Corrigendum to "Changing Phenotypes and Clinical Outcomes Over Time in Microscopic Polyangiitis" [Kidney International Reports Volume 8, Issue 10, October 2023, Pages 2107-2116]

[This corrects the article DOI: 10.1016/j.ekir.2023.07.008.].

Nonlupus Full House Nephropathy: A Systematic Review

Key Points

Background

The presence of a full house pattern at immunofluorescence on kidney biopsy in a patient without clinical and laboratory features of systemic lupus erythematosus (SLE) has led to the descriptive term nonlupus full house nephropathy. This systematic review and meta-analysis focus on nonlupus full house nephropathy nomenclature, clinical findings, and outcomes.

Methods

In a reiterative process, all identified terms for nonlupus full house nephropathy and other medical subject headings terms were searched in PubMed. Out of 344 results, 57 records published between 1982 and 2022 were included in the analysis. Clinical data of single patients from different reports were collected. Patients were classified into three pathogenetic categories, which were compared according to baseline characteristics, treatments, and outcomes.

Results

Out of the 57 records, 61% were case reports. Nonlupus full house nephropathy was addressed with 17 different names. We identified 148 patients: 75 (51%) were men; median age 35 (23–58) years. Serum creatinine and proteinuria at onset were 1.4 (0.8–2.5) mg/dl and 5.7 (2.7–8.8) g/d. About half of patients achieved complete response. A causative agent was identified in 51 patients (44%), mainly infectious (41%). Secondary nonlupus full house nephropathy was mostly nonrelapsing with worse kidney function at onset compared with idiopathic disease (P = 0.001). Among the 57 patients (50%) with idiopathic nonlupus full house nephropathy, complete response was comparable between patients treated with immunosuppression and supportive therapy; however, proteinuria and creatinine at onset were higher in patients treated with immunosuppression (P = 0.09 and P = 0.07). The remaining 7 patients (6%) developed SLE after a median follow-up of 5.0 (1.9–9.0) years.

Conclusions

Our data support that SLE and nonlupus full house nephropathy are distinct clinical entities, with comparable outcomes. A small subset of patients develops SLE during follow-up. Nonlupus full house nephropathy is addressed by many different names in the literature. The identification of three pathogenetic categories provides further clues for the management of the disease.

Changing Phenotypes and Clinical Outcomes Over Time in Microscopic Polyangiitis

Introduction

Diagnosis and management of microscopic polyangiitis (MPA) have evolved considerably over the past decades, but it is unknown whether clinical and histological presentation and patient and renal outcomes have changed accordingly.

Methods

We compared clinical and histopathological characteristic at diagnosis, risk of death, end-stage kidney disease (ESKD), and relapse rate in patients diagnosed with MPA between 1980 and 2022, after grouping them in 2 periods (p): p1980-2001 and p2002-2022. We compared the mortality rate between the 2 periods using Kaplan-Meier estimator and Cox-regression, and competing risks of ESKD and death using the Aalen-Johansen estimator, Fine-Gray multiple regression, and multistate models.

Results

Out of 187 patients, 77 were in p1980-2001 and 110 in p2002 to 2022. Patients in p2002 to 2022 were older (66.2 ± 14.0 SD vs. 57.7 ± 15.8; P < 0.001), had a better kidney function (estimated glomerular filtration rate [eGFR] 25.9 ± 24.8 vs. 21.5 ± 28.2 ml/min per 1.73 m2; P = 0.011) and a lower prevalence of the Berden sclerotic class (5.9 vs. 20.9%; P = 0.011). Despite a similar crude and adjusted patient survival, the risk of ESKD decreased during p2002 to 2022 (subdistribution hazard ratio [HR] 0.30, 95% confidence interval [CI]: 0.16-0.57; P < 0.001). The results remained significant after accounting for death after ESKD and after adjusting for potential confounders (HR 0.33 [95% CI: 0.18-0.63; P < 0.001]). The risk of relapse was numerically higher during p2002 to 2022 (subdistribution-HR 1.64 [95% CI: 0.95-2.83; P = 0.075]).

Conclusion

MPA kidney involvement has become less severe over the past decades, leading to a reduced risk of ESKD and a higher relapse rate, despite a comparable risk of death.

Thin Basement Membrane: An Underrated Cause of End-Stage Renal Disease

The term "thin basement membrane" (TBM) refers to a glomerular disorder characterized by diffuse uniform thinning of the glomerular basement membrane (GBM) on electron microscopy. Patients with TBM usually show an isolated hematuria with excellent renal prognosis. However, some patients can develop proteinuria and progressive kidney dysfunction in the long term. Most patients with TBM are heterozygous for pathogenic variants in genes encoding for both the α3 and α4 chains of collagen IV, a major constituent of GBM. Such variants are responsible for a wide range of clinical and histological phenotypes. The differential diagnosis between TBM and autosomal-dominant Alport syndrome and IgA nephritis (IGAN) may be difficult in some cases. Patients who progress to chronic kidney disease may show clinicopathologic features similar to those of primary focal and segmental glomerular sclerosis (FSGS). Without a shared classification of these patients, the risk of misdiagnosis and/or underestimation of the risk of progressive kidney disease is real. New efforts are needed to understand the determinants of renal prognosis and recognize the early signs of renal deterioration, allowing a custom-made diagnosis and therapeutic approach. For this purpose, a practical and simple clinical approach is supplied.

Primary Sclerosing Cholangitis and Amyloid A Amyloidosis: Association or Coincidence?

AA amyloidosis may complicate several chronic inflammatory conditions. From a clinical point of view, causality between inflammatory pathology and AA amyloidosis can be assumed because of the data described in the literature; some of the best known include rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, and chronic infections. Singles cases of inflammatory diseases have been found at AA amyloidosis. Causality becomes more plausible if at least two different cases with AA amyloidosis are both found to have the same rare inflammatory disease. We describe the case of a patient with primary sclerosing cholangitis (PSC) with development of AA amyloidosis conditioning a nephrotic syndrome, likely secondary to failure to control the chronic inflammatory process. Only two cases in the literature describe the association of this rare disease and the appearance of AA amyloidosis. The treatment of AA amyloidosis consists in treating the underlying inflammatory disorder; to date, few effective treatments are available for PSC. Therefore, and in view of the limited data in the literature, we believe it is important to describe its association.

Novel Therapies in Takayasu Arteritis

Takayasu Arteritis (TAK) is a large-vessel vasculitis that preferentially involves the aorta and its primary branches. Cardiac involvement is frequent in TAK and is a major determinant of the patient's outcome. Glucocorticoids (GC) are the mainstay of therapy for TAK, with high doses of GC effective to induce remission. However, relapses are common and lead to repeated and prolonged GC treatments with high risk of related adverse events. Potential GC toxicity is a major concern, especially because patients with TAK are young and need to be treated for several years, often for the whole life. Conventional immunosuppressive drugs are used in patients with severe manifestations but present some limitations. New therapeutic approaches are needed for patients with refractory disease or contraindications to conventional therapies. Fortunately, major progress has been made in understanding TAK pathogenesis, leading to the development of targeted biotherapies. In particular, IL-6 and TNF-α pathways seems to be the most promising therapeutic targets, with emerging data on Tocilizumab and TNF inhibitors. On the other hand, new insights on JAK-Inhibitors, Rituximab, Ustekinumab and Abatacept have been explored in recent studies. This review summarizes the emerging therapies used in TAK, focusing on the most recent studies on biologics and analyzing their efficacy and safety.

Novel Targets for Drug Use in Eosinophilic Granulomatosis With Polyangiitis

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare autoimmune disease characterized by medium and small vessels inflammation. Cardiac vasculitic involvement is one of the most severe manifestations with a significant impact on patients' long-term prognosis: anyway, a specific therapeutic approach for heart involvement in EGPA has not been explored yet. Current regimen consists of a long-term therapy with high dose of glucocorticoids, causing the well-known related-adverse events; immunosuppressive drugs are used in patients with severe manifestations, with some limitations. New therapeutic approaches are needed for patients with refractory disease or contraindications to conventional therapies. The quest for the ideal therapy is going toward a more and more personalized approach: on the one hand, efforts are made to use already existing therapies in the most appropriate way; on the other hand, new insights into EGPA pathogenesis allow the discovery of new targets, as demonstrated by mepolizumab and rituximab, targeting eosinophils, and B-cell compartments. This review summarizes the emerging therapies used in EGPA, focusing on the most recent studies on biologics and analyzing their efficacy and safety.

MO245OUTCOME OF DIFFERENT INDUCTION REGIMENS IN ANCA-ASSOCIATED GLOMERULONEPHRITIS ACCORDING TO THE HISTOPATHOLOGICAL CHARACTERISTICS: THE REASSESS STUDY*

Background and Aims

Renal involvement in ANCA-associated vasculitis (AAV) impacts significantly on patients’ prognosis. The role of different induction regimens on remission rates and long-term renal outcomes according to renal histological characteristics has not been explored yet.

Method

AAV patients with biopsy-proven renal involvement were collected retrospectively from eleven centers and stratified according to the induction regimen employed: Rituximab (RTX), Cyclophosphamide (CYC) or both (RTX-CYC). Kidney biopsies were classified according to the Berden and Brix classifications.

Renal remission rate was assessed 6 months after the induction regimen and defined as a renal Birmingham Vasculitis Activity Score (BVAS) of 0.

Among patients who achieved remission at 6 months, renal relapse was defined as a renal-BVAS&gt;0 associated with an increase in immunosuppressive treatment.

ESRD was defined as an eGFR&lt;15 ml/min/1,73m2, need for dialysis or renal transplant.

Results

323 patients were identified and followed-up for a median time of 36 months (IQR 18-72). The cohort included 38% patients with GPA and 62% with MPA, 53% patients were MPO-ANCA and 41% PR3-ANCA positive. The median baseline eGFR in the overall cohort was 19 ml/min/1,73m2 (IQR 12- 34). 58% of patients were treated with CYC, 24% with RTX-CYC and 18% with RTX.

According to the Berden classification, 24% biopsies were classified as Focal, 31% as Crescentic, 33% as Mixed and 12% as Sclerotic. The Brix score was assessable in 270/323 (84%) patients: 17%, 52% and 31% were respectively in the Low, Medium and High-risk class.

The overall renal remission at 6 months was 90%; according to the Berden classification, 94% patients achieved remission in the Focal, 88% in the Crescentic, 91% in the Mixed and 86% in the Sclerotic class. According to the Brix risk score, 88% patients achieved remission in the High risk, 91% in the Medium and 96% in the Low-risk class. According to induction regimen employed, 91%, 90% and 90% patients achieved remission in the RTX, CYC and RTX plus CYC group respectively.

In a logistic regression model adjusted for sex, age, ANCA type, AAV diagnosis, creatinine and proteinuria at onset, the induction regimen employed was not predictive of renal remission at 6 months, neither in Berden Focal plus Crescentic and Mixed plus Sclerotic classes, nor in Brix High and Low plus Medium risk classes.

Of the 185 patients with at least 6 months of follow-up available after remission, 25% experienced a renal relapse. In a Cox regression model adjusted for sex, age, ANCA type, AAV diagnosis, creatinine and proteinuria at onset, the induction regimen or histological score were not predictive of renal relapse. In the unadjusted survival analysis with the Kaplan-Maier curve, patients in the Crescentic group treated with RTX had a shorter ESRD-free survival compared to the CYC group (p=0.033) and the RTX-CYC group (p=0.044); figure 1:

This was confirmed also with a Cox regression analysis adjusted for sex, age, ANCA type, AAV diagnosis, creatinine and proteinuria when comparing the RTX group with the CYC one (HR 8.30 [95% CI 1.64 to 42.01], p=0.011); figure 2:

While the eGFR changes over time in the Focal plus Crescentic and Mixed plus Sclerotic classes showed a similar trend between treatment groups, in the Crescentic class the median eGFR values in the RTX group tended to be lower compared to the CYC and the RTX-CYC ones; figure 3:

The rate of severe infections in the RTX, CYC and RTX-CYC group was respectively 6.3, 8.5 and 8.8 per 100 patient-years during the first 12 months.

Conclusion

in a retrospective multicenter survey, response rates and relapse risk after different induction regimens in AAV patients with renal involvement were comparable in the overall cohort and in the different histopathological subgroups.

Although in a small subset of patients, the ESRD-free survival in the Crescentic class was shorter in the RTX group compared to the CYC one.

[State of art and new perspectives in the induction regimen of ANCA-associated vasculitis with renal involvement: from histopathology to therapy]

Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) are rare autoimmune diseases characterised by medium and small vessels inflammation. Renal vasculitic involvement is one of the most severe manifestations, with high mortality in case of a delayed diagnosis and a significant impact on patients' long-term prognosis. Histological classifications and scores for the definition of renal involvement in AAV exist and correlate with the renal outcome. Current induction regimen consists of a high dose of glucocorticoids and immunosuppressive drugs: cyclophosphamide (CYC), rituximab (RTX) or a combination of both. RTX use is expanding thanks to randomised control trials suggesting its non-inferiority compared to the standard CYC therapy in general AAV and a better safety profile; its cost has also reduced thanks to the availability of biosimilars. However, the equivalence of RTX and CYC in patients with severe renal involvement is still debated. The quest for the ideal induction regimen in AAV is moving towards a more personalized approach: on the one hand, efforts are made to use already existing therapies in the most appropriate way; on the other, new insights into AAV pathogenesis has allowed the discovery of new targets, such as the complement factor C5a. Thanks to this new AAV management, renal outcome and overall survival has visibly improved. New studies are needed to reach a more personalized approach in the induction regimen of ANCA-associated glomerulonephritis and AAV in general.