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We report the case of a patient diagnosed with a clinical relapse of acquired immune-mediated thrombotic thrombocytopenic purpura (TTP) who was successfully treated with low-dose rituximab plus corticosteroids without the use of plasma exchange (PEx), which was unavailable at the time due to the COVID-19 pandemic. Rituximab 100 mg weekly for 4 weeks was administered, combined with 1 mg/kg of prednisone, obtaining a complete hematological response in 6 weeks. This case suggests that PEx may be unnecessary for a subset of patients with relapsed TTP who are clinically stable without significant end-organ damage. A brief literature review regarding TTP patients treated without plasma exchange is also included.

Arterial obstruction in small diameter (<6 mm) vessels are many times treated with grafts, however autologous aren't always available and synthetic have a high rate of complications. Decellularization of umbilical arteries may provide a solution, but the ideal method is debatable. We compare effectiveness between SDS and Triton X-100. Umbilical cords obtained from full term pregnancies with normal development and no evident complications in the newborn, were micro-dissected within 12 h and stored in phosphate buffered saline without freezing. Arteries were then processed for decellularization using 0.1 % and 1 % SDS, and 1 % Triton X-100 protocols. Evaluation of cellular and nuclear material, collagen fibers, elastic fibers, and glycosoaminoglycans of the extracellular matrix (ECM) were evaluated as well as morphometric analysis under histological and immunohistochemical techniques. Triton X-100 was ineffective, preserving nuclear remains identified by immunofluorescence, had the most notable damage to elastic fibers, and decrease in collagen. SDS effectively eliminated the nuclei and had a less decrease in elastic fibers and collagen. Laminin was preserved in all groups. No significant differences were identified in luminal diameters; however the middle layer decreased due to decellularization of muscle cells. In conclusion, 0.1 % SDS decellularization was the most effective in eliminating cells and preserving the main components of the ECM.

Introduction Corticosteroids are the first line therapy for autoimmune hemolytic anemia (AIHA), but are associated with significant adverse events, dependency and frequent relapses. Rituximab is reserved for severe or steroid-resistant disease. Low-dose rituximab is also effective, but its efficacy in the first line has been poorly described. We report our results with this combination. Methods Adults older than 16 years newly diagnosed with warm antibody AIHA either primary or secondary were included. Patients systematically received dexamethasone 40 mg for 4 days followed by a 1 mg/kg rapid prednisone taper plus rituximab 100 mg weekly for 4 doses. Our primary outcome was response at day 28 based on the First International Consensus Meeting (complete response: normalization of Hb, no evidence of hemolysis and absence of transfusions; response: increase of Hb by &gt;2g/dl, or normalization of biochemical resolution of hemolysis or absence of transfusion in 7 days), secondary outcome was event-free survival with an event defined as a laboratory or clinical relapse or loss of response. Results Sixteen patients were treated with low-dose rituximab during the study period, ten women (62.5%), six men (37.5%). The median age was 34 years (range, 17-78). Three (18.75%) were secondary to lupus erythematosus. The median follow-up was 20 months (range, 0.4-66). Most received 4 doses of rituximab (87.5%). All patients responded at day 28, (100%) 31.2% achieved a complete response (CR). Subsequently, 81.3% achieved CR. Ten (62.5%) were considered steroid-dependent, however, most discontinued treatment without loss of response (75%). The event-free survival was 63.8% to 5 years. Conclusion Low-dose rituximab therapy as a first-line in AIHA showed encouraging results as most patients were able to discontinue treatment without relapse. Disclosures Gomez-Almaguer: Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

The COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus 2, a new and different coronavirus.Since almost every continent in the world has been affected, the global actions have been focused on prevention, detection, and patient monitoring with no specific treatment until now. Classical and historical interventions have remerged as options including convalescent plasma. The use of convalescent plasma has become more important during large-scale epidemics, such as Mid-East respiratory syndrome-CoV and influenza pneumonia, data regarding support its clinical use. Unfortunately, published clinical data on the usefulness of convalescent plasma in patients with COVID-19 are scarce, but it has shown good clinical outcomes. There are no reports of adverse events in clinical trials of patients receiving convalescent plasma treatment for COVID-19. Nevertheless, FDA has issued its recommendations for the use of convalescent plasma as an option that may provide clinical effect for treatment during the public health emergency caused by COVID-19, with recommendations to avoid adverse effects in centers developing clinical trials with coronavirus convalescent plasma.