A prospective multi-institutional study of eculizumab to treat high-risk stem cell transplantation-associated TMA.

ABSTRACT: High-risk, complement mediated, untreated transplant-associated thrombotic microangiopathy (hrTMA) has dismal outcomes due to multi-organ dysfunction syndrome (MODS). The complement C5 blocker eculizumab shows promising results in hrTMA, but has not been prospectively studied in hematopoietic stem cell transplant (HCT) recipients. We performed the first multi-institutional prospective study in children and young adults to evaluate eculizumab as an early targeted intervention for hrTMA/MODS. We hypothesized that eculizumab would more than double survival in HCT recipients with hrTMA, compared to our prior study of prospectively screened, untreated hrTMAs serving as historical controls. HrTMA features (elevated terminal complement (sC5b-9) and proteinuria measured by random urine protein/creatinine ratio (≥1mg/mg)) were required for inclusion. The primary endpoint was survival at 6 six-months from hrTMA diagnosis. Secondary endpoints were cumulative incidence of MODS 6 months after hrTMA diagnosis and 1-year posttransplant survival. Eculizumab dosing included intensive loading, induction, and maintenance phases for up to 24 weeks of therapy. All 21 evaluated study subjects had MODS. Primary and secondary study endpoints were met by demonstrating survival of 71% (P < .0001) 6 months after hrTMA diagnosis and 62% 1 year after transplant. Of fifteen survivors, 11 (73%) fully recovered organ function and are well. Our study demonstrates significant improvement in survival and recovery of organ function in hrTMA using an intensified eculizumab dosing and real time biomarker monitoring. This study serves as a benchmark for planning future studies that should focus on preventative measures or targeted therapy to be initiated prior to organ injury. This trial was registered at www.clinicaltrials.gov as #NCT03518203.

Gasdermin D drives focal crystalline thrombotic microangiopathy by accelerating immunothrombosis and necroinflammation.

ABSTRACT: Thrombotic microangiopathy (TMA) is characterized by immunothrombosis and life-threatening organ failure but the precise underlying mechanism driving its pathogenesis remains elusive. In this study, we hypothesized that gasdermin D (GSDMD), a pore-forming protein that serves as the final downstream effector of the pyroptosis/interleukin-1ß (IL-1ß) pathway, contributes to TMA and its consequences by amplifying neutrophil maturation and subsequent necrosis. Using a murine model of focal crystalline TMA, we found that Gsdmd deficiency ameliorated immunothrombosis, acute tissue injury, and failure. Gsdmd-/- mice exhibited a decrease in mature IL-1ß, as well as in neutrophil maturation, ß2-integrin activation, and recruitment to TMA lesions, in which they formed reduced neutrophil extracellular traps in both arteries and interstitial tissue. The GSDMD inhibitor disulfiram dose-dependently suppressed human neutrophil pyroptosis in response to cholesterol crystals. Experiments with GSDMD-deficient, human-induced, pluripotent stem cell-derived neutrophils confirmed the involvement of GSDMD in neutrophil ß2-integrin activation, maturation, and pyroptosis. Both prophylactic and therapeutic administration of disulfiram protected the mice from focal TMA, acute tissue injury, and failure. Our data identified GSDMD as a key mediator of focal crystalline TMA and its consequences, including ischemic tissue infarction and organ failure. GSDMD could potentially serve as a therapeutic target for the systemic forms of TMA.

A case-based narrative review of pregnancy-associated atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy.

Atypical hemolytic uremic syndrome is a complement-mediated thrombotic microangiopathy caused by uncontrolled activation of the alternative complement pathway in the setting of autoantibodies to or rare pathogenic genetic variants in complement proteins. Pregnancy may serve as a trigger and unmask atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy (aHUS/CM-TMA), which has severe, life-threatening consequences. It can be difficult to diagnose aHUS/CM-TMA in pregnancy due to overlapping clinical features with other thrombotic microangiopathy syndromes including hypertensive disorders of pregnancy. However, the distinction among thrombotic microangiopathy etiologies in pregnancy is important because each syndrome has specific disease management and treatment. In this narrative review, we discuss 2 cases to illustrate the diagnostic challenges and evolving approach in the management of pregnancy-associated aHUS/CM-TMA. The first case involves a 30-year-old woman presenting in the first trimester who was diagnosed with aHUS/CM-TMA and treated with eculizumab from 19 weeks' gestation. Genetic testing revealed a likely pathogenic variant in CFI. She successfully delivered a healthy infant at 30 weeks' gestation. In the second case, a 22-year-old woman developed severe postpartum HELLP syndrome, requiring hemodialysis. Her condition improved with supportive management, yet investigations assessing for aHUS/CM-TMA remained abnormal 6 months postpartum consistent with persistent complement activation but negative genetic testing. Through detailed case discussion describing tests assessing for placental health, fetal anatomy, complement activation, autoantibodies to complement regulatory proteins, and genetic testing for aHUS/CM-TMA, we describe how these results aided in the clinical diagnosis of pregnancy-associated aHUS/CM-TMA and assisted in guiding patient management, including the use of anticomplement therapy.

De novo thrombotic microangiopathy after kidney transplantation in adults: Interplay between complement genetics and multiple endothelial injury.

De novo thrombotic microangiopathy (dnTMA), after renal transplantation may significantly alter graft outcomes. However, its pathogenesis and the role of complement alternative pathway dysregulation remain elusive. We studied all consecutive adult patients with a kidney allograft biopsy performed between January 2004 and March 2016 displaying dnTMA. Ninety-two patients were included. The median time of occurrence was 166 (IQR 25-811) days. The majority (82.6 %) had TMA localized only in the graft. Calcineurin inhibitor toxicity and antibody-mediated rejection (ABMR) were the 2 most frequent causes (54.3% and 37.0%, respectively). However, etiological factors were multiple in 37% patients. Interestingly, pathogenic variants in the genes of complement alternative pathway were significantly more frequent in the 42 tested patients than in healthy controls (16.7% vs 3.7% respectively, P < .008). The overall graft survival after biopsy was 66.0% at 5 years and 23.4% at 10 years, significantly worse than a matched cohort without TMA. Moreover, graft survival of patients with TMA and ABMR was worse than a matched cohort with ABMR without TMA. The 2 main prognostic factors were a positive C4d staining and a lower estimated glomerular filtration rate at diagnosis. DnTMA is a severe and multifactorial disease, induced by 1 or several endothelium-insulting conditions, mostly calcineurin inhibitor toxicity and ABMR.

Age, GVHD prophylaxis, and timing matter in thrombotic microangiopathy after haematopoietic cell transplantation-A secondary CIBMTR analysis.

Most reports of risk factors (RF) for developing transplant-associated thrombotic microangiopathy (TA-TMA) and death are derived from paediatric and young adult cohorts, with minimal data on differences in RF and outcomes by age. In this secondary CIBMTR analysis, we used a previously prepared dataset that included all first allogenic haematopoietic cell transplantation (HCT) recipients with malignant or non-malignant diseases between 2008 and 2016. The incidence of TA-TMA 6 months post HCT was similar in children and adults 2.1% and 2.0% respectively. Grade 2-4 acute graft-versus-host disease (aGVHD) was a significant adjusted RF for developing TA-TMA in both children and adults. In adults, additional adjusted RFs for TA-TMA included female sex and black race, and in children an unrelated donor. Compared to a calcineurin inhibitor and sirolimus, other forms of GVHD prophylaxis had an adjusted decreased risk of developing TA-TMA in adults. Adjusted RF for death in those with TA-TMA (n = 652) included age ≥18 years old, early onset of TA-TMA diagnosis (<100 days post HCT), grade 3-4 aGVHD and a performance score of <90 prior to HCT. In this cohort, the incidence of TA-TMA was similar in children and adults, and TA-TMA timing was a newly identified RF for death.

Thrombotic microangiopathy - the importance of a multidisciplinary approach.

PURPOSE OF REVIEW: The purpose of this review is to highlight the importance of a multidisciplinary thrombotic microangiopathies (TMA) Team. This goal will be accomplished through review of the complement system, discuss various causes of thrombotic microangiopathies (TMA), and aspects of their diagnosis and management. In so doing, readers will gain an appreciation for the complexity of this family of disorders and realize the benefit of a dedicated multidisciplinary TMA Team. RECENT FINDINGS: TMA causes derive from multiple specialty areas, are difficult to timely recognize, pose complex challenges, and require multidisciplinary management. Hematopoietic stem cell transplant-associated TMA (TA-TMA) and TA-TMA related multiorgan dysfunction syndrome (TA-TMA MODS) are areas of burgeoning research; use of complement testing and eculizumab precision-dosing has been found to better suppress complement activity in TA-TMA than standard eculizumab dosing. Newer tests are available to risk-stratify obstetric patients at risk for severe pre-eclampsia, whose features resemble those of TA-TMA MODS. Numerous disorders may produce TMA-like findings, and a systematic approach aids in their identification. TMA Teams elevate institutional awareness of increasingly recognized TMAs, will help expedite diagnostic and therapeutic interventions, and create pathways to future TMA-related research and facilitate access to clinical trials. SUMMARY: Establishment of a TMA-Team is valuable in developing the necessary institutional expertise needed to promptly recognize and appropriately manage patients with TMA.

Neurological involvement in hematopoietic stem cell transplantation-associated thrombotic microangiopathy.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a well-recognized serious complication of hematopoietic stem cell transplantation (HSCT). The understanding of TA-TMA pathophysiology has expanded in recent years. Dysregulation of the complement system is thought to cause endothelial injury and, consequently, microvascular thrombosis and tissue damage. TA-TMA can affect multiple organs, and each organ exhibits specific features of injury. Central nervous system (CNS) manifestations of TA-TMA include posterior reversible encephalopathy syndrome, seizures, and encephalopathy. The development of neurological dysfunction is associated with a significantly lower overall survival in patients with TA-TMA. However, there are currently no established histopathological or radiological criteria for the diagnosis of CNS TMA. Patients who receive total body irradiation (TBI), calcineurin inhibitors (CNI), and severe acute and chronic graft-versus-host disease (GVHD) are at a high risk of experiencing neurological complications related to TA-TMA and should be considered for directed TA-TMA therapy. However, the incidence and clinical manifestations of TA-TMA neurotoxicity remain unclear. Studies specifically examining the involvement of CNS in TMA syndromes are limited. In this review, we discuss clinical manifestations and imaging abnormalities in patients with nervous system involvement in TA-TMA. We summarize the mechanisms underlying TA-TMA and its neurological complications, including endothelial injury, evidence of complement activation, and treatment options for TA-TMA.

Complement-mediated thrombotic microangiopathy treated with anticomplement protein 5 therapy, a retrospective study.

BACKGROUND: Complement-mediated thrombotic microangiopathy (CM-TMA), also called atypical hemolytic uremic syndrome (aHUS), is a difficult-to-diagnose rare disease that carries severe morbidity and mortality. Anti-C5 monoclonal antibodies (aC5-mab) are standard treatments, but large studies and long-term data are scarce. Here, we report our single institution experience to augment the knowledge of CM-TMA treated with aC5-mab therapy. METHODS: We aimed to assess the short and long-term effects of aC5-mab in patients diagnosed with CM-TMA treated outside of a clinical trial. This was a retrospective study. We included all patients diagnosed with CM-TMA and treated with aC5-mab at our institution. There were no exclusion criteria. Endpoints included complete TMA response (CR) defined as normalization of hematological parameters and ≥25% improvement in serum creatinine (Cr) from baseline in patients with renal disease, relapse defined as losing the previously achieved CR, morbidity, adverse events, and survival. RESULTS: We found 28 patients with CM-TMA treated with aC5-mab. The median age was 50 years. Baseline laboratories: platelet counts 93 × 109 /L, hemoglobin 8.6 g/dL, lactate dehydrogenase 1326 U/L, serum Cr 4.7 mg/dL, and estimated glomerular filtration rate 19 mL/min. One individual was on renal replacement therapy (RRT) and 10 initiated RRT within 5 days of the first dose of aC5-mab. Genetic variants associated with CM-TMA included mutations in C3, CFB, CFH, CFHR1/3, CFI, and MCP. The mean duration of hospitalization was 24 days. The median time to initiation of aC5-mab was 10 days. Sixteen subjects received RRT. At the time of hospital discharge, 27 were alive, 14 remained on RRT, and 4 had a CR. At 6 months, 23 patients were alive, 18 continued aC5-mab, 8 remained on RRT, and 9 had a CR. At the last follow-up visit past 6 months, 20 were alive, 14 continued aC5-mab, 5 remained on RRT, 12 had a CR, and 1 was lost to follow-up. CONCLUSIONS: Our study provides real-world experience and insight into the long-term outcomes of CM-TMA treated with aC5-mab. Our findings validate that CM-TMA is an aggressive disease with significant morbidity and mortality, and confirm that aC5-mab is a relatively effective therapy for CM-TMA. Our study adds practical, real-world experience to the literature, but future research remains imperative.

Late transplant-associated thrombotic microangiopathy verified in bone marrow biopsy specimens is associated with chronic GVHD and viral infections.

OBJECTIVES: To describe late transplant-associated thrombotic microangiopathy (TA-TMA) as chronic endothelial complication in bone marrow (BM) after allogeneic hematopoietic stem cell transplantation (HSCT). METHODS: BM specimens along with conventional diagnostic parameters were assessed in 14 single-institutional patients with late TA-TMA (more than 100 days after HCST), including 11 late with history of early TA-TMA, 10 with early TA-TMA (within 100 days), and 12 non TA-TMA patients. Three non-HSCT patients served as control. The time points of BM biopsy were +1086, +798, +396, and +363 days after HSCT, respectively. RESULTS: Late TA-TMA patients showed an increase of CD34+ and von Willebrand Factor (VWF)+ microvascular endothelial cells with atypical VWF+ conglomerates forming thickened VWF+ plaque sinus in the BM compared to patients without late TA-TMA and non-HSCT. Severe chronic (p = .002), steroid-refractory GVHD (p = .007) and reactivation of HHV6 (p = .002), EBV (p = .003), and adenovirus (p = .005) were pronounced in late TA-TMA. Overall and relapse-free survival were shorter in late TA-TMA than in patients without late TA-TMA (5-year OS and RFS: 78.6% vs. 90.2%, 71.4% vs. 86.4%, respectively). CONCLUSION: Chronic allo-immune microangiopathy in BM associated with chronic, steroid-refractory GVHD and/or viral infections are key findings of late, high-risk TA-TMA, which deserves clinical attention.

Risk factors of death or chronic renal replacement therapy requirements in patients with thrombotic microangiopathies without ADAMTS-13 deficiency.

Thrombotic microangiopathy (TMA), characterized by microangiopathic hemolytic anemia, thrombocytopenia, and multisystem organ dysfunction, is a life-threatening disease. Patients with TMA who do not exhibit a severe ADAMTS-13 deficiency (defined as a disintegrin-like and metalloprotease with thrombospondin type 1 motif no. 13 activity ≥10%: TMA-13n) continue to experience elevated mortality rates. This study explores the prognostic indicators for augmented mortality risk or necessitating chronic renal replacement therapy (composite outcome: CO) in TMA-13n patients. We included 42 TMA-13n patients from January 2008 to May 2018. Median age of 41 years and 60% were female. At presentation, 62% required dialysis, and 57% warranted intensive care unit admission. CO was observed in 45% of patients, including a 9-patient mortality subset. Multivariate logistic regression revealed three independent prognostic factors for CO: early administration of eculizumab (median time from hospitalization to eculizumab initiation: 5 days, range 0-19 days; odds ratio [OR], 0.14; 95% confidence interval [CI], 0.02-0.94), presence of neuroradiological lesions (OR, 6.67; 95% CI, 1.12-39.80), and a PLASMIC score ≤4 (OR, 7.39; 95% CI, 1.18-46.11). In conclusion, TMA-13n patients exhibit a heightened risk of CO in the presence of low PLASMIC scores and neuroradiological lesions, while early eculizumab therapy was the only protective factor.

D-dimer and sinusoidal obstructive syndrome-novel poor prognostic features of thrombotic microangiopathy in children after hematopoietic cellular therapy in a single institution prospective cohort study.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a common, severe complication of allogeneic hematopoietic cellular therapy (HCT). Even when treated in many studies, morbidity and mortality rates are high. This prospective single-institution cohort study serially enrolled all allogeneic HCT recipients from August 2019-August 2022. Patients were universally screened for TA-TMA and intermediate and high-risk patients were immediately treated with eculizumab. Sub-distribution cox-proportional hazards models were used to identify sub-distribution hazard ratios (sHR)  for multi-organ dysfunction (MOD) and non-relapse-related mortality (NRM). Of 136 patients, 36 (26%) were diagnosed with TA-TMA and 21/36 (58%) developed MOD, significantly more than those without TA-TMA, (p < .0001). Of those with TA-TMA, 18 (50%) had high-risk TA-TMA (HR-TA-TMA), 11 (31%) had intermediate-risk TA-TMA (IR-TA-TMA), and 8 (22%) had standard risk (SR-TA-TMA). Twenty-six were treated with eculizumab (1/8 SR, 7/11 IR, and 18/18 HR). Elevated D-dimer predicted the development of MOD (sHR 7.6, 95% confidence interval [CI] 1.8-32.3). Children with concurrent sinusoidal obstructive syndrome (SOS) and TA-TMA had an excess risk of MOD of 34% and data supported a biologic interaction. The adjusted NRM risk was significantly higher in the TA-TMA patients (sHR 10.54, 95% CI 3.8-29.2, p < .0001), despite prompt treatment with eculizumab. Significant RF for NRM in TA-TMA patients included SOS (HR 2.89, 95% 1.07-7.80) and elevated D-dimer (HR 3.82, 95% CI 1.14-12.84). An unrelated donor source and random urine protein to creatine ratio ≥2 mg/mg were significantly associated with no response to eculizumab (odds ratio 15, 95% CI 2.0-113.6 and OR 6.5, 95% CI 1.1-38.6 respectively). TA-TMA was independently associated with NRM despite early diagnosis and treatment with eculizumab in this large pediatric transplant cohort. Prognostic implications of D-dimer in TA-TMA merit further investigation as this is a readily accessible biomarker. Concurrent SOS is an exclusion criterion of many ongoing clinical trials, but these data highlight these patients could benefit from novel therapeutic approaches. Multi-institutional clinical trials are needed to understand the impact of TA-TMA-targeted therapies.

Outcomes of Early Thrombotic Microangiopathy in Renal Transplantation.

BACKGROUND: Alternate complement dysregulation postrenal transplantation can result in thrombotic microangiopathy (TMA). There is a scarcity of data regarding outcomes based on the timing of TMA post-transplant, coupled with a lack of follow-up biopsy findings post TMA diagnosis. This study aims to assess allograft and patient outcomes in individuals developing early TMA, defined within 4 months post-transplantation, and explore any differences in follow-up surveillance biopsies compared to a non-TMA group. DESIGN: This is a single center retrospective study between January 1, 2002 and October 10, 2019. Patients who developed TMA within 4 months post-transplantation were compared to a propensity matched non-TMA group. RESULTS: Thirty-one patients developed TMA within 4 months of renal transplantation. Index TMA biopsy featured noticeable glomerular, and vascular lesions along with acute tubular injury. Four-month surveillance biopsy showed significant glomerulitis, transplant glomerulopathy and chronic interstitial fibrosis as compared to non-TMA group. However, at 1 year, these differences were no longer significant. There was no significant difference in patient survival (TMA vs. non-TMA, p = 0.083); however, death censored graft survival was significantly lower in the TMA group (p < 0.001). TMA patients had a significantly lower estimated glomerular filtration rate at 4 months and at 1 year as compared to the non-TMA group. CONCLUSION: Early onset TMA post renal transplant leads to decreased renal function and lower graft survival. Early recognition and prompt treatment may help in reducing the adverse outcomes.

Eculizumab as Salvage Treatment for Thrombotic Microangiopathy After Lung Transplantation.

BACKGROUND: Thrombotic microangiopathy (TMA) is a rare complication after lung transplantation (LT) that has seldom been characterized in detail. Recent evidence has linked TMA other than primary atypical hemolytic uremic syndrome (aHUS) with hyperactivation of the complement alternative pathway. The focus of this investigation was to analyze the treatment response with eculizumab in TMA after LT. METHODS: Case series where we have studied 11 patients with TMA after LT from 2 Spanish tertiary healthcare centers. Clinical data and response rates to eculizumab are provided. RESULTS: The main indication for lung transplant was chronic obstructive pulmonary disease (COPD) (36%) and most cases (82%) received bilateral LT. The median time to TMA diagnosis was 11.6 months (4.7-28.9) and the TMA trigger in the majority of cases (73%) was immunosuppressive drugs. Platelet and hemoglobin nadir were 58 × 103/µL (24-108) and 7.7 g/dL (7.1-7.9), respectively. All cases presented acute kidney injury (AKI) with a median creatinine of 4 mg/dL (3.2-4.8) and 54.5% required acute dialysis. Eculizumab was started after a median time of 8 days (6-14) with a median duration of 3 weeks (2-8). Complete TMA response was observed in 7 (63.6%) cases and hematologic response in 10 (90.9%). The time to hematologic and renal response was 23 days (13-29) and 28 days (14-46), respectively. CONCLUSIONS: TMA after LT is infrequent but potentially devastating. Our findings suggest that short cycles of eculizumab may be effective for severe TMA after LT.

Endoscopic manifestation of intestinal transplant-associated microangiopathy after stem cell transplantation.

BACKGROUND: Endoscopic features of intestinal transplant-associated microangiopathy (iTAM) have not been comprehensively investigated. This study aimed to examine the endoscopic characteristics of patients diagnosed with iTAM. METHODS: This retrospective analysis included 14 patients pathologically diagnosed with iTAM after stem cell transplantation for hematolymphoid neoplasms (n = 13) or thalassemia (n = 1). The sex, age at diagnosis, endoscopic features, and prognosis of each patient were assessed. Serological markers for diagnosing transplant-associated thrombotic microangiopathy were also evaluated. RESULTS: The mean age at the time of iTAM diagnosis was 40.2 years. Patients diagnosed based on the pathognomonic pathological changes of iTAM presented with diverse symptoms at the times of endoscopic examinations, including diarrhea (n = 10), abdominal pain (n = 5), nausea (n = 4), appetite loss (n = 2), bloody stools (n = 2), abdominal discomfort (n = 1), and vomiting (n = 1). At the final follow-up, six patients survived, while eight patients succumbed, with a median time of 100.5 days (range: 52-247) post-diagnosis. Endoscopic manifestations included erythematous mucosa (n = 14), erosions (n = 13), ulcers (n = 9), mucosal edema (n = 9), granular mucosa (n = 9), and villous atrophy (n = 4). Erosions and/or ulcers were primarily observed in the colon (10/14, 71%), followed by the ileum (9/13, 69%), stomach (4/10, 40%), cecum (5/14, 36%), duodenum (3/10, 30%), rectum (4/14, 29%), and esophagus (1/10, 10%). Cytomegalovirus infection (n = 4) and graft-versus-host disease (n = 2) coexisted within the gastrointestinal tract. Patients had de novo prolonged or progressive thrombocytopenia (6/14, 43%), decreased hemoglobin concentration (4/14, 29%), reduced serum haptoglobin level (3/14, 21%), and a sudden and persistent increase in lactate dehydrogenase level (2/14, 14%). Peripheral blood samples from 12 patients were evaluated for schistocytes, with none exceeding 4%. CONCLUSIONS: This study provides a comprehensive exploration of the endoscopic characteristics of iTAM. Notably, all patients exhibited erythematous mucosa throughout the gastrointestinal tract, accompanied by prevalent manifestations, such as erosions (93%), ulcers (64%), mucosal edema (64%), granular mucosa (64%), and villous atrophy (29%). Because of the low positivity for serological markers of transplant-associated thrombotic microangiopathy in patients with iTAM, endoscopic evaluation and biopsy of these lesions are crucial, even in the absence of these serological features.

Thrombotic Microangiopathy After Hematopoietic Stem Cell and Solid Organ Transplantation: A Review for Intensive Care Physicians.

Intensive care physicians may assume the primary care of patients with transplant-associated thrombotic microangiopathy (TA-TMA), an uncommon but potentially critical complication of hematopoietic stem cell transplants (HSCTs) and solid organ transplants. TA-TMA can have a dramatic presentation with multiple organ dysfunction syndrome (MODS) associated with high morbidity and mortality. The typical presenting clinical features are hemolytic anemia, thrombocytopenia, refractory hypertension, proteinuria and worsening renal failure. Intestinal involvement, with abdominal pain, nausea and vomiting, gastrointestinal bleeding, and ascites are also common. Cardiopulmonary involvement may develop from various causes including pulmonary arteriolar hypertension, pleural and pericardial effusions, and diffuse alveolar hemorrhage. Due to other often concurrent complications after HSCT, early diagnosis and effective management of TA-TMA may be challenging. Close collaboration between ICU and transplant physicians, along with other relevant specialists, is needed to best manage these patients. There are currently no approved therapies for the treatment of TA-TMA. Plasma exchange and rituximab are not recommended unless circulating factor H (CFH) antibodies or thrombotic thrombocytopenic purpura (TTP; ADAMTS activity < 10%) are diagnosed or highly suspected. The role of the complement pathway activation in the pathophysiology of TA-TMA has led to the successful use of targeted complement inhibitors, such as eculizumab. However, the relatively larger studies using eculizumab have been mostly conducted in the pediatric population with limited data on the adult population. This review is focused on the role of intensive care physicians to emphasize the clinical approach to patients with suspected TA-TMA and to discuss diagnosis and treatment strategies.

Post-COVID-19 complement-mediated TMA: A case report.

Systemic COVID-19 disease is associated with a variety of organ involvement in infected patients. A rarely reported complication is the induction of complement-mediated thrombotic microangiopathy (TMA). TMA is an extremely rare pathological condition that results in thrombosis in capillaries and small arterioles, due to an endothelial injury. It is often combined with thrombocytopenia, Coombs-negative hemolytic anemia, and end-organ damage. This case involves a patient who was admitted to our hospital for the purpose of diagnosis and treatment of acute kidney injury (AKIN 3) with severe proteinuria after a preceding SARS-CoV-2 infection. A 77-year-old male patient had COVID-19 pneumonia in January 2021 with the need of high-flow oxygen therapy in the intensive care unit. In March 2021, he was hospitalized again due to elevated serum creatinine levels and proteinuria. The patient exhibited normal vital parameters. A renal biopsy showed severe TMA. A diagnosis of COVID-19-associated TMA was made, and treatment with high-dose glucocorticoid therapy and plasma exchange was initiated. Additionally, therapy with eculizumab was established. Unfortunately, the kidney failure was initially progressive, so that hemodialysis (HD) was temporarily necessary. In May 2021, kidney function recovered to an estimated glomerular filtration rate of ~ 30 mL/min/1.73m2 corresponding to chronic kidney disease stage 3bA3 - 4A3. COVID-19-associated TMA is an extremely rare disease. TMA may be a possible long-term complication with the risk of end-stage renal disease if not properly diagnosed and treated.

To bite the hand that feeds you: A case of thrombotic microangiopathy due to Tiger snake bite.

This report details the case of a 51-year-old man with a Tiger snake bite who developed systemic envenomation, coagulopathy and thrombotic microangiopathy (TMA) requiring renal replacement therapy. He received plasma exchange as additional therapy while awaiting confirmation of the cause of the TMA. We discuss clinical decision making in detection of systemic envenomation and management of the rare complication of TMA, as well as current Australian guidelines around antivenom administration. This is the fourth known documented case of TMA from a Tiger snake bite in Australia.

Complement-mediated thrombotic microangiopathy on a background of Alport syndrome: A case report.

Here we present a case of complement-mediated thrombotic microangiopathy (TMA) in a patient who has a background of Stage 5 chronic kidney disease secondary to Alport syndrome. We explain our approach to the diagnosis of TMA, especially the reliance on non-renal manifestations of TMA and the role of kidney biopsy given there was a background of advanced kidney impairment at baseline.

Renal thrombotic microangiopathy is associated with poor renal survival in children with immunoglobulin A nephropathy.

AIM: The aim of this study was to examine the clinical and pathological characteristics as well as the prognosis of immunoglobulin A nephropathy (IgAN) accompanied by renal thrombotic microangiopathy (rTMA) in paediatric patients. METHODS: After balancing epidemiological characteristics and pathological types between groups, 427 patients (rTMA group: 23, non-rTMA group: 46) were included. The clinical and pathological features, prognosis and clinical risk factors of the two groups were analysed. RESULTS: IgAN-rTMA children showed more severe clinical and pathological manifestations. The findings from the logistic regression analysis indicated that hypercellularity 1 (E1) (HR: 0.805, 95% CI: 0.763 ~ 1.452, P = .016), endocapillary proliferation (HR: 1.214, 95% CI: 0.093 ~ 4.815, P = .025) and C3 staining (HR: 7.554, 95% CI: 2.563 ~ 15.729, P = .037) were the risk factors for rTMA in children with IgAN. The renal survival in rTMA group was lower than non-rTMA group (χ2 = 18.467, P = .000). Cox regression analysis showed that E1 (HR: 7.441, 95% CI: 1.095 ~ 10.768, P = .037), C3 disposition (HR: 3.414, 95% CI: 0.834 ~ 11.578, P = .027) and rTMA (HR: 8.918, 95% CI: 1.032 ~ 16.754, P = .041) were identified as independent risk factors for the development of end-stage renal disease (ESRD). CONCLUSION: The presence of rTMA had a significant impact on the severity and prognosis of IgAN. And rTMA has been identified as an independent risk factor for the development of renal failure in children diagnosed with IgAN.

Renal manifestations in adult-onset Still's disease: a systematic review.

OBJECTIVE: We aimed to review the literature on the clinical presentation, renal pathology, treatment, and outcome of renal manifestations in adult-onset Still's disease (AOSD). METHODS: We used PRISMA guidelines for our systematic review and included all English-language original articles from inception till September 15, 2023, on AOSD and kidney involvement in any form. Data on patient demographics, diagnostic criteria, clinical presentation, renal pathology, treatment employed including dialysis, outcome, cause of death were collected and analyzed. RESULTS: The median age at the diagnosis of renal issues was 37, with a higher prevalence among females (58.1%). Among the cases, 28 experienced renal problems after being diagnosed with AOSD, 12 had simultaneous diagnoses of renal issues and AOSD, and in 4 cases, renal problems appeared before AOSD diagnosis. Out of the 44 cases, 36 underwent renal biopsy, revealing various pathology findings including AA amyloidosis (25%), collapsing glomerulopathy (11.4%), thrombotic microangiopathy (TMA) (11.4%), IgA nephropathy (9.1%), minimal change disease (6.8%), and others. Some cases were clinically diagnosed with TMA, proximal tubular dysfunction, or macrophage activation syndrome-related acute kidney injury. Treatment approaches varied, but glucocorticoids were commonly used. Renal involvement was associated with increased mortality and morbidity, with 6 out of 44 patients passing away, 4 progressing to end-stage renal disease (ESRD), and data on 2 cases' outcomes not available. CONCLUSION: Renal manifestations in AOSD are diverse but rarely studied owing to the rarity of the disease. Studies with larger data would be essential to study further on the pathogenesis and implications.