Quantitative and antigenic differences in complement component C4 between American blacks and whites

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Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells
06:29

Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells

Published on: January 29, 2014

J M Moulds1, N B Warner, F C Arnett

  • 1Division of Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center, Houston.

Complement and Inflammation
|January 1, 1991
PubMed

A population of 98 healthy Black Americans was studied in order to determine normal ranges for total C4, C4A and C4B. Mean total C4 in Blacks measured by an enzymelinked immunoassay (EIA) was 44 +/- 12.8 mg/dl which was significantly different (p less than 0.001) from Caucasian levels of 31.7 +/- 11.5 mg/dl. The difference in total C4 was due to increased levels of C4B in Blacks (means = 24.4 mg/dl) as compared to Whites (means = 15.7 mg/dl; p less than 0.001). These results remained significantly different even when 8 samples having the C4A 91 phenotype were excluded. Since EIAs using monoclonal antibodies with Ch 1 specificity may yield false results, C4 allotyping is recommended when quantitating C4A and C4B levels in Blacks.

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