Inherited Deficiency of the Seventh Component of Complement Associated with Meningococcal Meningitis: Lack of Serum Bactericidal Activity against Neisseria meningitidis in a Girl with C7 Deficiency and HLA Studies of a C7‐Deficient Japanese Family

Abstract

An 8-year-old girl with meningococcal meningitis lacked serum complement activity. The seventh component of complement (C7) could not be detected in her serum by either functional or immunochemical analysis. The levels of the other components were within the normal range.Her serum complement activity was restored by the addition of purified C7. Her fresh serum showed a total absence of bactericidal activity against Neisseria meningitidis, group Y, but her serum bactericidal activity was restored by the addition of purified C7. The restoration of her serum bactericidal activity was completely inhibited in the presence of Mg2+ EGTA.These findings suggest that restoration of the bactericidal activity of her serum against N. meningitidis might be mediated by the specific antibody against N. meningitidis and the reconstituted complement system in her serum. Heterozygous deficiency of C7 was found in 10 of her family members. Genetic studies showed that the mode of inheritance might be an autosomal codominant trait. No genetic linkage between deficiency of C7 and the HLA system was found.The biological significance of the complement system has been fully elucidated with the discovery of complement deficiencies associated with disease (9, 25). Deficiencies of the early-acting complement components (Cl, C4, and C2) are frequently associated with systemic lupus erythematosus (SLE) or other rheumatic diseases (2). In patients with C3 deficiency, recurrent bacterial infection has been shown to be the predominant complication (24) and lupus-like symptoms have also been reported as complications (26). It has been reported that the deficiencies Hamamatsu 430.

Inherited Deficiencies of the Late-Acting Complement Components Other than C9 Found among Healthy Blood Donors

“…A high incidence of C7 deficiency is thought to occur not only in Osaka but throughout Japan. In fact, since 1983 more than 10 cases of C7 deficiency in patients with diseases, such as meningococcal menin gitis [21], systemic lupus erythematosus [22] and renal illness [23], have been reported from several areas of Japan. However, only 2 cases of C6 deficiency with menigococcal meningitis have been report ed by Matsui et al [24] and by Hisa et al [25].…”