Villalba, Cristina A. Figueroa

ABSTRACTImmune thrombotic thrombocytopenic purpura (iTTP) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular occlusion secondary to acquired ADAMTS13 deficiency. Contemporary data regarding iTTP treatment practices in the US, including the use of caplacizumab, are lacking. We aimed to characterize the demographics and therapies, including medications and apheresis practices, in patients with iTTP in the US. We retrospectively analyzed iTTP cases at 15 sites in the US that provide comprehensive care for patients with iTTP. The time‐period assessed was from January 1, 2017 to December 31, 2021. Our primary objective was to analyze data by iTTP episode, inclusive of initial episodes and relapses. A total of 390 iTTP episodes were reported for 280 unique individuals (187 females, 93 males). Thirty‐day mortality was 3.7% (14/374), and 6‐month mortality was 7.4% (27/367). TPE details were reported for 343 episodes, among which 261 underwent at least one procedure (median 6, IQR 3–11). Among the 261 episodes with at least one therapeutic plasma exchange (TPE) performed, 82.0% (214/261) used only plasma. Caplacizumab was used either alone or in combination with other agents in 43 (11.0%) episodes. Management strategies for iTTP remain varied across centers in the US, with a variety of combinations for TPE replacement fluids and therapeutic agents, as well as limited use of caplacizumab. Further research and standardization of treatment regimens may further reduce mortality in this condition.

AbstractPrior studies have suggested that immune thrombotic thrombocytopenic purpura (iTTP) may display seasonal variation; however, methodologic limitations and sample sizes have diminished the ability to perform a rigorous assessment. This 5‐year retrospective study assessed the epidemiology of iTTP and determined whether it displays a seasonal pattern. Patients with both initial and relapsed iTTP (defined as a disintegrin and metalloprotease with thrombospondin type motifs 13 activity <10%) from 24 tertiary centers in Australia, Canada, France, Greece, Italy, Spain, and the US were included. Seasons were defined as: Northern Hemisphere—winter (December–February); spring (March–May); summer (June–August); autumn (September–November) and Southern Hemisphere—winter (June–August); spring (September–November); summer (December–February); autumn (March–May). Additional outcomes included the mean temperature in months with and without an iTTP episode at each site. A total of 583 patients experienced 719 iTTP episodes. The observed proportion of iTTP episodes during the winter was significantly greater than expected if equally distributed across seasons (28.5%, 205/719, 25.3%–31.9%; p = .03). Distance from the equator and mean temperature deviation both positively correlated with the proportion of iTTP episodes during winter. Acute iTTP episodes were associated with the winter season and colder temperatures, with a second peak during summer. Occurrence during winter was most pronounced at sites further from the equator and/or with greater annual temperature deviations. Understanding the etiologies underlying seasonal patterns of disease may assist in discovery and development of future preventative therapies and inform models for resource utilization.

SummaryThe thrombotic risk with haemoglobin C trait (HbAC) or haemoglobin C disease (HbCC) is unclear. However, individuals with HbCC have demonstrated chronic haemolysis, higher blood viscosity and altered rheology when compared to individuals with wild‐type haemoglobin (HbAA). These physiological alterations may theoretically translate to increased risk of thrombosis; therefore, a systematic literature review was performed to investigate the possible association between HbAC and/or HbCC and thrombosis. Twenty‐two studies met inclusion criteria representing 782 individuals with HbAC (n = 694) or HbCC (n = 88). Fifteen studies described the presence/absence of venous thromboembolism (VTE) in patients with HbAC (n = 685) or HbCC (n = 79), while seven studies described patients with HbAC (n = 9) or HbCC (n = 9) and arterial thrombosis. Most (n = 20) studies were case reports or case series; however, two studies suggested a potential increased VTE risk with HbAC compared to HbAA in (i) all patients (OR 2.2, 95% CI: 0.9–5.5) and in (ii) pregnant individuals (RR 3.7, 95% CI 0.9–16). This review is the largest assessment of patients with HbC trait or disease and thrombosis to date; despite its limitations, the findings suggest HbC may be a predisposing risk factor to thrombosis. Prospective cohort studies are warranted to definitively elucidate the risk of thrombosis in this population.

Abstract The Heidenhain variant of Creutzfeld-Jakob disease (CJD) is a rare form that initially presents with visual disturbances. In early stages, the presentation can mimic neuromyelitis optica spectrum disorders (NMOSD) and lead to unnecessary treatment modalities. Herein, we describe a case of a 66-year-old man who presented with bilateral vision loss and retro-orbital discomfort. In addition to immunosuppressive therapy, he received 4 rounds of therapeutic plasma exchange after his preliminary diagnosis of NMOSD. We were surprised to note that his condition did not show improvement but deteriorated, with severe neurocognitive symptoms. Eventually, CJD was suspected, and real-time quaking-induced conversion (RT-QuIC) was performed. By the time the diagnosis of Heidenhain variant of CJD was confirmed, the patient was discharged to hospice care and died shortly after.

Abstract Anti‐glomerular basement membrane (anti‐GBM) disease (formerly known as Goodpasture's syndrome) is a rare autoinflammatory condition that affects the renal and/or pulmonary capillaries. The standard therapeutic regimen for anti‐GBM disease involves therapeutic plasma exchange (TPE), cyclophosphamide, and corticosteroids to rapidly remove and inhibit autoantibody production and reduce organ inflammation. Herein we report an 82‐year‐old female who developed anti‐GBM disease but expired despite therapy, secondary to multi‐organ failure in the setting of disseminated adenovirus disease. We discuss the utility and potential adverse effect of daily TPE for a protracted course (ie, 10‐14 days), the recommended TPE intensity in the 2023 American Society for Apheresis guidelines, updated from every‐other‐day TPE in the 2019 guidelines, despite no new data. We also highlight the potential for unusual infections to occur in these patients due to the profound immunosuppression, and discuss the importance of balancing immunosuppression to treat the disease with close surveillance of any potential opportunistic infections.