Membranous nephropathy in chronic lymphocytic leukemia responsive to ibrutinib: A case report.

Membranous nephropathy (MN) is an uncommon renal presentation in patients with chronic lymphocytic leukemia (CLL), and as such, there is no standard therapy for these patients. A few cases of MN in CLL have been described with varying success in MN treatment involving alkylating agents and fludarabine. Here we report the first case of MN in a patient with CLL treated with ibrutinib with complete renal response. This presentation underlines the importance of recognizing rare glomerular diseases that may occur with CLL and offers a new therapeutic avenue to the treatment of CLL-associated MN.

Case Report: Successful treatment of late-onset immune checkpoint inhibitor-associated membranous nephropathy in a patient with advanced renal cell carcinoma.

Background: Diagnosing immune checkpoint inhibitor (ICI)-associated nephritis can be challenging since it is a rare complication of therapy, associated with a spectrum of immune-mediated pathologies, and can present months after ICI therapy discontinuation (i.e., late-onset). ICIs are increasingly administered in combination with other cancer therapies with associated nephrotoxicity, further obfuscating the diagnosis of ICI-associated nephritis. In this report, we describe the first suspected case of late-onset ICI-associated membranous nephropathy (MN) in a patient with metastatic clear cell renal cell carcinoma (RCC) who had discontinued ICI therapy 6 months prior to presentation. Prompt recognition of the suspected late-onset immune-related adverse event (irAE) resulted in the successful treatment of MN and continuation of RCC therapy. Case presentation: A 57-year-old man with metastatic clear cell RCC was responsive to third-line RCC therapy with lenvatinib (oral TKI) and everolimus (oral mTOR inhibitor) when he presented with nephrotic range proteinuria and acute kidney injury (AKI). His kidney biopsy revealed probable secondary MN with subendothelial and mesangial immune complex deposits and negative staining for both phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A). While a diagnosis of paraneoplastic MN could not be excluded, the patient was responding to cancer therapy and had tumor regression. However, 6 months prior to presentation, the patient had received pembrolizumab, an ICI, with his first-line RCC treatment. Due to concern that the patient may be presenting with late-onset ICI-associated MN, he was effectively treated with rituximab, which allowed for his continued RCC therapy. Conclusion: This report highlights the first case of suspected late-onset ICI-associated MN and the increasing complexity of recognizing renal irAEs. With the growing indications for the use of ICIs in combination with other cancer therapies, recognizing the various presentations of ICI-immune nephritis can help guide patient management and treatment.

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.

Immune checkpoint inhibitor associated reactivation of primary membranous nephropathy responsive to rituximab.

The same mechanisms that mediate antitumor immunity from checkpoint inhibitors (CPIs) can also lead to unintended targeting of normal tissues, characterized as immune-related adverse events (irAEs). Those with pre-existing autoimmune disease are believed to be particularly vulnerable for exacerbating underlying autoimmunity or inducing severe irAEs. We report the first case of CPI-associated reactivation of primary membranous nephropathy (MN) in a patient with pleural mesothelioma responding to immunotherapy. Due to its specificity in targeting B-lymphocytes, rituximab was used to treat primary MN with the expectation that this would not interfere with the benefits gained from T cell-mediated antitumor immunity. Rituximab was effective in treating CPI-associated reactivation of MN, and the patient was successfully rechallenged with nivolumab and maintained stable kidney function and sustained clinical antitumor effect. While exacerbation of pre-existing autoimmune diseases from CPIs is common, therapy for autoimmune reactivation can be rationally directed by an understanding of the immunosuppressive mechanism with goals of cancer treatment.

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.

Unique case of ANCA-negative pauci-immune necrotizing glomerulonephritis with diffuse alveolar hemorrhage, potentially associated with midostaurin.

We present a 61-year-old male with FLT3-mutated acute myeloid leukemia treated with midostaurin who developed acute kidney injury requiring hemodialysis and pulmonary renal syndrome. Antibodies to proteinase-3, myeloperoxidase, and glomerular basement membrane were negative. Renal biopsy confirmed acute pauci-immune focal necrotizing glomerulonephritis (GN) with fibrin crescents indicating rapidly progressing glomerulonephritis. He improved with pulse methylprednisolone, intravenous cyclophosphamide, and plasma exchange with resolution of hemoptysis. This case highlights the importance of prompt renal biopsy to guide early initiation of life-saving therapies. To our knowledge, this is the first reported case of ANCA-negative pauci-immune necrotizing GN likely secondary to midostaurin.

Nephrotoxicity of immune checkpoint inhibitors beyond tubulointerstitial nephritis: single-center experience.

RATIONALE & OBJECTIVE: The approved therapeutic indication for immune checkpoint inhibitors (CPIs) are rapidly expanding including treatment in the adjuvant setting, the immune related toxicities associated with CPI can limit the efficacy of these agents. The literature on the nephrotoxicity of CPI is limited. Here, we present cases of biopsy proven acute tubulointerstitial nephritis (ATIN) and glomerulonephritis (GN) induced by CPIs and discuss potential mechanisms of these adverse effects. STUDY DESIGN, SETTING, & PARTICIPANTS: We retrospectively reviewed all cancer patients from 2008 to 2018 who were treated with a CPI and subsequently underwent a kidney biopsy at The University of Texas MD Anderson Cancer Center. RESULTS: We identified 16 cases diagnosed with advanced solid or hematologic malignancy; 12 patients were male, and the median age was 64 (range 38 to 77 years). The median time to developing acute kidney injury (AKI) from starting CPIs was 14 weeks (range 6-56 weeks). The average time from AKI diagnosis to obtaining renal biopsy was 16 days (range from 1 to 46 days). Fifteen cases occurred post anti-PD-1based therapy. ATIN was the most common pathologic finding on biopsy (14 of 16) and presented in almost all cases as either the major microscopic finding or as a mild form of interstitial inflammation in association with other glomerular pathologies (pauci-immune glomerulonephritis, membranous glomerulonephritis, C3 glomerulonephritis, immunoglobulin A (IgA) nephropathy, or amyloid A (AA) amyloidosis). CPIs were discontinued in 15 out of 16 cases. Steroids and further immunosuppression were used in most cases as indicated for treatment of ATIN and glomerulonephritis (14 of 16), with the majority achieving complete to partial renal recovery. CONCLUSIONS: Our data demonstrate that CPI related AKI occurs relatively late after CPI therapy. Our biopsy data demonstrate that ATIN is the most common pathological finding; however it can frequently co-occur with other glomerular pathologies, which may require immune suppressive therapy beyond corticosteroids. In the lack of predictive blood or urine biomarker, we recommend obtaining kidney biopsy for CPI related AKI.

Leukocytoclastic vasculitis with late-onset Henoch-Schönlein purpura after trifluridine/tipiracil treatment.

Trifluridine/tipiracil has been approved for the treatment of refractory metastatic colorectal cancer. Adverse effects of this drug combination include leukopenia, neutropenia, fatigue, diarrhea, and vomiting. We present a case of trifluridine/tipiracil-induced leukocytoclastic vasculitis (LCV) with late-onset Henoch-Schönlein purpura (HSP) in a 42-year-old man with metastatic appendiceal cancer. The patient's biopsy-proven LCV developed one month after he began trifluridine/tipiracil treatment and resolved after discontinuation of the drug. He presented to the emergency department two months after the appearance of his LCV with shortness of breath, elevated blood pressure, elevated creatinine, hematuria, and proteinuria. A kidney biopsy was performed and the presence of IgA deposits and cellular crescents indicated rapidly progressive glomerulonephritis secondary to Henoch-Schönlein purpura (HSP). Neither LCV nor HSP have been reported as adverse effects of trifluridine/tipiracil treatment. Malignancy as a cause of our patient's HSP is another possibility. The delay between our patient's skin findings and acute renal failure indicates that suspected HSP should be monitored by urinalysis for a period of time owing to the risk of life-threatening renal disease.

Association of membranoproliferative glomerulonephritis with mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a rare and aggressive lymphoid neoplasm. It can involve the kidney, either by direct lymphomatous infiltration or by a paraneoplastic glomerulonephritis. We present here the case of a man with rectal bleeding and rapidly progressive renal failure, who had MCL in the gastrointestinal tract and paraneoplastic membranoproliferative glomerulonephritis, and whose renal dysfunction normalised after chemotherapy.

Nephrotic syndrome and unrecognized Plasmodium malariae infection in a US Navy sailor 14 years after departing Nigeria.

A 34-year-old Nigerian man presented with nephrotic syndrome. Renal biopsy revealed chronic membranous glomerulopathy with focal segmental sclerosis. Blood Giemsa smear contained rare Plasmodium sp. trophozoites and small subunit ribosomal RNA polymerase chain reaction amplification confirmed the presence of Plasmodium malariae. This case highlights the importance of obtaining even remote travel histories from ill immigrants and considering occult quartan malaria in patients from endemic locations with nephrotic syndrome.

Expression of alpha-actinin-1 in human glomerular mesangial cells in vivo and in vitro.

Recent studies have demonstrated important roles of alpha-actinins in glomerular disease, while little information is known about the expression profile of alpha-actinins in human glomerular mesangial cells. Here, immunofluorescence and confocal microscopy showed that alpha-actinin-1 exclusively distributed along mesangial cells in human glomeruli of IgA nephropathy. RT-PCR and Western blot further confirmed the expression of alpha-actinin-1 in primary cultured human mesangial cells. We also found that transforming growth factor-beta 1 (TGF-beta 1) stimulated ACTN1 gene transcription and that transiently transfected alpha-actinin-1 significantly increased TGF-beta 1-induced plasminogen activator inhibitor-1 (PAI-1) promoter activity in human mesangial cells. These findings suggest that alpha-actinin-1 may play a role in human glomerular disease.

Regulation of TGF-beta1/MAPK-mediated PAI-1 gene expression by the actin cytoskeleton in human mesangial cells.

The importance of transforming growth factor-beta1 (TGF-beta1) in plasminogen activator inhibitor-1 (PAI-1) gene expression has been established, but the precise intracellular mechanisms are not fully understood. Our hypothesis is that the actin cytoskeleton is involved in TGF-beta1/MAPK-mediated PAI-1 expression in human mesangial cells. Examination of the distributions of actin filaments (F-actin), alpha-actinin, extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) by immunofluorescence and immunoprecipitation revealed that ERK and JNK associate with alpha-actinin along F-actin and that TGF-beta1 stimulation promote the dissociation of ERK and JNK with F-actin. Disassembly of the actin cytoskeleton inhibited phosphorylation of ERK and JNK and modulated PAI-1 expression and promoter activity under both basal and TGF-beta1-stimulated conditions. Stabilizing actin prevented dephosphorylation of ERK and JNK. ERK and JNK inhibitors and overexpressed dominant negative mutants antagonized the ability of TGF-beta1 to increase PAI-1 expression and promoter activity. Disassembly of F-actin also inhibited AP-1 DNA binding activity as determined by electrophoretic mobility shift assay using AP-1 consensus oligonucleotides derived from human PAI-1 promoter. F-actin stabilization prevented loss of AP-1 DNA binding activity. Therefore, changes in actin cytoskeleton modulate the ability of TGF-beta1 to stimulate PAI-1 expression through a mechanism dependent on the activation of MAPK/AP-1 pathways.

Impact of the tumor microenvironment on host infiltrating cells and the efficacy of flt3-ligand combination immunotherapy evaluated in a treatment model of mouse prostate cancer.

We have previously reported that Fms-like tyrosine kinase-3 ligand (flt3-L) induced tumor stabilization and regression of palpable ectopic prostate tumors (TRAMP-C1). Although some mice remained "tumor free" for several months following termination of therapy, tumors invariably reappeared and grew progressively in all animals. The lack of a curative response suggests that TRAMP-C1 tumors may inhibit the development of a flt3-L-induced anti-tumor immune response. Consistent with this view, we demonstrate herein that TRAMP-C1 tumors isolated from flt3-L treated animals contained a marked dendritic cell (DC) infiltrate that was temporally correlated with tumor regression. However, tumor-associated DCs, especially in a flt3-L setting, progressively lost MHC class II antigen expression during tumor growth. Treatment with the DC maturation factor trimeric CD40 ligand (CD40-L) either alone or in combination with fl3-L neither prevented loss of DC class II antigens nor disease relapse. Because loss of class II antigens would prevent CD4+ helper T (Th) cell development, we treated tumor-bearing mice with agonistic anti-4-1BB antibody (Ab), which can promote cytotoxic T lymphocyte (CTL) development independent of Th cell function. However, anti-4-1BB Ab alone did not alter TRAMP-C1 growth kinetics, and, when used in combination, was no more effective than flt3-L alone. The inability of the 4-1BB co-stimulatory signal to promote tumor regression may have been related to two additional features of TRAMP-C1 tumors. First, tumor-associated T cells, but not splenic T cells from tumor-bearing animals, were profoundly deficient in expression of CD3-epsilon (CD3epsilon) and T cell receptor-beta chain (TCRbeta). Second, CTLs required 24 h to efficiently kill TRAMP-C1 target cells even after up-regulation of MHC class I antigens by interferon-gamma. This rate of tumor cell destruction by CTLs may not be sufficient to prevent tumor progression. Taken together, these data reveal several important immunosuppressive characteristics of the prostate tumor microenvironment (TME) that immunotherapeutic interventions must first overcome to achieve longterm cures. These data also highlight the importance of utilizing treatment versus vaccination models in the evaluation of immunotherapeutic modalities.

Orthotopic treatment model of prostate cancer and metastasis in the immunocompetent mouse: efficacy of flt3 ligand immunotherapy.

We established an orthotopic treatment model of prostate cancer to generate reproducible primary and metastatic carcinoma in immunocompetent C57BL/6 mice. Using an in vivo selection scheme of intraprostatic implantation of TRAMP-C1 cells, primary prostate tumors were cultured and recycled three times by intraprostatic injection resulting in the selection and establishment of the recycled cell line TRAMP-C1P3. Prostate tumors were detected approximately 30 days post-implantation with periaortic lymph node metastasis in 19/20 (95%) of mice. Tissue culture amplification, DNA ploidy and PCR amplification of the SV40 transgene were used to detect metastatic TRAMP-C1P3 in lymph node specimens. Tissue culture amplification and DNA ploidy were as sensitive as SV40 transgene amplification by PCR in detection of early metastatic disease in draining lymph nodes. To establish the use of the orthotopic model of prostate cancer for immunotherapy, mice were injected orthotopically with TRAMP-C1P3 cells and 7 days post-implantation treated daily for 28 days with either flt3L or carrier control. Carrier-treated mice had clinically detectable prostate tumors, lymph node metastasis and were moribund at 29-35 days, whereas flt3L therapy markedly suppressed primary TRAMP-C1P3 growth and lymph node metastasis, and prolonged survival. In summary, we have established a reproducible and clinically relevant orthotopic treatment model of prostate cancer in immunocompetent mice with application to a variety of therapeutic strategies. We demonstrate that flt3L treatment suppressed orthotopic prostate tumor growth and lymph node metastasis reinforcing a role for flt3L as an immunotherapeutic strategy for prostate cancer.

T-cell epitope of alpha3 chain of type IV collagen induces severe glomerulonephritis.

BACKGROUND: Anti-glomerular basement membrane (GBM) glomerulonephritis is among the earliest recognized human autoimmune diseases. However, the etiology of anti-GBM glomerulonephritis remains unclear. We have previously shown that CD4+ T cells, specific to alpha3 NC1 of type IV collagen (Col4alpha3NC1), were able to induce anti-GBM glomerulonephritis in Wistar-Kyoto (WKY) rats. In the present study, we continued to map the nephritogenic T cell epitope in Col4alpha3NC1. METHODS: Synthetic peptides, which covered Col4alpha3NC1, were used as immunogens to induce glomerulonephritis in WKY rats. T-cell and B-cell responses to the peptides in the animals were analyzed. RESULTS: One potent nephritogenic T-cell epitope, pCol(28-40) (SQTTANPSCPEGT), was identified. A single immunization with pCol(28-40) induced extremely severe glomerulonephritis in all 23 rats. Renal pathology revealed nearly 100% of glomeruli with crescentic lesions or tuft necrosis in 21 animals. pCol(28-40) elicited a T-cell response to the peptide; T cells isolated from rats immunized with recombinant Col4alpha3NC1 reacted with pCol(28-40). pCol(28-40) elicited a peptide specific antibody response, which did not react with polypeptide Col4alpha3NC1 or native GBM. An 11-mer peptide, pCol(a30-40) (Ac-TTANPSCPEGT), was further mapped to be the core of the T-cell epitope in pCol(28-40). As expected, immunization with pCol(a30-40) induced severe glomerulonephritis in 10 out of 19 rats. CONCLUSION: Our study not only demonstrated that a single T-cell epitope of Col4alpha3NC1 is sufficient to induce severe glomerulonephritis, but also provides a unique model for studying T-cell-mediated mechanisms in anti-GBM glomerulonephritis pathogenesis.

Regulation of the mesangial cell myofibroblast phenotype by actin polymerization.

Mesangial cells in diverse glomerular diseases become myofibroblast-like, characterized by activation of smooth muscle alpha-actin (alpha-SMA) expression. In cultured mesangial cells, serum-deprivation markedly increases alpha-SMA expression, cell size, and stress fiber formation. Since stress fibers are assembled from actin monomers, we investigated the hypothesis that alterations in stress fiber formation regulate alpha-SMA expression and hypertrophy. Human mesangial cells were treated with agents that disrupt or stabilize actin stress fibers. Depolymerization of actin stress fibers in serum-deprived cells with actin-depolymerizing agents, cytochalasin B (CytB) and latrunculin B (LatB), or with inhibitors of Rho-kinase, Y-27632 and HA-1077 decreased alpha-SMA mRNA as judged by Northern blot analysis. Western blot analysis showed that CytB also reduced alpha-SMA protein levels. In serum-fed cells, agents that stabilized actin stress fibers, jasplakinolide (Jas) and phalloidin, increased alpha-SMA mRNA and protein. Treatment of human or rat mesangial cells with CytB, LatB, or Y-27632 decreased alpha-SMA promoter activity. In contrast, Jas increased promoter activity 5.6-fold in rat mesangial cells. The presence of an RNA polymerase inhibitor blocked degradation of alpha-SMA mRNA in cells treated with CytB suggesting that destabilization of this message is dependent on a newly transcribed or rapidly degraded factor. Inhibition of actin polymerization by CytB, LatB, Y-27623, and HA-1077 inhibited incorporation of (3)[H]-leucine into newly synthesized protein. Additionally, CytB and LatB decreased cell volume as determined by flow cytometry. Collectively, these results indicate that the state of polymerization of the actin cytoskeleton regulates alpha-SMA expression, hypertrophy, and myofibroblast differentiation in mesangial cells.

COX-2 inhibition potentiates the antiproteinuric effect of enalapril in uninephrectomized SHR.

PGE(2) and PGI(2) reduce extracellular matrix deposition and their production is altered after ACE inhibitor (ACEi) treatment. We therefore hypothesized that cyclooxygenase (COX)-2 inhibition would exacerbate renal injury and antagonize the effects of ACEi. To test these hypotheses, WKY and SHR were uninephrectomized (UNX) and treated with either vehicle, enalapril, NS398 or enalapril+NS398. NS398 did not affect systolic blood pressure nor antagonize the antihypertensive effect of enalapril. Urinary protein excretion in UNX WKY was significantly decreased after treatment with either enalapril or NS398. In UNX SHR, enalapril reduced proteinuria, but NS398 alone had no effect. Administration of both drugs, however, further reduced proteinuria. In UNX WKY, treatment with either NS398 alone or both drugs reduced glomerular volume and similar results were observed in SHR. Surprisingly, these results disprove our original hypothesis and suggest that inhibition of COX-2 provides additional renoprotection to that of enalapril alone.