Zhang Ji, Huang Ziyuan, Lin Sishi, Hu Ya, Liang Yan, Qiu Wenxian, Chen Bo, Chen Chaosheng
Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, PR China.
Institute of Chronic Kidney Disease, Wenzhou Medical University, Wenzhou, Zhejiang, PR China.
Kidney Int Rep. 2022 Jan 26;7(4):776-785. doi: 10.1016/j.ekir.2022.01.1053. eCollection 2022 Apr.
Primary IgA nephropathy (IgAN) with light chain λ restriction in the mesangial deposits (IgAN-λ) has unique immunofluorescence (IF) features. Nevertheless, its clinicopathology and prognosis are still ambiguous.
From January 2002 to December 2020, the clinical and pathologic data of 3872 patients who were diagnosed with having primary IgAN by renal biopsy in our hospital were reviewed. A total of 187 patients who met the selection criteria for IgAN-λ were enrolled to conduct a retrospective single-center study. The selection criteria were that IF features conform to light chain λ restriction in the mesangial deposits. According to age, sex, renal function (estimated glomerular filtration rate [eGFR]), and follow-up time, the control group was constructed with 1:3 matched cases of IgAN. The clinicopathologic and prognostic differences between the 2 groups were analyzed.
Compared with that in the IgAN group, the serum fibrinogen level in the IgAN-λ group was significantly higher ( < 0.001). Furthermore, cluster analysis indicated the different clusters involved in fibrinogen between the IgAN-λ and IgAN groups and that fibrinogen is associated with factors reflecting renal function in IgAN-λ but proteinuria levels in IgAN. The light chain λ deposit in the mesangium is associated with the formation of crescents in those with IgAN-λ, but complement C3 deposition in those with IgAN. Our Kaplan-Meier analysis revealed that the prognosis of the IgAN-λ group was significantly worse than that of the IgAN group within >6 years of follow-up ( = 0.02). The multi-Cox analysis revealed that the light chain λ restriction in the mesangial deposits was an independent risk factor for poor outcomes (eGFR decreased from the baseline ≥ 30% continuously or reached end-stage renal disease [ESRD] or died).
The prognosis of those with IgAN-λ was worse than that of those with IgAN, which may be attributed to the light chain λ restriction in the mesangial deposits inducing a significant systemic inflammation manifested as severe clinical features and frequent crescent.
系膜沉积物中存在轻链λ限制的原发性IgA肾病（IgAN-λ）具有独特的免疫荧光（IF）特征。然而，其临床病理学和预后仍不明确。
回顾2002年1月至2020年12月期间我院经肾活检诊断为原发性IgA肾病的3872例患者的临床和病理资料。共纳入187例符合IgAN-λ选择标准的患者进行回顾性单中心研究。选择标准为IF特征符合系膜沉积物中的轻链λ限制。根据年龄、性别、肾功能（估计肾小球滤过率[eGFR]）和随访时间，以1:3匹配IgAN病例构建对照组。分析两组之间的临床病理和预后差异。
与IgA肾病组相比，IgAN-λ组的血清纤维蛋白原水平显著更高（<0.001）。此外，聚类分析表明IgAN-λ组和IgA肾病组中纤维蛋白原涉及不同的聚类，并且纤维蛋白原与反映IgAN-λ肾功能的因素相关，但与IgA肾病中的蛋白尿水平相关。系膜中的轻链λ沉积与IgAN-λ患者新月体的形成相关，但与IgA肾病患者中的补体C3沉积相关。我们的Kaplan-Meier分析显示，在随访>6年时，IgAN-λ组的预后明显比IgA肾病组差（=0.02）。多因素Cox分析显示，系膜沉积物中的轻链λ限制是不良结局的独立危险因素（eGFR从基线持续下降≥30%或达到终末期肾病[ESRD]或死亡）。
IgAN-λ患者的预后比IgA肾病患者差，这可能归因于系膜沉积物中的轻链λ限制诱导了显著的全身炎症，表现为严重的临床特征和频繁的新月体形成。
