SP-D levels also did not show significant differences among the IPF group (166.9 ± 111.1), CVD group (92.7 ± 67.7), CB/Pneumonia group (131 ± 71.0), and PCP group (194.1 ± 157.5) (Fig. 2c). This evidence concerns the gene SFTPD and idiopathic pulmonary fibrosis.