Molecular analysis of complement component C4 gene copy number.
Alison S L Castley1, O Patricia Martinez
1Department of Clinical Immunology, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, WA, Australia.
Methods in Molecular Biology (Clifton, N.J.)
|June 6, 2012
Summary
The complement system
Area of Science:
- Immunology
- Genetics
Background:
- The complement system cascade can be activated via classical, alternative, or lectin pathways.
- The classical pathway involves the C4 protein, crucial for preventing and clearing immune complex precipitation.
Purpose of the Study:
- To describe a quantitative TaqMan real-time PCR (qPCR) assay for determining C4 gene copy number (GCN).
- To highlight the clinical implications of distinguishing genetic C4 variations from complement consumption in autoimmune diseases.
Main Methods:
- Utilized a quantitative TaqMan real-time PCR (qPCR) assay.
- Focused on laboratory experience with the assay for C4 GCN determination.
Main Results:
- C4 genes (C4A and C4B) exhibit high homology but differ due to nucleotide variations.
- C4 GCN, gene size (short/long), and isotypes influence C4 plasma levels and autoimmune disease susceptibility.
- Low serum C4 levels in autoimmune disease can stem from consumption or genetic factors.
Conclusions:
- Accurate C4 GCN determination is challenging due to high homology between C4A and C4B.
- The described qPCR assay offers a method for precise C4 GCN quantification.
- Differentiating genetic C4 variations from complement consumption is clinically significant for autoimmune disease management.
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