BACKGROUND: Peripheral blood-derived hematopoietic stem cells (HSCs) are widely used for various adult stem cell transplants. To obtain sufficient HSCs from healthy volunteer donors during the apheresis process and ensure that the donors are exposed to fewer apheresis-related side effects, calculation methods have been developed for the prediction of processed blood volume or CD34+ count. However, there is no consensus on a formula to predict the volume of blood to be processed or the number of stem cells to be obtained.
OBJECTIVE: This study aimed to estimate the predicted blood volume and CD34+ cell counts using collection efficiency (CE)-based formulas and evaluate their accuracy compared to the actual CD34+ cell counts. It also seeks to identify the factors that affect CE.
METHODS: Data from 397 healthy, unrelated stem cell donors were retrospectively analyzed. An algorithm using four different CE2 metrics (1st quartile, mean, 3rd quartile, and median) was developed to predict the volume of blood to be processed using the Spectra Optia continuous mononuclear cell collection procedure.
RESULTS: When employing the mean CE2 algorithm, the results revealed a strong correlation (r = .894, p < .001) between predicted and actual CD34+ values. The study also identified strong associations between pre-apheresis CD34+, pre-apheresis leukocyte count, the use of two doses of G-CSF, and low CE2.
CONCLUSIONS: These findings suggest that the mean CE2 algorithm could be a potent, straightforward, and accurate tool for predicting CD34+ stem cell counts in healthy allogeneic stem cell donors and potentially optimizing stem cell collection procedures.

Collection of hematopoietic progenitor cell products [HPC(A)] is deferred if the donor is symptomatic and tests positive for Covid-19. However, donor questionnaires are subjective and may miss minimally symptomatic donors. Alternatively, myalgia associated with Covid-19 infection can be falsely dismissed as an adverse effect of granulocyte stimulating factor (Filgrastim) administered prior to product collection. The likelihood of donors with an underlying acute but minimally symptomatic infection undergoing successful product collection is significant. In these circumstances, it is less known whether Covid-19 infection results in product viremia or alters the clinical outcome of transplant. We aimed to evaluate the above question by studying a donor whose product was collected during acute Covid-19 infection. Aliquots of the product tested negative for SARS-CoV-2 RNA by reverse-transcriptase polymerase chain reaction assay (RT-PCR). Importantly, the donor received an autologous stem cell transplant using the product collected at the time of infection, and their case will be described in this report. We describe one of the very few reports of successful transplant of HPC(A) product collected during acute Covid-19 infection.

BACKGROUND: Myeloablative, high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) improves outcome in some high-risk malignant solid tumors and lymphomas in children and young adults.
METHODS: We performed 16 peripheral blood stem cell (PBSC) harvests in 12 children and 2 young adult patients with a high-risk malignant solid tumor or refractory/relapsed Hodgkin\'s lymphoma from August 2015 to December 2020. In our chemotherapy mobilization protocol, we used an absolute neutrophil count (ANC) of >1 × 109/L following the nadir after chemotherapy as the criterion for undertaking the apheresis.
RESULTS: The median CD34+ cell count per kg body weight of the 33 apheresis products was 4.92 × 106 cells/kg (range, 0.34-22.53 × 106 cells/kg). Thirteen of the 14 patients (93%) had successful PBSC collections that met their goals for PBSCT. Three patients did not receive PBSCT due to disease progression prior to transplantation. Prompt engraftment occurred in all the remaining 11 patients with 17 PBSCTs.
CONCLUSIONS: Our data suggest that ANC can be helpful as a surrogate parameter in clinical decision-making when the peripheral blood CD34+ count is unavailable.

OBJECTIVE: In patients with a need for frequent but intermittent apheresis, vascular access can prove challenging. We describe the migration of the use of a Vortex LP dual lumen port (Angiodynamics, Latham, NY) to one Powerflow and one ClearVUE power injectable port (Becton Dickinson, Franklin Lakes, NJ) in a series of patients undergoing intermittent apheresis.
METHODS: All patients had a need for long-term intermittent apheresis. Eight had double lumen Vortex port (pre) and were exchanged for one Powerflow port and one conventional subcutaneous venous port with 90° needle entry (post) while 12 did not have any port in place and received the same configuration. IRB approval was granted. We recorded the treatment time, flow rate, and tissue plasminogen activator (tPA) use for five treatment sessions after placement. When available, we compared five treatments with the Vortex port and the new configuration.
RESULTS: The mean treatment time is reduced with the new configuration (P = 0.0033). The predicted mean treatment time, adjusting for gender, race, BMI and age and accounting for correlations within a patient is 91.18 min pre and 77.96 min post. The flow rate is higher with the new configuration (P < 0.0001). The predicted mean flow rate in mL/min is 61.59 for the Vortex port and 71.89 for the new configuration. tPA use was eliminated in the population converted from Vortex ports and had a 48% reduction when compared to all other configurations in the study.
CONCLUSIONS: The introduction of a novel device configuration of venous access ports for intermittent apheresis resulted in higher flow rates and less total time for treatment. Use of tPA was greatly reduced. These results suggest that the new configuration could result in less expense for the hospital and better throughput in a busy pheresis practice. Clinical trial registration with ClinicalTrials.gov: NCT04846374.

Modern apheresis devices, with increased procedural precision, automation, and monitoring, have been shown to allow for safe delivery of apheresis therapies in young children. Medical advances are increasing demand for apheresis procedures like mononuclear cell collection in infants <10 kg, including stem-cell supported chemotherapy, cell collection for chimeric antigen receptor T cell development, and now ex vivo gene therapies for rare genetic diseases. Nevertheless, safe delivery in small infants involves a range of unique considerations and challenges, beyond just size, and experience will vary between centers. In this case report we describe our experience performing mononuclear cell collection in our smallest patient to date and outline a practice guideline developed following a literature review and discussion with both international experts and device representatives. This case may help to inform other clinicians aiming to provide apheresis care to very small infants in their own centers.

BACKGROUND: Apheresis is practiced widely to collect single donor platelets (SDPs). This procedure utilizes an anticoagulant acid citrate dextrose to prevent clotting of blood in the extracorporeal circuit which chelates divalent ions like calcium. This alters the calcium homeostasis resulting in hypocalcemia causing acute adverse events.
OBJECTIVE: The study aimed to know the calcium homeostasis in apheresis platelet donors.
METHODS: This cross-sectional study was conducted from January 2020 to December 2020 in the department of transfusion medicine. The sample size was 50. Donors who walk in for voluntary SDP donation were selected. Total and ionized calcium, pH, and serum albumin for all the donors at baseline and ionic calcium at the end of the procedure and 30 min after the procedure were measured.
RESULTS: According to statistical analysis of the ionic calcium level at pre procedure, immediate post procedure and 30 minutes post procedure, there was decrease in the value immediate post procedure and values returned to baseline within 30 minutes. The levels of pH change were analyzed. On comparing the preprocedure and immediate postprocedure values, there was a significant lowering of pH value from the baseline (P = 0.5), indicating acute lowering of pH immediate postprocedure. Hence, most of the citrate metabolism can be achieved within 30 min after completion of the apheresis procedure.
CONCLUSIONS: SDP collection is essentially a safe procedure with minimal adverse effects. Toxicity of citrate is not much pronounced. Recovery of calcium levels is within 30 min of completion of plateletpheresis.

Sickle cell disease (SCD) is an autosomal recessive genetic disorder characterized by the abnormal formation of sickle hemoglobin (HbS). Under conditions of deoxygenation, HbS undergoes polymerization, resulting in microvascular occlusion, tissue hypoxia, and infarction. The elevated mortality rate associated with SCD is primarily attributed to complications such as sepsis, acute chest syndrome, stroke, acute multiorgan failure, and pulmonary hypertension. Despite advancements in awareness and treatments, preventing mortality in young individuals with SCD remains a formidable challenge. In an effort to shed light on these challenges, we present a case of unexpected death associated with SCD to emphasize the pressing need for continued research and intervention strategies to improve patient outcomes.

BACKGROUND: Therapeutic plasma exchange (TPE) eliminates disease-contributing substances but may also affect drug concentrations. This study aimed to assess the prevalence of prescription drugs removable via TPE by reviewing patient medication histories.
METHODS: A retrospective, single-center study was conducted from January 1, 2021 to December 31, 2022. The study included 244 patients undergoing 1087 TPE sessions. Drugs prescribed to patients on TPE days were categorized as \"yes\" (probably removable), \"maybe\" (possibly removable), and \"no\" (unlikely removable) regarding their removability via TPE.
RESULTS: Among 3966 prescriptions, 556 (14.0%) were analyzed, with 21.8%, 36.5%, and 41.7% falling into the \"yes,\" \"maybe,\" and \"no\" categories for removability. Although only 14.0% were categorized, 83.6% of patients received at least one analyzable drug. Among them, 83.8% had at least one potentially removable drug.
CONCLUSIONS: Real-world data highlights the need for caution in drug treatments during TPE to ensure optimal therapeutic outcomes, particularly for specific drugs.

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.
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.
CONCLUSIONS: Prospective clinical trials are needed to determine which patients are most likely to benefit from chronic RCE and refine selection accordingly.

BACKGROUND: Neutrophils in sickle cell disease (SCD) are activated, contributing to disease. Red cell exchange (RCE), with the goal of lowering hemoglobin S (HbS), is an important part of therapy for many SCD patients. Whether RCE impacts neutrophil reactivity is unknown.
METHODS: To determine the effect of RCE on neutrophil activation, SCD patients undergoing RCE in steady-state were enrolled. Neutrophil degranulation responses were examined before/after RCE. Kinetic studies were completed to determine the duration of the effect of RCE on neutrophil function. Degranulation results were examined in relation to white blood cell count, neutrophil count, and HbS levels. The effect of RCE on RBC phosphatidylserine (PS) exposure was examined as a possible contributor to modulation of neutrophil function by RCE.
RESULTS: Twenty-two patients with SCD, genotype SS, who underwent RCE (average pre-RCE HbS 33 ± 14%) were included for the study. RCE significantly decreased neutrophil degranulation responses. The effect of RCE on neutrophil activation was unrelated to cell count and instead directly correlated with HbS. The effect of RCE on neutrophil activation was sustained over several days post-apheresis. Furthermore, while increased RBC PS exposure results in increased neutrophil degranulation, RCE decreases RBC PS exposure.
CONCLUSIONS: To our knowledge, this is the first study demonstrating that RCE significantly decreases neutrophil activation in a sustained HbS-dependent manner. Modulation of PS exposure by RCE may be a contributing mechanism by which RCE modulates neutrophil activation. These studies raise the possibility that modulation of neutrophil activation contributes significantly to the therapeutic effect of RCE.