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The distribution of autoantibodies against β2‐adrenoceptor from the sera of patients with heart failure

Synthetic peptides corresponded to amino acids sequences of the second extracellular loop of human β2‐adrenoceptor were used as antigens in a Streptavidin‐ Enzyme‐Linked Immunosorbent Assay (SA‐ELISA) to screen sera from 267 subjects among which 206 had CHF caused by different heart diseases and the remaining 61 healthy donors were as control. The frequency of autoantibodies against β2‐adrenoceptor in CHF group was significantly higher than that in normal control group (NC). The geometric mean titers of autoantibodies against β2‐adrenoceptor in patients with CHF were substantially higher than those in NC (1:89±2.03 vs.1:35±1.79, P<0.01). The autoantibodies decreased the heart rates from 26.43±3.63 to 9.42±3.03, 10.00±1.76, 9.25±2.56. Our results demonstrated that the autoantibodies against β2‐adrenoceptors not only exist in the sera of patients with heart failure resulting from different heart diseases, but also their titers were significantly higher than those in normal control group, and this autoantibody displayed ′agonistic activity′ on the corresponding receptors as evidenced by its decreasing effects on the beating rate of cultured cardiomyocytes.