Differences in Antibody Response to Streptococcal Antigens in Children with Rheumatic and Non-rheumatic Mitral Valve Disease

The usefulness of streptococcal antibody tests — anti-streptolysin O (ASO), anti-desoxyribonuclease B (anti-DNAse B), and anti-group A carbohydrate (A-antibody) — in differentiating rheumatic from non-rheumatic mitral disease was explored. Sera from 154 children with mitral disease were studied. Fifteen of 17 patients with chronic mitral insufficiency (MI) following acute rheumatic fever manifested persistence of elevated A-antibody levels following the decline of ASO and anti-DNAse B titers to normal 18-36 months after their acute illness. This antibody pattern was not observed among sera from 35 patients with congenital mitral valve deformities. Serologic study of 71 children with mitral disease of obscure etiology identified three groups: subgroup A includes those 12 who demonstrated the antibody pattern associated with rheumatic MI, while subgroup B is comprised of 39 children with normal A-antibody levels. Twenty patients (subgroup C) manifested evidence of recent streptococcal infection. These data suggest that the use of the A-antibody test in conjunction with other streptococcal antibody tests is of potential value in differentiating rheumatic from non-rheumatic mitral disease.