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Abstract Background and Aims Minimal change disease (MCD) in adults is one of the causes of nephrotic syndrome. Recently, anti-nephrin antibodies localized in glomerular podocytes have been described in a certain subset of patients with MCD, supporting the autoimmune etiology of the disease. Method A 79-year-old man with arterial hypertension, hypothirosis and mild dementia presented with new-onset nephrotic syndrome. Peripheral and periocular edema, hypoalbuminemia (serum albumin 17 g/l), proteinuria 15 g/day and hypercholesterolemia (serum cholesterol 6.7 mmol/l) were noted. Blood pressure was 133/85 mmHg. Creatinine was 165 mcmol/l on admission and increased to 361 mcmol/l in the following days. Immunologic tests were negative, including antibodies against phospholipase A2-receptor (anti-PLA2R) and thrombospondin-7A (anti-THSD7A). Anti-HBc was positive, HBV DNA was below 15 IU/ml. Liver tests and abdominal ultrasound were normal, with no signs of liver disease. Results Renal biopsy revealed 18 glomeruli with global sclerosis of one glomerulus (1/18) and 5% interstitial fibrosis. Tubular damage was noted, which could be attributed to severe proteinuria. Immunofluorescence showed discrete IgG podocyte deposits with a uniform kappa/lambda distribution and a high probability of idiopathic minimal change disease due to anti-nephrin antibodies. Electron microscopy showed diffuse effacement of the podocyte foot processes without deposits. The serum taken after the biopsy and before the start of immunosuppressive therapy was positive for anti-nephrin antibodies. Due to a possible pharmacokinetic interaction with tenofovir, which the patient was receiving because of his anti-HBc positivity, we decided not to use cyclosporine. In addition to standard therapy with angiotensin convertase inhibitors, calcium channel blockers and furosemide, the patient was treated with low-dose oral glucocorticoids and mycophenolic acid. In addition, he received rituximab. After a few weeks, the oral glucocorticoids and mycophenolic acid were discontinued. The nephrotic syndrome regressed completely and renal function improved. Conclusion Anti-nephrin antibodies have contributed to a subgroup of patients with MCD, they can be found in a renal biopsy and are also detected in the serum of these patients. Targeted anti-B-cell therapy should be introduced to improve the prognosis of patients.
Knehtl et al. (Wed,) studied this question.