Systemic lupus erythematosus (SLE) and other autoimmune rheumatic diseases (AIRD) tend to co-aggregate in families, making positive familial history a risk factor. We aimed to estimate familial aggregation of AIRD in SLE patients and to compare between ones having a positive and negative family history of autoimmunity in our cohort. We included families of 157 consecutive SLE patients in a hospital-based, cross-sectional design for a three-generation pedigree study. Clinical and laboratory parameters of these patients were recorded. AIRD was seen in families of 39 SLE patients amounting to a familial prevalence of 24.8% [95% confidence interval (CI) 18.1, 31.6] with a relative risk (λ) of 4.3 for first-degree relatives (FDRs) and 1.1 for second-degree relatives (SDRs). SLE was the commonest AIRD seen in families of 19 patients with a familial prevalence of 12.1% (95% CI 7.0, 17.2) and λ of 78.2 for FDRs and 18.1 for SDRs. AIRD as a whole and SLE alone were seen more commonly with parental consanguinity (p < 0.05). Familial aggregation in SLE patients also showed a relatively higher percentage of affected males and lesser presentation with constitutional features (p < 0.05) than sporadic SLE patients. Rheumatoid arthritis (RA) was the second most common AIRD seen in 16/39 (41%) families with a RR of 3.1 in FDRs of SLE patients. In conclusion, Asian Indian SLE patients seem to have a high familial aggregation of AIRD, which is more pronounced in the background of parental consanguinity. SLE is the commonest AIRD seen amongst FDRs and SDRs of SLE patients, followed by RA, with FDRs being at highest risk.

中文翻译：

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亚洲印度裔系统性红斑狼疮患者自身免疫性风湿性疾病家族聚集的研究。

系统性红斑狼疮（SLE）和其他自身免疫性风湿性疾病（AIRD）往往在家庭中共同聚集，使阳性家族史成为危险因素。我们旨在评估SLE患者中AIRD的家族聚集性，并比较我们队列中具有自身免疫阳性和阴性家族史的患者。在一项基于医院的横断面设计中，我们进行了三代谱系研究，纳入了157名连续SLE患者的家属。记录这些患者的临床和实验室参数。在39例SLE患者的家庭中发现AIRD，家族患病率为24.8％[95％置信区间（CI）18.1，31.6]，一级亲属（FDR）的相对风险（λ）为4.3，第二级亲属的相对风险（λ）为1.1度亲戚（SDR）。SLE是19例患者家庭中最常见的AIRD，家族病患率为FDR的12.1％（95％CI 7.0，17.2），λ为78.2，SDR为18.1。AIRD整体和单独的SLE在父母亲血尿中更为常见（p <0.05）。与散发性SLE患者相比，SLE患者的家族聚集也显示出相对较高的患病男性百分比和较少的体质特征（p <0.05）。类风湿关节炎（RA）是SLE患者FDR中16/39（41％）家庭中第二常见的AIRD，RR为3.1。总之，亚洲印度裔SLE患者似乎具有较高的AIRD家族聚集性，这在父母亲血染的背景下更为明显。在SLE患者的FDR和SDR中，SLE是最常见的AIRD，其次是RA，FDR的风险最高。