1997-871 ELISA Tltres of Antl-a Myosin Antibodies In Idiopathic Dilated Cardiomyopathy Patients Reduce with Disease Progression 1997-891 Effect of Local Angiotensin II Inhibition on Pattern of Ventricular Hypertrophy and Characteristics of Myocardium

Immunofluorescence detects anti-heart antibodies directed against a range of cardiac antigens in 30% of patients with idiopathic dilated cardiomyopathy (OCM), but is not antigen specific, Western blots showed that these antibodies recognise both a (organ specific, atrial) and fJ (cross reactive ventricular and skeletal) myosin but this technique is nonquantitative and unsuitable for screening purposes, To assess the frequency and titre of the anti-a myosin antibodies, we developed a biotin-streptavidin ELISA for detection of IgG to purified human atrial myosin. A pilot study of 40 OCM patients and 40 IHO controls revealed 94% concordance between ELISA and Western Blot. Studies were performed on sera (dilution 1/320) from 123 consecutive patients with OCM (WHO criteria) presenting to our hospital (age 42 ± 14). These were compared with sera from 52 normals (45 ± 16) and 58 patients with ischaemic heart disease (IHO) (65 ± 12), (40% had poor LV function, 65% had previous MI). Raised antibody levels to atrial myosin were found in 24 (20%) of OCM patients, 1 (2%1 normal control and 3 (5%) of the IHO patients (OCM v. IHO p 0.1 I. Repeat evaluation on 57 OCM patients after 20 ± 20 months showed significant reduction in antibody level from 0.3 ± 0.02 to 0.23 ± 0.01 (p = 0.04). In conclusion we confirm the presence of disease specific anti-a myosin antibodies in OCM patients and show a reduction in antibody level over time as in other autoimmune diseases.