Monoclonal gammopathy has emerged as an important cause of renal injury. Since the clinicopathologic features related to monotypic monoclonal gammopathy of renal significance with IgM monoclonal gammopathy (IgM-MGRS) are poorly described and it is uncertain if intervention improves renal survival and mortality, we report a series of such patients, characterizing their clinicopathologic spectrum and outcomes. We retrospectively analyzed 38 patients referred to one medical center between 2009 and 2019 with detectable serum monoclonal IgM by immunofixation, performance of a bone marrow biopsy and kidney biopsy-proven MGRS. Of the 38 patients identified, about half patients were amyloidosis, followed by cryoglobulinemic glomerulonephritis. Patients were divided into two groups on the basis of their kidney pathology: amyloid and non-amyloid. Patients with non-amyloidosis were more likely to have renal dysfunction, hematuria, anemia and hypocomplementemia and κ light chain was predominant in this sub-group. Amyloid patients were more often treated with chemotherapy than the non-amyloid patients (P = 0.002). There were no significant differences between amyloid and non-amyloid patients in mortality (48% vs 29%, P = 0.467) and incidence of ESRD (19% vs 59%, P = 0.103). The incidence of ESRD was lower in patients treated with chemotherapy and/or ASCT, compared to those without chemotherapy (25% vs 57%, P = 0.049), and it was also lower in the hematologic responders than non-responders (10% vs 40%, P = 0.047). Our study confirmed a diverse variety of clinicopathological features and outcomes in patients with IgM-MGRS. Chemotherapy and/or ASCT and deep hematologic responses might improve renal prognosis.

单克隆丙种球蛋白病已成为肾损伤的重要原因。由于与 IgM 单克隆丙种球蛋白病 (IgM-MGRS) 相关的具有肾脏意义的单型单克隆丙种球蛋白病相关的临床病理学特征描述很少，并且不确定干预是否会提高肾脏存活率和死亡率，我们报告了一系列此类患者，描述了他们的临床病理学谱和结果. 我们回顾性分析了 2009 年至 2019 年间转诊到一个医疗中心的 38 名患者，这些患者通过免疫固定、骨髓活检和肾活检证实的 MGRS 可检测到血清单克隆 IgM。在确定的 38 名患者中，约一半患者为淀粉样变性，其次为冷球蛋白血症性肾小球肾炎。根据肾脏病理将患者分为两组：淀粉样蛋白和非淀粉样蛋白。非淀粉样变性患者更容易出现肾功能不全、血尿、贫血和低补体血症，并且 κ 轻链在该亚组中占主导地位。淀粉样蛋白患者比非淀粉样蛋白患者更常接受化疗（P  = 0.002）。淀粉样蛋白和非淀粉样蛋白患者在死亡率（48% vs 29%， P  = 0.467）和 ESRD 发生率（19% vs 59%，P  = 0.103）方面没有显着差异。与未接受化疗的患者相比，接受化疗和/或 ASCT 治疗的患者的 ESRD 发生率较低（25% 对 57%，P  = 0.049），而且血液学反应者的 ESRD 发生率也低于无反应者（10% 对40%，P  = 0.047）。我们的研究证实了 IgM-MGRS 患者的多种临床病理学特征和结果。化疗和/或 ASCT 和深度血液学反应可能会改善肾脏预后。