BIK and pulmonary emphysema: Because emphysema develops in aged mice, we initially analyzed the lungs of bik–/– and bik+/+ mice at 56 to 80 weeks and found that the alveolar volume increased in the lungs of bik–/– compared with bik+/+ mice at 56 to 80 weeks of age (Supplemental Figure 1A; supplemental material available online with this article; https://doi.org/10.1172/JCI170594DS1).