Hypomorphic C4B∗ 15 variant of the fourth component of complement
- 29 January 1990
- journal article
- Published by Wiley in FEBS Letters
- Vol. 260 (2) , 183-186
- https://doi.org/10.1016/0014-5793(90)80099-5
Abstract
We report a rare ‘hypomorphic’ C4 allotype detected during routine screening in controls for the Rogers:1 epitope. C4B ∗ 15 was distinguished by having only faint staining when using polyclonal anti-C4 antibody on agarose inimunoelectrophoresis (e.g. hypomorphic), having relatively weak hemolytic activity but being strongly reactive with monoclonal antibody to Rodgers 1. TaqI restriction fragment length polymorphism (RFLP) demonstrated that C4B ∗ 15 segregated with 7 kb and 5.4 kb C4 gene fragments and with the haplotype HLA-A2,C-, B50,BW6,DR7,DQ2,DR52,S07C2(1,15) . The 5.4-kb fragment was more intense than the 7.0-kb fragment, suggesting duplication of the 5.4-kb fragment. This hypomorphic C4 allotype (genotype frequency = 0.0088) has diminished expression of C4 epitopes commonly recognized by polyclonal anti-C4 and may be missed by standard phenotyping methods.Keywords
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