Objective: To investigate the variance levels of plasma soluble leukocyte differentiation antigens CD₄₀ (sCD₄₀) and soluble CD₄₀ ligand (sCD₄₀ L) in preeclamptic patients with renal damage and its relationship.
Methods: A total of 63 pregnant women attended the Department of Obstetrics, Affiliated Hospital of Qingdao University Medical College between August 2008 and June 2010. In the present study included 28 pregnant women with mild preeclampsia and 35 patients with severe preeclampsia. Thirty matched normotensive pregnant women were enrolled in the study as the control group. Expression of sCD₄₀ and sCD₄₀ L were determined by ELISA. At the same time, the blood routine, C reaction protein (CRP), urine routine, 24 hours urine protein excretion, and serum uric acid (UA), creatinine (Cr), blood urea nitrogen (BUN) were measured. The correlation analysis was performed between the sCD₄₀/sCD₄₀ L and the blood biochemical indexes in 3 groups.
Results: (1) The median levels of CRP in severe preeclampsia (10.8 mg/L) and mild preeclampsia group (7.1 mg/L) are significantly higher than that of control group (3.3 mg/L, P < 0.05); The level of CRP in severe preeclampsia group was also higher than that of mild preeclampsia group (P < 0.05). The median gestational age at delivery in severe preeclampsia (32.5 weeks) was significantly less than that of mild preeclampsia group (37.2 weeks) and normal group (38.6 weeks, P < 0.05). However no significant differences were observed between mild preeclampsia group and normal group (P > 0.05). The platelet count in severe preeclampsia (132 × 10⁹/L) was significantly less than those of mild preeclampsia group (212 × 10⁹/L) and normal group (216 × 10⁹L, P < 0.01), but no significant differences were observed in blood platelet amount between mild preeclampsia group and normal group (P > 0.05). There was no significant difference in hemoglobin level and white blood cell in three groups (P > 0.05). (2) The sCD₄₀ plasma concentration in severe, mild preeclampsia and normal group was 133.6, 126.5 and 90.7 ng/L, respectively. The sCD₄₀ L plasma concentrations were 12.5, 10.4 and 4.4 ng/L respectively in the 3 groups. 24 hours urinary protein quantitative was 4.5 g/d, 0.8 g/d and 0 in the 3 groups respectively. And the UA level was 486 µmol/L, 289 µmol/L and 162 µmol/L. In the above three groups, the monitoring indicators were significantly higher in women with severe preeclampsia group compared with mild preeclampsia and control groups (P < 0.01), and there were also higher in mild preeclampsia group than that in control groups (P < 0.01). The level of plasma Cr (89 µmol/L) and BUN (5.32 mmol/L) in severe preeclampsia group were higher than those of mild preeclampsia group (66 µmol/L and 4.49 mmol/L) and control group (57 µmol/L and 3.32 mmol/L, P < 0.05). There was no significant difference between mild preeclampsia group and normal group (P > 0.05). (3) The correlation analysis indicated that the level of sCD₄₀ has a positive correlation with 24 hours urinary protein quantitative (r = 0.434, P < 0.05), also significant positive correlation (r = 0.536, 0.528, P < 0.01) between the level of sCD₄₀ and UA or CRP in women with preeclampsia. There was no significant correlation between the level of sCD₄₀ and systolic blood pressure, diastolic blood pressure, delivery gestational age, Cr, BUN, and platelet count (r = 0.135, 0.183, -0.133, 0.190, 0.167, -0.221, all P > 0.05). There were positive correlation between the level of sCD₄₀ L and 24 hours urine protein excretion, either UA or CRP (r = 0.591, 0.445, 0.539, all P < 0.01). No significant correlation was found between sCD₄₀ L and systolic blood pressure, diastolic blood pressure, delivery gestational age, Cr, BUN, and platelet count (r = 0.178, 0.212, -0.292, 0.144, 0.135, -0.273, all P > 0.05). There was significant positive correlation between plasma sCD₄₀ and sCD₄₀ L (r = 0.707, P < 0.01). There was no relationship between the level of sCD₄₀, sCD₄₀ L and the blood biochemical indexes in normotensive pregnant women (P > 0.05).
Conclusions: The plasma concentrations of sCD₄₀ and sCD₄₀ L are significantly higher in pregnant women with preeclampsia compared with the control, which may be involved in the development of preeclampsia and contribute to the kidney damage. The variance levels of sCD₄₀ and sCD₄₀ L may be also related to the severity of preeclampsia.