B-NHL (hazard ratio [HR]=3.7, 95% confidence interval [CI] 1.4–10.0, P=0.009), anti-CD20 therapy (HR=2.3, 95% CI 1.0–5.2, P=0.050), BTK inhibitor (HR=3.6, 95% CI 1.8–7.4, P<0.001), active therapy (HR=3.0, 95% CI 1.5–5.7, P=0.001), and lack of disease remission (HR=3.7, 95% CI 1.8–7.4, P=0.001) were high-risk factors for developing pneumonia. This evidence concerns the gene BTK and susceptibility to pneumonia measurement.