Effects of CTLA4-Fc on glomerular injury in humorally-mediated glomerulonephritis in BALB/c mice

Two acute kidney injury episodes after ICI therapy: a case report

A 74-year-old Japanese male with lung squamous cell carcinoma received his first dose of immune checkpoint inhibitors (ICIs): ipilimumab and nivolumab. He developed acute kidney injury (AKI) and was admitted to our department. We diagnosed kidney immune-related adverse effects (irAE), and a kidney biopsy revealed acute tubulointerstitial nephritis. We started oral prednisolone (PSL) and his AKI immediately improved. The patient maintained stable findings after PSL was tapered off. However, seven months after the ICI administration, he developed rapid progressive glomerular nephritis and was admitted to our department again. The second kidney biopsy showed findings consistent with anti-glomerular basement membrane glomerulonephritis. Although the patient was treated with pulse methylprednisolone followed by oral PSL and plasma exchange, he became dependent on maintenance hemodialysis. To our knowledge, no case report has described two different types of biopsy-proven nephritis. In cases of suspected relapsing kidney irAEs, both a relapse of previous nephritis and the development of another type of nephritis should be considered.

The Immunobiological Agents for Treatment of Antiglomerular Basement Membrane Disease

Combination therapy with glucocorticoids, cyclophosphamide, and plasmapheresis is recommended as the standard treatment for anti-glomerular basement membrane (anti-GBM) disease, but the prognosis of this disease remains poor. Several immunobiological agents have been administered or are expected to be useful for anti-GBM disease in light of refractory disease or the standard treatments' tolerability. Many data regarding the use of biologic agents for anti-GBM disease have accumulated, verifying the effectiveness and potential of biologic agents as a new treatment option for anti-GBM disease. Tumor necrosis factor (TNF) inhibitors were shown to be useful in animal studies, but these agents have no clinical use and were even shown to induce anti-GBM disease in several cases. Although the efficacy of the TNF-receptor antagonist has been observed in animal models, there are no published case reports of its clinical use. There are also no published reports of animal or clinical studies of anti-B-cell-activating factor, which is a member of the TNF family of agents. Anti-interleukin (IL)-6 antibodies have been demonstrated to have no effect on or to exacerbate nephritis in animal models. Anti-C5 inhibitor was observed to be useful in a few anti-GBM disease cases. Among the several immunobiological agents, only rituximab has been demonstrated to be useful in refractory or poor-tolerance patients or small uncontrolled studies. Rituximab is usually used in combination with steroids and plasma exchange and is used primarily as an alternative to cyclophosphamide, but there is insufficient evidence regarding the efficacy of rituximab for anti-GBM disease, and thus, randomized controlled studies are required.

Anti-glomerular basement membrane glomerulonephritis concurrent with membranous nephropathy and acute tubular interstitial nephritis in a lung cancer patient treated with pembrolizumab

Immune checkpoint inhibitors (ICIs) have become the standard treatment for many types of cancer and have improved patient prognosis. However, ICIs upregulate the immune system against tumors, leading to immune-related adverse events (irAEs). Kidney irAEs are less common, and most of them are acute tubulointerstitial nephritis (ATIN). However, there has been a recent increase in recognition of glomerular disease related to ICI therapies. We report the case of a 65-year-old man with lung adenocarcinoma who was treated with pembrolizumab (a monoclonal antibody targeting programmed cell death protein-1 [PD-1]). Pembrolizumab was discontinued after seven cycles due to the development of destructive thyroiditis. Within three months of discontinuing the pembrolizumab treatment, the patient developed rapid progressive glomerulonephritis (RPGN), liver dysfunction, and dysgeusia. The patient underwent renal biopsy and was diagnosed with crescentic glomerulonephritis due to anti-glomerular basement membrane (GBM) antibodies complicated with membranous nephropathy (MN) and ATIN. Treatment with systemic corticosteroids resulted in a favorable clinical response. Various ICI-associated glomerular diseases have been described; however, this is the first reported case of anti-GBM glomerulonephritis associated with MN and ATIN following ICI treatment.

Atypical anti-glomerular basement membrane glomerulonephritis in a patient with metastatic melanoma treated with mitogen-activated protein kinase and immune checkpoint inhibitors: a case report

Background

Immune checkpoint inhibitors and mitogen-activated protein kinase inhibitors have become the standard of care in patients with advanced melanoma bearing V600 mutations. However, little is known about their nephrotoxicity. To date, only two cases of anti-glomerular basement membrane glomerulonephritis after exposure to checkpoint inhibitors have been documented. Herein, we report the first case of a patient with metastatic melanoma who developed linear Immunoglobulin G 3+, Immunoglobulin A 2+, kappa 2+, lambda 1+ anti-glomerular basement membrane glomerulonephritis with negative serology following treatment with checkpoint inhibitors and subsequently mitogen-activated protein kinase inhibitors.

Case presentation

A 58-year-old Caucasian male was referred to our outpatient nephrology clinic with acute kidney injury and proteinuria. He had received three cycles of ipilimumab and nivolumab for recurrent melanoma positive for the BRAF V600E mutation with metastasis to the lungs. Immunotherapy had been discontinued in the setting of severe adverse effects including dermatitis, colitis, and hepatitis. Because of persistent bilateral lung metastases and left pleural metastases, the patient had been initiated on dabrafenib and trametinib until his presentation to our clinic 6 months later. On presentation, his blood pressure was 172/89 mm/Hg and had 2+ edema bilaterally. His creatinine level was 2.4 mg/dL from a previous normal baseline with a urinary protein-to-creatinine ratio of 2 g/g. His urinalysis showed dysmorphic erythrocytes and red blood cell casts. Serologic testing was negative for antineutrophilic cytoplasmic antibodies, proteinase 3 antigen, myeloperoxidase, and anti-glomerular basement membrane antibody. Complement levels were normal. A renal biopsy showed focal crescentic (2 of 15 glomeruli with cellular crescents), proliferative, and sclerosing glomerulonephritis with diffuse linear staining of glomerular capillary loops dominant for IgG (3+), IgA (2+), kappa (2+), and lambda (1+) minimal changes. He was initiated on oral cyclophosphamide and pulse intravenous methylprednisolone followed by oral prednisone for 6 months, which stabilized his renal function until reinitiation of immunotherapy.

Conclusions

Acute kidney injury is an increasingly reported adverse effect of both drug classes, mostly affecting the tubulointerstitial compartment and infrequently the glomerulus. Although the biologic effect of these drugs on immune cells is not entirely understood, it is possible that BRAF-induced podocyte injury in combination with direct T-cell-mediated glomerular injury facilitated by checkpoint inhibitors led to the unmasking of cryptic antigens, loss of self-tolerance, and autoimmunity. More importantly, we show that treatment with corticosteroids and cyclophosphamide was able to improve and stabilize our patient’s renal function until the reinitiation of immunotherapy.

Co-inhibitory Receptor Signaling in T-Cell-Mediated Autoimmune Glomerulonephritis

Autoimmune glomerulonephritis occurs as a consequence of autoantibodies and T-cell effector functions that target autoantigens. Co-signaling through cell surface receptors profoundly influences the optimal activation of T cells. The scope of this review is signaling mechanisms and the functional roles of representative T-cell co-inhibitory receptors in the regulation of autoimmune glomerulonephritis, along with current therapeutic challenges mainly on preclinical trials. Co-inhibitory receptors utilize both shared and unique signaling pathway, suggesting specialized functions that provide the rationale behind therapies for autoimmune glomerulonephritis by targeting these inhibitory receptors. These receptors largely suppress Th1 immunity, modify Th17 and Th2 immune response, and enhance Treg function. Anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) immunoglobulin (Ig), which is able to block both activating CD28 and inhibitory CTLA4 signaling, has been shown in preclinical and clinical investigations to have effects on glomerular disease. Other inhibitory receptors for treating glomerulonephritis have not been clinically tested, and efficacy of manipulating these pathways requires further preclinical investigation. While immune checkpoint inhibition using anti-CTLA4 antibodies and anti-programmed cell death 1 (PD-1)/PD-L1 antibodies has been approved for the treatment of several cancers, blockade of CTLA4 and PD-1/PD-L1 is associated with adverse effects that resemble autoimmune disorders, including systemic vasculitis. A renal autoimmune vasculitis model features an initial Th17 dominancy followed later by a Th1-dominant outcome and Treg cells that attenuate autoreactive T-cell function. Toward the development of effective therapies for T-cell-mediated autoimmune glomerulonephritis, it would be preferable to pay attention to the impact of the inhibitory pathways in immunological renal disease settings.

Critical role of rabphilin-3A in the pathophysiology of experimental lymphocytic neurohypophysitis

Autoimmune hypophysitis (AH) is thought to be an autoimmune disease characterized by lymphocytic infiltration of the pituitary gland. Among AH pathologies, lymphocytic infundibulo-neurohypophysitis (LINH) involves infiltration of the neurohypophysis and/or the hypothalamic infundibulum, causing central diabetes insipidus resulting from insufficiency of arginine vasopressin secretion. The pathophysiological and pathogenetic mechanisms underlying LINH are largely unknown. Clinically, differentiating LINH from other pituitary diseases accompanied by mass lesions, including tumours, has often been difficult, because of similar clinical manifestations. We recently reported that rabphilin-3A is an autoantigen and that anti-rabphilin-3A antibodies constitute a possible diagnostic marker for LINH. However, the involvement of rabphilin-3A in the pathogenesis of LINH remains to be elucidated. This study was undertaken to explore the role of rabphilin-3A in lymphocytic neurohypophysitis and to investigate the mechanism. We found that immunization of mice with rabphilin-3A led to neurohypophysitis. Lymphocytic infiltration was observed in the neurohypophysis and supraoptic nucleus 1 month after the first immunization. Mice immunized with rabphilin-3A showed an increase in the volume of urine that was hypotonic as compared with control mice. Administration of a cocktail of monoclonal anti-rabphilin-3A antibodies did not induce neurohypophysitis. However, abatacept, which is a chimeric protein that suppresses T-cell activation, decreased the number of T cells specific for rabphilin-3A in peripheral blood mononuclear cells (PBMCs). It ameliorated lymphocytic infiltration of CD3+ T cells in the neurohypophysis of mice that had been immunized with rabphilin-3A. Additionally, there was a linear association between the number of T cells specific for rabphilin-3A in PBMCs and the number of CD3+ T cells infiltrating the neurohypophysis. In conclusion, we suggest that rabphilin-3A is a pathogenic antigen, and that T cells specific for rabphilin-3A are involved in the pathogenesis of neurohypophysitis in mice. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Monoclonal antibodies for podocytopathies: rationale and clinical responses

The podocytopathies, including minimal-change nephropathy, focal segmental glomerulosclerosis, collapsing glomerulopathy, and diffuse mesangial sclerosis, involve diverse types of injury to podocytes. These injuries can have genetic causes, or can be caused by viral infection, mechanical stress, medication or-probably-immunologic injury. Several lines of evidence-including the immunosuppressive effects of standard therapies-suggest a role for immunologic injury in some cases, but the precise pathologic mechanisms are far from clear. Despite this uncertainty, newly available biologic therapies that target immune cells and cytokines have been used to treat a number of patients with different podocytopathies. Of these therapies, the greatest experience has been gained with rituximab. The data on all such therapies remain too fragmentary to provide firm conclusions, but further clinical research with such agents might help to define pathogenetic pathways and could potentially contribute to new therapies.

CD100 enhances dendritic cell and CD4+ cell activation leading to pathogenetic humoral responses and immune complex glomerulonephritis

CD100, a member of the semaphorin family, is a costimulatory molecule in adaptive immune responses by switching off CD72's negative signals. However, CD100's potential pathogenetic effects in damaging immune responses remain largely unexplored. We tested the hypothesis that CD100 plays a pathogenetic role in experimental immune complex glomerulonephritis. Daily injection of horse apoferritin for 14 days induced immune complex formation, mesangial proliferative glomerulonephritis and proteinuria in CD100-intact (CD100+/+) BALB/c mice. CD100-deficient (CD100-/-) mice were protected from histological and functional glomerular injury. They exhibited reduced deposition of Igs and C3 in glomeruli, reduced MCP-1 and MIP-2 intrarenal mRNA expression, and diminished glomerular macrophage accumulation. Attenuated glomerular injury was associated with decreased Ag-specific Ig production, reduced CD4+ cell activation and cytokine production. Following Ag injection, CD4+ cell CD100 expression was enhanced and dendritic cell CD86 expression was up-regulated. However, in CD100-/- mice, dendritic cell CD86 (but not CD80) up-regulation was significantly attenuated. Following i.p. immunization, CD86, but not CD80, promotes early Ag-specific TCR-transgenic DO11.10 CD4+ cell proliferation and IFN-gamma production, suggesting that CD100 expression enables full expression of CD86 and consequent CD4+ cell activation. Transfer of CD100+/+ DO11.10 cells into CD100-/- mice resulted in decreased proliferation demonstrating that CD100 from other sources in addition to CD100 from Ag-specific CD4+ cells plays a role in initial T cell proliferation. Although T cell-B cell interactions also may be relevant, these studies demonstrate that CD100 enhances pathogenetic humoral immune responses and promotes the activation of APCs by up-regulating CD86 expression.

Leukocyte recruitment to the inflamed glomerulus: a critical role for platelet-derived P-selectin in the absence of rolling

The renal glomerulus is one of the few sites within the microvasculature in which leukocyte recruitment occurs in capillaries. However, due to the difficulty of directly visualizing the glomerulus, the mechanisms of leukocyte recruitment to glomerular capillaries are poorly understood. To overcome this, we rendered murine kidneys hydronephrotic to allow the visualization of the functional glomerular microvasculature during an inflammatory response. These experiments demonstrated that following infusion of anti-glomerular basement membrane (GBM) Ab, leukocytes became adherent in glomerular capillaries via a process of immediate arrest, without undergoing prior detectable rolling. However, despite the absence of rolling, this recruitment involved nonredundant roles for the P-selectin/P-selectin glycoprotein ligand-1 and beta2 integrin/ICAM-1 pathways, suggesting that a novel form of the multistep leukocyte adhesion cascade occurs in these vessels. Anti-GBM Ab also increased glomerular P-selectin expression and induced a P-selectin-independent increase in platelet accumulation. Moreover, platelet depletion prevented both the increase in glomerular P-selectin, and the leukocyte recruitment induced by anti-GBM Ab. Furthermore, depletion of neutrophils and platelets also prevented the increase in urinary protein excretion induced by anti-GBM Ab, indicating that their accumulation in glomeruli contributed to the development of renal injury. Finally, infusion of wild-type platelets into P-selectin-deficient mice restored the ability of glomeruli in these mice to support leukocyte adhesion. Together, these data indicate that anti-GBM Ab-induced leukocyte adhesion in glomeruli occurs via a novel pathway involving a nonrolling interaction mediated by platelet-derived P-selectin.

Treatment of glomerulonephritis: will we ever have options other than steroids and cytotoxics?

Glomerulonephritis refers to a collection of primary renal disorders and those secondary to a systemic disease, all characterized by inflammation within the glomerulus. Given the underlying immunologic nature of these disorders, they are routinely treated with corticosteriods and various cytotoxic agents. Although in many instances such therapies are successful, they are associated with significant morbidity; as such, alternatives are clearly necessary. Our understanding of the pathogenesis of immunologic glomerular diseases has grown remarkably, in large part from the study of rodent disease models. Fundamental to each disorder is the development of an antigen-specific immune response followed by the effector stage of inflammation. To block the immune response, antigen-specific therapy can be used to induce tolerance, such as through the use of double-stranded DNA molecules in lupus nephritis. Since other antigen systems are less well characterized, inducing a more generalized impairment in the immune response by blocking costimulatory molecules CD40-CD154 and CD28-CD80/86 is a growing approach to treat various immunologic disorders and transplantation. To reduce glomerular inflammation, a variety of effector systems have been targeted, including complement, cytokines/chemokines, adhesion molecules, and mediators of cellular proliferation. Of these, antibodies targeting C5 in the complement system, and antibody and receptor antagonists of tumor necrosis factor-alpha (TNF-alpha) have already been used in glomerular disorders with some promise. Less specific blockade of receptor-mediated events stimulated by platelet-derived growth factors and cell cycle proteins may soon be applied to glomerulonephritis. Finally, interruption of fibrosing pathways, which lead to glomerulosclerosis and interstitial fibrosis common to the end-stage of all glomerulonephritis, is the subject of intense effort which may yield effective biologic therapies. In spite of all these advances, we still are dependent on steroids and cytotoxics to treat glomerulonephritis. To get past this, we must devote significant resources to take observations made in basic research laboratories to develop therapeutics and prove their utility in human disease.

Upcoming biologic agents for the treatment of rheumatic diseases

The development of biologic agents has provided rheumatologists with a variety of new and effective treatment options. The success of early biologics, especially etanercept and infliximab for the treatment of rheumatoid arthritis, has spurred research into novel targets for the management of systemic inflammatory and autoimmune diseases. In addition, existing biologics approved for use in other diseases, such as rituximab, are now under study for the treatment of new indications. This article reviews ongoing research on the treatment of rheumatic diseases with new and existing biologic agents.