Minimal change disease associated with anti-PD1 immunotherapy: a case report

PD-1 immunology in the kidneys: a growing relationship

In recent years, knowledge regarding immune regulation has expanded rapidly, and major advancements have been made in immunotherapy for immune-associated disorders, particularly cancer. The programmed cell death 1 (PD-1) pathway is a cornerstone in immune regulation. It comprises PD-1 and its ligands mediating immune tolerance mechanisms and immune homeostasis. Accumulating evidence demonstrates that the PD-1 axis has a crucial immunosuppressive role in the tumor microenvironment and autoimmune diseases. PD-1 receptors and ligands on immune cells and renal parenchymal cells aid in maintaining immunological homeostasis in the kidneys. Here, we present a comprehensive review of PD-1 immunology in various kidney disorders, including renal cell carcinoma, glomerulonephritis, kidney transplantation, renal aging, and renal immune-related adverse events secondary to PD-1 immunotherapy.

Acute Kidney Disease in Oncology: A New Concept to Enhance the Understanding of the Impact of Kidney Injury in Patients with Cancer

BACKGROUND

Cancer patients are prone to developing acute kidney disease (AKD), yet this phenomenon remains understudied compared to acute kidney injury (AKI). AKD, which often develops insidiously, can cause treatment interruptions, extended hospital stays, and increased mortality.

SUMMARY

This perspective article explores the intricate relationship between AKD and cancer, focusing on prevalence, risk factors, implications for anticancer therapy, and long-term outcomes, including chronic kidney disease progression.

KEY MESSAGES

To emphasize the importance of early detection and intervention, this work advocates for increased research and awareness among clinicians to improve patient outcomes and manage healthcare burdens associated with AKD in cancer patients.

Drug-induced glomerular diseases

Drug-induced kidney diseases represent a wide range of diseases that are responsible for a significant proportion of all acute kidney injuries and chronic kidney diseases. In the present review, we focused on drug-induced glomerular diseases, more precisely podocytopathies - minimal change diseases (MCD), focal segmental glomerulosclerosis (FSGS) - and membranous nephropathies (MN), from a physiological and a pharmacological point of view. The glomerular filtration barrier is composed of podocytes that form foot processes tightly connected and directly in contact with the basal membrane and surrounding capillaries. The common clinical feature of these diseases is represented by the loss of the ability of the filtration barrier to retain large proteins, leading to massive proteinuria and nephrotic syndrome. Drugs such as non-steroidal anti-inflammatory drugs (NSAIDs), D-penicillamine, tiopronin, trace elements, bisphosphonate, and interferons have been historically associated with the occurrence of MCD, FSGS, and MN. In the last ten years, the development of new anti-cancer agents, including tyrosine kinase inhibitors and immune checkpoint inhibitors, and research into their renal adverse effects highlighted these issues and have improved our comprehension of these diseases.

Immune checkpoint inhibitors and acute kidney injury

As a new type of anti-tumor immunotherapy, immune checkpoint inhibitors (ICIs) have improved the prognosis of multiple malignancies. However, renal complications are becoming more frequent. Nephrotoxicity often manifests as acute kidney injury (AKI), and the most common histopathological type is acute tubulointerstitial nephritis (ATIN). Based on previous studies of the incidence and potential risk factors for nephrotoxicity, in this review, we describe the mechanism of AKI after ICIs treatment, summarize the incidence, risk factors, and outcomes of AKI, and discuss the diagnosis and management of immune checkpoint inhibitors-associated acute kidney injury (ICI-AKI). In addition, we review the current status of ICIs rechallenge and the therapeutic strategies of ICIs applied in kidney transplant recipients. Finally, we emphasize the importance of collaboration between nephrologists and oncologists to guide the treatment of ICIs and the management of renal complications.

Nephrotic syndrome with acute kidney injury due to combination therapy of immune checkpoint inhibitors: a case report and review of the literature

BACKGROUND

Recent studies have focused on immune checkpoint inhibitors. Renal complications associated with the use of immune checkpoint inhibitors are uncommon compared with other immune-related adverse events. Acute interstitial nephritis accounts for most of these renal complications, with nephrotic syndrome quite rare. We herein report a case of nephrotic syndrome associated with immune checkpoint inhibitors that was more severe than that in previous cases. By comparing this case with previous reports, the possible reasons for the particular severity of this case are discussed.

CASE PRESENTATION

A 75-year-old man developed nephrotic syndrome with acute kidney injury after the first combination therapy of nivolumab and ipilimumab for malignant pleural mesothelioma. The results of a kidney biopsy indicated minimal change disease with mild atherosclerosis, acute interstitial nephritis, and fusion of nearly all podocyte foot processes. Nivolumab and ipilimumab therapy were stopped, and treatment with corticosteroids was initiated. We investigated previously reported cases of nephrotic syndrome using immune checkpoint inhibitors. Seventeen cases of immune checkpoint inhibitor-related nephrotic syndrome, including ours, have been reported. Two of the 17 patients with immune checkpoint inhibitor-related nephrotic syndrome required hemodialysis treatment for acute kidney injury. Unlike many previously reported cases, the present patient was administered two different immune checkpoint inhibitors, which may be one of the reasons for the development of severe nephrotic syndrome.

CONCLUSIONS

In addition to previously reported risk factors, immune checkpoint inhibitor combination therapy can exacerbate nephrotic syndrome compared to immune checkpoint inhibitor monotherapy.

Adverse Renal Effects of Anticancer Immunotherapy: A Review

Modern oncological therapy utilizes various types of immunotherapy. Immune checkpoint inhibitors (ICIs), chimeric antigen receptor T cells (CAR-T) therapy, cancer vaccines, tumor-targeting monoclonal antibodies (TT-mAbs), bispecific antibodies and cytokine therapy improve patients' outcomes. However, stimulation of the immune system, beneficial in terms of fighting against cancer, generates the risk of harm to other cells in a patient's body. Kidney damage belongs to the relatively rare adverse events (AEs). Best described, but still, superficially, are renal AEs in patients treated with ICIs. International guidelines issued by the European Society for Medical Oncology (ESMO) and the American Society of Clinical Oncology (ASCO) cover the management of immune-related adverse events (irAEs) during ICI therapy. There are fewer data concerning real occurrence and possible presentations of renal adverse drug reactions of other immunotherapeutic methods. This implies the need for the collection of safety data during ongoing clinical trials and in the real-life world to characterize the hazard related to the use of new immunotherapies and management of irAEs.

Immune Checkpoint Inhibitors’ Associated Renal Toxicity: A Series of 12 Cases

We present a series of twelve patients, bearing a wide range of solid malignancies, who received either PD-L1 or a combination of PD-L1 and CTLA-4 inhibitors. Following immunotherapy administration, they exhibited the clinical signs indicative of renal toxicity, including increased serum creatinine levels, proteinuria, nephrotic syndrome and/or hematuria. All patients underwent renal biopsy. Results: All cases demonstrated some degree of interstitial inflammation and tubular injury, while in five patients, glomerular alterations consistent with a specific glomerulopathy were also observed: secondary “lupus-like” membranous glomerulopathy in two cases and membranoproliferative glomerulonephritis, IgA glomerulonephritis and secondary AA amyloidosis in each of the remaining three patients. The two patients with “lupus-like” nephritis and the one with amyloidosis experienced nephrotic syndrome, while their creatinine was within normal range. In the remaining nine cases, deterioration of renal function was the main manifestation. Conclusion: Our findings harmonize with bibliographical data that identify tubulointerstitial nephritis as the most frequent histological lesion related to ICIs administration. The preferential involvement of tubulointerstitial tissue could be associated with the reported higher expression levels of PD-L1 on tubular epithelial cells, compared to glomeruli. On the other hand, glomerular involvement is probably a consequence of a systemic immune system reconstruction, induced by immune-checkpoints inhibition.

Nivolumab-induced membranous nephropathy in a patient with stage IV lung adenocarcinoma

Immune check point inhibitors (ICIs) are now increasingly used for cancer therapy. At the same time, by activating the immune system, ICIs induce unique side effects, termed immune-related adverse events (irAEs). Renal irAEs, although uncommon, result in acute tubulointerstitial nephritis. Recently, because of an increase in ICI administration, renal irAEs, including glomerulonephritis, are being increasingly reported. A 69-year-old man presented with nephrotic syndrome after use of the ICI nivolumab. He underwent renal biopsy and was diagnosed with membranous nephropathy (MN) without acute tubulointerstitial nephritis. Immunofluorescence staining was negative for IgG4 and phospholipase A2 receptor (PLA2R), suggesting a malignancy-associated pattern. Oral glucocorticoid therapy was started as the standard treatment for irAEs, which resulted in complete remission of the nephrotic syndrome in 20 months. We suggest his MN was induced or accelerated by immune activation due to nivolumab. It means that ICIs possibly induce not only acute tubulointerstitial nephritis but also nephrotic syndrome due to MN as renal irAEs which is treatable with glucocorticoid.

PD-1 immunobiology in glomerulonephritis and renal cell carcinoma

BACKGROUND

Programmed cell death protein (PD)-1 receptors and ligands on immune cells and kidney parenchymal cells help maintain immunological homeostasis in the kidney. Dysregulated PD-1:PD-L1 binding interactions occur during the pathogenesis of glomerulopathies and renal cell carcinoma (RCC). The regulation of these molecules in the kidney is important to PD-1/PD-L1 immunotherapies that treat RCC and may induce glomerulopathies as an adverse event.

METHODS

The expression and function of PD-1 molecules on immune and kidney parenchymal cells were reviewed in the healthy kidney, PD-1 immunotherapy-induced nephrotoxicity, glomerulopathies and RCC.

RESULTS

PD-1 and/or its ligands are expressed on kidney macrophages, dendritic cells, lymphocytes, and renal proximal tubule epithelial cells. Vitamin D3, glutathione and AMP-activated protein kinase (AMPK) regulate hypoxic cell signals involved in the expression and function of PD-1 molecules. These pathways are altered in kidney disease and are linked to the production of vascular endothelial growth factor, erythropoietin, adiponectin, interleukin (IL)-18, IL-23, and chemokines that bind CXCR3, CXCR4, and/or CXCR7. These factors are differentially produced in glomerulonephritis and RCC and may be important biomarkers in patients that receive PD-1 therapies and/or develop glomerulonephritis as an adverse event CONCLUSION: By comparing the functions of the PD-1 axis in glomerulopathies and RCC, we identified similar chemokines involved in the recruitment of immune cells and distinct mediators in T cell differentiation. The expression and function of PD-1 and PD-1 ligands in diseased tissue and particularly on double-negative T cells and parenchymal kidney cells needs continued exploration. The possible regulation of the PD-1 axis by vitamin D3, glutathione and/or AMPK cell signals may be important to kidney disease and the PD-1 immunotherapeutic response.

Renal adverse effects of immune checkpoints inhibitors in clinical practice: ImmuNoTox study

BACKGROUND/OBJECTIVES

Acute Kidney Injury (AKI), induced by Checkpoint Inhibitors therapies (CPI-induced AKI), is an uncommon but severe Immune-Related Adverse Event (IRAE). The aim was to describe the epidemiology, risks factors, clinical, and laboratory characteristics of these renal adverse events (AEs) in a real-life cohort treatment.

DESIGN/PARTICIPANTS

Consecutive patients undergoing a checkpoint inhibitor (CPI) therapy at the Hôpital Lyon Sud from January 2015 to July 2017 were included. A systematic retrospective analysis of medical files was performed, monthly serum creatinine levels, associated treatments, and occurrence of other IRAEs data were collected. AKI episodes explained by classic AKI aetiologies (prerenal, obstructive, septic) were excluded from the analysis.

RESULTS

CPI-induced AKI incidence was 3.7% (13/352) and appeared to be time-dependent (7.7% (11/143) for patients with >3 months of CPI exposure), ranging from 1 to 16 months. All cases with available histology were acute tubulointerstitial nephritis (ATIN), with poor urinary sediment. The severity of AKI was mild (stage 1 in 50% of cases), with no need for renal-replacement therapy. Although CPI-induced AKI patients had more frequently other IRAEs (77% versus 39%), this was not associated with a greater risk of AKI. Pre-existing chronic kidney disease (defined as an estimated glomerular filtration rate (eGFR) <60 ml/min) was not associated with a greater risk of CPI-induced AKI. Treatments of CPI-induced AKI were heterogeneous, with discontinuation of CPIs, and inconstant systemic corticosteroid therapy.

CONCLUSION

The monitoring of renal function and early identification of AKI during CPIs treatment is essential. The optimal management of CPI-induced AKI remains unclear and requires a close collaboration between the oncology and nephrology departments.

CLINICAL RELEVANCY STATEMENT

Immune checkpoint inhibitors (CPIs) have dramatically improved patient outcomes in different malignant contexts such as melanoma, non-small cell lung cancers (NSCLC) and urologic cancers. Usually well-tolerated, CPIs are however associated with immune-related adverse events (IRAEs). Among them, acute kidney injury (AKI) is uncommon, and not well-described. Following the exponential increase in the prescription of CPIs, previously uncommon cases of IRAEs (such as AKI) have become common occurrence in referral centres. Data regarding the epidemiology, risk factors, or management of CPI-induced AKI are currently lacking or can be discordant. Data regarding CPI-induced AKI, in a large real-life cohort were reported herein.

A Systematic Review of Immune Checkpoint Inhibitor-Associated Glomerular Disease

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are increasingly used to treat cancers. Kidney immune-related adverse events (IRAEs) are now well recognized, with the incidence of IRAEs ranging from 2% to 5%. Most of the initial data related to kidney IRAEs have focused on acute interstitial nephritis (AIN). There are minimal data on the types and relative frequencies of glomerular diseases associated with ICIs, their treatment, and outcomes.

METHODS

We performed a systematic review and meta-analysis of all biopsy-proven published cases/series of glomerular pathology associated with ICIs. We searched the MEDLINE, EMBASE, and Cochrane databases from inception to February 2020. We abstracted patient-level data, including demographics, cancer and ICI therapy details, and characteristics of kidney injury.

RESULTS

After screening, 27 articles with 45 cases of biopsy-confirmed ICI-associated glomerular disease were identified. Several lesion types were observed, with the most frequent being pauci-immune glomerulonephritis (GN) and renal vasculitis (27%), podocytopathies (24%), and complement 3 GN (C3GN; 11%). Concomitant AIN was reported in 41%. Most patients had ICIs discontinued (88%), and nearly all received corticosteroid treatment (98%). Renal replacement therapy (RRT) was required in 25%. Most patients had full (31%) or partial (42%) recovery from acute kidney injury (AKI), although 19% remained dialysis-dependent, and approximately one-third died. Complete or partial remission of proteinuria was achieved in 45% and 38%, respectively.

CONCLUSION

Multiple forms of ICI-associated glomerular disease have been described. Pauci-immune GN, podocytopathies, and C3GN are the most frequently reported lesions. ICI-associated glomerular disease may be associated with poor kidney and mortality outcomes. Oncologists and nephrologists must be aware of glomerular pathologies associated with ICIs and consider obtaining a kidney biopsy specimen when features atypical for AIN are present.

Successful Treatment of Non-small-cell Lung Cancer with Atezolizumab Following Tubulointerstitial Nephritis Due to Pembrolizumab

We herein report a 75-year-old man with non-small-cell lung cancer who developed tubulointerstitial nephritis due to pembrolizumab administration. He was successfully treated with atezolizumab following steroid administration. He was initially diagnosed with lung adenocarcinoma (T1bN3M1b, stage IV), with a programmed cell death-ligand 1 tumor proportion score of 25-49%. Although the tumor responded well to pembrolizumab, the drug was discontinued because of the diagnosis of tubulointerstitial nephritis on a renal biopsy. Tubulointerstitial nephritis was treated with 30 mg prednisolone, the dose of which was tapered to and maintained at 5 mg. Following lung cancer progression, atezolizumab was administered, and the tumor responded again. Its efficacy has been sustained for >15 months without recurrence of tubulointerstitial nephritis.

Minimal change disease in a patient receiving checkpoint inhibition: Another possible manifestation of kidney autoimmunity?

BACKGROUND

Nivolumab has been associated with immune-related adverse events, including nephritis, with acute interstitial nephritis being the most commonly reported renal manifestation.

CASE

We describe the first case to our knowledge of minimal change disease with nephrotic syndrome associated with the PD-1 checkpoint inhibitor, Nivolumab. Minimal change disease has been reported with other immune checkpoint inhibitors; however, this is the first reported case with Nivolumab. We report development of nephrotic syndrome with acute kidney injury in a 57-year-old man, 1 month after commencement of Nivolumab for metastatic squamous cell carcinoma of the tongue. Minimal change disease was confirmed by renal biopsy. Management with corticosteroids and cessation of Nivolumab failed to improve kidney function or nephrosis.

CONCLUSION

This case adds to current literature identifying minimal change as an additional complication of immune checkpoint inhibitor-associated acute kidney injury. Given the increasing use of immune checkpoint inhibitors for a range of malignancies, nephrologists, oncologist and generalists should be aware of the spectrum of kidney pathologies associated with their use.

Clinical recommendations on diagnosis and treatment of immune checkpoint inhibitor-induced renal immune-related adverse events

Immune checkpoint inhibitors (ICIs) are nowadays widely used in clinical oncology treatment, and significantly improve the prognosis of cancer patients. However, overactivation of T cells and related signaling pathways caused by ICIs can also induce immune‐related adverse effects (irAEs). Renal immune side‐effects are relatively rare, but some are serious and fatal. Acute kidney injury (AKI), diagnosed mainly by percentage increases in serum creatinine (sCr), is the most common clinical manifestation, while acute tubulointerstitial nephritis (ATIN) is the main cause of ICI‐related AKI. Urinalysis analysis and sediment evaluation, 24 hour urine protein and sCr are helpful in screening and monitoring renal irAEs. Multiple potential causes for AKI are involved during cancer therapy, and should be differentiated from the immune mechanisms of ICIs. Under these circumstances, a renal biopsy should be considered which is essential for clinical decision‐making. Steroids are an effective treatment option for renal irAEs. Most patients who experience ICI‐related ATIN achieve a partial or complete renal recovery with prompt diagnosis and treatment. Multidisciplinary collaborations of different specialists will improve the effectiveness and outcome in the management of ICI irAEs.

[Renal toxicities of targeted therapies in oncology]

The advent of new molecules oncology including targeted therapies, has resulted in improved patient survival over standard chemotherapy. The renal toxicities of these anticancer agents are more and more recognized and vary according to the targeted therapeutic target. This article reviews the renal toxicity associated with targeted anticancer therapies directed against Epidermal growth factor receptor, Human epidermal growth factor-2, B-rapidly accelerated fibrosarcoma, Mitogen-activated protein kinase, Anaplastic lymphoma kinase, Programmed cell death-1/programmed cell death ligand-1, Cytotoxic T lymphocyte antigen-4 and Vascular endothelial growth factor/receptor. The early diagnosis and management of these renal adverse events is essential for the clinician who cares for such patients.

The Incidence, Causes, and Risk Factors of Acute Kidney Injury in Patients Receiving Immune Checkpoint Inhibitors

BACKGROUND AND OBJECTIVES

Immune checkpoint inhibitor use in oncology is increasing rapidly. We sought to determine the frequency, severity, cause, and predictors of AKI in a real-world population receiving checkpoint inhibitors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included all patients who received checkpoint inhibitor therapy from May 2011 to December 2016 at Massachusetts General Hospital. Baseline serum creatinine, averaged 6 months before checkpoint inhibitor start date, was compared with all subsequent creatinine values within 12 months of starting therapy. AKI was defined by Kidney Disease: Improving Global Outcomes criteria for fold changes in creatinine from baseline. Sustained AKI events lasted at least 3 days and was our primary outcome. The cause of sustained AKI was determined by chart review. Cumulative incidence and subdistribution hazard models were used to assess the relationship between baseline demographics, comorbidities, and medications, and sustained AKI and potential checkpoint inhibitor-related AKI.

RESULTS

We included 1016 patients in the analysis. Average age was 63 (SD 13) years, 61% were men, and 91% were white. Mean baseline creatinine was 0.9 mg/dl (SD 0.4 mg/dl), and 169 (17%) had CKD (eGFR<60 ml/min per 1.73 m²) at baseline. A total of 169 patients (17%) experienced AKI, defined by an increase in creatinine at least 1.5 times the baseline within 12 months; 82 patients (8%) experienced sustained AKI and 30 patients (3%) had potential checkpoint inhibitor-related AKI. The first episode of sustained AKI occurred, on average, 106 days (SD 85) after checkpoint inhibitor initiation. Sixteen (2%) patients experienced stage 3 sustained AKI and four patients required dialysis. Proton pump inhibitor use at baseline was associated with sustained AKI.

CONCLUSIONS

AKI is common in patients receiving checkpoint inhibitor therapy. The causes of sustained AKI in this population are heterogenous and merit thorough evaluation. The role of PPI and other nephritis-inducing drugs in the development of sustained AKI needs to be better defined.

The mechanisms of acute interstitial nephritis in the era of immune checkpoint inhibitors in melanoma

Treatment with immune checkpoint inhibitors (ICIs) has improved the prognosis of patients with a number of types of cancer, but the frequent development of immune-related adverse effects (irAEs) can worsen the outcome. The most common irAEs involve the gastrointestinal, cutaneous, and endocrine systems, but nephrotoxicity, resulting from damage to the tubule-interstitial compartment, may occur in some patients. The early phases of acute interstitial nephritis (AIN) are characterized by systemic symptoms that indicate a poor clinical state as well as a mild deterioration of renal function. Tubular injury is due to a direct effect mediated by cytotoxic CD8⁺ T cells, which sustain the local production of pro-inflammatory cytokines that progressively impair renal function. The treatment of AIN is mainly based on high-dose steroids, which in most instances leads to the recovery of renal function. However, the premature discontinuation of ICI therapy may prevent the impact of treatment on the clinical progression of the malignancy. Adequately addressing irAEs requires a standardized therapy that is based on the results of large clinical trials.

Response to combined ipilimumab and nivolumab after development of a nephrotic syndrome related to PD-1 monotherapy

Background

High response rates of metastatic melanoma have been reported upon immune checkpoint inhibition by PD-1 blockade alone or in combination with CTLA-4 inhibitors. However, the majority of patients with a primary resistance to anti-PD-1 monotherapy is also refractory to a subsequent combined checkpoint inhibition. In BRAF wildtype patients with a primary resistance to PD-1 inhibitors, therapeutic options are therefore limited and immune-related adverse events (irAE) have to be taken into consideration when discussing a subsequent immunotherapy.

Case presentation

We report the case of a 68-year-old male patient with metastatic melanoma who experienced an acute renal failure with nephrotic syndrome due to a minimal change disease developing after a single dose of the anti-PD-1 antibody pembrolizumab. A kidney biopsy revealed a podocytopathy without signs of interstitial nephritis. Renal function recovered to almost normal creatinine and total urine protein levels upon treatment with oral steroids and diuretics. Unfortunately, a disease progression (PD, RECIST 1.1) was observed in a CT scan after resolution of the irAE. In a grand round, re-exposure to a PD-1-containing regime was recommended. Consensually, a combined immunotherapy with ipilimumab and nivolumab was initiated. Nephrotoxicity was tolerable during combined immunotherapy and a CT scan of chest and abdomen showed a deep partial remission (RECIST 1.1) after three doses of ipilimumab (3 mg/kg) and nivolumab (1 mg/kg).

Conclusion

This case illustrates that a fulminant response to combined checkpoint inhibition is possible after progression after anti-PD-1 monotherapy and a severe irAE.

Anti-PD-1 Immunotherapy May Induce Interstitial Nephritis With Increased Tubular Epithelial Expression of PD-L1

Introduction

Novel anticancer therapies include anti–programmed cell death protein-1 (PD-1) and anti–programmed death ligand-1 (PD-L1) drugs. These novel medications have side effects in different organs, including the kidney. The most common adverse effect in the kidney is acute interstitial nephritis (AIN). No diagnostic criteria are available to distinguish AIN associated with anti–PD-1 therapy from other AINs.

Methods

Kidney biopsy specimens from patients on anti–PD-1 therapy were stained with antibodies to PD-1 and PD-L1. Herein we report morphologic and immunohistochemical findings in 15 patients who received anti–PD-1 therapy and developed acute kidney injury requiring a kidney biopsy.

Results

Among these patients, 9 had AIN and 6 had no AIN but showed acute tubular necrosis (ATN). Immunohistochemistry with antibodies to PD-1 and PD-L1 was performed on all of these biopsy specimens and on 9 randomly selected biopsy specimens with AIN from patients who did not receive anti–PD-1 medications, as well as 9 patients with lupus nephritis and active-appearing interstitial inflammation. There was weak staining for PD-1 in T cells in all patients with AIN and lupus; however, tubular epithelial cell membrane staining for PD-L1 was seen only in patients with anti–PD-1 therapy−associated AIN, and not in patients with anti–PD-1 therapy−associated ATN, and not in those with AIN secondary to other medications, or patients with lupus nephritis.

Conclusion

We propose that immunohistochemistry with PD-L1 could be a useful tool to differentiate AIN associated with anti–PD-1 therapy from other AINs.

Diagnosis and Management of Immune Checkpoint Inhibitor-Associated Renal Toxicity: Illustrative Case and Review

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies directed at negative regulatory components on T cells, such as cytotoxic T lymphocyte-associated antigen 4, programmed cell death-1 (PD-1), and its ligand, programmed cell death ligand-1. ICIs initate antitumor immunity; however, these agents are associated with immune-related adverse events (irAEs) that may affect a variety of organs. Renal irAEs most commonly present with asymptomatic acute kidney injury (AKI), which is often detected by routine laboratory testing. The severity of AKI associated with irAEs ranges from mild (grade 1-2) to severe (grade 3-4). It is often challenging to diagnose because this group of patients often have multiple reasons to have AKI (dehydration, sepsis, or nephrotoxic medication exposure). We present an illustrative case of a 60-year-old man with metastatic melanoma who presented with AKI during treatment with nivolumab and review the literature to address frequently asked questions concerning the diagnosis and management of renal irAEs in patients with advanced cancer. Importantly, most patients will recover completely, and some may tolerate a rechallenge of ICI therapy, with prompt and effective treatment. KEY POINTS: Renal immune-related adverse events (irAEs) are less frequently reported than other irAEs; however, it is possible that available data underestimate their true incidence because of missed diagnoses and under-reporting. Although severe renal irAEs are more easily detected, smaller rises in creatinine may not be appreciated or may be attributed to other causes, because the differential diagnosis of acute kidney injury (AKI) in patients with cancer is broad.Baseline creatinine should be established prior to beginning immune checkpoint inhibitorss (ICIs), and it should be monitored with every cycle. If a patient develops AKI, the ICI should be held while the evaluation is pursued. A thorough workup of suspected renal irAEs must exclude other potential causes of AKI such as infection, dehydration, urinary tract obstruction, and nephrotoxin exposure.Acute kidney injury after ICI therapy does not appear to be more common in patients with baseline estimated glomerular filtration rate <60 mL per min per 1.73 m. One particular concern, however, is that those with baseline renal disease have less "renal reserve," and repeated AKI events may push a patient closer to end-stage renal disease. Thus, clinicians must exert caution when rechallenging patients with pre-existing renal disease with ICI therapy in the event of a prior AKI from ICI-related allergic interstitial nephritis.