The main limitations of this study were: (1) the small number of patients with each of these gene mutations; (2) the ending of clinical follow-up in 2010, with the result that we have no data on the treatments received by these patients since then; and (3) the fact that the randomised treatments in LRF CLL4 are no longer in general use, raising the question as to whether deaths from infection may follow a different pattern in the era of BCR and BCL2 inhibitors. The gene discussed is BCR; the disease is infection.