[Role of serum S1P levels during asthma attack in the evaluation of asthma severity].

OBJECTIVE: To observe the changes of serum sphingosine-1-phosphate (S1P) level in asthmatic patients with different severity of bronchial asthma, and to explore the evaluation value of S1P on the severity of asthma.

METHODS: A prospective observational study was conducted. Fifty-two patients with asthma admitted to Department of Respiratory Medicine of the First Affiliated Hospital of Jiamusi University from November 2015 to January 2017 were enrolled. According to the severity of the disease, the patients were divided into mild, moderate and severe groups. In the same period, 25 healthy subjects were served as healthy control group. All the subjects got the peripheral venous blood collection in the morning fasting, the level of serum S1P was determined by enzyme linked immunosorbent assay (ELISA), the peripheral blood eosinophil (EOS) was counted, and the pulmonary function test was performed. The correlation among the parameters was analyzed by Pearson correlation analysis. Receiver operating characteristic curve (ROC) was plotted, and the value of serum S1P on evaluating the severity of asthma was analyzed.

RESULTS: Fifty-two asthma patients were enrolled, including 17 patients of the mild, 19 of the moderate, and 16 of the severe. Compared with the healthy control group, serum S1P level and peripheral blood EOS in different degree asthma groups were significantly increased, and forced expiratory volume in 1 second (FEV1) was decreased significantly; and with asthma exacerbations, serum S1P levels and peripheral blood EOS were gradually increased [mild, moderate and severe S1P (nmol/L) were 1 537.0±120.3, 1 980.7±149.5, 2 202.2±117.2 (F = 274.624, P = 0.001); EOS (×10(9)/L) were 0.13±0.06, 0.20±0.07, 0.37±0.14 , respectively (F = 44.093, P = 0.001)], and FEV1 was decreased gradually [mild, moderate and severe were 0.89±0.05, 0.63±0.06, 0.42±0.10, respectively (F = 159.756, P = 0.001)]. Correlation analysis showed that there were significant positive correlations between serum S1P level and peripheral blood EOS in patients with mild, moderate and severe asthma (r value was 0.696, 0.746, 0.508, all P < 0.05), and negatively correlations with FEV1 were found (r value was -0.761, -0.655, -0.815, all P < 0.01). There was no significant correlation between serum S1P level and EOS, FEV1 in healthy control group (r value was 0.324 and -0.048, both P > 0.05). ROC curve analysis showed that the area under curve (AUC) of serum S1P for assessing mild, moderate and severe asthma was 0.948, 1.000, 1.000, respectively; when the cut-off of S1P was 1 181.8, 1 534.2, 1 708.6 nmol/L, the sensitivity was 88.2%, 100%, 100%, and the specificity was 88.0%, 100% and 100%, respectively.

CONCLUSIONS: During asthma attack, the serum S1P level was gradually increased with the exacerbation of the disease. Serum S1P level has significant evaluative effect on the severity of asthma.