The immunologic response following several varieties of vaccination (especially meningococcal C conjugate vaccines) has been described as a potential trigger for the development of nephrotic syndrome (NS).[1,2] Coronavirus disease 2019 (COVID-19) vaccine, administered worldwide, appears to be safe. However, rare reports of both de novo and recurrent NS and vasculitis are emerging.
Vaccines for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed in an accelerated manner as a response to a pandemic. They use different mechanisms to generate immunity. Pfizer BNT162b2 and Moderna mRNA-1273 use a pioneer mechanism, a lipid nanoparticle nucleoside-modified mRNA that encodes SARS-CoV-2 spike (S) protein, which medicates host attachment and viral entry. AstraZeneca uses a replication-deficient chimpanzee adenovirus vector, containing the SARS-CoV-2 S protein. Studied subjects generated T cell response, CD8+ and CD4+ expansion, to a Th1-biased response with production of Interferon-γ, tumor necrosis factor-α (TNF-α), interleukin-2 and antibody (Ab) production predominantly of immunoglobulin G1 (IgG1) and IgG3 subclasses.[3–5] These immune responses might be associated with a recurrence of glomerular disease or as a possible trigger for podocytopathies.
To date, 11 NS [new onset (5 patients) and relapsed (6 patients)] linked to minimal change disease (MCD) (10 patients) or membranous nephropathy (1 patient) after SARS-CoV-2 vaccines—Pfizer BNT162b2 (4 patients, 3 patients), Moderna mRNA-1273 (1 patient, 0 patient), AstraZeneca (0 patient, 2 patients) or SINOVAC (0 patient, 1 patient) vaccine have been reported (Table 1).[6–15] All cases appeared 3 days to 2 weeks after the first vaccine dose followed by remission under corticosteroid treatment, except in one patient with underlying diabetic change nephropathy.[7]
As of this date, there are six cases of de novo crescentic glomerulonephritis after the SARS-CoV-2 vaccines—[Pfizer BNT162b2 (2 patients), Moderna mRNA-1273 (4 patients)] described in the literature (Table 2).[16–19] Two patients had a past medical history significant for hypertension. Kidney biopsies showed anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (Moderna mRNA-1273), IgA nephritis (Pfizer BNT162b2, Moderna mRNA-1273) and anti-glomerular basement membrane (anti-GBM) disease (Pfizer BNT162b2, Moderna mRNA-1273), respectively, each 2 patients. All patients were treated with corticosteroids and cyclophosphamide. Three and one patients required plasma exchange and rituximab, respectively. Two patients had improvement of symptoms and two remained in hemodialysis (Table 2).[16–19]
Vaccination (notably influenza) is a recognized trigger for the relapse of idiopathic NS[16] and ANCA-associated vasculitis.[17] Acute onset of MCD has been reported at 4 and 18 days following the influenza vaccine[1,18] and 6 weeks following a tetanus–diphtheria–poliomyelitis vaccination.[20–22] The association between the timing of vaccination and the development of both new onset and relapsed MCD and/or membranous nephropathy raises questions as to the mechanisms involved. The strong temporal association with vaccination and MCD cases suggests a more generalized cytokine-mediated response[23] and/or a rapid T cell-mediated immune response to viral mRNA as a possible trigger for podocytopathy.[13,24] The Pfizer–BioNTech vaccine is reported to induce robust T cell activation, as previously described, which might contribute to MCD. It is also possible that these phenomena are completely circumstantial and unrelated. Regardless, prompt initiation of steroid treatment should be considered. S protein data were not reported in most of the cases to raise the timing of the formation of the Ab and the glomerular disease finding. Is this more common than for the influenza vaccine? This cannot be answered at this moment as mass vaccination leads to clustering of rare side effects and true incidence is hard to define.
The mechanism of de novo ANCA-associated vasculitis post-SARS-CoV-2 vaccine remains to be elucidated but the temporal association suggests a neutrophilic immune response to the S protein or mRNA of SARS-CoV-2 in predisposed individuals. It is possible that the vaccines lead to proinflammatory cytokines such as TNF and interleukin-1B, which can prime neutrophils leading to formation of neutrophil extracellular traps (NETs). Persistent NETs and prolonged exposure to their contents can lead to disruption of tolerance and formation of Abs to myeloperoxidase and proteinase 3. This could be the mechanism of triggering an ANCA-associated vasculitis.[25] However, crescents may take time to form, suggesting an unrecognized underlying pre-existing glomerulonephritis was present at the time of receiving SARS-CoV-2 vaccination, which more likely potentiated an immune response in the described patients. In addition, there is a seasonal variation of vasculitis that may be playing a role here as well,[26] and not all related to the vaccine.
Reports of temporal and spatial clustering suggest that environmental factors such as infections may play a role in anti-GBM disease induction.[27,28] Infectious associations, particularly with influenza A,[29,30] and high prevalence of prodromal upper and lower respiratory tract infection in a cohort of 140 Chinese patients[31] may account for the aforementioned seasonal or geographic 'clustering' of anti-GBM disease cases.
COVID-19 may be one such infection,[32,33] as suggested by a report of a cluster of cases in London during the current pandemic[34] with a 5-fold increased incidence. Although five of eight tested patients presenting with anti-GBM Ab were negative for SARS-CoV-2 infection by PCR, four had IgM and/or IgG Abs to SARS-CoV-2 S protein, raising the possibility that immune response to SARS-CoV-2 could be related to development of anti-GBM in some patients.[34]
However, there is no anti-GBM case following vaccination reported in the literature. Therefore, one can ask the question about the seasonality of anti-GBM Ab and/or the possibility that these patients were already infected with COVID-19, since none of the patients reported had a serological test before vaccination. Whether current cases can be attributed to SARS-CoV-2 vaccine-related immune response warrants investigation.
Pharmacovigilance of SARS-CoV-2 vaccines will be important to determine the incidence of these potential adverse events since many millions of doses of the various available SARS-CoV-2 vaccines have been administered worldwide. However, we also should be mindful that this may be a coincidence and not causation, and vaccinations should be continued in order to end the pandemic.
Nephrol Dial Transplant. 2021;36(9):1565-1569. © 2021 Oxford University Press
