Aggarwal Rohit, Lucas Mary, Fertig Noreen, Oddis Chester V, Medsger Thomas A
University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Arthritis Rheum. 2009 Apr;60(4):1112-8. doi: 10.1002/art.24409.
To describe the classification, demographic and clinical features, and survival in anti-U3 RNP autoantibody-positive patients with systemic sclerosis (SSc).
Medical records of 108 anti-U3 RNP-positive and 2,471 anti-U3 RNP-negative SSc patients first evaluated during 1985-2003 were reviewed. Anti-U3 RNP antibody was detected by protein and RNA immunoprecipitation. Disease classification, demographic and clinical features, organ system involvement, and survival were compared between the 2 patient groups, by Student's t-test, chi-square analysis, and Mantel-Haenszel test.
The anti-U3 RNP-positive group had a higher proportion of African American patients (27% versus 5%; P < 0.001) and male patients (29% versus 19%; P = 0.021), and was younger at the time of first physician diagnosis (mean age 42.8 years versus 47.4 years; P = 0.001). The 2 groups had similar proportions of patients with diffuse cutaneous involvement (47% and 45% in those with and those without anti-U3 RNP, respectively). However, among patients with diffuse cutaneous involvement, the mean maximum modified Rodnan skin score was significantly lower in the anti-U3 RNP group (22.3 versus 27.9; P < 0.001). Skeletal muscle involvement was more frequent in anti-U3 RNP-positive patients (25% versus 14%; P = 0.002), as was "intrinsic" pulmonary arterial hypertension (PAH) (31% versus 13%; P < 0.001). The frequency of gastrointestinal involvement, cardiac involvement, pulmonary fibrosis, and "renal crisis" did not differ significantly between the 2 groups. Survival was worse in the anti-U3 RNP-positive group (hazard ratio 1.38 [95% confidence interval 1.05-1.82]). PAH was the most common known cause of death in patients with anti-U3 RNP (30%, versus 10% in the anti-U3 RNP-negative group; P < 0.001).
The present findings demonstrate that the frequencies of African American race and male sex are greater among SSc patients with anti-U3 RNP antibody than those without, and the former group is younger at SSc diagnosis. Anti-U3 RNP-positive patients have more frequent skeletal muscle involvement and PAH, the latter being the most common cause of death.
描述抗U3核糖核蛋白（RNP）自身抗体阳性的系统性硬化症（SSc）患者的分类、人口统计学和临床特征以及生存率。
回顾了1985年至2003年期间首次评估的108例抗U3 RNP阳性和2471例抗U3 RNP阴性的SSc患者的病历。通过蛋白质和RNA免疫沉淀检测抗U3 RNP抗体。采用学生t检验、卡方分析和Mantel-Haenszel检验比较两组患者的疾病分类、人口统计学和临床特征、器官系统受累情况及生存率。
抗U3 RNP阳性组中非裔美国患者的比例更高（27%对5%；P<0.001），男性患者比例也更高（29%对19%；P = 0.021），且首次诊断时年龄更小（平均年龄42.8岁对47.4岁；P = 0.001）。两组弥漫性皮肤受累患者的比例相似（抗U3 RNP阳性和阴性患者中分别为47%和45%）。然而，在弥漫性皮肤受累患者中，抗U3 RNP组的平均最大改良Rodnan皮肤评分显著更低（22.3对27.9；P<0.001）。抗U3 RNP阳性患者骨骼肌受累更常见（25%对14%；P = 0.002），“特发性”肺动脉高压（PAH）也是如此（31%对13%；P<0.001）。两组间胃肠道受累、心脏受累、肺纤维化和“肾危象”的发生率无显著差异。抗U3 RNP阳性组的生存率更差（风险比1.38[95%置信区间1.05 - 1.82]）。PAH是抗U3 RNP患者最常见的已知死亡原因（30%，抗U3 RNP阴性组为10%；P<0.001）。
目前的研究结果表明，抗U3 RNP抗体阳性的SSc患者中非裔美国人和男性的比例高于抗体阴性患者，且前者在SSc诊断时更年轻。抗U3 RNP阳性患者骨骼肌受累和PAH更常见，后者是最常见的死亡原因。
