A role for mannose-binding lectin, a component of the innate immune system in pre-eclampsia

Abstract

Problem: Mannose-binding lectin (MBL) is a pattern-recognition receptor that activates complement and modulates inflammation. Homozygosity for the most common allele of the MBL2 gene that is associated with high MBL serum concentrations is more prevalent among patients with pre-eclampsia. The objective of this study was to determine maternal plasma MBL concentrations in normal pregnant women and patients with pre-eclampsia.

Method of study: This cross-sectional study included normal pregnant women (n = 187) and patients with pre-eclampsia (n = 99). Maternal plasma MBL concentrations were determined by ELISA.

Results: Women with pre-eclampsia had a higher median maternal plasma MBL concentration than normal pregnant women. MBL concentration distribution curves were three-modal, the subintervals in normal pregnancy were low (< 143.7), intermediate (143.7-1898.9) and high (> 1898.9 ng/mL). The proportion of normal pregnant women was larger in the low subinterval, while the proportion of patients with preeclampsia was larger in the high subinterval (P = 0.02). Normal pregnant women in the high subinterval had a larger rate of placental underperfusion than those in the low and intermediate subintervals (P = 0.02).

Conclusions: The median maternal plasma MBL concentration is elevated in patients with pre-eclampsia and a larger proportion of these patients are in the high subinterval than normal pregnant women, suggesting that this component of the innate immune system is involved in the mechanisms of disease in pre-eclampsia.

Figure 1. Maternal plasma MBL concentrations in the study groups

Women with preeclampsia had significantly higher maternal plasma MBL concentrations [median: 1128 ng/ml (range: 13.6–11870.0)] than normal pregnant women [median: 886.3 ng/ml (range: 6.1–7805.1), p<0.01].

Figure 2. Data mass densities and ranges of maternal plasma MBL concentrations in the study groups. (A)

The log₁₀ MBL concentrations showed a common three-modal distribution with three typical subintervals in both groups. The area under both density curves is 1; the density values represent the probability of observing the concentration given at the X axis. (A–B) The cut-offs between the concentration subintervals were empirically determined by using the concentration values (143.7 ng/ml and 1898.9 ng/ml) corresponding to the two local minimums on the normal pregnancy group distribution curve. (B) Concentration values are represented in ng/ml.