SEVERE AND RECURRENT MENINGOCOCCAL INFECT IONS IN 2 SIBLINGS WITH ABSENT COMPLEMENT COMPONENT-6

Several complement deficiencies (C2, 3, 4, 5, 6, 7, 8, 9, Properdin, F actor H) were found in patients with severe and recurrent meningococca l infections, in recurrent infections predominantly deficiencies of th e late components of the complement system. In June 1993 a nine and a half year old son of non related Turkish parents developed symptoms of a Waterhouse-Friderichsen-Syndrome. He survived after instant antibio tic therapy, infusion of fresh frozen plasma and artificial ventilatio n. Three days later his 16 year old sister presented with meningitis, which was cured by Cefotaxim, penicillin and dexamethasone. Two months later she was again admitted with meningism. While cerebrospinal liqo ur was sterile we found meningococci in the blood culture. The clinica l course was uncomplicated after parenteral administration of antibiot ics. The two patients, two younger healthy siblings and the parents we re tested for complement activity. We couldn't find any hemolytic acti vity of the classical (CH 50) or alternative (AP 50) pathway in both a ffected siblings, while the other members of the family had normal val ues. Further investigation showed a complete absence of C6 activity an d C6 antigen. Hemolytic activity could be reconstituted in vitro by ad ding purified C6. In older children with severe meningococcal infectio ns, recurrent meningitis, multiple cases in a family, and infections w ith uncommon serotypes, complement deficiencies should be ruled out.