neisserial
Complement C7 deficiency presenting as recurrent aseptic meningitis
Background:
Complement deficiency states are rare inherited disorders that may predispose affected individuals to angioedema,
collagen vascular disease, or infection due to encapsulated organisms, especially Neisseria meningitidis. Objectives:
To report the case of a 36-year-old man of Irish descent with recurrent culture-negative neutrophilic meningitis, to
offer potential reasons for the inability to recover a causative pathogen, and to review the genetics and prevalence
of complement deficiency states, the methods of screening for such deficiencies, the features of meningococcal
infection as they relate to such deficiencies, and management strategies for clinicians caring for patients with such
deficiencies. Methods: The patient presented in 1988 and again in 2002 with culture-negative neutrophilic
meningitis. His second episode was characterized by a rash suggestive of meningococcal infection, prompting
immunologic evaluation. Results: Immunologic evaluation revealed an undetectable CH[50] level. Levels of Cl, C2,
and C5 through C9 were normal except for C7, which was undetectable. Further testing revealed that the patient's
sister was also C7 deficient. Conclusions: Complement component deficiencies are relatively rare; individuals with
collagen vascular disease and systemic neisserial infection should be screened using either the CH[50] or the
APH-50 assay. Key to the management of a late-complement component-deficient host is counseling, education
about meningococcal infection, and discussions about the potential benefits of chemoprophylaxis and
immunoprophylaxis. The ability to detect the bacterial cause of meningitis in such patients is organism dependent
and may be influenced by factors such as cerebrospinal fluid bacterial concentration and previous antibiotic drug
exposure.
Annals of allergy, asthma, & immunology, 2004, vol. 93, no2, pp. 200-205
Advances in Immunology COMPLEMENT
Three types of complement deficiency can cause increased susceptibility to pyogenic infections: a deficiency
of the opsonic activities of the complement system, which causes a general susceptibility to pyogenic
organisms; any deficiency that compromises the lytic activity of complement, which can increase the
susceptibility to neisserial infections; and deficient function of the mannose-binding lectin pathway.
The sole clinical association between inherited deficiency of components of the membrane-attack complex complex
and infection is with neisserial disease, particularly Neisseria meningitidis. 1-3 This complex is necessary
for the complement system to form a lytic channel in neisseriae. Extracellular lysis is a major mechanism
of killing these organisms, which are capable of intracellular survival.
N Engl J Med, Vol. 344, No. 14, April 5, 2001
Complement Deficiencies
Article Last Updated: Jun 2, 2006
Synonyms and related keywords: C1qrs deficiency, C3 deficiency, C2-C4 deficiency, C5-9 deficiency,
terminal membrane attack complex deficiency, MAC deficiency, mannan-binding lectin deficiency, MBL
deficiency, immune system, bacterial infection, sepsis, host defense mechanism, immune complex
disease, systemic lupus erythematosus, SLE, complement activation, disseminated meningococcal
disease, Streptococcus pneumoniae, S pneumoniae, Haemophilus influenzae, H influenzae, Neisseria
meningitidis, N meningitidis, meningococcemia
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Also see Neisseria