Objective Autoantibodies against cardiac troponin I (cTnI) have been described in the serum from patients with dialated cardiomyopathy and heart failure. The clinical significance of these autoantibodies remains unknown. The present study was designed to evaluate the relationship between the serum level of autoantibodies against cardiac troponin I and the prognosis of patients with myocardial infarction (MI) and chronic heart failure (CHF).

Methods 97 patients were studied in the present study, including 38 patients (68.3±7.9 years, 28 males) with MI and 59 patients (63.3±14.6 years, 44 males) with CHF. The patients were recruited in the First Affiliated Hospital of Nanjing Medical University from 2005 to 2008. 78 healthy control subjects were enrolled in the study. The control subjects were excluded from any cardiac events. The serum samples were collected from the patients after the admission to the hospital. A sandwich-like ELISA assay was established with human cTnI and anti-human IgG to detect the serum level of autoantibodies against cTnI. The level of the autoantibodies was expressed as the relative absorbance of optical density and the level exceeds 3XSD was defined as positive. After the patients were discharged from the hospital, a follow-up from 3 months to 6 months was performed.

Results The levels of the autoantibodies were 0.49±0.10 for control subjects, 0.72±0.38 for patients with MI and 0.55±0.24 for patients with CHF. Among 38 MI and 59 CHF patients, eight were positive (8/38) and nine were positive (9/59), respectively. During the follow-up period, one patient died and one patient underwent MI again in the eight positive patients with MI. Among 59 CHF patients, 34 patients finished follow-up investion. Three of the seven positive CHF patients were death whereas only two of the 27 negative CHF patients were death. The life quality decreased in the positive CHF patients compared with that in negative CHF patients.

Conclusion The present study suggested that the level of autoantibodies against cTnI could be a worse prognositic marker in patients with MI or CHF. The underlying mechnasim remains to be illustrated.