β_3肾上腺素受体自身抗体在扩张型心肌病患者中的检测及临床意义

DETERMINATION AND CLINICAL IMPLICATION OF AUTOANTIBODIES AGAINST BETA3-ADRENOCEPTORS IN PATIENTS WITH DILATED CARDIOMYOPATHY

[目的]检测扩张型心肌病(CDM)患者血清中β3肾上腺素受体(β3AR)自身抗体,并分析其类型和可能的医学意义。[方法]以合成的人β3AR细胞外第一、二、三环肽段作为抗原,应用酶联免疫吸附实验,检测临床甄选的60例CDM患者及103例正常对照者血清中β3AR自身抗体。[结果]DCM患者血清中β3AR细胞外第一环和第二环的IgG类自身抗体阳性率(30.0%和41.7%)及抗体水平(0.46±0.08和1.17±0.17)均显著高于正常对照者,且与心功能有关;β3AR细胞外第二环IgM类自身抗体阳性率(50.0%)也显著高于正常人,但与心功能无关。β3AR细胞外第二环的自身抗体水平明显高于第一环和第三环的自身抗体。而IgG类自身抗体水平明显高于IgM类。[结论]β3AR自身抗体,尤其是β3AR细胞外第二环的IgG类自身抗体可能作为重要的功能性抗体,参与DCM的病理生理过程。

[Objective] To investigate the immunoglobulin fractions in sera from healthy subjects and patients with dilated cardiomyopathy （DCM） for the presence of autoantibodies against beta3-adrenoceptors and their possible clinical implication. [Methods] Three synthetic peptides corresponding to the sequence of the first, second and third extraceUular loops of beta3-adrenoceptors respectively were used as the antigens to screen sera from patients with DCM （n = 60） and healthy blood donors （n = 103） as control. [ Results ] In DCM, the frequency and responses of autoantibodies of IgG isotype against the first and second extracellular loops of beta3-adrenoceptors were significant higher （30.0%, 0.5± 0.1 and 41.7%, 1.2± 0.2, respactively） than control group, and had close relation to the cardiac function, Statistically raised reactivity of IgG compared to IgM in controls and DCM group implied that the predominant response to the antigen was IgG. A statistically signifieant difference in response of autoantibodies against the second extracellular loop of beta3-adrenoceptors compared to autoantibodies against the first and third extracellular loops of beta3-adrenoceptors implied it was an isoform of comparatively greater antigenicity. [Conclusion] These findings indicates that the autoantibodies against the human beta3-adrenoeeptor may participate in the pathophysiological changes in patients with DCM.