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Complement system in healthy term newborns: reference values in umbilical cord blood
J Sonntag1, U Brandenburg, D Polzehl
1Department of Neonatology, Charité-Virchow-Hospital, Humboldt University Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany.
Insights
This study establishes crucial reference ranges for complement system components in healthy newborns. These values aid in identifying complement activation or deficiencies in neonates.
Area of Science:
- Immunology
- Neonatal Medicine
- Clinical Chemistry
Background:
- Complement system activation is implicated in various diseases.
- Reliable identification of complement activation in neonates is challenging due to a lack of established reference ranges.
- Perinatal conditions can lead to complement system activation.
Purpose of the Study:
- To establish reference ranges for complement system components in cord blood of healthy term newborns.
- To provide baseline data for detecting complement deficiencies or activation in neonates.
Main Methods:
- Cord blood samples were collected from 125 healthy term newborns.
- Concentrations of C1r, C2, C5, C7, Properdin, factor D, factor H, and factor I were measured using single radial immunodiffusion.
- C3a and C5a levels were determined by enzyme immunoassay (EIA), and complement function was assessed via hemolytic assays.
Main Results:
- Specific reference ranges (5th percentile, median, 95th percentile) were determined for nine complement components.
- Functional activity of the whole complement system and alternative pathway were quantified.
- Concentrations of activated complement split products, C3a and C5a, were established.
Conclusions:
- The established reference values for complement components and activation markers are vital for neonatal diagnostics.
- These findings support the detection of complement protein deficiencies and perinatal complement activation in newborns.
- This study provides essential data for clinical assessment of the neonatal complement system.
Abstract:
Activation of the complement system occurs in several diseases. For reliable identification of complement activation in neonates, we establish reference ranges of several components in cord blood of healthy term newborns. For this study, cord blood samples were taken from 125 healthy term newborns. Concentrations of C1r, C2, C5, C7, Properdin, and factors D, H, and I were determined by single radial immunodiffusion. C3a and C5a were measured by specific EIA and complement function was measured by hemolytic assays. The results were expressed as 5th percentile, median, and 95th percentile. The following respective concentrations were found: C1r: 27, 47, 65 mg/l; C2: 12.0, 18.0, 24.0 mg/l; C5: 64, 92, 127 mg/l; C7: 32, 60, 89 mg/l; Properdin: 5.6, 9.7, 14.2 mg/l; factor D: 3.6, 5.2, 7.3 mg/l; factor H: 178, 234, 296 mg/l; and factor I: 15, 24, 32 mg/l. The functional activity of the whole complement system was 24%, 43%, 97% and for the alternative pathway 39%, 58%, 76%. The concentration of the activated split products C3a was 4, 65, 255 microg/l and of C5a, 0.11, 0.26, 1.19 microg/l. These reference values may be important for the detection of deficiencies of native complement proteins or perinatal processes leading to an activation of the complement system.