Related Experiment Videos
Deficiency of human complement factor I associated with lowered factor H.
G M Naked1, M P Florido, P Ferreira de Paula
1Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, 05508-900, Brazil.
Clinical Immunology (Orlando, Fla.)
|July 20, 2000
Summary
This study details a rare case of human factor I deficiency with low factor H, leading to impaired complement system function. This results in increased susceptibility to infections due to complement consumption.
Area of Science:
- Immunology
- Complement System Biology
Background:
- Factor I and Factor H are critical regulators of the complement system.
- Deficiencies in these factors lead to complement overconsumption and increased infection risk.
Purpose of the Study:
- To describe a unique case of combined factor I deficiency and low factor H levels.
- To investigate the functional consequences of these deficiencies on the complement system.
Main Methods:
- Assessed C3 concentration and hemolytic activity of classical and alternative complement pathways.
- Evaluated Candida albicans killing and chemotactic factor production using patient serum.
- Analyzed C3 antigen electrophoretic mobility.
Main Results:
- Significantly reduced C3 levels and classical pathway activity.
- Complete absence of alternative pathway activity.
- Impaired leukocyte killing of Candida albicans and reduced complement-dependent chemotaxis.
- Abnormal C3 antigen electrophoretic mobility indicating complement activation deregulation.
Conclusions:
- The described case represents the first reported instance of combined factor I deficiency and low factor H in Chile.
- The observed complement system dysregulation explains the patient's heightened susceptibility to recurrent infections.