SFTPD and hypersensitivity pneumonitis: Ten months after the first bCII injection, we also found an increase in lung density on lung CT images (Figure 3A,D,J) and increased serum SP‐D levels (Figure S1 and Figure 3K), which were consistent with the histological findings of active alveolitis with pneumocyte hyperplasia (Figures 2 and 3B,C,E,F).