A Case of Membranous Nephropathy Following Pfizer-BioNTech mRNA vaccine against Coronavirus 2019.

To the editor:

We read a recent report describing the relapse of membranous nephropathy (MN) following the administration of inactivated vaccine against coronavirus disease 2019 (COVID-19). Here, we describe a case of new-onset MN following vaccination with the Pfizer–BioNTech mRNA-based COVID-19 vaccine.

A 70-year-old man with no significant past medical history was referred to our institution for generalized edema, which occurred a week after his first dose of the Pfizer–BioNTech vaccine and got worse a day after the second dose, which was given 3 weeks after the first dose. He denied other symptoms. On examination, his blood pressure was 155/86 mm Hg, and he had bilateral pitting edema up to his thighs. Laboratory tests revealed a serum creatinine level of 114 μmol/l, an albumin level of 17 g/l, a total cholesterol level of 9.24 mmol/l, 17 red blood cells/μl in urine analysis, and a 24-hour total urine protein level of 4.4 grams. Secondary causes, including drugs and infections (hepatitis B, hepatitis C, HIV), were excluded. He was found to have IgM kappa monoclonal gammopathy of undetermined significance. A thorough malignancy screening, including enhanced computed tomography of the thorax, abdomen, and pelvis, gastroscope plus colonoscope, and prostate-specific antigen testing yielded no significant results.

A percutaneous kidney biopsy was performed, and diagnosis of MN was confirmed. The results are shown in Figure 1 .

Figure 1

(a) Electron microscopy. Glomerular capillary loops showed numerous small subepithelial electron-dense deposits. The overlying podocytes showed extensive foot process effacement. (b) IgG immunofluorescence showed diffuse 2+ finely granular capillary loop staining. To optimize viewing of this image, please see the online version of this article at www.kidney-international.org.

Serum anti-phospholipase A2 receptor (PLA2R) was negative, and a kidney biopsy stained negative for PLA2R antigen as well. Serum thrombospondin type-1 domain-containing 7A (THSD7A) antibody was positive by indirect immunofluorescence assay. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein antibody was 147.0 U/ml 3 months after his second dose of vaccine. The patient is currently being managed with irbesartan, frusemide, and warfarin. There are no signs of spontaneous remission after 2 months.

Our observation, together with other case reports of MN development post–COVID-19 infection, , and MN relapse post–COVID-19 vaccine administration, supports a possible immune dysregulation process causing loss of tolerance to certain podocyte antigens. Elucidation of this possibility requires further studies.