Complement Split Products C3a/C5a and Receptors: Are They Regulated by Circulating Angiotensin II Type 1 Receptor Autoantibody in Severe Preeclampsia?
BACKGROUND
This study measured the serum levels of complement component (C)3a and C5a and the placental expressions of C3a receptor (R) and C5aR to determine a potential correlation with circulating angiotensin II type 1 (AT1) receptor agonistic autoantibody (AT1-AA) in severe pre-eclampsia.


METHODS
A total of 118 women were recruited and divided into 2 groups: the control group (normotensive preterm pregnancies, n = 66) and severe pre-eclampsia group (n = 52). Levels of C3a, C5a and AT1-AA in serum were measured by enzyme-linked immunosorbent assay and C3aR and C5aR in placenta by Western blotting.


RESULTS
Levels of C3a, C5a and AT1-AA in serum from the severe pre-eclampsia group were significantly higher than in controls (p < 0.05). Placental expression of C3aR and C5aR in the pre-eclampsia group was lower than that in controls (p < 0.05). There were significant positive correlations between levels of C3a, C5a and AT1-AA in serum from the pre-eclampsia group (p < 0.05). In contrast, there was no correlation between C3aR and C5aR in the placenta and AT1-AA in serum in the pre-eclampsia group (p > 0.05).


CONCLUSIONS
Increased C3a, C5a and AT1-AA in the serum provide indirect evidence that AT1-AA-mediated activation contributes to activate complement, which is a key mechanism underlying the pathogenesis of severe pre-eclampsia.
Department of Obstetrics and Gynecology, Affiliated Hospital of the Medical College of Qingdao University, Qingdao, Shandong, China.
Yuanhua
Y
Ye
Yujie
Y
Kong
Yan
Y
Zhang
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D010920:Placenta / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000097:blood / Q000276:immunology* / Q000378:metabolism*; D011247:Pregnancy; D044087:Receptor, Anaphylatoxin C5a / Q000097:blood / Q000378:metabolism*; D044140:Receptor, Angiotensin, Type 1 / Q000276:immunology*; D011951:Receptors, Complement / Q000097:blood / Q000378:metabolism*
C544065:AGTR1 protein, human; D001323:Autoantibodies; C488033:C5AR1 protein, human; D044087:Receptor, Anaphylatoxin C5a; D044140:Receptor, Angiotensin, Type 1; D011951:Receptors, Complement; C085567:complement C3a receptor