Renal Division, Peking University First Hospital, Beijing, China.
Peking University Institute of Nephrology, Beijing, China.
Nephrol Dial Transplant. 2020 Dec 4;35(12):2117-2123. doi: 10.1093/ndt/gfz151.
Immunoglobulin A (IgA) vasculitis nephritis (IgAV-N) is the most common secondary IgA nephropathy (IgAN). Many studies have demonstrated that galactose-deficient IgA1 (Gd-IgA1) in the IgA1 hinge region is associated with the development and also progression of primary IgAN. In this study, we aimed to evaluate the roles of Gd-IgA1 in kidney disease progression in a large Chinese cohort of IgAV-N patients.
This cohort study enrolled 112 patients with IgAV-N, 15 patients with IgA vasculitis (IgAV) without kidney involvement and 108 patients with IgAN. Plasma IgA1 and Gd-IgA1 levels at kidney biopsy were measured by enzyme-linked immunosorbent assay. The primary endpoint was a 30% decline in estimated glomerular filtration rate or end-stage renal disease or death.
The levels of Gd-IgA1 in IgAV-N and IgAN patients were higher than in healthy controls (mean ± SD, 302.86 ± 54.93 U/mL versus 303.16 ± 59.43 U/mL versus 281.30 ± 43.74 U/mL, respectively; P = 0.047), as well as compared with those with IgAV without kidney involvement (272.65 ± 53.14 U/mL; P = 0.036). After adjusting clinical data, higher levels of Gd-IgA1 were found to be independently associated with a greater risk for kidney failure [hazard ratio (HR) = 1.703 per 1 SD, 95% confidence interval (CI) 1.233-2.352; P = 0.001]. Compared with the first Gd-IgA1 quartile group (as reference), the fourth Gd-IgA1 quartile group retained a predictive value for poor renal outcome (HR = 3.740, 95% CI 1.204-11.619; P = 0.023).
These data indicate that Gd-IgA1 levels were similarly elevated in adult patients with IgAN and those with IgAV-N. Moreover, increased Gd-IgA1 levels were associated with both the development and progression of IgAV-N, as observed in IgAN.
免疫球蛋白 A（IgA）血管炎肾炎（IgAV-N）是最常见的继发性 IgA 肾病（IgAN）。许多研究表明，IgA1 铰链区缺乏半乳糖（Gd-IgA1）与原发性 IgAN 的发生和进展有关。在这项研究中，我们旨在评估大中国队列的 IgAV-N 患者中 Gd-IgA1 在肾脏病进展中的作用。
这项队列研究纳入了 112 例 IgAV-N 患者、15 例无肾脏受累的 IgA 血管炎（IgAV）患者和 108 例 IgAN 患者。通过酶联免疫吸附试验测量肾活检时的血浆 IgA1 和 Gd-IgA1 水平。主要终点是估算肾小球滤过率下降 30%或终末期肾病或死亡。
IgAV-N 和 IgAN 患者的 Gd-IgA1 水平高于健康对照组（平均值±标准差，分别为 302.86±54.93 U/mL 比 303.16±59.43 U/mL 比 281.30±43.74 U/mL；P=0.047），也高于无肾脏受累的 IgAV 患者（272.65±53.14 U/mL；P=0.036）。在调整临床数据后，发现较高的 Gd-IgA1 水平与更高的肾功能衰竭风险独立相关[每增加 1 个标准差的危险比（HR）为 1.703，95%置信区间（CI）为 1.233-2.352；P=0.001]。与第一 Gd-IgA1 四分位组（参考）相比，第四 Gd-IgA1 四分位组保留了不良肾脏结局的预测价值（HR=3.740，95%CI 1.204-11.619；P=0.023）。
这些数据表明，成人 IgAN 患者和 IgAV-N 患者的 Gd-IgA1 水平同样升高。此外，在 IgAN 中观察到，增加的 Gd-IgA1 水平与 IgAV-N 的发生和进展均有关。
