Efficacy of Plasmapheresis in Nivolumab-Associated ANCA Glomerulonephritis: A Case Report and Pathophysiology Discussion

Immune checkpoint inhibitors (ICIs) have revolutionized solid organ and hematologic cancer treatments by improving overall prognoses. However, they can lead to overactivation of the immune system and several immune-related adverse events and sometimes affecting the renal system. Although acute interstitial nephritis is well described, we know little about ICI-associated glomerular injury. Herein, we report an exceptional case of renal ANCA positive-associated vasculitis (AAV) after nivolumab therapy. Three weeks after the last nivolumab injection, the patient presented with proteinuria at 1.73 g/g of creatininuria, hematuria, and acute kidney injury needing dialysis associated with lung hemorrhage; anti-neutrophil cytoplasmic antibody (ANCA titer ≥1,280 with myeloperoxidase specificity of 780 U/mL) was positive, and kidney biopsy confirmed glomerular injury with crescents. The patient underwent treatment with steroid pulses, rituximab, and plasmapheresis, resulting in an improvement of the renal function and lung hemorrhage and produced a negative ANCA titer. Despite the results of the PEXIVAS study and the absence of clear benefit of plasmapheresis demonstrated in idiopathic AAV, we suggest that drug-induced AAV may be effectively treated by plasmapheresis, steroids, and rituximab.

Abstract 13747: Targeting Urokinase-Type Plasminogen Activator (uPA) and the uPA Receptor, Reduces Vascular Inflammation and Lung Hemorrhage in Systemic Lupus and SARS CoV2 Infection in Mouse Models of Respiratory Distress Syndromes

Introduction: Acute respiratory distress syndromes with vascular inflammation and alveolar hemorrhage have high mortality and limited treatment. Autoimmune disease and severe viral infection cause vascular inflammation and hemorrhage. Serine protease coagulation pathways increase inflammatory cell activation and damage. Viruses have evolved highly effective immune modulating ser ine p roteinase in hibitors, serpins . Myxomavirus Serp-1 improves survival and reduces inflammation, vasculitis and lung hemorrhage in MHV68 gamma herpes infections (P < 0.01). Serp-1 also reduces Lupus alveolar hemorrhage (DAH) and proved safe and effective in a randomized, blinded, dose escalating trial in patients with coronary stent implant. Hypothesis: We hypothesize that treatment with PEGylated Serp-1 (PEGSerp-1) will reduce hemorrhage and inflammatory vasculitis in autoimmune and infectious lung disease. Methods: Pristane induced DAH and SARS-CoV-2 virus infections were treated with PEGSerp-1 in mouse models. Results: Serp-1 and PEGSerp-1 given daily IP for 14 days significantly reduced pristane induced DAH (N = 30 C57Bl/6 mice; P < 0.05) at 14 days follow up. PEGSerp-1 also reduced lung hemorrhage given for 7days treatment (N = 6 mice; P <0.01) or when given 7 days after pristane induction of DAH (N = 6 mice; P < 0.01). Macrophage invasion (P < 0.01), Prussian blue staining for hemosiderosis, C5b-9 complex deposition and soluble uPAR (suPAR) were significantly reduced with PEGSerp-1 treatment. PEGSerp-1 given daily after SARS-CoV-2 infection (48hrs, BALB/c mice, N = 16) also significantly reduced lung inflammation; decreased F4/80+ and iNOS+ macrophage staining (P < 0.02). Virus titer was also reduced in TMPRS2+ Vero cells (10μg/mL), and in SARS infected lungs. PEG Serp-1 homes to areas of pristane lung damage, but not normal lungs, indicating targeting of protease activation. No adverse effects were detected. Conclusion: Treatment for vascular inflammation and hemorrhage in severe autoimmune and virus induced respiratory distress syndromes is very limited. Targeting thrombolytic and inflammatory serine protease uPA/ uPAR complex activation provides a new therapeutic approach to severe respiratory distress in autoimmune disease and viral infection.

Laminin-521 is a Novel Target of Autoantibodies Associated with Lung Hemorrhage in Anti-GBM Disease

BackgroundAntiglomerular basement membrane (anti-GBM) disease is characterized by GN and often pulmonary hemorrhage, mediated by autoantibodies that typically recognize cryptic epitopes within α345(IV) collagen—a major component of the glomerular and alveolar basement membranes. Laminin-521 is another major GBM component and a proven target of pathogenic antibodies mediating GN in animal models. Whether laminin-521 is a target of autoimmunity in human anti-GBM disease is not yet known.MethodsA retrospective study of circulating autoantibodies from 101 patients with anti-GBM/Goodpasture’s disease and 85 controls used a solid-phase immunoassay to measure IgG binding to human recombinant laminin-521 with native-like structure and activity.ResultsCirculating IgG autoantibodies binding to laminin-521 were found in about one third of patients with anti-GBM antibody GN, but were not detected in healthy controls or in patients with other glomerular diseases. Autoreactivity toward laminin-521 was significantly more common in patients with anti-GBM GN and lung hemorrhage, compared with those with kidney-limited disease (51.5% versus 23.5%, P=0.005). Antilaminin-521 autoantibodies were predominantly of IgG1 and IgG4 subclasses and significantly associated with lung hemorrhage (P=0.005), hemoptysis (P=0.008), and smoking (P=0.01), although not with proteinuria or serum creatinine at diagnosis.ConclusionsBesides α345(IV) collagen, laminin-521 is another major autoantigen targeted in anti-GBM disease. Autoantibodies to laminin-521 may have the potential to promote lung injury in anti-GBM disease by increasing the total amount of IgG bound to the alveolar basement membranes.

PEGylated Serp-1 Markedly Reduces Pristane-Induced Experimental Diffuse Alveolar Hemorrhage, Altering uPAR Distribution, and Macrophage Invasion

Diffuse alveolar hemorrhage (DAH) is one of the most serious clinical complications of systemic lupus erythematosus (SLE). The prevalence of DAH is reported to range from 1 to 5%, but while DAH is considered a rare complication there is a reported 50–80% mortality. There is at present no proven effective treatment for DAH and the therapeutics that have been tested have significant side effects. There is a clear necessity to discover new drugs to improve outcomes in DAH. Serine protease inhibitors, serpins, regulate thrombotic and thrombolytic protease cascades. We are investigating a Myxomavirus derived immune modulating serpin, Serp-1, as a new class of immune modulating therapeutics for vasculopathy and lung hemorrhage. Serp-1 has proven efficacy in models of herpes virus-induced arterial inflammation (vasculitis) and lung hemorrhage and has also proved safe in a clinical trial in patients with unstable coronary syndromes and stent implant. Here, we examine Serp-1, both as a native secreted protein expressed by CHO cells and as a polyethylene glycol modified (PEGylated) variant (Serp-1m5), for potential therapy in DAH. DAH was induced by intraperitoneal (IP) injection of pristane in C57BL/6J (B6) mice. Mice were treated with 100 ng/g bodyweight of either Serp-1 as native 55 kDa secreted glycoprotein, or as Serp-1m5, or saline controls after inducing DAH. Treatments were repeated daily for 14 days (6 mice/group). Serp-1 partially and Serp-1m5 significantly reduced pristane-induced DAH when compared with saline as assessed by gross pathology and H&amp;E staining (Serp-1, p = 0.2172; Serp-1m5, p = 0.0252). Both Serp-1m5 and Serp-1 treatment reduced perivascular inflammation and reduced M1 macrophage (Serp-1, p = 0.0350; Serp-1m5, p = 0.0053), hemosiderin-laden macrophage (Serp-1, p = 0.0370; Serp-1m5, p = 0.0424) invasion, and complement C5b/9 staining. Extracellular urokinase-type plasminogen activator receptor positive (uPAR+) clusters were significantly reduced (Serp-1, p = 0.0172; Serp-1m5, p = 0.0025). Serp-1m5 also increased intact uPAR+ alveoli in the lung (p = 0.0091). In conclusion, Serp-1m5 significantly reduces lung damage and hemorrhage in a pristane model of SLE DAH, providing a new potential therapeutic approach.

N-Acetylcysteine Overdose: A Case Report

Background: N-Acetylcysteine (NAC) is a cost-effective antioxidant and very useful treatment for several diseases. Methods: Here we report a rare case of iatrogenic NAC overdose following the mistake in calculation of the loading dose. Results: The patient was 14 years old girl referred to a local hospital due to history of intentional ingesting about 7grams acetaminophen. The physician prescribed her 6 grams NAC as a loading dose but 42grams NAC were infused by mistake. After infusion, the patient showed signs of anaphylactic shock and then transferred to Imam Reza toxicology-unite with weakness, lethargy, extreme fatigue, nausea, and dizziness. NAC overdosing, in a short period of time, led to coagulopathy, reduced platelet count, acute renal failure and metabolic acidosis. After 24 h, the patient died. The Medical forensic examination showed minor lung hemorrhage and presence of little amount of Aluminum phosphide in tissues they did not find no vital organ hemorrhage. It is unclear related to NAC overdose, phosphine intoxication or synergic effects. Conclusion: Massive transfusion of NAC was associated with impairment of coagulation factors, intracranial hypertension, renal failure and metabolic acidosis. Thus, NAC administration should be with caution. The medical history of patients committed suicide are not always accurate and complete evaluation are recommended.

Pulmonary alveolar regrowth in an adult COVID-19 patient

We detected active alveolar regrowth in the lung of a 58-year-old COVID-19 patient who underwent lung transplantation due to severe lung hemorrhage. Specifically, immunohistological and scanning electronic microscopy analyses revealed that alveolar type II epithelial cells (AT2 cells) accumulate in response to viral pneumonia and that these AT2 cells actively proliferate and differentiate into squamous AT1-like alveolar epithelial cells. Thus, our work establishes that alveolar regrowth does occur in post-COVID-19 injury adult human lungs.