Recent advances in the management of immune-mediated thrombotic thrombocytopenic purpura

ADAMTS13 in the New Era of TTP

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening, often immune-mediated disease that affects 2-13 persons per million per year. Hemolytic anemia, thrombocytopenia, and end-organ damage due to the formation of microthrombi are characteristic of TTP. ADAMTS13 is a disintegrin, metalloproteinase, cleaving protein of von Willebrand factor (VWF) that processes the VWF multimers to prevent them from interacting with platelets and, in turn, to microvascular thrombosis. Prompt diagnosis of TTP is critical yet challenging. Thrombotic microangiopathies have similar clinical presentation. Measurement of ADAMTS13 activity helps in the differential diagnosis. Less than 10% ADAMTS13 activity is indicative of TTP. Laboratory ADAMTS13 activity assays include incubating the test plasma with the substrate (full-length VWM multimers) and detection with direct or indirect measurement of the cleavage product. The purpose of this study is to examine the diagnostic potential, advantages, and weaknesses of the ADAMTS13 potency in TTP.

Uncommon Manifestation: Thrombotic Thrombocytopenic Purpura Presenting Solely as Petechial Rash

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening disorder typically presenting with a classic pentad of symptoms: thrombocytopenia, microangiopathic hemolytic anemia, neurological abnormalities, renal dysfunction, and fever. This report explores an unusual presentation of TTP in a 47-year-old female with a medical history of hypertension, hyperlipidemia, and chronic TTP, who exhibited only petechial rashes, generalized weakness, and headache. Notably, the petechial rash, a less common manifestation of TTP, became a pivotal clue for the diagnosis, underscoring the necessity for vigilance even when classic symptoms are absent. This case reinforces the imperative of a high suspicion index for TTP, especially in patients with thrombocytopenia and hemolytic anemia, irrespective of other traditional signs. Plasmapheresis remains the treatment cornerstone, removing autoantibodies and replenishing ADAMTS13, as evidenced by the patient's initial response. The administration of rituximab, targeting B cells to mitigate autoantibody production against ADAMTS13, featured prominently in her management, aligning with its recognized role in refractory or relapsing TTP cases. Despite an encouraging response to rituximab, a subsequent decline in platelet count indicated the unpredictable nature of TTP and the necessity for multi-pronged therapeutic strategies. The patient's medical background and persistently low ADAMTS13 levels hinted at a chronic relapsing trajectory associated with increased morbidity and mortality. This necessitates ongoing vigilance and treatment flexibility. Highlighting this atypical TTP presentation, the report calls for immediate, robust intervention, serving as a critical reminder of the heterogeneity of TTP manifestations and the complexities in its management, thereby contributing to broader clinical awareness and improved patient prognoses.

Successful Use of Bortezomib in an Adolescent with Refractory TTP

With increasing early and upfront use of rituximab and caplacizumab in the modern management of immune-mediated thrombotic thrombocytopenic purpura (iTTP), the risk of refractory disease is expected to decline. However, despite the use of adequate initial therapy, a small subset of patients develop a refractory disease which is difficult to manage. Bortezomib has come to be known as a safe and effective treatment option for refractory iTTP, but its use in children is limited. Here, we describe the case of an adolescent patient with refractory iTTP who had a satisfactory and sustained response to the use of bortezomib.

Clinical Features and Risk Factors of Relapse and Mortality in Thrombotic Thrombocytopenic Purpura Patients: A Seven-Year Experience

Background: Thrombotic thrombocytopenic purpura (TTP) is associated with microangiopathic hemolytic anemia, thrombocytopenia, and microvascular thrombosis. No comprehensive report exists on clinical characteristics and risk factors of relapse and mortality in Iranian TTP patients. In this study, we aimed to report clinical features of Iranian TTP patients, to evaluate disease relapse and mortality rate and their associated risk factors. Materials and Methods: This study was a cohort study of patients diagnosed with microangiopathic hemolytic anemia admitted to the Shariati Hospital, Tehran, a referral center for TTP patients, from 2010 to 2017. Demographic, clinical, and laboratory data were recorded and patients were followed for 3 years regarding disease relapse and mortality. Results:  114 patients (80 females, 34 males) with a mean age of 39.3 ± 14.99 years were included.  Hematologic and neurologic symptoms were the most common manifestations. Abnormal laboratory findings at the presentation included thrombocytopenia, anemia, and elevated LDH. All patients were treated with plasma exchange, and 75.5% of them had a response to treatment, while the 3-year relapse and mortality rate was 23.6 and 26.3%.  Lower platelet count was a predictor of disease relapse. Age, hematological, or neurological initial presentation were associated with TTP mortality. Conclusion: Based on the largest study of TTP patients ever in Iran, the demographic and clinical characteristics of Iranian TTP patients are similar to other existing reports. Knowledge of the risk factors for TTP relapse and mortality could be useful to alert hematologists for prompt therapeutic actions when necessary.

N-Acetylcistein for thrombotic thrombocytopenic purpura: an observational case series study

Acquired thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder. N-Acetylcysteine (NAC) rapidly degrades ultra-large von Willebrand factor multimers by disrupting the disulfide bonds. We report a series of twelve consecutive patients diagnosed with acquired TTP successfully treated with high-dose NAC (150 mg/kg/day) in combination with plasma exchange and steroids. Eight patients also received rituximab. Two patients presented refractory TTP. All patients achieved a quick clinical response in a median time of 5.5 days after starting NAC and are alive after a median follow-up of 29 months. The treatment was feasible and well tolerated. These data provide further evidence of the potential benefit and safety of adding NAC to the standard of care.