According to the multivariate analysis, CLL progressive(OR=2.98, 95% CI 1.10–8.10, P=0.033)was an independent risk factor for severe/critical COVID-19 and administration of the BTK(Bruton tyrosine kinase)inhibitor monotherapy might exert a protective effect and influence a positive outcome of the COVID-19 infection(OR=0.38, 95% CI 0.16–0.90, P=0.028). This evidence concerns the gene BTK and COVID-19.