Onconephrology: mitigation of renal injury in chemotherapy administration.

PURPOSE OF REVIEW: Onconephrology was first coined as a name for the intersection of cancer medicine and nephrology in the early 2010s. It was recognized then that beyond and understanding of kidney physiology, a new generation of nephrologists skilled in both molecular biology and precision medicine were needed to deal with the challenges of emerging cancer therapies. Stem cell transplants, biologic agents, adjuvants blocking basic cellular signaling pathways, immunotherapy were found to promote novel anticancer outcomes, but also to pose new risks to the kidneys. The field rapidly overlapped with emerging expertise in vascular glomerular disease, glomerular disease, and the same biologic agents now applied to auto immune systemic and kidney diseases. RECENT FINDINGS: Many categories of chemotherapeutic agents have been discovered to have adverse renal side effects. In this review, we address classic chemotherapeutic nephrotoxicity and oncologic clinical situations leading to acute kidney injury. We also review the frontiers of nephrotoxicity reported with cell cycle inhibitors, diverse classes of tyrosine kinase inhibitors, immune checkpoint inhibitors, chimeric antigen receptor T-cell therapy, anticancer vaccines, and thrombotic microangiopathies triggered by malignancy and chemotherapy. The aim will be to focus on published strategies to mitigate nephrotoxicity. SUMMARY: As onconephrology expands into its own field, it gives birth to new subdisciplines. An understanding that patient populations want the benefits of chemotherapy without the renal (and other) systemic toxicities is emerging. A need to develop a new class of molecular and genetic experts in onconephrology to mitigate nephrotoxicity from chemotherapy is apparent and urgent.

Nephrotoxicity induced by intravitreal vascular endothelial growth factor inhibitors: emerging evidence.

Vascular endothelial growth factor (VEGF) inhibitors have emerged as powerful tools to treat malignant neoplasms and ocular diseases by virtue of their ability to inhibit angiogenesis. Recent data indicate that intravitreal injections of VEGF inhibitors can lead to significant systemic absorption as well as a measurable reduction of plasma VEGF activity. There is increasing evidence showing that vitreal absorption of these drugs is associated with cases of accelerated hypertension, worsening proteinuria, glomerular disease, thrombotic microangiopathy, and possible chronic renal function decline. In this review, the 3 most commonly used anti-VEGF agents-bevacizumab, ranibizumab, and aflibercept-are discussed, highlighting their intravitreal absorption and associated effects on the kidney as a target organ system. We provide clinical suggestions for clinicians to both better manage patients receiving anti-VEGF agents intravitreally and detect any putative systemic renal effects of these agents. While acknowledging the risks of aberrant retinal angiogenesis, it is important for clinicians to be aware of the potential for adverse renal risks with use of these agents.

Ruxolitinib therapy is associated with improved renal function in patients with primary myelofibrosis.

Recent evidence suggests that renal dysfunction may be a direct consequence of primary myelofibrosis (PMF). We performed a retrospective analysis of 100 patients with previously untreated PMF, receiving frontline treatment with single agent ruxolitinib, and compared them to 105 patients, receiving frontline treatment with a non-ruxolitinib-based therapy, matched by age, sex, DIPSS plus, and estimated glomerular filtration rate (eGFR). Use of ruxolitinib associated with a significantly higher rate of renal improvement (RI) > 10% (73% vs 50%, p = 0.01) confirmed on multivariate analysis (MVA) [odds ratio 3, 95% confidence interval (CI) 1.6-5.5, p < 0.001]. After a median follow-up of 41 months (range, 1-159 months), median failure-free survival (FFS) was 14 months (range, 1-117 months). Achievement of a RI > 10% maintained its independent association with prolonged FFS on MVA (hazard ratio 1.4, 95% CI 1.1-2, p = 0.02). Ruxolitinib can significantly improve renal function in patients with PMF, significantly impacting failure-free survival.

Successful use of eculizumab to treat atypical hemolytic uremic syndrome in patients with inflammatory bowel disease.

BACKGROUND: Atypical hemolytic uremic syndrome is a rare group of disorders that have in common underlying complement amplifying conditions. These conditions can accelerate complement activation that results in a positive feedback cycle. The known triggers for complement activation can be diverse and include, infection, autoimmune disease, and malignancy. Recent reports suggest that certain autoimmune and rheumatological triggers of complement activation may result in atypical hemolytic uremic syndrome that does not resolve despite treating the underlying disorder. Specifically, patients with systemic lupus erythematosus and microangiopathic hemolysis may not respond to treatment of their underlying rheumatological trigger but responded to complement blockade. CASE PRESENTATIONS: We report two patients with inflammatory bowel disease complicated by development of atypical hemolytic uremic syndrome. In both cases, patients were on treatment for inflammatory bowel disease, that was not well controlled/flaring at the time. The first patient is a male who developed Crohn's disease and microangiopathic hemolysis at age 5 and was treated with eculizumab successfully. Discontinuation of the medication led to multiple relapses, and the patient currently is being treated with eculizumab and has normal hematological and stable renal parameters. The second patient is a 49-year-old female with Ulcerative Colitis treated with 6-Mercaptopurine. She developed acute kidney injury and microangiopathic hemolysis. Prompt diagnosis and treatment with eculizumab resulted in the recovery of kidney injury along with a complete hematological response. CONCLUSIONS: These two cases are the fifth and sixth patients to be published in the literature with atypical hemolytic uremic syndrome and inflammatory bowel disease treated with complement blockade. This confirms that C5 complement blockade is effective in treating complement mediated thrombotic microangiopathy/atypical hemolytic uremic syndrome when it is triggered in patients with inflammatory bowel disease.

Serum Calcitriol Concentrations and Kidney Function Decline, Heart Failure, and Mortality in Elderly Community-Living Adults: The Health, Aging, and Body Composition Study.

RATIONALE & OBJECTIVES: Lower 25-hydroxyvitamin D concentrations have been associated with risk for kidney function decline, heart failure, and mortality. However, 25-hydroxyvitamin D requires conversion to its active metabolite, calcitriol, for most biological effects. The associations of calcitriol concentrations with clinical events have not been well explored. STUDY DESIGN: Case-cohort study. SETTING & PARTICIPANTS: Well-functioning community-living older adults aged 70 to 79 years at inception who participated in the Health, Aging, and Body Composition (Health ABC) Study. PREDICTOR: Serum calcitriol measured using positive ion electrospray ionization-tandem mass spectrometry. OUTCOMES: Major kidney function decline (≥30% decline in estimated glomerular filtration rate from baseline), incident heart failure (HF), and all-cause mortality during 10 years of follow-up. ANALYTIC APPROACH: Baseline calcitriol concentrations were measured in a random subcohort of 479 participants and also in cases with major kidney function decline [n=397]) and incident HF (n=207) during 10 years of follow-up. Associations of serum calcitriol concentrations with these end points were evaluated using weighted Cox regression to account for the case-cohort design, while associations with mortality were assessed in the subcohort alone using unweighted Cox regression. RESULTS: During 8.6 years of mean follow-up, 212 (44%) subcohort participants died. In fully adjusted models, each 1-standard deviation lower calcitriol concentration was associated with 30% higher risk for major kidney function decline (95% CI, 1.03-1.65; P=0.03). Calcitriol was not significantly associated with incident HF (HR, 1.16; 95% CI, 0.94-1.47) or mortality (HR, 1.01; 95% CI, 0.81-1.26). We observed no significant interactions between calcitriol concentrations and chronic kidney disease status, baseline intact parathyroid or fibroblast factor 23 concentrations. LIMITATIONS: Observational study design, calcitriol measurements at a single time point, selective study population of older adults only of white or black race. CONCLUSIONS: Lower calcitriol concentrations are independently associated with kidney function decline in community-living older adults. Future studies will be needed to clarify whether these associations reflect lower calcitriol concentrations resulting from abnormal kidney tubule dysfunction or direct mechanisms relating lower calcitriol concentrations to more rapid loss of kidney function.

Relationship of dietary phosphate intake with risk of end-stage renal disease and mortality in chronic kidney disease stages 3-5: The Modification of Diet in Renal Disease Study.

KDIGO guidelines recommend dietary phosphate restriction to lower serum phosphate levels in CKD stages 3-5. Recent studies suggest that dietary phosphate intake is only weakly linked to its serum concentration, and the relationship of phosphate intake with adverse outcomes is uncertain. To evaluate this, we used Cox proportional hazards models to assess associations of baseline 24-h urine phosphate excretion with risk of end-stage renal disease (ESRD), all-cause mortality, and mortality subtypes (cardiovascular disease [CVD] and non-CVD) using the Modification of Diet in Renal Disease data. Models were adjusted for demographics, CVD risk factors, iothalamate GFR, and urine protein and nitrogen excretion. Phosphate excretion was modestly inversely correlated with serum phosphate concentrations. There was no association of 24-h urinary phosphate excretion with risk of ESRD, CVD, non-CVD, or all-cause mortality. For comparison, higher serum phosphate concentrations were associated with all-cause mortality (hazard ratio per 0.7 mg/dl higher, 1.15 [95% CI 1.01, 1.30]). Thus, phosphate intake is not tightly linked with serum phosphate concentrations in CKD stages 3-5, and there was no evidence that greater phosphate intake, assessed by 24-h phosphate excretion, is associated with ESRD, CVD, non-CVD, or all-cause mortality in CKD stages 3-5. Hence, factors other than dietary intake may be key determinants of serum phosphate concentrations and require additional investigation.

Kidney involvement in myelodysplastic syndromes.

Introduction: The objective of this study was to describe kidney involvement in patients with myelodysplastic syndromes (MDS), their treatments, and outcomes. Methods: We conducted a multicenter retrospective study in seven centers, identifying MDS patients with acute kidney injury (AKI), chronic kidney disease (CKD), and urine abnormalities. Results: Fifteen patients developed a kidney disease 3 months after MDS diagnosis. Median urine protein-to-creatinine ratio was 1.9 g/g, and median serum creatinine was 3.2 mg/dL. Ten patients had AKI at presentation, and 12 had extra-renal symptoms. The renal diagnoses included anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), ANCA negative vasculitis, C3 glomerulonephritis, immune complex-mediated glomerulonephritis, polyarteritis nodosa, and IgA vasculitis. All patients but one received a specific treatment for the MDS-associated kidney injury. The effect of MDS treatment on kidney injury could be assessed in six patients treated with azacitidine, and renal function evolution was heterogenous. After a median follow-up of 14 months, four patients had CKD stage 3, five had CKD stage 4, and three had end stage kidney disease. On the other hand, three evolved to an acute myeloid leukemia and three died. Compared to 84 MDS controls, patients who had kidney involvement were younger, had a higher number of dysplasia lineages, and were more eligible to receive hypomethylating agents, but no survival difference was seen between the two groups. Compared to 265 AAV without MDS, the ten with MDS-associated pauci-immune vasculitis were older, ANCA serology was more frequently negative, and more cutaneous lesions were seen. Conclusion: The spectrum of kidney injuries associated with MDS is mostly represented by vasculitis with glomerular involvement, and especially AAV.

Clinical Outcomes of Monoclonal Gammopathy of Renal Significance Without Detectable Clones.

Introduction: Monoclonal gammopathy of renal significance (MGRS) is characterized by monoclonal immunoglobulin deposition in kidneys. However, monoclonal immunoglobulin and responsible clone(s) are not always detectable. Treatment response and kidney outcome of MGRS without detectable clones remain unclear. Methods: In this single-center, retrospective cohort study, we identified MGRS without detectable clones from our biopsy repository between 2010 and 2022. We investigated the correlations between treatment regimens and kidney outcomes defined by proteinuria and estimated glomerular filtration rate (eGFR), and the impact of repeat kidney biopsy. Results: Our study cohort included 29 cases (27 native kidney and 2 transplant allograft biopsies) of MGRS without detectable clones. At diagnosis, median serum creatinine was 1.8 mg/dl (interquartile range [IQR] 1.3-2.7), with proteinuria 4.6 g/gCr (IQR 2.3-7.9). Treatment regimens were variable: 6 (21%) received conservative therapy, 13 (45%) received plasma cell clone-directed therapy, 8 (28%) received lymphocytic clone-directed therapy, and 2 (7%) received nonclone-directed immunosuppressive therapy. Of 24 patients with proteinuria >0.5 g/gCr at diagnosis, 9 (38%) and 6 (25%) achieved complete response (CR) and partial response (PR), respectively. If interstitial fibrosis and tubular atrophy (IFTA) was >50% at the initial biopsy, less proportion of patients achieved CR. Six of 7 repeat biopsies showed progression of chronic changes (e.g., IFTA) but provided limited information on treatment response. Conclusion: Treatment regimens and outcomes of MGRS without detectable clones were extremely variable. Repeat biopsy provided limited information to assess disease activity or the need for additional treatment. More sensitive tools are needed to detect clones and to assess treatment response.

Infliximab for Treatment of Immune Adverse Events and Its Impact on Tumor Response.

Background: Immune-related adverse events (irAEs) challenge the use of immune checkpoint inhibitors (ICIs). We performed a retrospective study to evaluate response to infliximab for immune-related adverse event management, and infliximab's effect on progression-free survival (PFS) and overall survival (OS) with a focus on melanoma and genitourinary cancers. Methods: We retrospectively reviewed records of all cancer patients exposed to infliximab after immune checkpoint inhibitor (ICI) treatment from 2004 to 2021 at the MD Anderson Cancer Center. Survival was assessed utilizing the Kaplan-Meier method. Univariate and multivariate logistic regression was utilized to evaluate predictors of infliximab response, OS, and PFS. Results: We identified 185 cancer patients (93 melanoma and 37 genitourinary cancers) treated with ICI and who received infliximab to treat irAEs. Within 3 months of treatment initiation, 71% of the patients responded to infliximab, 27% had no response, and 2% had unknown response. Among different irAEs, colitis was associated with increased response to infliximab at 3 months, irrespective of the type of malignancy. We evaluated best tumor response before and after infliximab in the entire cohort and again in the melanoma and genitourinary (GU); the findings were similar in the melanoma cohort and the entire cohort, where best tumor response before and after infliximab was not significantly different. In the melanoma cohort, acute kidney injury (AKI) was associated with increased risk of death, p = 0.0109, and having response to infliximab was associated with decreased risk of death, p = 0.0383. Interestingly in GU cancer patients, myositis was associated with increased risk of death, p = 0.0041, and having a response to infliximab was marginally associated with decreased risk of death, p = 0.0992. As regards PFS, in a multivariate Cox regression model, having a history of cardiovascular disease remained significantly associated with shorter PFS in the melanoma cohort. For patients with GU cancers, response to infliximab was associated with longer PFS. Conclusions: Our study is among the largest retrospective analyses of infliximab use for irAE management. Patients with colitis were the best responders to infliximab. AKI before initiation of infliximab in the melanoma subcohort and myositis in GU subcohort are associated with higher risk of death. Our results indicate no association between infliximab and cancer progression with the exception of genitourinary cancers.

Chronic Myelomonocytic Leukemia Patients With Lysozyme Nephropathy and Renal Infiltration Display Markers of Severe Disease.

Introduction: Chronic myelomonocytic leukemia (CMML) is a hematologic disorder that is an overlap syndrome between myelodysplastic syndromes and myeloproliferative neoplasms, and can be associated with autoimmune and inflammatory diseases. This study aimed to describe kidney involvement in patients with CMML, their treatments, and outcomes. Methods: We conducted a French and American multicenter retrospective study in 15 centers, identifying patients with CMML with acute kidney injury (AKI), chronic kidney disease (CKD), and urine abnormalities. Results: Sixteen patients (males, n = 14; median age 76.5 years [71.9-83]) developed a kidney disease 6 months [1.6-25.6] after the diagnosis of CMML. At the time of kidney disease diagnosis, median urinary protein-to-creatinine ratio was 2 g/g [1.25-3.4], and median serum creatinine was 2.26 mg/dl [1.46-2.68]. Fourteen patients (87.5%) underwent a kidney biopsy, and the 2 main pathological findings were lysozyme nephropathy (56%) and renal infiltration by the CMML (37.5%). Ten patients received a new treatment following the CMML-associated kidney injury. Among patients with monitored kidney function, and after a median follow-up of 15 months [9.9-34.9], 4 patients had CKD stage 3, 4 had CKD stage 4, 1 had an end-stage kidney disease. In our patient series, 2 patients evolved to an acute myeloid leukemia (AML), and 5 died. Compared with 116 CMML controls, patients who had a kidney involvement had a higher monocyte count (P < 0.001), had more CMML-1 (P = 0.005), were more susceptible to develop an AML (P = 0.02), and were more eligible to receive a specific hematologic treatment, with hydroxyurea, or hypomethylating agents (P < 0.001), but no survival difference was seen between the 2 groups (P = 0.6978). Conclusion: In this cohort of patients with CMML with a kidney injury, the 2 most frequent renal complications were lysozyme-induced nephropathy and renal infiltration by the CMML. Kidney involvement should be closely monitored in patients with CMML.

Updates in Plasma Cell Dyscrasias and Related Monoclonal Immunoglobulin-Mediated Renal Disease.

Pathogenic roles of monoclonal immunoglobulins in kidney disease have been attributed previously to malignant plasma cell and lymphoproliferative disorders such as multiple myeloma, lymphoplasmacytic lymphoma, chronic lymphocytic leukemia, or amyloid light chain amyloidosis. Improved technology, advancements in molecular diagnostics, and highly sensitive imaging techniques have established the need to redefine monoclonal gammopathies and the kidney disorders that are associated with monoclonal immunoglobulins regardless of tumor burden. This has led to the establishment of monoclonal gammopathy with renal significance (MGRS). MGRS was defined by the International Kidney and Monoclonal Gammopathy Research Group in 2012 as a clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin and does not meet previously defined hematological criteria for treatment of a specific malignancy. MGRS encompasses a wide array of pathologies with knowledge surrounding its incidence, prognosis, and management continuously increasing. This review examines the current evidence on the diagnosis, prognosis, pathogenesis, and therapy of plasma cell dyscrasias and related MGRS.

Infliximab for the treatment of patients with checkpoint inhibitor-associated acute tubular interstitial nephritis.

Acute tubular interstitial nephritis (ATIN) is the most frequently reported pathology in patients with checkpoint inhibitor (CPI) induced acute kidney injury (AKI). Glucocorticoid (GC) therapy and discontinuation of CPI are the mainstay of treatment to prevent permanent renal dysfunction and dialysis. However, less than 50% of patients have complete kidney recovery and relapse of ATIN can occur. Infliximab is effective in treating other immune-related adverse events but its use for the treatment of CPI-ATIN is not well established. We report the first retrospective study examining the steroid-sparing potential of infliximab in achieving durable and complete renal recovery for patients with CPI-ATIN. Data were collected from medical records of patients diagnosed with CPI-AKI with a kidney biopsy or clinical diagnosis of ATIN that was managed with GC and infliximab. Infliximab-containing regimens were used to treat 10 patients with CPI-ATIN. Four patients relapsing after GC therapy achieved durable and complete renal recovery, four patients experienced partial renal recovery, and two patients showed no improvement in kidney function. This is the first study evaluating clinical outcomes using an infliximab-containing regimen for treatment of relapsed CPI-ATIN in patients or patients failing to achieve complete response after primary therapy. Our data suggest that infliximab may be a treatment option for achieving durable and complete renal recovery in this patient population and represents a potential steroid-sparing strategy in challenging cases of CPI-ATIN. Rigorous clinical studies are warranted to evaluate the risk-benefit analysis for infliximab usage in CPI-ATIN patients.

Incidence, predictors, and survival impact of acute kidney injury in patients with melanoma treated with immune checkpoint inhibitors: a 10-year single-institution analysis.

Background: The incidence of renal immune-related adverse events (irAEs) is reported to be 3.8%, with varied definitions of acute kidney injury (AKI). This study reports a 10-year experience at MD Anderson Cancer Center of patients diagnosed with melanoma and treated with immune checkpoint inhibitors (ICIs) and evaluated the incidence of AKI, associated factors, and its association with overall survival. Methods: A retrospective chart review (2010-2019) of all patients with melanoma treated with ipilimumab, nivolumab, pembrolizumab, or atezolizumab was performed. All available serum creatinine data were extracted and used to calculate the estimated GFR (eGFR) using the CKD Epi equation, and to diagnose AKI using the two KDIGO (Kidney Disease: Improving Global Outcomes) criteria for defining stage I AKI in 1664 unique patients. Cumulative incidence rates of AKI after initiation of ICIs were calculated in the presence of death as a competing risk. The effects of covariates on the cumulative incidence function of AKI were evaluated in a univariant and multivariable analysis. Overall survival was estimated by Kaplan-Meier method in accordance to the occurrence of AKI. Results: The incidence of AKI by definitions 1a and 1b were 3.49% and 3.33%, respectively. After adjudication, AKI attributable to ICI was 58% and 65% of the overall incidence of AKI in each definition respectively. Increasing age was associated with decreased risk of AKI. Asian race was associated with a higher risk of AKI. Comorbidities were not associated with increased risk of AKI while use of proton pump inhibitors (PPI), ipilimumab or ICI combinations were significantly associated with AKI. AKI was not significantly associated with overall survival. Immune-related adverse events (irAEs) occurred in 30% of patients with AKI but their incidence was not different in patients with AKI attributable to ICI versus other AKI. Conclusions: In a large population of patients with melanoma treated with ICIs, an accurate documentation of AKI in setting of ICI use and predictors associated is presented. AKI following ICI use is infrequent, not associated with mortality, and associated with the use of ipilimumab, ICI combinations and PPIs.

Evaluation of visual evoked potentials in chronic renal failure patients with different treatment modalities.

BACKGROUND: Uremia causes central nervous system (CNS) dysfunction. Modern diagnostic methods are useful for the recognition of CNS complications in uremic patients. Data concerning visual evoked potentials (VEPs) of chronic renal failure (CRF) patients is limited. OBJECTIVE: In this study, we aimed to assess and compare VEPs abnormalities in CRF patients managed by only medical therapy (pre-dialysis) or medical therapy plus renal replacement therapy (continuous ambulatory peritoneal dialysis (CAPD) or hemodialysis (HD)). MATERIALS AND METHODS: Fifty-nine patients diagnosed with CRF of various etiologies were divided into 3 groups according to the treatment modalities used to manage CRF; pre-dialysis group, HD group and CAPD group. For the comparison of VEPs parameters, an age matched control group was formed with 10 healthy subjects. RESULTS: Bilateral N2 latency (p<0.001), bilateral P2 latency (p=0.003), right N2 latency (p=0.006) and left VEP N2 latency (p=0.002) in the HD group was significantly higher than the control group. The CAPD group had significantly increased bilateral N2 latency (p<0.001), right eye VEP N2 latency (p=0.004), right eye P2 latency (p=0.001), left eye N2 latency (p=0.005) and left eye P2 latency (p=0.001) levels than the control group. There was no significant difference between VEPs of the CAPD and HD groups. CONCLUSION: The renal replacement treatments that we evaluated have similar effects on VEPs. Diminished VEPs indicating visual neuronal system damage were observed, when CRF progresses. CNS dysfunctions can be diagnosed and additional therapeutic approaches could be followed using VEPs during the treatment of CRF.

Intravitreal bevacizumab-induced exacerbation of proteinuria in diabetic nephropathy, and amelioration by switching to ranibizumab.

Certain diabetic and hypertensive patients started on intravitreal vascular endothelial growth factor inhibition for diabetic retinopathy may experience worsening of hypertension and proteinuria. The etiology of this is the newly recognized absorption of intravitreally injected vascular endothelial growth factor inhibitors, and the susceptibility of patients with pre-existing renal disease to exacerbations depends on the degree of systemic absorption. There are eighteen reported cases of worsening hypertension, woresening proteinuria, worsening renal function, thrombotic microangiopathy, and glomerular disease noted after initiation of intravitreal vascular endothelial growth factor blockade. This nineteenth case demonstrates worsening hypertension and proteinuria with the start of bevacizumab. Both blood pressure and proteinuria parameters showed overall improvement with switching to the less absorbed and lower potency agent ranibizumab. There was a slight rise in serum creatinine after bevacizumab therapy, which stabilized at a new baseline, and the serum creatinine remained stable on ranibizumab. There were no other nephrotoxic exposures that explained the mild rise in serum creatinine. Because of improvement in renal function and proteinuria, a renal biopsy was deferred for the time. This case re-demonstrates the risk of worsening proteinuria with vascular endothelial growth factor inhibitors when given intravitreally in some patients. The demonstration of improvement in blood pressure and proteinuria with the use of lower potency agents like ranibizumab is novel and an important concept confirming observations from pharmacokinetic studies. The switch to ranibizumab offers a therapeutic option when proteinuria worsens with intravitreal vascular endothelial growth factor blockade, and the patient requires ongoing intravitreal therapy for treatment of diabetic retinopathy.

Acute interstitial nephritis and drug-induced systemic lupus erythematosus due to chlorthalidone and amiodarone: A case report.

Drug-induced lupus erythematosus has features distinct from primary systemic lupus erythematosus. It can occur with a wide variety of agents that result in the generation of anti-histone or other types of antibodies. Systemic manifestations of drug-induced systemic lupus erythematosus may include renal dysfunction due to circulating immune complexes or due to other immune reactions to the culprit medication(s). Acute interstitial nephritis occurs due to DNA-drug or protein-drug complexes that trigger an allergic immune response. We report a patient who developed acute kidney injury, rash, and drug-induced systemic lupus diagnosed by serologies after starting chlorthalidone and amiodarone. A renal biopsy showed acute interstitial nephritis and not lupus-induced glomerulonephritis. It is important to note that systemic lupus erythematosus and acute interstitial nephritis can occur together, and this report highlights the role of the kidney biopsy in ascertaining the pathological diagnosis and outlining therapy in drug-induced lupus erythematosus.

Checkpoint inhibitor-related renal vasculitis and use of rituximab.

The percentage of patients with cancer eligible for checkpoint inhibitor (CPI) therapy has increased rapidly over the past few years and approaches 45%. As a result, more cases of CPI-related nephrotoxicity, including a rare subset with vasculitis, are being reported. To elucidate the clinical presentation of CPI-associated renal vasculitis and its possible mechanisms, treatment options and prognosis, we describe cases from a comprehensive cancer center and reviewed the literature for similar cases. We retrospectively reviewed the charts of all patients with cancer from 2014 to 2020 who were diagnosed with CPI-related nephrotoxicity and underwent a kidney biopsy. We identified five cases of renal vasculitis: three patients were diagnosed with seronegative antineutrophil cytoplasm antibody (ANCA)-associated vasculitis, one case with seropositive ANCA-associated vasculitis and one case was diagnosed with IgA vasculitis. Of these cases, four patients were receiving nivolumab, and one patient was receiving tremelimumab. All patients had microscopic hematuria, four out of five patients had negative ANCA serology, one patient had concurrent lung involvement and positive ANCA serology, and all had severe acute kidney injury with creatinine >4.50 mg/dL on diagnosis. All patients were treated by discontinuing CPI and initiating corticosteroids and rituximab. Three patients received plasmapheresis; two of these required renal replacement therapy including the patient with lung involvement. All patients after rituximab had a partial or complete renal response. Two patients died within 8 months of diagnosis due to malignancy progression. None of the patients had a relapse of vasculitis. We demonstrated that CPI can be associated with different types of renal vasculitis that are predominantly ANCA negative and manifest as severe acute kidney injury. Despite the lack of strong evidence, treatment similar to treatment of primary seropositive ANCA-associated vasculitis with corticosteroids and rituximab is well tolerated with favorable renal outcomes.

Equivalent Efficacy and Decreased Rate of Overcorrection in Patients With Syndrome of Inappropriate Secretion of Antidiuretic Hormone Given Very Low-Dose Tolvaptan.

RATIONALE & OBJECTIVE: Euvolemic hyponatremia often occurs due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Vasopressin 2 receptor antagonists may be used to treat SIADH. Several of the major trials used 15 mg of tolvaptan as the lowest effective dose in euvolemic and hypervolemic hyponatremia. However, a recent observational study suggested an elevated risk for serum sodium level overcorrection with 15 mg of tolvaptan in patients with SIADH. STUDY DESIGN: A retrospective chart review study comparing outcomes in patients with SIADH treated with 15 versus 7.5 mg of tolvaptan. SETTINGS & PARTICIPANTS: Patients with SIADH who were treated with a very low dose of tolvaptan (7.5 mg) at a single center compared with patients using a 15-mg dose from patient-level data from the observational study described previously. PREDICTORS: Tolvaptan dose of 7.5 versus 15 mg daily. OUTCOMES: Appropriate response to tolvaptan, defined as an initial increase in serum sodium level > 3 mEq/L, and overcorrection of serum sodium level (>8 mEq/L per day, and >10 mEq/L per day in sensitivity analyses). ANALYTICAL APPROACH: Descriptive study with additional outcomes compared using t tests and F-tests (Fischer's Exact χ2 Test). RESULTS: Among 18 patients receiving 7.5 mg of tolvaptan, the mean rate of correction was 5.6 ± 3.1 mEq/L per day and 2 (11.1%) patients corrected their serum sodium levels by >8 mEq/L per day, with 1 of these increasing by >12 mEq/L per day. Of those receiving tolvaptan 7.5 mg, 14 had efficacy, with increases ≥ 3 mEq/L; similar results were seen with the 15-mg dose (21 of 28). There was a statistically significant higher chance of overcorrection with the use of 15 versus 7.5 mg of tolvaptan (11 of 28 vs 2 of 18; P = 0.05; and 10 of 28 vs 1 of 18; P = 0.03, for >8 mEq/L per day and >10 mEq/L per day, respectively). LIMITATIONS: Small sample size, retrospective, and nonrandomized. CONCLUSIONS: Tolvaptan, 7.5 mg, daily corrects hyponatremia with similar efficacy and less risk for overcorrection in patients with SIADH versus 15 mg of tolvaptan.

Diverse Clinical Presentations of C3 Dominant Glomerulonephritis.

C3 dominant immunofluorescence staining is present in a subset of patients with idiopathic immune complex membranoproliferative glomerulonephritis (iMPGN). It is increasingly recognized that iMPGN may be complement driven, as are cases of "typical" C3 glomerulopathy (C3G). In both iMPGN and C3G, a frequent membranoproliferative pattern of glomerular injury may indicate common pathogenic mechanisms via complement activation and endothelial cell damage. Dysregulation of the alternative complement pathway and mutations in certain regulatory factors are highly implicated in C3 glomerulopathy (which encompasses C3 glomerulonephritis, dense deposit disease, and cases of C3 dominant MPGN). We report three cases that demonstrate that an initial biopsy diagnosis of iMPGN does not exclude complement alterations similar to the ones observed in patients with a diagnosis of C3G. The first patient is a 39-year-old woman with iMPGN and C3 dominant staining, with persistently low C3 levels throughout her course. The second case is a 22-year-old woman with elevated anti-factor H antibodies and C3 dominant iMPGN findings on biopsy. The third case is a 25-year-old woman with C3 dominant iMPGN, dense deposit disease, and a crescentic glomerulonephritis on biopsy. We present the varied phenotypic variations of C3 dominant MPGN and review clinical course, complement profiles, genetic testing, treatment course, and peri-transplantation plans. Testing for complement involvement in iMPGN is important given emerging treatment options and transplant planning.

Thrombotic Microangiopathy and Acute Kidney Injury Induced After Intravitreal Injection of Vascular Endothelial Growth Factor Inhibitors VEGF Blockade-Related TMA After Intravitreal Use.

Vascular endothelial growth factor (VEGF) inhibition can cause worsening hypertension, proteinuria, chronic kidney injury, and glomerular disease. Thrombotic microangiopathy (TMA) and other nephrotic disorders have been reported with systemic VEGF blockade. These same agents are given intravitreally for age-related macular degeneration (AMD) and diabetic retinopathy (DR), albeit at lower doses than those given for systemic indications. Systemic absorption of anti-VEGF agents when given intravitreally has been shown consistently along with evidence of significant intravascular VEGF suppression. While worsening hypertension has only been seen in some large-scale studies, case reports show worsening proteinuria and diverse glomerular diseases. These include TMA-associated lesions like focal and segmental glomerulosclerosis with collapsing features (cFSGS). In this paper, we report three cases of TMA likely associated with the use of intravitreal anti-VEGF therapy. These patients developed the signature lesion of VEGF blockade in a 6 to 11 month time frame after starting intravitreal VEGF inhibitors. The literature is reviewed showing similar cases. Intravitreal VEGF blockade may cause these adverse events in a hitherto unidentified subgroup of patients. Well-controlled prospective observational trials are needed to determine the event rate and identify which subgroups of patients are at increased risk. A registry for patients who develop worsening hypertension, proteinuria exacerbation, and glomerular diseases from intravitreal VEGF blockade is proposed.