Calprotectin plasma level is elevated in preeclampsia

BACKGROUND: Calprotectin is a protein found in myelomonocytic cells and plays a role in various physiological functions such as inflammatory processes and antiproliferation of cells, and in the neutrophil defense against bacterial infections. Preeclampsia is characterized by maternal endothelial dysfunction and by insufficient trophoblast invasion into the maternal endometrium (decidua). In addition, preeclampsia is associated with maternal leukocyte activation and we therefore wanted to investigate whether calprotectin levels in plasma from women with preeclampsia differed from the levels in normotensive pregnant and nonpregnant women. METHOD: Calprotectin measurements were included in a case-control study of 20 preeclamptic women matched with 20 normotensive pregnant women regarding age, pregnancy length, parity and body mass index (BMI). We also measured calprotectin in 12 nonpregnant women. Calprotectin plasma levels were analyzed using an enzyme-linked immunosorbent assay (ELISA). RESULTS: We discovered significantly elevated plasma calprotectin levels in preeclamptic patients compared to matched normotensive pregnancies: 768 (612-1016) microg/L vs. 445 (276-598) microg/L (medians, 25, 75 percentiles, respectively), p = 0.002. CONCLUSIONS: The elevated plasma calprotectin levels demonstrated in the preeclampsia group supports the notion that leukocytes are activated in preeclampsia. The elevated calprotectin level might constitute a part of the innate defense in myelomonocytic cells against microorganisms in pregnancy. We suggest further elucidation of a role for calprotectin in the development of pregnancy disorders such as preeclampsia.