抗肾小球基底膜（GBM）病和免疫球蛋白A肾病（IgAN）的结合已经在零星案例中得到充分记录，但在大量集合体中缺乏整体评估。在此研究中，我们调查了这种实体的临床和免疫学特征以及结果。我们筛选了2012年3月至2020年3月间75例经活检证实的抗GBM病患者。其中，我们识别并纳入了合并IgAN的患者。对照组包括同一期间活检的经典抗GBM病患者，排除了患有IgAN、其他肾小球疾病或肿瘤、无法获得血样和缺失数据的患者。我们通过酶联免疫吸附试验检测了血清中针对GBM的IgG和IgA自身抗体，以及循环中对GBM的IgG亚类。识别了15例合并抗GBM病和IgAN的患者，占所有患者的20%（15/75）。其中，男性9例，女性6例，平均（±标准差）年龄为46.7±17.3岁。将30例经典抗GBM病患者纳入对照组，其中男性10例，女性20例，平均年龄为45.4±15.3岁。合并抗GBM病和IgAN的患者具有局限的肾脏受累，没有肺出血。与经典患者相比，具有IgAN的抗GBM患者在诊断时的血清肌酐水平显著较低（6.2±2.9 vs 9.5±5.4 mg/dL，P=0.03），少见尿少/尿无（20%，3/15 vs 57%，17/30，P=0.02），但尿蛋白排泄更多[2.37 (1.48, 5.63) vs 1.11 (0.63, 3.90) g/24 h，P=0.01]。随访期间，与经典患者相比，患有IgAN的抗GBM病患者肾脏病情有所改善（ESKD: 47%，7/15 vs 80%，24/30，P=0.03）。两组之间的自身抗原和表位谱相当，但循环中抗-α3(IV)NC1 IgG1（67% vs 97%，P=0.01）和IgG3（67% vs 97%，P=0.01）在IgAN患者中较低。抗GBM病中合并IgAN并不罕见。患者表现出较轻的肾脏病变和更好的免疫抑制治疗后恢复。这可能部分解释了这些患者中抗GBM IgG1和IgG3的更低患病率。© The Author(s) 2023. Published by Oxford University Press on behalf of the ERA.

The combination of anti-glomerular basement membrane (GBM) disease and immunoglobulin A nephropathy (IgAN) has been well documented in sporadic cases, but lacks overall assessment in large collections. Herein, we investigated the clinical and immunological characteristics and outcome of this entity.Seventy-five consecutive patients with biopsy-proven anti-GBM disease from March 2012 to March 2020 were screened. Among them, patients with concurrent IgAN were identified and enrolled. The control group included biopsied classical anti-GBM patients during the same period, excluding patients with IgAN, other glomerular diseases or tumors, or patients with unavailable blood samples and missing data. Serum IgG and IgA autoantibodies against GBM were detected by enzyme-linked immunosorbent assay, as were circulating IgG subclasses against GBM.Fifteen patients with combined anti-GBM disease and IgAN were identified, accounting for 20% (15/75) of all patients. Among them, nine were male and six were female, with an average (± standard deviation) age of 46.7 ± 17.3 years. Thirty patients with classical anti-GBM disease were enrolled as controls, with 10 males and 20 females at an average age of 45.4 ± 15.3 years. Patients with combined anti-GBM disease and IgAN had restricted kidney involvement without pulmonary hemorrhage. Compared with classical patients, anti-GBM patients with IgAN presented with significantly lower levels of serum creatinine on diagnosis (6.2 ± 2.9 vs 9.5 ± 5.4 mg/dL, P = .03) and less occurrence of oliguria/anuria (20%, 3/15 vs 57%, 17/30, P = .02), but more urine protein excretion [2.37 (1.48, 5.63) vs 1.11 (0.63, 3.90) g/24 h, P = .01]. They showed better kidney outcome during follow-up (ESKD: 47%, 7/15 vs 80%, 24/30, P = .03). The autoantigen and epitope spectrum were comparable between the two groups, but the prevalence of circulating anti-α3(IV)NC1 IgG1 (67% vs 97%, P = .01) and IgG3 (67% vs 97%, P = .01) were lower in patients with IgAN.Concurrent IgAN was not rare in anti-GBM disease. Patients showed milder kidney lesions and better recovery after immunosuppressive therapies. This might be partly explained by lower prevalence of anti-GBM IgG1 and IgG3 in these patients.© The Author(s) 2023. Published by Oxford University Press on behalf of the ERA.