Sato H, Iwano M, Akai Y, Nishino T, Fujimoto T, Shiiki H, Dohi K
First Department of Internal Medicine, Nara Medical University, Kashihara, Japan.
Lupus. 2001;10(2):97-101. doi: 10.1191/096120301677569675.
Systemic lupus erythematosus (SLE) is an immune complex-mediated disease and organ damage is caused by the deposition of immune complex. Receptors which recognize the Fc portion of immunoglobulin G (FcgammaR) play a key role in the phagocytosis of immune complexes. As the gene encoding for FcgammaR of class IIa (FcgammaRIIa) has two allelic forms, H131 and R131, which differ in their affinity to IgG2, this polymorphism might have implications in handling immune complex. We studied the distribution of the FcgammaRIIa polymorphism in 90 Japanese patients with SLE. We also examined the association between FcgammaRIIa polymorphism and the disease activity of SLE and the histopathological findings of lupus nephritis. FcgammaRIIa polymorphism was determined by PCR and dot blot analysis. The allelic frequency of H131 in patients with SLE was significantly lower (H131/R131 = 0.44/0.56) than that of normal controls (H131/R131 = 0.62/0.38; P < 0.05). No significant association was observed between FcgammaRIIa polymorphism and the clinical parameters for the activity of SLE. There was no association between FcgammaRIIa polymorphism and the histological findings in lupus nephritis. The difference in the distribution of FcgammaRIIa alleles between patients with SLE and normal subjects indicates that this polymorphism is a candidate of susceptibility gene for SLE in Japanese.
系统性红斑狼疮（SLE）是一种免疫复合物介导的疾病，器官损伤由免疫复合物沉积所致。识别免疫球蛋白G（IgG）Fc段的受体（FcγR）在免疫复合物的吞噬过程中起关键作用。由于编码IIa类FcγR（FcγRIIa）的基因有两种等位基因形式，即H131和R131，它们对IgG2的亲和力不同，这种多态性可能与免疫复合物的处理有关。我们研究了90例日本SLE患者中FcγRIIa多态性的分布情况。我们还检测了FcγRIIa多态性与SLE疾病活动度以及狼疮性肾炎组织病理学表现之间的关联。通过聚合酶链反应（PCR）和斑点印迹分析确定FcγRIIa多态性。SLE患者中H131的等位基因频率（H131/R131 = 0.44/0.56）显著低于正常对照组（H131/R131 = 0.62/0.38；P < 0.05）。未观察到FcγRIIa多态性与SLE活动度的临床参数之间存在显著关联。FcγRIIa多态性与狼疮性肾炎的组织学表现之间也无关联。SLE患者与正常受试者之间FcγRIIa等位基因分布的差异表明这种多态性是日本人群中SLE易感基因的一个候选因素。
