We monitored CLL incidence, as described above, in cohorts of Cd40l-deficient IgH.TEμ mice (IgH.TEμ.Cd40l−/−, n = 13), Aicda-deficient IgH.TEμ mice (IgH.TEμ.Aicda−/−, n = 26) and IgH.TEμ control littermates, n = 69 or n = 56, respectively for ~400 days (Figure 2). The gene discussed is CD40LG; the disease is B-cell chronic lymphocytic leukemia.