title: Mitral regurgitation may be related with previous streptococcal infection.
abstract: We measured anti M protein antibody (AMPA) titres in children with idiopathic mitral regurgitation (MR), streptococcal infection, rheumatic fever (RF), post-streptococcal acute glomerulonephritis (AGN) and normal healthy children. We investigated the association of MR with streptococcal infection and whether high AMPA titres can be used as persisting evidence of previous streptococcal infection. AMPA titres were measured with an enzyme-linked immunosorbent assay. We found significantly higher antibody titres in patients with MR and in streptococcal infection, RF, and AGN than in healthy controls. In the MR group (n = 15), 54% patients had AMPA titres above the 90th percentile value that was found in normal controls. An elevated AMPA titre persisted for a long period even when the anti-streptolysin O titres had declined to normal in RF patients. Our data suggest that the high AMPA titres in MR should be further investigated to clarify the probable association with previous streptococcal infection.
  
  
  CONCLUSIONS
  High AMPA titre is a risk factor for developing complications after streptococcal infection. Our serological evidence suggests that in some patients, MR may be related to previous streptococcal infection.
authors.affiliation: Department of Paediatrics, Faculty of Medicine, Kagoshima University, Japan.
authors.forename: M R
authors.initials: MR
authors.lastname: Wahid
authors.forename: M
authors.initials: M
authors.lastname: Yoshinaga
authors.forename: Y
authors.initials: Y
authors.lastname: Nomura
authors.forename: S
authors.initials: S
authors.lastname: Oku
authors.forename: S
authors.initials: S
authors.lastname: Takei
authors.forename: S
authors.initials: S
authors.lastname: Narahara
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000276:immunology; D015153:Blotting, Western; D002352:Carrier Proteins; D002648:Child; D005260:Female; D005921:Glomerulonephritis / Q000175:diagnosis / Q000209:etiology / Q000276:immunology; D006801:Humans; D008297:Male; D008944:Mitral Valve Insufficiency / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology; D010612:Pharyngitis / Q000150:complications* / Q000175:diagnosis / Q000276:immunology; D012214:Rheumatic Heart Disease / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology; D013290:Streptococcal Infections / Q000150:complications* / Q000175:diagnosis / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein