Pulmonary surfactant protein A in sera for assessing neonatal lung maturation.
To examine whether surfactant protein A (SP-A) in postnatal serum can predict the development of respiratory distress syndrome (RDS), we analyzed the relationship between serum concentrations of SP-A and the risk of RDS using sera from neonates within 24 h after birth. A total of 104 blood samples including 23 samples from newborn infants with RDS were obtained. SP-A content in sera was measured with an enzyme-linked immunosorbent assay system consisting of a standard of native SP-A and two monoclonal antibodies against human SP-A. The level of serum SP-A increased with advancing gestation. Since the mean level of serum SP-A in patients with RDS (3.8 ng/ml) was significantly lower than those without RDS (12.0 ng/ml) (P<0.001), we calculated the diagnostic index values at various cutoff points and chose cutoff values to predict the risk of RDS. Maximum diagnostic value of 85% was obtained at a cutoff point of 3.8 ng/ml (sensitivity 57% and specificity 93%). We also chose a cutoff value of 2.1 ng/ml for definitive diagnosis of RDS, and 8.3 ng/ml for exclusive diagnosis of RDS. The adjusted odds ratios of RDS was significantly elevated when SP-A concentration in serum was under the cutoff values. The presence of SP-A in cord blood serum was also confirmed by immunoblotting analysis. We emphasize the value of SP-A examination in cord blood or postnatal serum from infants who exhibited respiratory difficulties at birth. We believe that our results are consistent with the hypothesis that SP-A is a useful serum marker in predicting the development of RDS.
Department of Pediatrics, Saitama Medical Center, Saitama Medical School, 1981 Kamoda-Tsujido, 350-8550, Kawagoe Saitama, Japan.
K
K
Kaneko
H
H
Shimizu
H
H
Arakawa
Y
Y
Ogawa
D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005325:Fetal Organ Maturity; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology*; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011510:Proteolipids / Q000097:blood* / Q000276:immunology; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000097:blood* / Q000276:immunology; D012372:ROC Curve; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood* / Q000209:etiology
D015415:Biomarkers; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants