Anti-heart and anti-intercalated disk autoantibodies: evidence for autoimmunity in idiopathic recurrent acute pericarditis.
BACKGROUND
Idiopathic recurrent acute pericarditis (IRAP) is a rare disease of suspected, yet unproved, immune-mediated origin. The finding of serum heart-specific autoantibodies in IRAP would strengthen the autoimmune hypothesis and provide aetiology-specific non-invasive biomarkers. Objective To assess frequency of serum anti-heart (AHA), anti-intercalated-disk (AIDA) and non-cardiac-specific autoantibodies and their clinical and instrumental correlates in patients with IRAP. Patients 40 consecutive patients with IRAP, 25 male, aged 37+/-16 years, representing a large single-centre cohort collected at a referral centre over a long time period (median 5 years, range 1-22 years). Control groups included patients with non-inflammatory cardiac disease (NICD) (n=160), ischaemic heart failure (n=141) and normal subjects (n=270).


METHODS
AHA (organ-specific, cross-reactive 1 and 2 types) and AIDA were detected in serum samples from patients, at last follow-up, and control subjects by indirect immunofluorescence (IIF) on human myocardium and skeletal muscle. Non-cardiac-specific autoantibodies were detected by IIF, and anti-Ro/SSA, anti-La/SSB by ELISA.


RESULTS
The frequencies of cross-reactive 1 AHA and of AIDA were higher (50%; 25%) in IRAP than in NICD (4%; 4%), ischaemic (1%; 2%) or normal subjects (3%; 0%) (p=0.0001). AHA and/or AIDA were found in 67.5% patients with IRAP. Of the non-cardiac-specific antibodies, only antinuclear autoantibodies at titre > or =1/160 were more common in IRAP (5%) versus normal (0.5%, p<0.04). AIDA in IRAP were associated with a higher number of recurrences (p=0.01) and hospitalisations (p=0.0001), high titre (1/80 or higher) AHA with a higher number of recurrences (p=0.02).


CONCLUSIONS
The detection of AHA and of AIDA supports the involvement of autoimmunity in the majority of patients with IRAP.
Caforio
A L P
AL
Division of Cardiology, Department of Cardiological, Thoracic and Vascular Sciences, Centro V Gallucci,University of Padova-Policlinico, Via Giustiniani, 2, Padova 35128, Italy. alida.caforio@unipd.it
Brucato
A
A
Doria
A
A
Brambilla
G
G
Angelini
A
A
Ghirardello
A
A
Bottaro
S
S
Tona
F
F
Betterle
C
C
Daliento
L
L
Thiene
G
G
Iliceto
S
S
D000208:Acute Disease; D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology*; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000276:immunology*; D032383:Myocytes, Cardiac / Q000276:immunology; D010493:Pericarditis / Q000276:immunology*; D012008:Recurrence; D055815:Young Adult
D001323:Autoantibodies; D015415:Biomarkers