Division of Rheumatology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Tennessee Valley Healthcare System - Nashville Campus, Nashville, Tennessee, USA.
Lupus Sci Med. 2022 Nov;9(1). doi: 10.1136/lupus-2022-000790.
SLE is more prevalent in populations of African (AA) than European ancestry (EA) and leucopenia is common. A homozygous variant in (rs2814778-CC) is associated with lower white cell counts; the variant is common in AA but not EA populations. We hypothesised that in SLE: (1) leucopenia is more frequent in patients of AA than EA, and (2) the CC genotype accounts for the higher frequency of leucopenia in AA patients.
We performed a retrospective cohort study in patients with SLE at a tertiary care system. Ancestry was defined by genetic principal components. We compared the rate of leucopenia, thrombocytopenia and anaemia between (a) EA and AA patients, and (b) -CT/TT and CC genotype in AA patients.
The cohort included 574 patients of EA and 190 of AA; -CC genotype was common in AA (70%) but not EA (0%) patients. Rates of leucopenia for ancestry and genotype were AA 60.0% vs EA 36.8 % (p=1.9E-08); CC 67.7% vs CT/TT 42.1% (p=9.8E-04). The rate of leucopenia did not differ by ancestry comparing EA patients versus AA with CT/TT genotype (p=0.59). Thrombocytopenia (22.2% vs 13.2%, p=0.004) and anaemia (88.4% vs 66.2%, p=3.7E-09) were more frequent in AA patients but were not associated with genotype (p=0.82 and p=0.84, respectively).
SLE of AA had higher rates of anaemia, leucopenia, and thrombocytopenia than those of EA; only the difference in leucopenia was explained by -CC genotype. This genotype could affect clinical practice.
系统性红斑狼疮（SLE）在非裔（AA）人群中的发病率高于欧洲裔（EA）人群，且白细胞减少症较为常见。一种名为 （rs2814778-CC）的纯合变体与白细胞计数降低有关；该变体在 AA 人群中较为常见，但在 EA 人群中并不常见。我们假设在 SLE 中：（1）AA 患者的白细胞减少症比 EA 患者更为常见，（2）CC 基因型解释了 AA 患者白细胞减少症的更高发生率。
我们在一家三级医疗系统中进行了一项 SLE 患者的回顾性队列研究。通过遗传主成分来定义种族。我们比较了（a）EA 和 AA 患者之间以及（b）AA 患者中 -CT/TT 和 CC 基因型之间白细胞减少症、血小板减少症和贫血的发生率。
该队列包括 574 名 EA 患者和 190 名 AA 患者；CC 基因型在 AA（70%）中很常见，但在 EA（0%）患者中不存在。根据种族和基因型，AA 患者的白细胞减少症发生率为 60.0%，而 EA 患者为 36.8%（p=1.9E-08）；CC 基因型为 67.7%，CT/TT 基因型为 42.1%（p=9.8E-04）。比较 EA 患者与携带 CT/TT 基因型的 AA 患者，AA 患者的白细胞减少症发生率在种族间并无差异（p=0.59）。血小板减少症（22.2% vs 13.2%，p=0.004）和贫血（88.4% vs 66.2%，p=3.7E-09）在 AA 患者中更为常见，但与 基因型无关（p=0.82 和 p=0.84）。
AA 患者的 SLE 贫血、白细胞减少症和血小板减少症发生率高于 EA 患者；只有白细胞减少症的差异可以用 -CC 基因型来解释。该基因型可能会影响临床实践。
