To investigate this possibility, we tested all S +NAb− CLL patients (n=25) and a subset of the healthy controls (n=15) for IgG binding to recombinant spike proteins of six HCoVs: SARS-CoV, MERS-CoV, HCoV-HKU1, HCoV-OC43, HCoV-NL63, and HCoV-229E. This evidence concerns the gene CHMP5 and B-cell chronic lymphocytic leukemia.