Nephrotic syndrome with acute kidney injury due to combination therapy of immune checkpoint inhibitors: a case report and review of the literature.

BACKGROUND: Recent studies have focused on immune checkpoint inhibitors. Renal complications associated with the use of immune checkpoint inhibitors are uncommon compared with other immune-related adverse events. Acute interstitial nephritis accounts for most of these renal complications, with nephrotic syndrome quite rare. We herein report a case of nephrotic syndrome associated with immune checkpoint inhibitors that was more severe than that in previous cases. By comparing this case with previous reports, the possible reasons for the particular severity of this case are discussed. CASE PRESENTATION: A 75-year-old man developed nephrotic syndrome with acute kidney injury after the first combination therapy of nivolumab and ipilimumab for malignant pleural mesothelioma. The results of a kidney biopsy indicated minimal change disease with mild atherosclerosis, acute interstitial nephritis, and fusion of nearly all podocyte foot processes. Nivolumab and ipilimumab therapy were stopped, and treatment with corticosteroids was initiated. We investigated previously reported cases of nephrotic syndrome using immune checkpoint inhibitors. Seventeen cases of immune checkpoint inhibitor-related nephrotic syndrome, including ours, have been reported. Two of the 17 patients with immune checkpoint inhibitor-related nephrotic syndrome required hemodialysis treatment for acute kidney injury. Unlike many previously reported cases, the present patient was administered two different immune checkpoint inhibitors, which may be one of the reasons for the development of severe nephrotic syndrome. CONCLUSIONS: In addition to previously reported risk factors, immune checkpoint inhibitor combination therapy can exacerbate nephrotic syndrome compared to immune checkpoint inhibitor monotherapy.

A case of acute kidney injury and Fanconi syndrome while taking multiple supplements, including Red Yeast Rice Cholesterol Help®.

A 62-year-old man visited his primary care physician with the complaints of loss of appetite and fatigue. He was admitted to our hospital based on a diagnosis of acute kidney injury, Fanconi syndrome as indicated by hypokalemia, hypouricemia, hypophosphatemia, elevated glucose levels in urine, and aminoaciduria. He had been taking multiple supplements, including Red Yeast Rice Cholesterol Help®, for one and a half years. After admission, all the supplements were stopped. Blood samples were collected; however, the samples were negative for diseases that could cause Fanconi syndrome. Renal biopsy revealed renal proximal tubular damage, mainly characterized by simplification of the proximal tubular epithelium. The mycotoxin, citrinin, which is reported to be produced by the mold used for producing red yeast rice, but not the mold Monascus pilosus used for Red Yeast Rice Cholesterol Help®, reportedly causes proximal tubular damage. However, although the causative agent has not been identified, it was thought that a substance similar to citrinin, produced by the mold used for Red Yeast Rice Cholesterol Help®, caused proximal tubular damage, leading to acute kidney injury and Fanconi syndrome. Hence, all supplements were stopped, and the patient was treated with oral potassium and phosphorus preparations, leading to gradual recovery of his kidney function. We herein report the first case of acute kidney injury and Fanconi syndrome in a patient taking multiple health supplements, including Red Yeast Rice Cholesterol Help®. Early discontinuation of the oral supplements was probably useful in improving the patient's kidney function.