BACKGROUNDThrombotic thrombocytopenic purpura (TTP) patients have increased risk for allergic transfusion reactions (ATR) due to the number of plasma products they require. This study evaluated the efficacy of solvent detergent treated plasma (S/D treated plasma) to reduce ATRs.STUDY DESIGN AND METHODSAll TTP patients who presented from April 2014 to February 2015 and experienced a moderate–severe ATR to untreated plasma with TPE were switched to S/D treated plasma (Octaplas) for their remaining procedures and included in the study. Patient records were retrospectively reviewed.RESULTSThe overall ATR rate per procedure decreased from 35.0% (95% CI = 15.4%‐59.2%) with untreated plasma to 1.4% ([1/73] 95% CI = 0.0%‐7.4%) with S/D treated plasma. The moderate–severe ATR rate decreased from 20.0% ([4/20] 95% CI = 5.7%‐43.7%) with untreated plasma to 0.0% ([0/73] 95% CI = 0.0%‐4.9%) with S/D treated plasma. The overall ATR rate per plasma unit decreased from 2.6% (95%CI = 1.0%‐5.1%) with untreated plasma to 0.1% (95% CI = 0.0%‐0.4%) with S/D treated plasma. No patients experienced VTE while receiving untreated plasma. Four patients experienced VTE events while receiving S/D treated plasma. All patients who experienced a VTE had additional risk factors for VTE.CONCLUSIONS/D plasma has promise as an effective product to reduce the risk of ATRs in TTP patients. Given the high risk of ATR in TTP patients, consideration of S/D plasma instead of untreated plasma for TPE in these patients may be warranted, especially for patients with a history of moderate to severe ATR. More extensive studies are needed to confirm these findings.

Introduction Necrotizing autoimmune myopathy (NAM) is strongly associated with pathognomonic autoantibodies targeting 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase (HMGCR) or signal recognition particle (SRP), whose levels in turn are correlated with serum creatine kinase (CK) and necrosis. Thus, NAM may be amenable to therapeutic plasma exchange (TPE) to remove pathogenic antibodies and improve patient symptoms. Methods A retrospective case series and literature review of patients presenting with NAM and undergoing treatment with TPE was performed. Clinical data including patient demographics, symptoms, physical exam findings, muscle biopsy, lower extremity imaging, prior therapy, and duration from diagnosis to TPE initiation were collected retrospectively for adult patients with NAM treated with TPE after failing to respond to immunomodulatory therapy. Laboratory data including change in CK levels and myositis‐specific antibody titers from baseline were measured in some patients. Results Six patients (median age at diagnosis 52.5 years, interquartile range [IQR] 35.8‐64.5 years, four male/two female) underwent a median of 7.5 (IQR: 5‐10) TPE procedures with 5% albumin as replacement. All patients exhibited a statistically significant reduction in CK level from pre‐TPE baseline (range: 43.0%‐58.7% reduction). Responses in this cohort were best in patients with antibodies targeting HMGCR and SRP, which are most strongly associated with NAM. These results compare favorably to a literature review of NAM patients (n = 19) treated with TPE, who also exhibited positive clinical and laboratory responses across varying treatment lengths. Conclusion TPE can play a role in the management of NAM, particularly in patients with HMGCR or SRP antibodies who are refractory to pharmacologic immunosuppression.

Background: Automated red cell exchange (RCE) is a common treatment for patients with sickle cell disease (SCD). Two key parameters are used to determine the volume of blood for RCE to reduce sickle hemoglobin (eg, HbS): fraction of cells remaining (FCR) and target hematocrit. We evaluated how the calculated FCR-using the manufacturer's algorithm-impacted blood utilization and incidence of acute care encounters.Study design and methods: Retrospective chart review was conducted of 15 adults with SCD who underwent chronic RCE from July 1, 2015 to August 31, 2019. Blood utilization and acute care encounters were compared across three time periods: (a) when a fixed FCR of 30% was used (12 months);(b) transition period during which physicians made ad hoc changes to the FCR (25 months); (c) algorithm phase when a procedural FCR between 30% and 50% was selected using an algorithm generated by the manufacturer's built-in software to target a HbS fraction of 8% post-procedure (12 months). Wilcoxon signed rank test was used to determine statistical significance.Results: Median blood utilization per procedure decreased from 2398 mL (interquartile range [IQR]: 2271-2759 mL) during the fixed FCR phase to 1887 mL (IQR: 1495-2241 mL) during the algorithm phase (P < 0.001). Simi-