UNASSIGNED: Legionella pneumophila can cause a wide spectrum of clinical manifestations, ranging from a mild flu-like illness to fulminant multi-organ involvement, characterised by severe pneumonia, diarrhoea, encephalopathy, shock, hepatic dysfunction and renal failure. Very rarely, it can be associated with haematologic conditions such as thrombotic thrombocytopenic purpura (TTP), haemolytic uraemic syndrome (HUS) and immune thrombocytopenic purpura (ITP). We report a rare case of L. pneumophila causing ITP and review previously published cases of thrombocytopenia associated with Legionellosis in the literature.
UNASSIGNED: A 53-year-old male presented with fevers, chills, a productive cough and severe haemoptysis. Blood work was remarkable for leukocytosis, severe thrombocytopenia and hyponatraemia. Computed tomography (CT) imaging showed left lower lobe lung consolidation, and a peripheral blood smear showed giant platelets consistent with ITP. Legionella urine antigen testing returned positive. He was treated with intravenous immunoglobin, steroid taper and a ten-day course of azithromycin, which led to normalisation of his platelet count and resolution of the pneumonia.
UNASSIGNED: L. pneumophila can lead to complement-mediated destruction of platelets resulting in ITP. Antibodies against L. pneumophila can also cross-react with the enzyme ADAMTS13, inhibiting its function and resulting in TTP and HUS. Additionally, L. pneumophila can infect vascular endothelial cells causing their death and stimulating release of von Willebrand factor (vWF) multimers into the bloodstream, promoting thrombosis and platelet consumption.
UNASSIGNED: It is important for internists to consider L. pneumophila in the differential for any patient presenting with pneumonia and severe thrombocytopenia. Earlier detection and intervention can lead to prevention of critical bleeding and better outcomes.
CONCLUSIONS: Legionella pneumophila is rarely associated with different haematologic disorders resulting in severe bleeding diathesis as well as thrombosis.It is important for internists to consider Legionella pneumophila in the differential diagnosis for any patient presenting with pneumonia and severe thrombocytopenia.Earlier detection and intervention can lead to prevention of critical bleeding and better outcomes.

The immunosuppressive treatment of immune-mediated thrombotic thrombocytopenic purpura (iTTP) in patients with intolerance or refractoriness to the B-cell depleting monoclonal antibody rituximab remains debated. Daratumumab, a plasma cell-directed monoclonal antibody targeting CD38, represents a therapeutic option, but data are scarce. The French Thrombotic Microangiopathies Reference Center conducted a nationwide survey on iTTP patients treated with daratumumab. Nine episodes from seven patients were identified. Treatment was administered for A Disintegrin And Metalloproteinase with ThromboSpondin-1 motifs, 13th member (ADAMTS13) relapses while patients were otherwise in clinical response (N = 8), or during the acute phase of the disease following rituximab intolerance (N = 1). Patients have received a median of three previous therapeutic lines. ADAMTS13 activity improved in eight cases following daratumumab administration, including three cases where ADAMTS13 normalized. ADAMTS13 relapses occurred in three patients; in two cases, retreatment with daratumumab was successful. Median ADAMTS13 relapse-free survival was not reached; 12-month ADAMTS13 relapse-free survival was 56%. Daratumumab-related adverse events occurred in five cases and were non-severe infusion-related reactions in all cases. These results suggest that daratumumab may be an effective treatment option for iTTP patients with intolerance or refractoriness to rituximab.

UNASSIGNED: A patient with Sjögren\'s syndrome (SS), immune-mediated thrombotic thrombocytopenic purpura (ITTP), and posterior reversible encephalopathy syndrome (PRES) was reported, and all published cases with thrombotic thrombocytopenic purpura (TTP), PRES, and SS were retrieved and analysed. The patient\'s clinical data and treatment procedure have been discussed.
UNASSIGNED: A 45-year-old Chinese female was hospitalized with headache and low platelet count. She had previously presented to a local hospital with a 7-month history of epigastric discomfort and anorexia, and was diagnosed with SS and ITTP. Laboratory investigations after admission showed platelet (PLT) of 13*10^9/L, red blood cell (RBC) fragments of 6 %, ADAMTS13 Activity＜0.2 %, anti-ADAMTS13 IgG of 88.3U/mL. Brain magnetic resonance imaging (MRI) showed gyriform restricted diffusion along with increased T2-FLAIR signal in the left frontal cortex and bilateral parietal temporal cortex. She was diagnosed with SS, ITTP and PRES, and received the treatment of methylprednisolone, cyclosporine, plasma exchange, IVIG, and rituximab. This patient did not experience the recurrence during the 8-month follow-up period.
UNASSIGNED: ITTP and PRES are rare manifestations of SS. After a suspected or confirmed diagnosis of ITTP, plasma exchange and immunosuppressive therapy should be immediately administered. We suggest that rituximab could have additional therapeutic value for SS combined with ITTP and PRES.

UNASSIGNED: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) may lead to microvascular thrombosis and mortality, despite patients receiving appropriate standard of care treatment (immunosuppressive therapy and therapeutic plasma exchange). Caplacizumab directly inhibits von Willebrand factor-platelet interaction and consequently prevents microthrombi formation.
UNASSIGNED: This study aimed to determine the efficacy and safety of caplacizumab in diverse, clinically relevant patient subgroups.
UNASSIGNED: In this post hoc analysis of phase 3 HERCULES study (NCT02553317), patients were categorized by clinically relevant subgroups (prior iTTP history, iTTP severity at presentation, and initial immunosuppression regimen).
UNASSIGNED: In patients with previous acute iTTP episodes, less severe disease at presentation, or those who received a corticosteroid-only initial immunosuppression regimen, time to platelet count response was shorter with caplacizumab vs placebo. Across all subgroups, fewer patients experienced a composite outcome of iTTP-related death, exacerbation, or major thromboembolic event on caplacizumab vs placebo. Placebo-treated patients remained at risk of exacerbations and refractoriness on either initial immunosuppression regimen (ie, corticosteroids only or corticosteroids plus rituximab). In the corticosteroids plus rituximab group, no exacerbations were reported in caplacizumab-treated patients, but 8 of the 16 (50%) patients experienced exacerbations in the placebo group. Safety outcomes were consistent with the findings of the main HERCULES study.
UNASSIGNED: Caplacizumab treatment of acute iTTP, in combination with therapeutic plasma exchange and immunosuppression, was safe and effective regardless of prior iTTP history, severity, or initial immunosuppression regimen and improved patient outcomes across clinically diverse subgroups. These findings emphasize the need for treatments with rapid onset of action that can reduce mortality and iTTP-related complications.

UNASSIGNED: Thrombotic thrombocytopenic purpura, particularly its immune-mediated variant (iTTP), necessitates accurate diagnostic approaches for effective management.
UNASSIGNED: To compare a chemiluminescence immunoassay (CLIA) and an enzyme-linked immunosorbent assay (ELISA) for testing ADAMTS-13 activity and detecting anti-ADAMTS-13 autoantibodies (AAbs) in patients with iTTP.
UNASSIGNED: This study involved 31 paired samples from 12 iTTP patients. ADAMTS-13 activity was measured using the HemosIL AcuStar (Instrumentation Laboratory, CLIA) and Technozym (Technoclone) activity assay (ELISA). The presence of AAbs was assessed using Technozym ADAMTS-13-INH assay (ELISA) and HemosIL AcuStar activity (CLIA) within a Bethesda assay following mixing with normal pool plasma. von Willebrand factor (VWF) multimers were analyzed using the HYDRASYS-2 SCAN system and the HYDRAGEL 5- or 11-VW Multimer kits (Sebia). VWF activity levels were measured with the HemosIL AcuStar VWF:GPIbR on the ACL AcuStar Analyzer (IL).
UNASSIGNED: For ADAMTS-13 activity, a strong linear relationship and no bias between CLIA and ELISA were confirmed (slope = 1.01 [0.91, 1.11], intercept = 0.00 [-0.47, 0]). However, significant discrepancies were found in AAb detection during remission phases with ADAMTS-13 activity between 10% and 50%, with CLIA and ELISA showing significant divergence (P < .001, Cohen\'s g = 0.34). Consistently, VWF multimers and activity levels exhibited significantly different values between remission samples with ADAMTS-13 activity below 50% and above 50%. In longitudinal analysis of patients with multiple iTTP relapses, positivity to CLIA appears to precede ELISA in predicting exacerbations.
UNASSIGNED: While CLIA and ELISA might be interchangeable for assessing ADAMTS-13 activity, they are not equivalent for detecting AAbs, particularly in patients in clinical remission with ADAMTS-13 activity between 10% and 50%.

Thrombotic microangiopathy (TMA) encompasses a range of disorders characterized by blood clotting in small blood vessels, leading to organ damage. It can manifest as various syndromes, including thrombotic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), and others, each with distinct causes and pathophysiology. Thrombo-inflammation plays a significant role in TMA pathogenesis: inflammatory mediators induce endothelial injury and activation of platelet and coagulation cascade, contributing to microvascular thrombosis. Primary TMA, such as TTP, is primarily caused by deficient ADAMTS13 metalloproteinase activity, either due to antibody-mediated inhibition or intrinsic enzyme synthesis defects. In cancer patients, a significant reduction in ADAMTS13 levels and a corresponding increase in VWF levels is observed. Chemotherapy further decreased ADAMTS13 levels and increased VWF levels, leading to an elevated VWF/ADAMTS13 ratio and increased thrombotic risk. Drug-induced TMA (DITMA) can result from immune-mediated or non-immune-mediated mechanisms. Severe cases of COVID-19 may lead to a convergence of syndromes, including disseminated intravascular coagulation (DIC), systemic inflammatory response syndrome (SIRS), and TMA. Treatment of TMA involves identifying the underlying cause, implementing therapies to inhibit complement activation, and providing supportive care to manage complications. Plasmapheresis may be beneficial in conditions like TTP. Prompt diagnosis and treatment are crucial to prevent serious complications and improve outcomes.

Thrombotic thrombocytopenic purpura (TTP) is a rare but life-threatening hematologic disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, renal impairment, and fever. The etiology of TTP often involves a severe deficiency in ADAMTS13 activity, resulting in the accumulation of ultra-large von Willebrand factor multimers and subsequent microvascular thrombosis. Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can affect multiple organ systems, and although the initial presentation of SLE with TTP is rare, it necessitates a comprehensive diagnostic and therapeutic approach. We present a case of a 27-year-old male with no significant past medical history who developed altered mental status, headache, and right-sided numbness, leading to the diagnosis of TTP and subsequent detection of SLE.

Clinical manifestations of triple X syndrome (karyotype 47, XXX) can include autoimmune diseases. We describe the occurrence of acquired thrombotic thrombocytopenic purpura (TTP), an autoimmune condition, refractory to plasmapheresis and rituximab in a patient with triple X syndrome who required vincristine administration for disease remission. To our knowledge, this rare coexistence is the first of its kind reported in Brazil.

Thrombotic thrombocytopenic purpura is a rare but life-threatening emergency. Tuberculosis can have hematologic complications. However, concurrent tuberculosis and thrombotic thrombocytopenic purpura are extremely rare. In this study, we report a 53-year-old man who was initially treated for pulmonary tuberculosis but later developed weakness and an altered mental status. Laboratory tests revealed evidence of thrombocytopenia, acute renal insufficiency, and microangiopathic hemolytic anemia. Brain imaging identified intracranial hemorrhage. Further testing revealed low ADAMTS13 activity (1.8%) and positive anti-ADAMTS13 antibody, confirming the diagnosis of thrombotic thrombocytopenic purpura. The patient had a full recovery after anti-tuberculosis treatment, plasma exchange, and supportive care. We present this rare case and review previous relevant studies to remind clinicians about the potential connections between tuberculosis and thrombotic thrombocytopenic purpura. In patients with signs of severe thrombocytopenia and microangiopathic hemolysis, necessary diagnostic tests should be performed to eliminate the possibility of thrombotic thrombocytopenic purpura occurring concurrently with tuberculosis.

Congenital (cTTP) and immune-mediated (iTTP) thrombotic thrombocytopenic purpura are serious and rare clotting disorders resulting from a deficiency in the ADAMTS13 enzyme. A systematic review was conducted using the Ovid® MEDLINE & Embase databases to synthesize the epidemiology and burden of cTTP and iTTP worldwide (from January 1, 2010, to February 6, 2020, with an update that covered the period January 1, 2020-February 11, 2022). Outcomes of interest were incidence and prevalence of TTP, incidence of acute episodes, mortality, burden of illness (eg complications, healthcare utilization, patient-reported outcomes) and disease management. A total of 221 eligible observational studies were included. The incidence rate of acute episodes ranged from 0.19-0.35 person-years in adult patients with cTTP, and 1.81-3.93 per million persons per year for iTTP in the general population. Triggers of acute episodes were similar for cTTP and iTTP, with pregnancy and infection the most commonly observed. Exacerbation in patients with iTTP varied widely, ranging from 2.4-63.1%. All-cause mortality was observed in 0-13.4% of patients with cTTP, across studies and follow-up periods, and in 1.1% (median follow-up: 0.4 years) to 18.8% (1 year) of patients with iTTP during acute episodes. Cardiovascular, renal, and neurological disease were common complications. TTP also led to work disturbances, feelings of anxiety and depression, and general activity impairment. TTP treatment regimens used were generally reflective of current treatment guidelines. The evidence identified describes a high patient burden, highlighting the need for effective treatment regimens leading to improvements in outcomes. Considerable evidence gaps exist, particularly for disease epidemiology, patient-reported outcomes, costs of disease management, and associated healthcare resource utilization. This review may help increase disease awareness and highlights the need for additional real-world studies, particularly in geographical regions outside the United States and Western Europe.