New-Onset and Relapsed Membranous Nephropathy post SARS-CoV-2 and COVID-19 Vaccination

IgG4-Related Membranous Nephropathy After COVID-19 Vaccination: A Case Report

Although immunoglobulin G4 (IgG4)-related kidney diseases are typically characterized by tubulointerstitial nephritis with abundant infiltration of IgG4-positive plasma cells and fibrosis, there have been relatively rare cases of IgG4-related glomerulonephritis. Several cases of IgG4-related disease (IgG4-RD) following coronavirus disease 2019 (COVID-19) mRNA vaccination have been reported. However, there are no reports of IgG4-related glomerulonephritis following COVID-19 vaccination. Herein, we present a case of IgG4-related membranous nephropathy (MN) occurring after COVID-19 vaccination. A 69-year-old Japanese male presented to our hospital with edema that started the day after his second COVID-19 vaccination. The patient exhibited nephrotic syndrome and was diagnosed with MN based on the results of a kidney biopsy. Although serum IgG4 levels were elevated to 946 mg/dL, no evidence of organ involvement suggestive of IgG4-RD was observed. Treatment with prednisolone and cyclosporine resulted in complete remission, and immunosuppressive agents were tapered. However, one month after discontinuing the immunosuppressive agents, the patient was readmitted with swelling around the submandibular glands and exertional dyspnea. Serum IgG4 level was markedly elevated at 2,320 mg/dL, and computed tomography revealed submandibular gland swelling and thickening of the interlobular septum and bronchovascular bundles in both lungs. The patient was diagnosed with IgG4-RD based on elevated serum IgG4 levels and infiltration of IgG4-positive plasma cells in the submandibular gland biopsy. Upon resuming treatment with prednisolone, the symptoms attributed to IgG4-RD improved within a few days. In cases of nephrotic syndrome following COVID-19 vaccination, it may be advisable to conduct detailed examinations to assess the possibility of the development of IgG4-RDs.

Combination of rituximab and short-term glucocorticoids in the treatment of anti-phospholipase A2 receptor antibody positive idiopathic membranous nephropathy

Rituximab (RTX) has been the first option in idiopathic membranous nephropathy (IMN). However, the clinical effect was not very satisfactory. This study aimed to explore the clinical efficacy and safety of the combination of RTX and glucocorticoids (GC) in anti-phospholipase A2 receptor (anti-PLA2R) antibody positive IMN. Sixty-six patients were randomly divided into RTX/GC group (RTX infusion plus short-term oral GC) and RTX group (RTX infusion alone) in this prospective cohort study. Complete remission (CR) and partial remission (PR) were the primary outcomes. Adverse events were the secondary outcomes. The laboratory index including serum albumin, 24 h urinary protein, serum creatinine, estimated glomerular filtration rate, and anti-PLA2R antibody titer were also monitored. All patients were followed for at least 12 months. During the 12-month follow-up, the composite remission rates in RTX/GC and RTX groups were 74.3% and 67.7%, and the CR rates were 34.3% and 19.4%, respectively. The median time of remission in RTX/GC group was shorter than the RTX group (P < 0.001). Compared with RTX monotherapy, the combination of RTX and GC significantly decreased the anti-PLA2R antibody titer (P = 0.028). No significant difference was observed in the incidence of adverse events. The results of the Kaplan-Meier survival analysis indicated that the cumulative CR rate and cumulative composite remission rate in RTX/GC group were all better than the RTX group (P = 0.043, P = 0.040, respectively). The combination of RTX and GC was better than RTX monotherapy without increasing the adverse events in the treatment of IMN.

Molecular characteristics of circulating B cells and kidney cells at the single-cell level in special types of primary membranous nephropathy

Background

Although primary membranous nephropathy (pMN) associated with podocyte autoantibodies (POS) is becoming well-known, the molecular characteristics of the specific type of pMN that is negative for podocyte autoantibodies (NEG) is still unclear.

Methods

We performed single-cell transcriptome sequencing and single-cell B cell receptor sequencing on circulating CD19+ cells and kidney cells of a NEG paediatric patient with pMN. The single-cell datasets of POS patients and healthy control individuals were included for integrative analysis.

Results

The gene expression characteristics and clonal expansion of naïve and memory B cells in the NEG patient changed significantly. We found that a group of CD38+ naïve B cells expanded in the NEG patient, which had the functional characteristics of cell activation. In addition, the conversion between immunoglobulin M (IgM)/IgD and IgG1 in the NEG patient was increased. Parietal epithelial cells (PECs) and podocytes shared similar signature genes (WT1, CLIC5), and new candidate marker genes for PECs, such as NID2, CAV1 and THY1, might contribute to the definition of cell subsets. PECs might have undergone significant changes in the disease, mainly manifested by changes in the expression of CCN2, PLAAT4 and SEPTIN2. The scores of gene sets related to extracellular matrix, cell adhesion and calcium channel in podocytes of the NEG patient was significantly increased. The gene expression of sodium transporter in a group of proximal tubule cells in the disease was significantly increased, especially SLC5A12, which might be related to the oedema of patients.

Conclusions

Our research demonstrated the cell type-specific molecular features in the circulation and kidney of the NEG pMN patient.

Membranous Nephropathy following Full-Dose of Inactivated SARS-CoV-2 Virus Vaccination: A Case Report and Literature Review

Vaccination against the SARS-CoV-2 virus (COVID-19) has proven to be the most effective measure to prevent the spread and reduce infection severity. A case report of de novo membranous nephropathy (MN) following immunization with inactivated virus vaccine (CoronaVac^®, Sinovac Biotech) is presented here. A 53-year-old man presented with a sudden onset of leg edema a week after receiving an inactivated virus vaccine and a relapse of nephrotic syndrome (NS) with acute kidney injury (AKI) after a booster dose. Screening for serum anti-phospholipase A2 receptor antibody and secondary causes of MN were negative. Kidney biopsy revealed an early MN pattern with focal spike formation, whilst numerous subepithelial electron-dense deposits and a few small deposits in the mesangial area were observed through electron microscopy. A short course of steroids and oral cyclophosphamide was prescribed, resulting in the complete remission of NS and AKI. MN following SARS-CoV-2 vaccination should call for medical importance. Awareness of the association between vaccination and MN should be kept in mind to avoid unnecessary treatment with long-term immunosuppressive agents.