Objective: Complement protein deficiency of the classical pathway or in proteins of the alternate pathway is rare but considerably increase the risk of infection with Neisseria meningitidis. The aim of this study was to determine the clinical criteria of the group at risk.
Methods: Retrospective study of the clinical and biological data of patients exhibiting complement protein deficiency associated with one or several N. meningitidis infections.
Results: Forty cases were studied, including 35 classical pathway protein deficiencies, with a predominance of C7 deficiency, 3 properdin deficiencies and 2 acquired C3 deficiencies. More than 60% of the patients exhibited recurrent N. meningitidis infections. Serogroups of rare strains were isolated in 50% of cases. Properdin deficiency was associated with a fulminating form in 2 cases out of 3. The age at onset of the first manifestations varied from 2 months to 32 years.
Conclusion: A deficiency must be systematically searched for in all patients presenting with a N. meningitidis infection before the age of 6 months or after the age of 5 years. Identification of deficient patients permits the proposal of family screening and appropriate prophylaxis, including preventive vaccination.