Automated red blood cell exchange with a post-procedure haematocrit targeted at 34% in the chronic management of sickle cell disease.

Optimal targets for red blood cell exchange (RCE) are not well defined in the chronic management of sickle cell disease. We analysed transfusion requirements and iron-related outcomes in 101 patients on chronic RCE with a post-procedure haematocrit (Ht) targeted at 34%, which is higher than typically used. A majority were of HbSS/HbSß0 genotype (n = 72) and enrolled for neurological complications (n = 53). Fifty patients had a positive Ht balance with RCE (>2% mean increase from pre-procedure level), while 43 patients maintained a neutral balance. The first group required fewer red blood cell units/year (65 vs. 80, p < 0.001), but a significant proportion were iron overloaded based on R2* with liver MRI (32% vs. none performed) and prescription of iron chelation (52% vs. 0%, p < 0.001, after a median of 19 months). The second group was more likely to receive iron supplementation (6% vs. 56%, p < 0.001). Chronic automated RCE with a post-procedure Ht targeted at 34% is not iron-neutral, and personalized Ht goals may be more appropriate in certain settings. This higher target should be compared with a lower Ht strategy in individuals with similar baseline red cell volumes to assess iron homeostasis and blood product requirements.

Euvolemic automated transfusion to treat severe anemia in sickle cell disease patients at risk of circulatory overload.

BACKGROUND: Red blood cell (RBC) transfusion remains a major treatment for sickle cell disease (SCD). Patients with SCD have a high prevalence of renal impairment and cardiorespiratory disease, conferring risk of transfusion-associated circulatory overload (TACO). STUDY DESIGN AND METHODS: We describe an approach, titled euvolemic automated transfusion (EAT), to transfuse SCD patients with severe anemia who are at risk of TACO. In EAT, plasmapheresis is performed using donor RBCs, rather than albumin or plasma, as replacement fluid. Euvolemia is maintained. A retrospective analysis was conducted of patients with SCD who underwent EAT at our institution over a 10-year period, to evaluate the efficacy and safety of EAT. RESULTS: Eleven SCD patients underwent 109 EAT procedures (1-59 procedures per patient). The median age was 42 years (IQR = [30-49]) and 82% (n = 9) were female. Most (82%; n = 9) patients had severe chronic kidney disease and 55% (n = 6) had heart failure. One (9%) patient had a history of life-threatening TACO. Mean pre- and post-procedure Hct values were 19.8% (SD ± 1.6%) and 29.1% (SD ± 1.4%), respectively. The average Hct increment was 3.2% per RBC unit. Only two EAT-related complications were recorded during the 109 procedures: central line-associated infection and citrate toxicity (muscle cramping). EAT used an average of two RBC units less than that projected for standard automated RBC exchange. CONCLUSION: Our findings suggest that EAT is safe and effective to treat patients with SCD and severe anemia, who are at risk for TACO. EAT requires fewer RBC units compared to automated RBC exchange.

Chronic automated red cell exchange therapy for sickle cell disease.

BACKGROUND: The data to support chronic automated red cell exchange (RCE) in sickle cell disease (SCD) outside of stroke prevention, is limited, especially in adults. STUDY DESIGN AND METHODS: A retrospective analysis was conducted of patients with SCD who were referred for chronic RCE at our institution over a 10-year period. Data that were evaluated included patient demographics, referral indications, and procedural details (e.g., vascular access, adverse events, etc.). In a subanalysis, the number of annual acute care encounters during 3 years of chronic RCE was compared with that in the year preceding the first RCE. RESULTS: A total of 164 patients were referred for chronic RCE: median age was 28 years (interquartile range [IQR] = 22-36) at referral and 60% were female. Seventy (42.6%) were naïve to chronic transfusion (simple or RCE) prior to referral. The leading indications for referral were refractory pain (73/164, 44.5%) and iron overload (57/164, 34.7%). A total of 5090 procedures occurred during the study period (median = 19, IQR = 5-45). Of the 138 patients who had central vascular access, 8 (6%) and 16 (12%) had ≥1 central-line-related thrombosis and/or infection, respectively. Of those who were not RBC alloimmunized at initiation of RCE, 12/105 (11.4%) developed new antibodies during chronic RCE. In those 30 patients who were adherent to therapy for 3 years, there was no significant difference in acute care encounters following initiation of RCE. CONCLUSION: Prospective clinical trials are needed to determine which patients are most likely to benefit from chronic RCE and refine selection accordingly.

Transfusion-transmitted babesiosis in a patient with sickle cell disease undergoing chronic red cell exchange.

BACKGROUND: Prior to laboratory-based blood donor screening for Babesia, transfusion-transmitted babesiosis (TTB) was a leading infectious risk to the blood supply in the United States. CASE REPORT: A 30-year-old man with sickle cell disease (SCD) who had been on a chronic automated red cell exchange (RCE) regimen since childhood, presented approximately 2 months after an RCE, with fever, neck pain, and photophobia. Meningitis was excluded, and he was discharged. He presented again 2 days later with persistent fever, chills, headache, fatigue, and loss of appetite. RESULTS: On examination, the patient was febrile but hemodynamically stable. Intra-erythrocytic inclusions were identified on a peripheral blood smear (<0.5%). B. microti IgM and IgG titers were >1:320 (Reference <1:20) >1:1024 (Reference <1:64), respectively. B. microti was confirmed by nucleic acid testing. The patient lived in a Babesia endemic state but had no risk factors for tick-borne acquisition. Of the 65 units he received in the preceding 6 months, 58 had been screened for Babesia. One of the donors of the 7 untested units was B. microti seropositive (titer 1:128; Reference 1: 64). The donor was asymptomatic and resided in a state in which Babesia screening was not required. He reported traveling in the year before his donation. CONCLUSION: Although rare, TTB is still possible despite regional screening, underscoring the need for provider vigilance and education, especially in non-endemic areas. Patients with SCD are particularly vulnerable given their high frequency of transfusion and complex needs requiring blood procurement from states where Babesia screening is not mandatory.

Therapeutic plasma exchange in the management of stiff person syndrome spectrum disorders: a case series and review of the literature.

Background: Stiff person syndrome spectrum disorders (SPSD) are a rare group of disabling neuroimmunological disorders. SPSD often requires immune therapies, especially in the setting of inadequate response to symptomatic treatments. The safety and efficacy of therapeutic plasma exchange (TPE) in SPSD remains uncertain. Objectives: To describe the safety, tolerability, and efficacy of TPE in patients with SPSD. Design: A retrospective observational study. Methods: A retrospective review of SPSD patients seen at Johns Hopkins Hospital (JHH) from 1997 to 2021 was performed. Patient demographics/history, examination/diagnostic findings, treatment response, and TPE-related complications were recorded. Assessment for any associations between clinical characteristics, including age, sex, clinical phenotype, and time on immunotherapy, and response to TPE 3 months after treatment was performed. A subgroup of 18 patients treated with TPE at JHH and 6 patients treated with TPE at outside institutions were evaluated for any change in usage of symptomatic medications 3 months after the TPE treatment. Literature review of SPSD and TPE was also conducted. Results: Thirty-nine SPSD patients were treated with TPE (21 at JHH and 18 at outside institutions); median age 48 years, 77% female, median modified Rankin Scale 3; mean initial anti-GAD65 antibody titer was 23,508 U/mL. Twenty-four patients (62%) had classic SPS, 10 (26%) had SPS-plus, 2 (5%) had progressive encephalomyelitis with rigidity and myoclonus, and 3 (8%) had pure cerebellar ataxia. All patients were on symptomatic treatments, 30 (77%) previously received IVIg, and 3 (8%) previously received rituximab. Four patients (10%) had a TPE-related adverse event. One developed asymptomatic hypotension, another had both line thrombosis and infection, and two had non-life-threatening bleeding events. Twenty-three (59%) patients reported improvement in symptoms after TPE. Of the subgroup of 24 patients evaluated for any change in usage of symptomatic medications 3 months after the TPE treatment, 14 (58%) required fewer GABAergic symptomatic medications. Literature review identified 57 additional patients with SPSD; 43 (75%) reported temporary improvement after TPE. Conclusion: The majority of patients treated with TPE had improvement. Moreover, most patients evaluated for any change in usage of symptomatic medications after the TPE treatment no longer required as much symptomatic medications months after TPE. TPE appears safe and well-tolerated in SPSD. Further studies are needed to assess the long-term efficacy of TPE in SPSD and identify which patients may benefit the most from TPE.