Characterization of patients with IgA nephropathy with and without associated minimal change disease

Introduction

Immunoglobulin A nephropathy (IgAN) presents various clinical manifestations and pathological phenotypes. Approximately 5% of patients with IgAN present with early onset nephrotic syndrome, mild mesangial lesions, and diffuse foot process effacement of podocytes, which resemble minimal change disease (MCD). These patients are defined as MCD-IgAN. Whether MCD-IgAN is a special type of IgAN or simply MCD accompanied by IgA deposition remains controversial.

Methods

A total of 51 patients diagnosed with MCD-IgAN at Beijing Anzhen Hospital from January 2010 to September 2022 were recruited. The clinical and pathological characteristics of IgA-MCD were analyzed. Patients with IgAN but without MCD (non-MCD-IgAN) and healthy participants were enrolled as controls. Galactose-deficient immunoglobulin A1 (Gd-IgA1) and complement C3 were detected both in the circulation and in renal tissues.

Results

We found that the levels of serum Gd-IgA1 were lower in participants with MCD-IgAN than in those with non-MCD-IgAN, but higher than in healthy participants. Gd-IgA1 was rarely deposited in the glomeruli of participants with MCD-IgAN, with a positive rate of only 13.7% (7/51); in contrast, the positive rate in participants with non-MCD-IgAN was 82.4% (42/51). Among renal Gd-IgA1-positive patients, Gd-IgA1 and immunoglobulin A (IgA) colocalized along the glomerular mesangial and capillary areas. Interestingly, we found that the circulating levels of complement C3 were significantly higher in participants with MCD-IgAN than in participants with non-MCD-IgAN. In addition, the intensity of C3c in glomeruli in participants with MCD-IgAN was significantly weaker than in participants with non-MCD-IgAN.

Conclusions

Our study suggests that, in MCD-IgAN, most of the IgA that is deposited on glomeruli is not the same pathogenic Gd-IgA1 as found in general IgAN. Complement activation both in the circulation and in the renal locality was much weaker in MCD-IgAN than in non-MCD-IgAN. Our study suggests that IgAN with MCD might be MCD with coincidental IgA deposition.

Minimal change disease following the Moderna COVID-19 vaccine: first case report

BACKGROUND

There have been cases of minimal change disease (MCD) reported following previous vaccines. During the COVID-19 era, only 3 cases of new-onset MCD and a case of MCD relapse were reported following the Pfizer-BioNTech COVID-19 vaccine. We herein report the first case of MCD after receiving the Moderna COVID-19 vaccine.

CASE PRESENTATION

A 43-year-old man presented to hospital 3 weeks after receiving the first dose of the Moderna vaccine, with both bilateral lower extremities and scrotal edema. He initially developed a sudden-onset bilateral lower extremities swelling on day 7 post-vaccine. He, then, developed dyspnea and scrotal swelling over a time span of 2 weeks. On physical examination, his blood pressure was 150/92 mmHg. There was a decreased air entry at lung bases, bilateral lower extremities and scrotal edema. Labs revealed hypoalbuminemia, hyperlipidemia and 15 g of proteinuria. His immunologic and serologic work up was negative. Renal biopsy showed concomitant MCD and IgA nephropathy. Patient was treated with oral steroids and had a good response; his edema resolved, serum albumin improved, and proteinuria decreased to 1 g within 2 weeks of treatment.

CONCLUSIONS

To the best of our knowledge, MCD has not been previously reported after receiving the Moderna COVID-19 vaccine. It remains unclear whether the COVID-19 mRNA vaccines are associated with the development of MCD, or it coincided with the mass vaccination. Further studies are needed to determine the incidence of MCD post COVID-19 vaccines and the underlying pathophysiology of glomerular injury post vaccination.

Steroid therapy in children with IgA nephropathy

IgA nephropathy (IgAN) is one the most common primary glomerulonephritis in children and adolescents worldwide, with 20% of children developing end-stage kidney disease (ESKD) within 20 years of diagnosis. There is a need for treatment guidelines, especially for steroids in children with primary IgAN, since the STOP-IgA trial casts doubts on the use of steroids in adults with intermediate risk. Pediatricians are prone to prescribe steroids in addition to renin-angiotensin system blockade (RASB) when proteinuria is > 0.5 g/l, eGFR deteriorates < 70 ml/min/1.73 m², or when a biopsy sample shows glomerular inflammation. Lack of randomized controlled trials (RCTs) in children with IgAN has led to an absence of consensus on the use of immunosuppressive agents in the treatment of progressive IgAN. This literature review evaluates the available evidence on steroid treatment in children with IgAN.

[IgA nephropathy: Unusual forms]

IgA nephropathy can have various initial presentation and evolutive characteristics. In this article, specific forms of IgA nephropathy are described, such as hypertensive emergency, nephrotic syndrome, rapidly progressive glomerulonephritis, monotypic IgA deposits, or IgA nephropathy associated with inflammatory diseases. Identification of these specific forms is needed to better characterize and treat these rare pathologies.

Increased PD-1+CD154+ Tfh cells are possibly the most important functional subset of PD-1+ T follicular helper cells in adult patients with minimal change disease

T follicular helper (Tfh) cells, especially programmed cell death protein 1 (PD-1)⁺ Tfh cells, exert important functions in the normal immune response. The purpose of this study was to determine the frequency of different subsets of PD-1⁺ Tfh cells and their functional effects in adult patients with minimal change disease (MCD). The frequencies of circulating PD-1⁺, PD-1⁺CD154⁺, and PD-1⁺interleukin (IL)-21⁺ Tfh cells, and CD38⁺CD19⁺ and CD38⁺CD19⁺CD40⁺ B cells, as well as serum IL-2, IL-4, IL-17A, IL-6, IL-21, and interferon (IFN)-γ were significantly increased in the MCD patients compared with the healthy controls (HCs) (P < 0.05). However, no significant difference was found in PD-1⁺BCL-6⁺ or PD-1⁺ICOS⁺ Tfh cells. Furthermore, the percentages of PD-1⁺ Tfh and PD-1⁺CD154⁺ Tfh cells were negatively correlated with the estimated glomerular filtration rate (eGFR), but positively correlated with the 24-h urinary protein concentration and serum IL-21 level. The percentages of PD-1⁺ Tfh and PD-1⁺CD154⁺ Tfh cells were positively correlated with the percentages of CD38⁺ plasma cells and active CD38⁺CD40⁺ plasma cells, respectively. After an 8-12-week treatment with prednisolone, the percentages of PD-1⁺, PD-1⁺CD154⁺, and PD-1⁺IL-21⁺ Tfh cells as well as the serum level of IL-21 were significantly reduced; in contrast, the serum levels of IL-4 and IL-10 were increased (P < 0.05). We conclude that increased PD-1⁺CD154⁺ Tfh cells are possibly the most important functional subset of PD-1⁺ Tfh cells and may contribute towards the pathogenesis of MCD.

IgA nephropathy with presentation of nephrotic syndrome at onset in children

BACKGROUND

Despite a low incidence, nephrotic syndrome (NS) can present with IgA nephropathy (IgAN). The clinical characteristics and long-term outcomes of pediatric patients with IgAN presenting with NS (NS-IgAN) at onset have not been fully elucidated.

METHODS

We retrospectively analyzed 426 patients, and compared clinical and pathological (Oxford) findings between those with NS-IgAN and those with non-NS-IgAN.

RESULTS

Among 426 patients, 30 (7.0 %) had NS-IgAN. Logistic analyses showed that male sex (OR: 7.6, p = 0.0002), M1 (OR: 10.3, p = 0.002), and E1 (OR: 15.2, p = 0.0001) were significantly related to NS. The mean observation period was 6.2 ± 3.2 years. Although NS-IgAN was associated with significantly lower renal survival than non-NS-IgAN according to Kaplan-Meier analysis (p = 0.02), renal survival of NS-IgAN was good (92.4 % at 10 years). The most significant prognostic factor for renal survival was remission of proteinuria after treatment, and NS at onset is also a significant prognostic factor for renal survival after adjusting for remission of proteinuria. Twenty children with NS-IgAN were treated with prednisolone alone, or prednisolone and immunosuppressant. Remission of proteinuria occurred in 21 patients. Three cases of NS-IgAN progressed to stage III-V chronic kidney disease at the most recent observation. They all demonstrated heavy proteinuria after the 2-year initial treatment. The significant factor for persistent proteinuria at 5 years was S1 in NS-IgAN.

CONCLUSIONS

The most significant factor for renal survival was responsiveness to treatment, not NS itself. As modifiable acute lesions are the dominant pathological findings in NS-IgAN, histological improvements achieved by appropriate treatments can result in a favorable prognosis.