SFTPD and hypersensitivity pneumonitis: Interestingly, we noted that one of the common interactions, involving the SFTPB (rs3024798 and rs2077079) and the rs2243639 of the SFTPD, was associated with increased risk of HP compared to the homogeneous antigen exposed control group, however, the same interaction was associated with decreased risk of HP compared to the heterogeneous non-exposed control group, in which the history of exposure and living conditions were unknown.