SFTPD and lung disorder: HMW and LMW SP-D structural variants have been examined in BAL by native gel electrophoresis in various clinical pulmonary diseases and, as described above, different studies have demonstrated that levels of trimeric SP-D increase in BAL in inflammatory disease, and that trimeric SP-D is composed of both partially degraded, oxidized, and inactive SP-D, as well as a Thr11-glycosylation variant (50 kDa) (18, 19, 242, 249, 252, 262, 267, 285).