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Primary anti-phospholipid syndrome: any role for serum complement levels in predicting pregnancy complications?
Rossella Reggia1, Tamara Ziglioli, Laura Andreoli
1Rheumatology and Clinical Immunology, Spedali Civili and University of Brescia, Brescia, Italy.
Insights
Serum complement levels (C3 and C4) were evaluated in pregnancies of patients with primary antiphospholipid syndrome (PAPS) and other conditions. Low C3 and C4 were common, but not predictive of obstetric complications in PAPS.
Area of Science:
- Immunology
- Obstetrics
- Rheumatology
Background:
- The complement system, particularly C3 and C4, plays a role in antiphospholipid antibody (aPL)-mediated damage.
- Obstetric complications are a concern in patients with autoimmune conditions like primary antiphospholipid syndrome (PAPS).
Purpose of the Study:
- To investigate the association between serum complement levels (C3 and C4) and obstetric complications in pregnancies.
- To establish normality ranges for C3 and C4 during pregnancy in healthy women.
Main Methods:
- Compared serum C3 and C4 levels in 57 PAPS pregnancies and 49 UCTD/SS pregnancies with 175 healthy pregnant women.
- Defined hypocomplementaemia based on normality ranges and assessed its prevalence in PAPS and UCTD/SS groups.
- Analyzed the relationship between hypocomplementaemia and obstetric complications in PAPS pregnancies.
Main Results:
- Both PAPS and UCTD/SS patient groups exhibited significantly lower C3 and C4 levels across trimesters compared to healthy controls.
- No significant difference in C3 or C4 levels was observed between PAPS and UCTD/SS patient groups.
- No association was found between low C3 or C4 levels and the occurrence of obstetric complications in PAPS pregnancies.
Conclusions:
- Hypocomplementaemia was not found to be associated with obstetric complications in primary antiphospholipid syndrome (PAPS).
- All pre-eclampsia cases in the study presented with low C3 levels throughout pregnancy.
- While the complement system contributes to aPL-mediated damage, its predictive value for pregnancy outcomes appears limited.
Objective:
To evaluate the association between serum complement levels (C3 and C4) and obstetric complications.
Methods:
Fifty-seven pregnancies in primary APS (PAPS) patients were compared with 49 pregnancies in patients with UCTD and SS. A group of 175 healthy pregnant women were studied to calculate a normality range for C3 and C4 during pregnancy. Such a range was applied to define hypocomplementaemia in PAPS and UCTD/SS.
Results:
Both groups of patients (PAPS and UCTD/SS) showed significantly lower levels of C3 and C4 in each trimester as compared with healthy women; conversely, no significant difference was found between PAPS and UCTD/SS. Comparing PAPS pregnancies with and without complications, no difference was found in the prevalence of low C3 or low C4.
Conclusion:
No association was found between hypocomplementaemia and obstetric complications in PAPS. However, both cases of pre-eclampsia were characterized by low C3 throughout pregnancy. There is evidence that the complement system is a contributor to the mechanisms of aPL-mediated damage, but its predictive role on the final pregnancy outcome does not seem to be of major impact.
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