Department of Nephrology and Dialysis, Medical Research Institute Kitano Hospital, PIIF Tazuke-Kofukai, 2-4-20 Ohgimachi, Kita-Ku, Osaka, 530-8480, Japan.
Rokushima Clinic, Hyogo, Japan.
Int Urol Nephrol. 2024 Oct;56(10):3389-3396. doi: 10.1007/s11255-024-04104-7. Epub 2024 Jun 3.
High serum IgA and low serum C3 levels resulting from lectin and alternative pathway activation might be related to IgA nephropathy (IgAN) progression and exacerbation. This study examined whether the serum IgA/C3 ratio can serve as an IgAN progression marker.
(1) This nationwide multicenter retrospective study in Japan included 718 patients with biopsy-confirmed IgAN. The patients whose serum creatinine levels at the time of renal biopsy had doubled were defined as having disease progression. (2) Furthermore, to investigate the pathological significance of a reduction in serum IgA/C3 ratio, we reviewed 63 patients whose serum IgA and C3 data at the end of the observation period were obtained.
(1) A Kaplan-Meier analysis of the patients with IgAN revealed that the group with a high serum IgA/C3 (≥ 3.3) had a significantly worse renal outcome. In a multivariate analysis of eGFR ≥ 60 mL/min per 1.73m at the time of biopsy, poor renal outcome was significantly predicted by a serum IgA/C3 ratio of ≥ 3.3. (2) A 15% reduction in the change of serum IgA/C3 ratio was associated with a significantly higher percentage of complete remission of proteinuria. Among the four groups divided by treatment, both the serum IgA/C3 ratio and proteinuria were reduced only in the tonsillectomy and steroid pulse group.
The serum IgA/C3 level might reflect the disease activity and be a potent surrogate marker of therapeutic efficacy in patients with IgAN.
由于凝集素和替代途径的激活导致血清 IgA 升高和 C3 降低，可能与 IgA 肾病（IgAN）的进展和恶化有关。本研究探讨了血清 IgA/C3 比值是否可作为 IgAN 进展的标志物。
（1）本研究是在日本进行的全国多中心回顾性研究，共纳入 718 例经肾活检证实的 IgAN 患者。将肾活检时血清肌酐水平翻倍的患者定义为疾病进展。（2）此外，为了探讨血清 IgA/C3 比值降低的病理意义，我们回顾了 63 例在观察期末获得血清 IgA 和 C3 数据的患者。
（1）对 IgAN 患者的 Kaplan-Meier 分析表明，血清 IgA/C3 较高（≥3.3）的患者肾脏结局显著较差。在对活检时 eGFR≥60 mL/min/1.73m2 的患者进行多变量分析时，血清 IgA/C3 比值≥3.3 显著预测了不良的肾脏结局。（2）血清 IgA/C3 比值变化减少 15%与蛋白尿完全缓解的百分比显著增加相关。在根据治疗分组的四个组中，仅扁桃体切除术和类固醇脉冲组的血清 IgA/C3 比值和蛋白尿均降低。
血清 IgA/C3 水平可能反映疾病活动度，并可作为 IgAN 患者治疗效果的有效替代标志物。
