Elevated plasma surfactant protein D (SP-D) levels and a direct correlation with anti-severe acute respiratory syndrome coronavirus-specific IgG antibody in SARS patients.
Pulmonary SP-D is a defence lectin promoting clearance of viral infections. SP-D is recognized to bind the S protein of SARS-CoV and enhance phagocytosis. Moreover, systemic SP-D is widely used as a biomarker of alveolar integrity. We investigated the relation between plasma SP-D, SARS-type pneumonia and the SARS-specific IgG response. Sixteen patients with SARS, 19 patients with community-acquired pneumonia (CAP) (Streptococcus pneumonia) and 16 healthy control subjects were enrolled in the study. Plasma SP-D and anti-SARS-CoV N protein IgG were measured using ELISA. SP-D was significantly elevated in SARS-type pneumonia [median (95% CI), 453 (379-963) ng/ml versus controls 218 (160-362) ng/ml, P < 0.05] like in patients with CAP. SP-D significantly correlated with anti-SARS-CoV N protein IgG (r(2) = 0.5995, P = 0.02). The possible re-emergence of SARS or SARS-like infections suggests a need for minimal traumatic techniques for following the alveolar compartment, e.g. during testing of antivirals. We suggest that monitoring systemic SP-D may be useful in monitoring the alveolar integrity in SARS-type pneumonia. The significant correlation between plasma SP-D and anti-SARS-CoV-specific antibodies support the role for SP-D in interlinking innate and adaptive immune pathways.
Department of Basic Medicine, Taishan Medical University, Taian, China.
Y P
YP
Wu
Z H
ZH
Liu
R
R
Wei
S D
SD
Pan
N Y
NY
Mao
B
B
Chen
J J
JJ
Han
F S
FS
Zhang
U
U
Holmskov
Z L
ZL
Xia
P G
PG
de Groot
K B M
KB
Reid
W B
WB
Xu
G L
GL
Sorensen
D000293:Adolescent; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D000086462:Coronavirus Nucleocapsid Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D019590:Nucleocapsid Proteins / Q000276:immunology*; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*; D011994:Recombinant Proteins / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology*
D000914:Antibodies, Viral; D015415:Biomarkers; D000086462:Coronavirus Nucleocapsid Proteins; D007074:Immunoglobulin G; D019590:Nucleocapsid Proteins; D037663:Pulmonary Surfactant-Associated Protein D; D011994:Recombinant Proteins