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Hereditary properdin deficiency in three families of Tunisian Jews
M Schlesinger1, U Mashal, J Levy
1Pediatric Department, Barzilai Medical Center, Ashkelon, Israel.
Insights
Hereditary properdin deficiency, a complement system disorder, was identified in three Tunisian Jewish families. These individuals experienced milder infections than previously reported, suggesting this condition may be more common.
Area of Science:
- Immunology
- Genetics
- Complement System
Background:
- Hereditary properdin deficiency is a rare genetic disorder affecting the complement system.
- Properdin is crucial for the alternative complement pathway's amplification loop.
Purpose of the Study:
- To investigate the prevalence and clinical presentation of hereditary properdin deficiency.
- To identify individuals with properdin deficiency among survivors of specific bacterial infections.
Main Methods:
- Analysis of hemolytic activity of classical (CH50) and alternative (AP50) complement pathways.
- Radial immunodiffusion and Western blotting to confirm undetectable properdin levels.
Main Results:
- Three non-related families of Tunisian Jewish origin were identified with properdin deficiency.
- Affected individuals exhibited milder courses of meningococcal and Haemophilus influenza infections compared to literature.
- Properdin deficiency was associated with specific ethnic origins.
Conclusions:
- Hereditary properdin deficiency may be more prevalent than previously assumed.
- Testing AP50 alongside CH50 in at-risk populations can aid in diagnosis.
- Ethnic background may be a factor in the prevalence of complement deficiencies.
Abstract:
Hereditary properdin deficiency is a rare genetic disorder of the complement system. Three propositi and six additional family members with properdin deficiency have been found following analysis of the hemolytic activity of the classical (CH50) and the alternative (AP50) complement pathways in the sera of 101 survivors of meningococcal infections and 59 survivors of severe pneumococcal and Haemophilus influenza infections. All the properdin-deficient individuals had undetectable levels of properdin by radial immunodiffusion and by Western blotting. They belonged to three non-related families of Tunisian Jews who came from different parts of Tunisia. Two patients had a meningococcal infection at 15 and 16 years of age, respectively, and one had Haemophilus influenza meningitis at 1.5 years of age. In contrast to the fulminant and fatal course of meningococcal infection which was previously described in some properdin-deficient patients, our patients had a relatively mild disease. Properdin deficiency may not be as rare as previously thought. Analysis of AP50, in addition to CH50, in sera of patients who had meningococcal infection, will probably disclose many more cases of hereditary properdin deficiency. In addition, our findings indicate that, as in other complement abnormalities, hereditary properdin deficiency may also be associated with the ethnic origin of the patient.