Clinical significance of serum surfactant protein D (SP-D) in patients with polymyositis/dermatomyositis: correlation with interstitial lung disease.
OBJECTIVE
To determine the clinical significance of serum surfactant protein D (SP-D) levels in patients with polymyositis/dermatomyositis (PM/DM).


METHODS
Serum SP-D levels were assayed using a sensitive enzyme-linked immunosorbent assay in 59 patients with PM/DM and in 29 healthy controls.


RESULTS
The serum level of SP-D was significantly higher in patients with PM/DM than in healthy controls (mean+/-S.D. 61.7+/-122.6 vs 31.0+/-12.4 ng/ml, P < 0.01). The serum SP-D level in patients with interstitial lung disease (ILD) was significantly higher than in those without ILD (118.7+/-220.2 vs 38.7+/-21.0 ng/ml, P < 0.001). Serum level of SP-D was correlated with the presence of ILD. The incidences of decreased vital capacity (%VC) and of decreased diffusing capacity of carbon monoxidase (%DLCO) were also significantly greater in patients with an elevated SP-D level than in those with a normal level (64 vs 7%, P < 0.02; 73 vs 27%, P < 0.01). Moreover, the serum SP-D level was inversely correlated with %VC (r=-0.452, P < 0.01) and %DLCO (r=-0.349, P < 0.05).


CONCLUSIONS
The serum SP-D level may be a useful marker for ILD in patients with PM/DM.
Ihn
H
H
Department of Dermatology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
Asano
Y
Y
Kubo
M
M
Yamane
K
K
Jinnin
M
M
Yazawa
N
N
Fujimoto
M
M
Tamaki
K
K
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D003882:Dermatomyositis / Q000097:blood* / Q000150:complications; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D017285:Polymyositis / Q000097:blood* / Q000150:complications; D011336:Probability; D037663:Pulmonary Surfactant-Associated Protein D / Q000032:analysis / Q000378:metabolism*; D012016:Reference Values; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
D015415:Biomarkers; D037663:Pulmonary Surfactant-Associated Protein D