefore autoantibody mediated inflammation), CLL progression was almost completely halted in RK-BLKOmice, with stable B1/CLL cell levels ranging around 20–30% in the spleen at six-eight months and when mice became moribund at a median age of two years. This evidence concerns the gene PRDM1 and B-cell chronic lymphocytic leukemia.