Familial late complement component (C6, C7) deficiency with chronic meningococcemia.

Two patients with chronic meningococcemia were found to lack hemolytic complement, one because of C6 deficiency, the other because of C7 deficiency. In both cases family studies were consistent with inheritance of the deficiencies as non-HLA-linked, autosomal co-dominant traits. Functional studies showed the deficient sera to support monocyte chemotaxis but not phagocytosis or lysis of meningococci. Both patients have remained well following antibiotic treatment.