Steroid resistant nephrotic syndrome with collapsing focal segmental glomerulosclerosis in a 12-year-old Japanese female after SARS-CoV-2 vaccination

Excerpt

A 12-year-old female was referred to our hospital because of severe edema. She had no specific past or family history, including prior infection. School-based urine screening had never detected any abnormalities. Two days after initial administration of the BNT162b2 (Pfizer/BioNTech) vaccine, edema began to gradually appear, and 8 days after the injection, her body weight had increased by 7 kg. Physical examination showed no purpura or arthralgia. Blood test showed severe hypoalbuminemia but no kidney dysfunction or hypocomplementemia (Table 1). Spot urinalysis showed nephrotic range proteinuria (urine protein to creatinine ratio: 12.8 g/gCr) and microhematuria, indicating nephrotic syndrome (NS). The screening polymerase chain reaction test for severe acute respiratory syndrome coronavirus (SARS-CoV-2) was negative. After admission, an albumin infusion was given as supportive treatment. Twenty-one days after vaccination and before initiating steroid treatment, kidney biopsy was performed. Light microscopy study (periodic acid-Schiff stain) revealed mesangial consolidation and loss of endocapillary patency and extracapillary epithelial proliferation, which is consistent with focal segmental glomerulosclerosis (FSGS) collapsing variant (Fig. 1A–C) [1]. Electron microscopy showed foot process fusion, but no tubuloreticular inclusions (Fig. 1D). Treatment with prednisolone 60 mg/m²/day with an upper limit of 60/mg/day was started according to clinical guidelines on childhood NS. Twenty-eight days after initiation of prednisolone, the patient had not achieved complete remission, so we started cyclosporine treatment and lisinopril therapy. Two cycles of methylprednisolone pulse therapy (1000 mg for 3 days) were also administered. Complete remission was finally achieved after 10 weeks of treatment (Table 1) with no adverse events. Comprehensive genetic testing with targeted sequence panel by next generation sequencing revealed no gene variants causing steroid-resistant NS or asymptomatic proteinuria (sTable 1) [2]. Human immunodeficiency virus (HIV) testing was not performed because of the low probability of infection. After complete remission, prednisolone was tapered, and therapy with cyclosporine and lisinopril was continued. At the last observation (6 months later), eGFR tended to be lower compared with values at the beginning of the disease. It is impossible to determine whether this is the effect of cyclosporine or the progression of the underlying disease. Follow-up renal biopsy is scheduled for 2 years after the start of treatment.

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