The advent of immune checkpoint inhibitors (ICIs) has significantly improved the prognosis of patients with advanced malignancies. On the other hand, these drugs might cause immune-related adverse events (irAEs) including endocrinopathies and nephropathies. Thyroid dysfunction is one of the most common irAEs. For ICIs-induced nephropathies, most cases are due to tubulointerstitial nephritis, which might require steroid treatment. Here, we report a patient with non-small cell lung cancer treated with ICI who developed increased serum creatinine (s-Cr) levels due to ICIs-induced hypothyroidism. A 57-year-old Asian man with refractory non-small cell lung cancer under ICIs therapy (pembrolizumab, an anti-programmed cell death-1 monoclonal antibody) developed increased s-Cr levels 5 months after the pembrolizumab initiation. His laboratory data, renal biopsy, and Gallium-67 scintigraphy findings denied pembrolizumab-induced tubulointerstitial nephritis. His renal function was correlated with thyroid function. Despite the increase of s-Cr levels, serum cystatin C levels were normal, which could be explained by the hypothyroidism. Levothyroxine treatment improved renal function as well as thyroid function. Then pembrolizumab was resumed, and both his thyroid and renal function remained normal level. Ultimately, we concluded that the increased s-Cr levels were caused by pembrolizumab-induced hypothyroidism. All clinicians involved in ICI treatment need to recognize the possible increase in s-Cr levels caused by ICIs-induced hypothyroidism, and we propose monitoring serum cystatin C levels to differentiate ICIs-induced hypothyroidism from tubulointerstitial nephritis before invasive renal biopsies or steroid treatment, which are recommended by the prescribing information for pembrolizumab, are performed.

中文翻译：

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派姆单抗引起的甲状腺功能减退症导致血清肌酐水平可逆性升高：病例报告

免疫检查点抑制剂（ICIs）的出现显着改善了晚期恶性肿瘤患者的预后。另一方面，这些药物可能会导致免疫相关不良事件 (irAE)，包括内分泌疾病和肾病。甲状腺功能障碍是最常见的 irAE 之一。对于 ICI 诱发的肾病，大多数病例是由于肾小管间质性肾炎，这可能需要类固醇治疗。在这里，我们报告了一名接受 ICI 治疗的非小细胞肺癌患者，由于 ICI 引起的甲状腺功能减退，其血清肌酐 (s-Cr) 水平升高。一名 57 岁亚洲男性患有难治性非小细胞肺癌，接受 ICIs 治疗（pembrolizumab，一种抗程序性细胞死亡 1 单克隆抗体），在 pembrolizumab 开始 5 个月后出现 s-Cr 水平升高。他的实验室数据，肾活检和镓 67 闪烁扫描结果否认派姆单抗引起的肾小管间质性肾炎。他的肾功能与甲状腺功能有关。尽管 s-Cr 水平升高，但血清胱抑素 C 水平正常，这可以用甲状腺功能减退症来解释。左旋甲状腺素治疗改善了肾功能和甲状腺功能。然后恢复了 pembrolizumab，他的甲状腺和肾功能都保持正常水平。最终，我们得出结论，s-Cr 水平升高是由派姆单抗引起的甲状腺功能减退症引起的。所有参与 ICI 治疗的临床医生都需要认识到 ICI 引起的甲状腺功能减退症可能导致 s-Cr 水平升高，