Department of Clinical Medicine and Immunological Sciences, Division of Clinical Immunology, University of Siena, Siena, Italy.
Arthritis Care Res (Hoboken). 2011 Oct;63(10):1463-70. doi: 10.1002/acr.20540.
Recent evidence suggests that anti-Ro/SSA antibodies, strongly associated with the development of congenital heart block, may also be arrhythmogenic for the adult heart. In fact, anti-Ro/SSA-positive patients with connective tissue disease (CTD) frequently display corrected QT (QTc) prolongation associated with an increase in ventricular arrhythmias. However, QTc prolongation prevalence markedly differs throughout the studies (10-60%), but the reason why is not yet clear. The aim of this study was to evaluate whether anti-Ro/SSA-associated QTc prolongation in adult patients with CTD is related to antibody level and specificity.
Forty-nine adult patients with CTD underwent a resting 12-lead electrocardiogram recording to measure QTc interval, and a venous withdrawal to determine anti-Ro/SSA antibody level and specificity (anti-Ro/SSA 52 kd and anti-Ro/SSA 60 kd) by immunoenzymatic methods and Western blotting.
In our population, a direct correlation was demonstrated between anti-Ro/SSA 52-kd level and QTc duration (r = 0.38, P = 0.007), patients with a prolonged QTc had higher levels of anti-Ro/SSA 52 kd with respect to those with a normal QTc (P = 0.003), and patients with a moderate to high level (≥50 units/ml) of anti-Ro/SSA 52 kd showed a longer QTc interval (P = 0.008) and a higher QTc prolongation prevalence (P = 0.008) than those with a low positive/negative level (<50 units/ml). On the contrary, no association was found between QTc and anti-Ro/SSA 60-kd level.
In anti-Ro/SSA-positive adult patients with CTD, the occurrence of QTc prolongation seems strictly dependent on the anti-Ro/SSA 52-kd level. This finding, possibly explaining the different QTc prolongation prevalence reported, strengthens the hypothesis that an extremely specific autoimmune cross-reaction is responsible for the anti-Ro/SSA-dependent interference on ventricular repolarization.
最近的证据表明，与先天性心脏传导阻滞的发展密切相关的抗 Ro/SSA 抗体也可能对成人心脏有致心律失常作用。事实上，患有结缔组织病 (CTD) 的抗 Ro/SSA 阳性患者常表现出校正 QT（QTc）延长，伴有室性心律失常增加。然而，QTc 延长的患病率在不同的研究中差异显著（10-60%），但原因尚不清楚。本研究旨在评估成人 CTD 患者抗 Ro/SSA 相关的 QTc 延长是否与抗体水平和特异性有关。
49 例成人 CTD 患者接受静息 12 导联心电图记录以测量 QTc 间期，并抽取静脉血以免疫酶法和 Western blot 法测定抗 Ro/SSA 抗体水平和特异性（抗 Ro/SSA 52kd 和抗 Ro/SSA 60kd）。
在我们的人群中，抗 Ro/SSA 52kd 水平与 QTc 持续时间呈直接相关性（r = 0.38，P = 0.007），QTc 延长的患者抗 Ro/SSA 52kd 水平高于 QTc 正常的患者（P = 0.003），中等至高水平（≥50 单位/ml）的抗 Ro/SSA 52kd 患者的 QTc 间隔较长（P = 0.008），且 QTc 延长的患病率较高（P = 0.008）。相反，QTc 与抗 Ro/SSA 60kd 水平之间无相关性。
在抗 Ro/SSA 阳性的成人 CTD 患者中，QTc 延长的发生似乎严格依赖于抗 Ro/SSA 52kd 水平。这一发现可能解释了报道的不同 QTc 延长患病率的差异，进一步支持了一种极其特定的自身免疫交叉反应导致抗 Ro/SSA 依赖性对心室复极干扰的假说。
