RT Journal Article SR Electronic T1 Circulating Surfactant Protein D Is Decreased in Systemic Lupus Erythematosus JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 2449 OP 2453 DO 10.3899/jrheum.090069 VO 36 IS 11 A1 SILJE VERMEDAL HOEGH A1 ANNE VOSS A1 GRITH LYKKE SORENSEN A1 ANETTE HØJ A1 CHRISTIAN BENDIXEN A1 PETER JUNKER A1 UFFE HOLMSKOV YR 2009 UL http://www.jrheum.org/content/36/11/2449.abstract AB Objective. Deficiencies of innate immune molecules like mannan binding lectin (MBL) have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Surfactant protein D (SP-D) and MBL belong to the same family of innate immune molecules — the collectins, which share important structural and functional properties. We aimed to compare concentrations of serum SP-D in patients with SLE and in healthy controls, and to investigate if SP-D is associated with selected disease indicators. We investigated the possible association of the Met11Thr polymorphism with disease, since this polymorphism is an important determinant for serum level, oligomerization pattern, and function of SP-D. Methods. Serum SP-D was measured using a 5-layer ELISA in 70 SLE patients and 1476 healthy subjects. DNA was genotyped for the Met11Thr variant. Results. Median SP-D level in serum was 911 ng/ml (95% CI 776–1118) in patients and 1068 ng/ml (95% CI 901–1246) in controls (p = 0.0004). Circulating SP-D did not differ significantly in patients with high, intermediate, or low SLE disease activity. Similarly, SP-D did not correlate with C-reactive protein, erythrocyte sedimentation rate, and anti-dsDNA seropositivity. Genetic analysis did not support an association of the Met11Thr genotype with SLE. Conclusion. These findings suggest that low SP-D, unrelated to conventional disease indicators, represents an aspect of SLE etiopathogenesis.