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Prevalence of hereditary properdin, C7 and C8 deficiencies in patients with meningococcal infections
M Schlesinger1, Z Nave, Y Levy
1Department of Paediatrics and Clinical Immunology, Barzilai Medical Centre, Ashkelon, Israel.
Insights
Hereditary complement deficiencies, including C7, C8, properdin, and C2, are common in meningococcal disease patients. Genetic complement defects and ethnic background influence susceptibility to this infection.
Area of Science:
- Immunology
- Genetics
Background:
- Hereditary complement deficiencies are linked to increased susceptibility to severe bacterial infections.
- Meningococcal disease is a serious infection often associated with complement system defects.
Purpose of the Study:
- To investigate the incidence of hereditary complement deficiencies in patients with meningococcal disease.
- To identify specific complement component deficiencies and their genetic basis.
- To explore the relationship between ethnic origin and complement abnormalities in meningococcal disease.
Main Methods:
- Screening of 101 patients with meningococcal disease for complement deficiencies.
- Detailed characterization of complement component levels and functional activity.
- Genetic analysis and family studies to identify affected individuals and inheritance patterns.
Main Results:
- Eleven non-related patients had complete complement deficiencies: 5 C7, 3 C8, 2 properdin, and 1 C2.
- C8-deficient patients exhibited selective C8-beta subunit deficiency and reduced C8 alpha/gamma subunit expression.
- All identified C7, C8, and properdin deficient patients were Sephardic Jews with specific geographic origins.
- Complement abnormalities associated with meningococcal infections varied by ethnic origin.
Conclusions:
- Hereditary complement deficiencies are highly prevalent in patients with meningococcal disease.
- Specific complement deficiencies, such as C7, C8, and properdin, are significant risk factors for meningococcal infections.
- Ethnic background plays a role in the type of complement deficiency observed in meningococcal disease patients.
Abstract:
High incidence of hereditary complement (C) deficiencies was found among 101 patients who had a meningococcal disease. This study revealed 11 non-related patients with complete C deficiency: five deficient in C7, three in C8, two in properdin and one in C2. Additional C-deficient individuals, most of them with no history of severe bacterial infections, were detected in family studies. The C8-deficient patients were found to have a selective deficiency of the C8-beta subunit and a reduced expression of the alpha/gamma subunit. Only a few families with properdin deficiency have been described so far. However, it is likely that frequent analysis of the activity of the alternative C pathway in survivors of severe bacterial infections will disclose numerous properdin-deficient patients. All our C7-, C8- and properdin-deficient patients are Sephardic Jews whose families originated from Morocco, Yemen (C7 and C8 deficient) or Tunisia (properdin deficient). This and other findings indicate that the type of complement abnormality found in association with meningococcal infections varies with the ethnic origin of the patient.