The Relationship Between Autoantibodies Against Cardiac G Protein-coupled Receptors And Hypertrophic Cardiomyopathy

Part ?:The Study on the Relationship between ?1 Adrenergic Receptor Autoantibody and Hypertrophic Cardiomyopathy Objective:The purpose of the study was to investigate the concentration of serum?1-adrenergic receptor autoantibody(?1-AAB)in patients with hypertrophic cardiomyopathy(HCM),and the relationship between ?1-AAB and clinical parameters.Methods:One hundred and thirty three HCM patients and fourty normal controls were enrolled in this study.Serum samples of peripheral venous blood were collected to test the concentration of ?1-AAB by ELISA technique.The clinical data of HCM patients were collected in order to study the relationship between the concentration of serum ?1-AAB and clinical parameters.Results:The concentration of serum ?1-AAB in HCM patients[48.25(38.41-56.09)ng/ml]was significantly higher than normal controls(24.51 ± 6.89ng/ml),P<0.01.Respectively compared with the other two subgroups,there was no significant difference in serum ?1-AAB concentration among the three subgroups of patients with obstructive hypertrophic cardiomyopathy(HOCM),latent obstructive hypertrophic cardiomyopathy(LHOCM and non-obstructive hypertrophic cardiomyopathy(NOCM).The concentration of serum ?1-AAB in patients with history of syncope was significantly higher than that in those without(P<0.05).The concentration of serum ?1-AAB in patients with moderate or severe mitral regurgitation was significantly higher than that in those without(P<0.01).The maximum thickness of ventricular wall(r=0.215,P=0.030)and interventricular septum(r=0.222,P=0.025)were significantly positively correlated with log?1-AAB.In HOCM patients,log?1-AAB was positively correlated with resting left ventricular outflow tract gradient(LVOTG).Conclusions:The concentration of serum ?1-AAB in HCM patients was significantly higher than that in normal controls,and the concentration was correlated with the maximum ventricular wall thickness,interventricular septal thickness,and resting LVOTG in HOCM patients.Those HCM patients with history of syncope or moderate/severe mitral regurgitation have significantly higher concentration of ?1-AAB than those without.Part ?:Relationship between M2-muscarinic Receptor Autoantibody and Hypertrophic CardiomyopathyObjective:The purpose of the study was to investigate the concentration of serum M2-muscarinic receptor autoantibody(M2-AAB)in patients with hypertrophic cardiomyopathy(HCM),and the relationship between M2-AAB and clinical parameters.Methods:One hundred and thirty three patients with HCM were consecutively enrolled as HCM group.The HCM group was further divided into obstructive hypertrophic cardiomyopathy(HOCM)subgroup(n=72),latent obstructive hypertrophic cardiomyopathy(LHOCM)subgroup(n=22),and nonobstructi ve hypertrophic cardiomyopathy(NOCM)subgroup(n=39).Since there was no obstruction of left ventricular outflow tract(LVOT)in LHOCM and NOCM patients when they were resting,LHOCM and NOCM patients could be combined as LHOCM+NOCM subgroup,and compared with the HOCM subgroup.A total of 40 subjects with no organic heart disease and autoimmune diseases were confirmed by electrocardiogram,transthoracic echocardiography and hematological routine tests.All of the 40 subjects were enrolled as normal controls without taking any P-blockers,glucocorticoids and immunosuppressants.Serum samples of peripheral venous blood were collected to test the concentration of M2-AAB by enzyme-linked immunosorbent assay(ELISA).The clinical data of HCM patients were collected in order to study the relationship between the concentration of serum M2-AAB and clinical parameters.Results:The concentration of serum M2-AAB in HCM patients[22.91(17.21-29.64)ng/ml]was significantly higher than normal controls(17.14±5.66 ng/ml),P<0.01.There was no significant difference in serum M2-AAB concentration among the three subgroups of patients with HOCM,LHOCM and NOCM,Female HCM patients have higher concentration of M2-AAB than male patients(P=0.001).The concentration of M2-AAB in HCM patients with family history of sudden cardiac death was significantly higher than that in those without(P<0.05).The concentration of M2-AAB in HCM patients with atrial fibrillation,or left atrial diameter?50mm or moderate-severe mitral regurgitation was significantly higher than that in those without(P<0.05).There was a significantly positive correlation between logM2-AAB in HCM patients and resting LVOT gradient(r=0.178,P=0.040),and a marginally positive correlation between IogM2-AAB in HOCM patients and resting LVOT gradient(r=0.224,P=0.058).Conclusions:The concentration of serum M2-AAB in HCM patients was significantly higher than that in normal controls,and sex and family history of sudden cardiac death may affect the concentration.Those HCM patients with atrial fibrillation,or left atrial diameter?50mm or moderate-severe mitral regurgitation have significantly higher concentration of M2-AAB than those without.What's more,the concentration of serum M2-AAB in HCM patients was correlated with resting LVOT gradient.