Microangiopathic Hemolytic Anemia Research Articles

Association of thrombotic microangiopathy with interferon therapy for hepatitis B: a case report

BackgroundThrombotic microangiopathy is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ injury. The pathological features include vascular damage that is manifested by arteriolar and capillary thrombosis with characteristic abnormalities in the endothelium and vessel wall. Thrombocytopenia is one of the common adverse effects of interferon therapy. However, a more serious but rare side effect is thrombotic microangiopathy.Case presentationWe report the case of a 36-year-old Asian male patient with clinical manifestations of hypertension, blurred vision, acute renal failure, thrombocytopenia, and thrombotic microangiopathy. Renal biopsy showed interstitial edema with fibrosis, arteriolar thickening with vitreous changes, and epithelial podocytes segmental fusion. Immunofluorescence microscopy showed C3(+), Ig A(+) deposition in the mesangial region, which was pathologically consistent with thrombotic microangiopathy renal injury and Ig A deposition. The patient had a history of hepatitis B virus infection for more than 5 years. Lamivudine was used in the past, but the injection of long-acting interferon combined with tenofovir alafenamide fumarate was used since 2018. The comprehensive clinical investigation and laboratory examination diagnosed the condition as thrombotic microangiopathy kidney injury caused by interferon. After stopping interferon in his treatment, the patient’s renal function partially recovered after three consecutive therapeutic plasma exchange treatments and follow-up treatment without immunosuppressant. The renal function of the patient remained stable.ConclusionsThis report indicates that interferon can induce thrombotic microangiopathy with acute renal injury, which can progress to chronic renal insufficiency.

Atypical hemolytic uremic syndrome during induction chemotherapy in neuroblastoma, a rare phenomenon or common congenital predisposition?

Atypical hemolytic uremic syndrome (aHUS) is a complement-mediated thrombotic microangiopathy sometimes associated with germline variants in genes of the complement system. Clinical findings of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury arise due to aberrant complement protein activation in the circulation. A 13-month-old boy with metastatic neuroblastoma (NB) developed aHUS during his first cycle of induction chemotherapy with germline testing revealing a complement factor H(CFH) gene mutation, currently classified as a variant of uncertain significance (VUS). Now he is in disease remission after successful complement blockade therapy, thus highlighting a unique presentation of aHUS in a patient with newly diagnosed NB.

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.

A fatal case of diphtheria endocarditis complicated with microangiopathic haemolytic anaemia and multiple septic emboli causing brain infarctions in a patient with smear-positive pulmonary tuberculosis

ndocarditis due to non-toxigenic Corynebacterium diphtheriae is emerging as a rare subtype of endocarditis, with limited case reports available. It has been related to the presence of prosthetic valves, underlying cardiac disease, or the use of injectable drugs. We present a fatal case of endocarditis due to non-toxigenic Corynebacterium diphtheriae in a native aortic valve complicated with microangiopathic haemolytic anaemia and multiple septic emboli in the brain causing infarctions in a patient with smear-positive pulmonary tuberculosis who was on anti-tuberculosis therapy (ATT). Following blood culture positivity and suggestive evidence from the echocardiogram, the patient was initially treated with intravenous ceftriaxone and vancomycin along with ATT. Evolution was assessed by sterile blood cultures post therapy and follow-up transthoracic echocardiograms (TTE) and transesophageal echocardiograms (TOE). Even though the patient's condition improved with intravenous antibiotic therapy, it later deteriorated with disseminated intravascular coagulation and liver injury followed by prerenal acute kidney injury and multiple septic emboli causing the patient’s demise, which may have necessitated surgical interventions.

Immune Thrombotic Thrombocytopenic Purpura: Pathophysiology, Diagnosis, Therapy and Open Issues.

Immune thrombotic thrombocytopenic purpura (iTTP) is a life-threatening thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and ischemic end-organ injury due to microvascular platelet-rich thrombi. iTTP pathophysiology is based on a severe ADAMTS13 deficiency, the specific von Willebrand factor (vWF)-cleaving protease, due to anti-ADAMTS13 autoantibodies. Early diagnosis and treatment reduce the mortality. Frontline therapy includes daily plasma exchange (PEX) with fresh frozen plasma replacement and immunosuppression with corticosteroids. Caplacizumab has recently been added to frontline therapy. Caplacizumab is a nanobody that binds to the A1 domain of vWF, blocking the interaction of ultra-large vWF multimers with the platelet and thereby preventing the formation of platelet-rich thrombi. Caplacizumab reduces mortality due to ischemic events, refractoriness, and exacerbations after PEX discontinuation. Until now, the criteria for response to treatment mainly took into account the normalization of platelet count and discontinuation of PEX; with the use of caplacizumab leading to rapid normalization of platelet count, it has been necessary to redefine the response criteria, taking into account also the underlying autoimmune disease. Monitoring of ADAMTS13 activity is important to identify cases with a low value of activity (<10IU/L), requiring the optimization of immunosuppressive therapy with the addition of Rituximab. Rituximab is effective in patients with refractory disease or relapsing disease. Currently, the use of Rituximab has expanded, both in frontline treatment and during follow-up, as a pre-emptive approach. Some patients do not achieve ADAMTS13 remission following the acute phase despite steroids and rituximab treatment, requiring an individualized immunosuppressive approach to prevent clinical relapse. In iTTP, there is an increased risk of venous thrombotic events (VTEs) as well as arterial thrombotic events, and most occur after platelet normalization. Until now, there has been no consensus on the use of pharmacological thromboprophylaxis in patients on caplacizumab because the drug is known to increase bleeding risk.

Idiopathic Atypical Hemolytic Uremic Syndrome: A Case Report

Thrombotic microangiopathies (TMAs) are a spectrum of disorders characterized by hemolytic anemia, thrombocytopenia, and formation of microthrombi in blood vessels, resulting in tissue injury due to compromised blood flow. This classical presentation of TMA is characterized by varying degrees of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and ischemic damage to the brain, kidneys, heart, lungs and GI tract. TMA can be classified into different types based upon the etiology and pathogenesis like thrombotic thrombocytopenic purpura (TTP), Complement mediated TMA (atypical Hemolytic uremic syndrome [aHUS]), infection associated TMA (shiga toxin producing E.coli, streptococcus pneumoniae) secondary to systemic causes like malignancy, autoimmune diseases and medications. In this article, we discuss a case of a female diagnosed with aHUS with acute kidney injury complicated by hypertension and severe anemia. As aHUS is known to be associated with high mortality and morbidity, prompt recognition of aHUS is crucial for efficient treatment. Here we have discussed the clinical presentation, histopathological hallmarks, and the diagnostic approach for TMA.

#626 C3 glomerulonephritis and thrombotic microangiopathy—a prospective observational study

Abstract Background and Aims Complement mediated TMA (cTMA) and complement component 3 glomerulonephritis (C3GN) are two distinct complement mediated kidney diseases. cTMA is characterized by acute kidney injury, thrombocytopenia and microangiopathic hemolytic anemia. C3GN results from uncontrolled activation of the alternative complement pathway leading to the deposition of C3 in the glomerulus. We sought to describe characteristic differences between these two conditions in a large cohort of patients from Bengaluru, India. Method All cases of cTMA and kidney biopsy proven C3GN from 2019-2022 at a tertiary care centre in India were included. Patients with C3GN had persistently low C3 for more than 12 weeks and no identifiable source of infection. All patients received protocolized medical therapy; patients with C3GN were treated with steroids and cyclophosphamide, while those with complement mediated TMA received plasmapheresis in addition to cyclophosphamide and steroids. Protocolised medical management (renin-angiotensin-aldosterone inhibition and diuretics) was provided in both the cases. Demographic, clinical and lab parameters were reported and compared. Results A total of 25 cTMA cases and 19 C3GN cases were included in the study. Both C3GN (52.7%) and cTMA (48%) were more common in males. Patients with C3GN typically presented in the third decade of life while cTMA cases presented in the fourth decade. Secondary hypertension was common in the cTMA group (92% vs 78.9%, compared to C3GN). 60% of patients with cTMA had either recent or current infection compared to 21.1% of C3GN patients (P = 0.04). The majority of cTMA cases had IFTA of &amp;lt;25% (84%) compared to C3GN (57.9%) although this was not statistically significant. Both C3GN and cTMA most commonly presented as rapidly progressive kidney failure and acute kidney injury. A total of 76% of patients in the cTMA group required kidney replacement therapy as compared to 47.4% in the C3GN group (P = 0.009). 44% of cTMA cases had anti factor H antibody positivity compared to 15.8% of C3GN patients (P = 0.02). Finally, 44% of cases in cTMA group had complete recovery compared to 47.4% in C3GN group at the end of 2.8 years of followup. Conclusion Although both conditions result from dysregulation of the alternative pathway, there are several important clinical characteristic differences between patients with cTMA and C3GN including presence or absence of secondary hypertension, concurrent infection, anti-factor H positivity and requirement of kidney replacement therapy. This information may be helpful to inform both diagnosis and prognosis for patients presenting with a complement mediated kidney disease.

#2262 Renal outcomes of postpartum atypical hemolytic uremic syndrome treated with plasma exchange

Abstract Background and Aims Postpartum acute kidney injury (AKI) with features of thrombotic microangiopathy (TMA) are particularly challenging and complex cases. Causes include Preeclampsia (PE), hemolysis, elevated liver enzymes and low platelet count syndrome (HELLP) and atypical hemolytic uremic syndrome (aHUS). In a limited resource setting, it is difficult to diagnose such cases with more than standard blood tests. Therapeutic Plasma exchange (TPE) is the only available option for treatment in the absence of complement inhibitors. This study evaluates renal outcomes in patients with aHUS treated with plasma exchange. Method This is a single centre observational study conducted in a Tertiary Obstetric Intensive Care unit. The data of women who were admitted with postpartum AKI from January 2021 to October 2023 was retrospectively collected and analyzed. We used the following criteria to diagnose postpartum atypical HUS (Serum creatinine ≥1.9 mg/dL, Lactate dehydrogenase (LDH) ≥1832 U/L, or serum creatinine ≥1.9 mg/dL in combination with LDH ≥600 U/L) [1]. Inclusion criteria include women older than 18 yrs with microangiopathic hemolytic anaemia, schistocytes on peripheral blood film, negative direct antiglobulin test (DAT) and platelet count &amp;lt;100 /mm3.Lack of improvement of kidney functions and hemolysis 72 hours after delivery. Patients with sepsis, disseminated intravascular coagulopathy (DIC), postpartum hemorrhage (PPH) and chronic kidney disease were excluded. We identified 10 patients with postpartum aHUS. Peak creatinine, LDH, AST and Nadir platelet count and hemoglobin were recorded. Patients were followed up in the nephrology outpatient clinic. Results Fifty-two patients developed postpartum AKI in the study period. Ten patients (19%) were diagnosed with aHUS according to the above-mentioned criteria. Mean age was 24.5 ± 6.9 yrs. Median peak creatinine 5.1 (2.6-7) mg/dl, LDH 1950 (612-4000) U/L, AST 246 (150-699) U/L. Median nadir hemoglobin 7.25 (6-8.2) g/dl and platelets 57 (41-95)/mm3. All 10 patients received 3 to 6 sessions of TPE guided by platelets and LDH levels. All patients required at least 3 sessions of hemodialysis. Eight patients received TPE with plasma filter and 2 had centrifugal TPE (due to lack of plasma filters). Two patients died during ICU admission. Two months after discharge 4 (50%) patients had partial recovery of kidney functions average creatinine (3.5 ± 0.8) mg/dl and four (50%) remained dialysis dependent. Six of these patients had kidney biopsies, three biopsies showed a picture of thrombotic microangiopathy and two showed thrombotic microangiopathy with renal cortical necrosis. The other patient was lost to follow up. Conclusion It is difficult to diagnose and treat aHUS in a resource limited setting. The available treatment with therapeutic plasma exchange has poor renal outcomes.

#271 The nexus between TMA/TTP, MIS-C, and SLE

Abstract Background and Aims The long-term complications of COVID-19 infection &amp; Multisystem inflammatory syndrome in children (MIS-C) on immune system are still unknown, however there're reports on development of autoimmune disease, highlighting their immune-related nature. MIS-C can induce Thrombotic Microangiopathy (TMA), by inducing endothelial dysfunction, platelet activation, &amp; microthrombi formation, whereas SLE induces TMA/Thrombotic thrombocytopenic purpura (TTP), with ADAMTS13 activity &amp;lt; 10%, or 2ry TMA with ADAMTS13 activity ≥ 10%, where SLE/TTP carries a bad prognosis. Method Our case is one of its kind, where a 12-year- old girl, who was previously infected with SARS-CoV-2, presented with new-onset SLE, associated MIS-C &amp; 2ry TMA/TTP. She presented with convulsions, oliguria, heart failure, impaired kidney function, microangiopathic hemolytic anemia, pancytopenia, highly elevated LDH, &amp; was diagnosed as TMA. Results COVID serology was +ve for IgG, &amp; -ve for IgM, &amp; -ve SARS-CoV-2 PCR, a diagnosis of MIS-C was postulated. Further investigations revealed low C3, C4, +ve ANA, anti-ds DNA &amp; anti-phospholipid Antibodies. Brain imaging showed left cerebellar calcification. Echocardiography showed biventricular dysfunction with EF 30%, where the diagnosis of SLE according to Euler/ACR criteria was confirmed, with 2ry TMA. Emergency hemodialysis, PRBCs transfusion, pulse steroid with total plasma exchange (TPE), were initiated without marked improvement. Rituximab was started on 4th day, but she had generalized convulsion, arrythmia &amp; sudden death occurred. Results of ADAMTS13 activity was &amp;lt; 1%, with +ve autoantibodies, so diagnosis of TMA/TTP was confirmed. Conclusion TMA are a diverse group of disorders that causes microvasculature thrombosis, which is inherited, or acquired 2ry to SLE or COVID-19 infection, where high index of suspicions should be raised for early diagnosis and prompt management, meanwhile COVID-19 infection can induce the development of autoimmune diseases. Herein we raise the question of cause of TMA/TTP, was it 2ry only SLE, or to the previous COVID-19 infection &amp; MIS-C, and if this SLE itself was 2ry also to the previous COVID infection, or all it was by chance?

#2989 Superposition of atypical hemolytic syndrome and tubulointerstitial nephritis, a case report

Abstract Background and Aims Hemolytic uremic syndrome is a heterogeneous group of diseases that have in common the development of thrombotic microangiopathy with diffuse endothelial damage, resulting in the classic triad composed of microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury, on the other hand, tubulointerstitial nephritis is characterized by the presence of inflammatory infiltrates and edema and of the interstitial compartment that causes deterioration of renal function. Method The following is the case of a patient with acute kidney injury of etiology composed of thrombotic microangiopathy and tubulointerstitial nephritis. Results 27-year-old female patient without significant history, began 3 weeks prior to admission with fever, chills, asthenia, nausea and vomiting of food content, approximately 5 episodes per day for 3 days, presenting intermittent episodes of jaundice of the mucous membranes and conjunctivae, with progressive increase of the symptoms to the point of preventing daily activities, she was admitted for study, detecting hemolytic anemia, thrombocytopenia and severe acute kidney injury, so she was referred to our center was decided for evaluation by Nephrology and Hematology. In our institution, urinary sediment with dysmorphic erythrocytes was documented, peripheral blood smear without the presence of schistocytes, positive Coombs 4 crosses, renal ultrasound with data compatible with acute kidney injury, and supportive management with hemodialysis was initiated. Due to suspicion of autoimmune glomerulopathy, an autoantibody panel was indicated with negative antinuclear antibodies, anti-double-stranded DNA, anti-Sm, anti-B2 glycoproteins, and lupus anticoagulant, with normal complement values, stool culture, and negative stool Shiga protein assay, angiotomography of the abdomen where the integrity of renal circulation is verified, so renal biopsy with immunohistochemical study is performed, finding data compatible with thrombotic microangiopathy and acute tubulointerstitial nephritis. The patient is maintained with supportive care, steroids and hemodialysis as required with progressive recovery of renal function until renal replacement therapy is weaned, she is discharged with a steroid regimen and clinical nephrology and hematology follow-up. Conclusion Acute kidney injury is a complex and multifactorial entity, which requires a comprehensive approach in order to identify the best therapeutic option and to offer a better outcome in the renal function of these patients. The case of our patient presented a sudden deterioration of renal injury composed of two entities with different pathophysiology, demonstrating that, although the approach to these two entities converge in certain etiologies, it is imperative that the clinician does not forget the wide variety of factors that contribute to the development of renal injury.

Thrombotic microangiopathy (TMA) associated with pregnancy: role of the clinical laboratory in differential diagnosis

Abstract Objectives Thrombotic microangiopathy (TMA) is characterized by thrombocytopenia, microangiopathic hemolytic anemia and target organ damage. Pregnancy is associated with several forms of TMA, including preeclampsia (PE), HELLP syndrome, thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). When HUS is secondary to a deregulation of the alternative complement pathway, it is known as atypical HUS (aHUS). Differential diagnosis is challenging, as these forms share clinical characteristics. However, early diagnosis is crucial for a specific treatment to be established and improve prognosis. Case presentation We present the case of a 43 year-old primiparous woman admitted to hospital for an urgent C-section at 33 gestational weeks due to a diagnosis of severe preeclampsia and fetal distress. In the immediate postpartum, the patient developed acute liver failure and anuric renal failure in the context of the HELLP syndrome, anemia, thrombocytopenia, arterial hypertension (HTN) and neurological deficit. TMA study and differential diagnosis confirmed pregnancy-associated aHUS. Treatment with eculizumab was initiated, with good response and progressive improvement of clinical and analytical parameters. Conclusions aHUS is a rare multifactorial disease that used to be associated with high mortality rates before the advent of eculizumab. Due to challenging diagnosis, the clinical laboratory plays a major role in the differential diagnosis and management of the disease.

Refractory Anemia and Pigment Nephropathy in a Case with Mitral Prosthesis

We present a case of refractory microangiopathic hemolytic anemia with pigment nephropathy in a case of paravalvular leak, emphasizing an early detailed evaluation of anemia in a patient with a prosthetic valve despite having an alternative etiology, which is completely reversible if treated adequately.

Thrombotic Microangiopathy in Solid Organ Transplantation

Thrombotic Microangiopathy (TMA) is a syndrome characterized by microangiopathic hemolytic anemia (MAHA) and thrombocytopenia. The presence of schistocytes on peripheral smear, a negative Coombs test, elevated lactate dehydrogenase, increased reticulocyte count and low haptoglobin are often the clues for MAHA. The microvascular process often targets vasculature in kidneys, brain, gastrointestinal system, heart, and skin. A timely diagnosis and treatment are often crucial to prevent severe end organ damage and death. TMA is classified into primary and secondary forms. Primary TMA includes TTP and complement mediated or atypical hemolytic uremic syndrome (aHUS), often related to a mutation or deficiency and clinically expressed in the setting of a precipitant condition. Secondary TMA is a manifestation of underlying disorder and can occur in clinical scenarios associated with autoimmune disease, malignancy, infections, SOT (Solid Organ Transplant), pregnancy, HSCT (Hematopoietic Stem Cell Transplantation), medications, or methylmalonic acidemia. Transplant associated TMA (TA-TMA) can be complement mediated or aHUS and could be related to the ischemic reperfusion injury, induction regimen, calcineurin inhibitor (CNI) use, mammalian target of rapamycin (MTOR) inhibitor use, or could be infection related. Cost, access, and turnaround time are often the limitations for certain TTP and complement specific testing. Treatment should not be delayed while waiting for such tests. Treatment must be individualized based on the underlying cause of TMA. Terminal complement blockade utilizing monoclonal antibodies directed against C5 complement is the treatment for complement mediated TMA. C5 inhibitors have also been used successfully in treatment of secondary HUS cases where, unlike aHUS, defects in complement cannot be demonstrated. Such treatment has demonstrated improvement in renal function, MAHA and platelet counts.

A case of hemolytic-uremic syndrome that developed in a 5-year-old child due to acute intestinal infection with hemocolitis

Purpose: to demonstrate a case of hemolytic-uremic syndrome (HUS) in a 5-year-old child associated with an acute intestinal infection of unknown etiology, occurring with hemocolitis. Results. During clinical and laboratory observation, edematous syndrome, oligoanuria, severe microangiopathic hemolytic anemia (decrease in hemoglobin, haptoglobin, increase in Lactate dehydrogenase), thrombocytopenia, consumption coagulopathy, hyperazotemia, acute kidney injury (AKI) according to KDIGO grade 2 (increase in serum creatinine more than 2 times) developed. As part of complex therapy with balanced crystalloid solutions with stimulation of diuresis, it was possible to achieve rapid restoration of diuresis on the 2nd day of hospital stay without the use of renal replacement therapy; he also received antibiotics, anticoagulants, transfusion of fresh frozen plasma and red blood cell suspension. Hyperazotemia was relieved within 5 days, as was thrombocytopenia. The follow-up recovery of renal function showed.

Aetio-pathological profile of anaemic children belonging to upper socioeconomic society in a tertiary care hospital of North India

Introduction: Anaemia is a major public health problem especially in the preschool age group. It is rampant even in children of upper and middle classes of the society.Objectives: To study the aetio-pathology of anaemia in children belonging to upper and upper middle socio-economic scale and to correlate it with their nutritional status. Method: It was a cross-sectional descriptive study on 165 preschool children aged 6-59 months who presented with pallor on clinical examination. They were advised to undergo a complete haemogram and further specific tests as required. Results: The most common cause of anaemia was nutritional, including iron deficiency (92%), combined iron and B12 deficiency (2%) and isolated B12 deficiency (0.6%). Thalassaemia was the next common cause (3%) followed by B-acute lymphoblastic leukaemia (1%) and microangiopathic haemolytic anaemia (0.6%). Maternal education and nutritional awareness had positive correlation with anaemia. Majority of children were normally nourished despite being anaemic, However, undernourished children were more severely anaemic. Conclusions: Nutritional anaemia is the commonest cause of anaemia even in children belonging to higher socio-economic classes.

Complement Blockade, a New Therapeutic Approach in Malignant Hypertension

Abstract Atypical hemolytic uremic syndrome (aHUS) represents a major challenge due to its rare nature and severe impact on patients, characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. This paper describes the case of a 41-year-old patient diagnosed with aHUS in the context of malignant arterial hypertension and severe renal impairment, manifested by anuria and significant azotemic retention syndrome. The complex management of the case, including the use of Eculizumab, a complement inhibitor, highlighted significant therapeutic benefits, especially in improving hematological parameters. Despite a positive response, challenges related to dosing, monitoring treatment efficacy, and maintaining remission without relapses emphasize the need for adapted therapeutic strategies and a deeper understanding of the disease mechanisms. This case also highlights the importance of individualized approaches and consideration of the possible benefits of dose adjustments based on specific clinical and pharmacological parameters, as well as continuous evaluation of treatment efficacy and safety, in the context of such a variable and potentially devastating syndrome as aHUS.

The role of anticomplement therapy in the management of the kidney allograft.

As the number of patients living with kidney failure grows, the need also grows for kidney transplantation, the gold standard kidney replacement therapy that provides a survival advantage. This may result in an increased rate of transplantation from HLA-mismatched donors that increases the rate of antibody-mediated rejection (AMR), which already is the leading cause of allograft failure. Plasmapheresis, intravenous immunoglobulin therapy, anti-CD20 therapies (i.e., rituximab), bortezomib and splenectomy have been used over the years to treat AMR as well as to prevent AMR in high-risk sensitized kidney transplant recipients. Eculizumab and ravulizumab are monoclonal antibodies targeting the C5 protein of the complement pathway and part of the expanding field of anticomplement therapies, which is not limited to kidney transplant recipients, and also includes complement-mediated microangiopathic hemolytic anemia, paroxysmal nocturnal hemoglobinuria, and ANCA-vasculitis. In this narrative review, we summarize the current knowledge concerning the pathophysiological background and use of anti-C5 strategies (eculizumab and ravulizumab) and C1-esterase inhibitor in AMR, either to prevent AMR in high-risk desensitized patients or to treat AMR as first-line or rescue therapy and also to treat de novo thrombotic microangiopathy in kidney transplant recipients.

Management of pediatric hemolytic uremic syndrome.

Classical clinical triad of hemolytic uremic syndrome (HUS) is microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury associated with endothelial cell injury. Several situations, including infections, medications, malignancies, and transplantation can trigger endothelial damage. On the HUS spectrum, atypical hemolytic uremic syndrome (aHUS) deserves special attention in pediatric patients, as it can cause endstage kidney disease and mortality. A dysfunction in the alternative complement pathway, either acquired or genetic, has been shown to be the main underlying cause. In the last decades, breathtaking advances have been made in understanding the pathophysiology of this rare disease, which has led to more efficient treatment. Recent studies have implicated genes in pathways beyond the alternative complement system, such as DGKE, TSEN2, and INF2 highlighting the importance of personalized management. Eculizumab has brought about dramatic improvements in the treatment of aHUS. Beyond eculizumab, there are many alternative therapeutics in the pipeline that target the complement system. Because of the rarity of aHUS, data from multiple patient registries are very important. The present report aimed to summarize the most important aspects of diagnosing and treating aHUS based on the Turkish national registry and the literature so as to improve clinical practice.

Hematologic complications in vascular malformations: A case study of 2 patients

Vascular malformations are congenital vascular anomalies resulting from a disruption in the vasculogenesis process. (1) They are congenital changes that enlarge as the child develops and do not undergo spontaneous involution. They can be classified based on the type of vessels involved (capillary, arterial, venous, lymphatic, mixed) and the nature of the vascular flow (low-flow and high-flow). The clinical presentation of vascular malformations is highly diverse, and despite being congenital, they can remain asymptomatic for a long time, complicating the diagnostic process. (1,3)&#x0D; &#x0D; The presence of malformations carries the risk of health-threatening complications. One such complication is Kasabach-Merritt syndrome, characterized by thrombocytopenia, microangiopathic hemolytic anemia, and consumptive coagulopathy in the presence of a rapidly enlarging vascular tumor. (4,5) Another threat is a coagulopathy limited to the vascular anomaly (LIC). It is characterized by elevated D-dimers and fibrin degradation products, low levels of fibrinogen, FV, FVIII, FXIII, and antithrombin, and sometimes mild to moderate thrombocytopenia. (6,7) Early implementation of anticoagulant therapy allows for the avoidance of health-threatening conditions and the development of disseminated intravascular coagulation syndrome (DIC). (8)

HELLP Syndrome and Differential Diagnosis with Other Thrombotic Microangiopathies in Pregnancy.

Thrombotic microangiopathies (TMAs) comprise a distinct group of diseases with different manifestations that can occur in both pediatric and adult patients. They can be hereditary or acquired, with subtle onset or a rapidly progressive course, and they are particularly known for their morbidity and mortality. Pregnancy is a high-risk time for the development of several types of thrombotic microangiopathies. The three major syndromes are hemolysis, elevated liver function tests, and low platelets (HELLP); hemolytic uremic syndrome (HUS); and thrombotic thrombocytopenic purpura (TTP). Because of their rarity, clinical information and therapeutic results related to these conditions are often obtained from case reports, small series, registries, and reviews. The collection of individual observations, the evolution of diagnostic laboratories that have identified autoimmune and/or genetic abnormalities using von Willebrand factor post-secretion processing or genetic-functional alterations in the regulation of alternative complement pathways in some of these TMAs, and, most importantly, the introduction of advanced treatments, have enabled the preservation of affected organs and improved survival rates. Although TMAs may show different etiopathogenesis routes, they all show the presence of pathological lesions, which are characterized by endothelial damage and the formation of thrombi rich in platelets at the microvascular level, as a common denominator, and thrombotic damage to microcirculation pathways induces "mechanical" (microangiopathic) hemolytic anemia, the consumption of platelets, and ischemic organ damage. In this review, we highlight the current knowledge about the diagnosis and management of these complications during pregnancy.