Comparing the clinical characteristics of patients with and without pneumonia, patients who developed pneumonia had a higher median age (58 vs. 52 years, P=0.034; Table 2), higher prevalence of B-cell lymphoma (91.8% vs. 75.0%, P=0.020), and were more likely to have previously received anti-CD20 therapy (86.9% vs. 74.4%, P=0.048) as well as Bruton’s tyrosine kinase (BTK) inhibitor therapy (32.8% vs. 11.9%, P=0.001). Here, BTK is linked to susceptibility to pneumonia measurement.