Surfactant protein D (SP-D) and systemic scleroderma (SSc).

We measured serum levels of SP-D in collagen diseases (110 cases) such as systemic scleroderma (SSc), scleroderma spectrum disorders (SSD), systemic lupus erythematodes (SLE), Sjogren syndrome (Sjs), dermatomyositis (DM), rheumatoid arthritis (RA), and dermatitis (DE) (109 cases) as a control. Additionally, we performad a correlation analysis to determine how these levels were related to pulmonary fibrosis and function test (vital capacity, %DLco). The serum levels of SP-D increased in SSc patients with Barnett type III more than in SSc patients with Barnett type I or II, while they increased slightly in SSD (incomplete type of SSc) patients. The differences in these figures were statistically significant between the SSc (SSc & SSD) and non-SSc (SLE, DM, Sjs & RA) groups (p<0.005). The serum levels of SP-D in SSc patients with anti-topoisomerase I antibodies were statistically higher than those in SSc patients with other types of anti-nuclear antibodies. There was a statistically significant correlation between the severity of pulmonary fibrosis and the serum levels of SP-D, and a statistically negative correlation between SP-D levels and vital capacity or %DLco, but there was no proportional correlation with the forced expiatory volume (FEV1.0%). There was no statistical relationship between pre- and post-therapy with photopheresis; however, there was a statistical correlation between the serum levels of SPD and KL-6. In the group of collagen diseases, plasma levels of SP-D were higher than serum levels of SP-D. Patients with SSc possess higher levels of SP-D than do those with other collagen diseases and dermatitis, which may correspond to the severity of pulmonary fibrosis.