Functional abnormalities of complement in familial and sporadic ankylosing spondylitis

Levels of complement fractions of 12 patients with sporadic ankylosing Spondylitis and 6 patients with familial Ankylosing Spondylitis (N. Y. Criteria) were studied by an hemolytic and functional method (microhemolysis in plate. Cordis Lab. Miami, Fla. USA). Abnormal levels were found in 94% of them high levels of C1 and C2 (p 0.002), and C3 (p 0.05) C8 and C9 (p 0.001) deficiencies, mixed or isolated, correlated with the severity of the diseases. C9 deficiency belongs to familial Ankylosing Spondylitis. These functional deficiencies of serum complement can favor the colonization and persistence of germs, which could mediate in the genesis of Ankylosing Spondylitis.