[Presence of bacterial DNA in valvular tissue of patients with chronic rheumatic heart disease].
BACKGROUND
Rheumatic heart disease (RHD) is a delayed consequence of a pharyngeal infection with Group A streptococcus (GAS), usually ascribed to a cross-reactive immune response to the host cardiac tissues. Acute rheumatic fever (ARF) and its ensuing valvular sequelae are thus considered the prototype of a post-infectious autoimmune disease, with no direct evidence of residual streptococcal antigen in diseased valvular tissues. However, recent studies concerning the antigenic specificity and clonality of intralesional lymphocytes have revealed oligoclonal expansions characteristic of an antigen specific response, that might be related to GAS.


OBJECTIVE
To search for bacterial DNA in valvular tissue from RHD patients and controls.


METHODS
We extracted DNA from surgically excised valve specimens from 15 RHD patients and 6 non RHD controls and tested for the presence of bacterial DNA by Polymerase Chain Reaction (PCR) with primers for 16S rRNA.


RESULTS
Eighty percent (12/15) of valve specimens from RHD patients were positive for bacterial DNA, as opposed to none of the valves (n =6) from non RHD controls.


CONCLUSIONS
These results suggest that GAS might persist in valvular tissue in patients with ARF and contribute to the inflammatory scarring lesion that leads to cardiovascular sequelae.
Figueroa
Fernando E
FE
Laboratorio de Inmunología, Facultad de Medicina, Universidad de los Andes, Santiago, Chile. ffigueroa@uandes.cl
Carrión A
Flavio
F
Valenzuela M
Sylvia
S
Turner G
Eduardo
E
Aceitón E
Cristian
C
Hirigoyen P
Carolina
C
Bogdanic W
Katherine
K
Solís D
Claudia
C
Mansilla A
Karina
K
Urra G
Soledad
S
D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis; D002908:Chronic Disease; D004269:DNA, Bacterial / Q000302:isolation & purification*; D005260:Female; D006351:Heart Valves / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010612:Pharyngitis / Q000382:microbiology*; D010614:Pharynx / Q000382:microbiology; D012214:Rheumatic Heart Disease / Q000382:microbiology*; D013290:Streptococcal Infections / Q000150:complications*; D013291:Streptococcus / Q000302:isolation & purification*
D000942:Antigens, Bacterial; D004269:DNA, Bacterial