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[Complement factor I deficiency revealed by repeated systemic Streptococcus pneumoniae infection]
M Monfort-Gouraud1, C Vignon, A Vincens
1Service de pédiatrie, centre hospitalier intercommunal de Montfermeil-Le-Raincy, 10, avenue du Général-Leclerc, 93370 Montfermeil, France. marie.monfortgouraud@laposte.net
Summary
A rare Factor I deficiency was diagnosed in a 6-year-old girl with recurrent infections. Prompt diagnosis and management, including antibiotics and vaccinations, significantly improve her prognosis and quality of life.
Area of Science:
- Immunology
- Complement System Biology
- Pediatric Infectious Diseases
Background:
- Recurrent infections, including otitis media and Streptococcus pneumoniae bacteremia, can indicate underlying immune deficiencies in children.
- The complement system plays a crucial role in innate and adaptive immunity, protecting against bacterial infections.
Observation:
- A 6-year-old girl presented with recurrent serious otitis media and Streptococcus pneumoniae bacteremia.
- Complement investigation revealed moderately reduced CH50 activity, normal C4 levels, low C3 levels, and undetectable Factor I.
- These findings suggested a deficiency in the complement system, specifically Factor I.
Findings:
- The patient was diagnosed with a rare Factor I deficiency.
- Factor I is essential for regulating complement activation, and its absence leads to uncontrolled complement cascade and increased susceptibility to infections.
Implications:
- Diagnosis of Factor I deficiency has significant practical consequences for patient management and prognosis.
- Preventive strategies, such as antibiotic prophylaxis (penicillin V) and vaccination (Neisseria meningitidis, S. pneumoniae), are vital.
- Effective management can significantly improve the child's life expectancy and quality of life by reducing infection frequency and severity.