Clinical management of a patient following a granulocyte transfusion from a donor positive for COVID-19.

Granulocyte transfusions are indicated for patients with severe neutropenia and evidence of bacterial or fungal infection who are unresponsive to standard antimicrobial therapy. With a limited expiration time of 24 hours after collection, granulocytes are often transfused before results of infectious-disease screening tests are available, and before a transfusion service can perform a risk assessment if postdonation information is provided after the collection. The case we describe herein demonstrates a clinical scenario meeting indications for granulocyte transfusion, coupled with the clinical management undertaken after the granulocyte donor disclosed a positive result for a COVID-19 self-test taken 1 day after donation. In this case, the patient did not develop new COVID-19 symptoms and tested negative for COVID-19 after transfusion of the implicated unit. These findings add to the body of evidence in the literature that COVID-19 is not transmitted via blood transfusion.

Addition of plerixafor in poorly mobilized allogeneic stem cell donors.

BACKGROUND: Peripheral blood stem cells (PBSCs) are the predominant graft source for adult allogeneic hematopoietic stem cell transplantation (HSCT). In poorly mobilized autologous donors, plerixafor improves collection outcomes. We examine plerixafor use in allogeneic donors who mobilize poorly with granulocyte colony-stimulating factor (G-CSF) in those who are healthy and those with pre-existing medical conditions, and determine the optimal threshold to add plerixafor. STUDY DESIGN/METHODS: We retrospectively examined all allogeneic PBSC collections from January 2013 to October 2020 at our center. Donors received G-CSF 10 mcg/kg daily for 4 days before undergoing apheresis collection on day 5. Plerixafor was added based on poor CD34+ cell collection yield after the first or second collection day. RESULTS: Of the 1008 allogeneic donors, 41 (4.1%) received one dose of plerixafor in addition to G-CSF due to poor collection yield. After starting plerixafor there was a 0.75- to 7.74-fold (median 2.94) increase in CD34+ yield from the previous day. No donors with G-CSF-only mobilization who collected <2.0 × 106 CD34+ cells/kg recipient weight on day one achieved the goal of ≥4.0 × 106 CD34+ cells/kg recipient weight total over 2 days but 59.2% of donors who used rescue plerixafor did. CONCLUSION: Donors both healthy and those with pre-existing disease responded well to plerixafor with minimal side effects. If the first-day collection yield is less than ~63% of the collection goal, addition of plerixafor may be necessary to reach the collection goal and limit the number of collection days in allogeneic donors.

Red blood cell and platelet transfusion support in the first 30 and 100 days after allogeneic hematopoietic cell transplant.

BACKGROUND: Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients often require substantial but variable transfusion support. STUDY DESIGN AND METHODS: This single-center, retrospective study evaluated the red blood cell (RBC) and platelet (PLT) transfusion data of first-time allo-HSCT recipients transplanted in 2011 to 2017. Multivariate analyses were performed to assess the associations between patient and transplant-related factors and transfusion requirements. RESULTS: The study included 1762 patients who received peripheral blood stem cells (88.2%), marrow (7.0%), or umbilical cord (4.8%) from matched related (38.3%), unrelated (49.2%), or haploidentical (7.8%) donors. Almost all patients required RBCs (88.3%) or PLTs (97.4%) during the first 30 days, with medians of 3 (range, 1-37) RBC and 6 (range, 1-144) PLT units transfused. Fewer patients required RBC (43.8%) or PLT (27.3%) transfusions during Days 31 to 100, but the median (range) numbers of RBC and PLT units remained high at 3 (1-36) and 6 (1-116) among transfused patients. RBC and PLT transfusion independence was reached in medians of 24 (95% confidence interval [CI], 22-26) and 12 (95% CI, 11-12) days, respectively. Haploidentical donor, cord graft, and requiring RBC transfusions in the 10 days before HSCT were the most significant independent factors predictive of increased transfusion requirements. Advanced disease, diagnosis, ABO incompatibility, conditioning intensity, CD34+ cell dose, presence of severe acute graft-vs-host disease, and changes in recommended transfusion triggers were also shown to independently impact transfusion requirements. CONCLUSIONS: This study provided for the first time quantitative and comparative transfusion data on a large contemporary cohort of HSCT recipients, including haploidentical and cord graft recipients, and identified factors predictive of increased transfusions.

Third time's a charm? Mobilization of autologous peripheral blood stem cells in patients with two previous failed mobilizations with plerixafor.

BACKGROUND: Patients who respond inadequately to plerixafor salvage during autologous peripheral blood stem cell (PBSC) collection are frequently remobilized with plerixafor to collect additional stem cells. However, in patients who fail remobilization, it is unclear whether additional mobilization efforts with plerixafor are useful. STUDY DESIGN AND METHODS: We retrospectively examined the PBSC collections of 15 consecutive patients with lymphoma and multiple myeloma who underwent three mobilizations with plerixafor. RESULTS: Of the 821 patients who underwent autologous stem cell collections, 15 patients were mobilized three times with plerixafor (1.8%), which enabled 11 (73.3%) patients to reach 2.0 × 106 CD34+ cells/kg or greater. Among patients who eventually collected successfully the median yields from the three collection attempts were 0.46, 0.76, and 1.54 × 106 CD34+ cells/kg, respectively. Among those who collected less than 2.0 × 106 CD34+ cells/kg cumulatively, the median yields were 0.14, 0.33, and 0.22 × 106 CD34+ cells/kg from the three collection attempts. The combined collection yields from the first two mobilization attempts were significantly lower (p = 0.003; range, 0.09-0.73 vs. 0.63-1.84; median, 0.51 vs. 1.36) in those who failed collection. CONCLUSIONS: The majority (73.3%) of patients who underwent three mobilization attempts were eventually able to collect enough cells to permit autologous transplantation. Extremely low peripheral blood CD34+ count after the first dose of plerixafor and collection yields during the first two attempts were associated with a poor collection yield on the third attempt. The risks and benefits of a third mobilization should be weighed to facilitate judicious use of resources.

RBC and platelet transfusion support in the first 30 and 100 days after haploidentical hematopoietic stem cell transplantation.

BACKGROUND: The volume of haploidentical hematopoietic stem cell transplant (haplo-HSCT) has increased dramatically in recent years. However, the associated higher risk of delayed engraftment may increase patient transfusion requirements. STUDY DESIGN AND METHODS: The post-HSCT RBC and platelet transfusions of 195 haplo-HSCT recipients were evaluated. Patient and transplant-related factors potentially impacting the number of products transfused and time to transfusion independence were assessed. RESULTS: Nearly all (98.4%) patients were transfused in the first 30 days, and 59.2% were transfused between days 31 and 100. Among the transfused patients, medians of 5 units (interquartile range [IQR] = 3-8) of RBCs and 11 units (6-20) platelets were given in the first 30 days, and medians of 3 units (IQR = 1-7) of RBCs and 6 units (2-18) of platelets were transfused between days 31 and 100. Median times for achieving RBC and platelet transfusion independence were 34 (95% CI: 28-40) and 25 (95% CI: 23-27) days, respectively. Multivariable analyses showed that RBC transfusions in the 10 days before HSCT were associated with significantly increased and sustained RBC and platelet transfusion requirements. Major ABO incompatibility led to increased RBC transfusions. Advanced disease was associated with increased transfusions during the first 30 days, whereas GVHD increased platelet transfusions between days 31 and 100. Effects of age, sex, CD34+ cell dose, stem cell source, and conditioning regimen were limited or insignificant. CONCLUSIONS: This study for the first time provided quantitative transfusion data on a large cohort of haplo-HSCT recipients and identified factors predictive of increased transfusions.

High-throughput, single-cell analysis of macrophage interactions with fluorescently labeled Bacillus anthracis spores.

The engulfment of Bacillus anthracis spores by macrophages is an important step in the pathogenesis of inhalational anthrax. However, from a quantitative standpoint, the magnitude to which macrophages interact with and engulf spores remains poorly understood, in part due to inherent limitations associated with commonly used assays. To analyze phagocytosis of spores by RAW264.7 macrophage-like cells in a high-throughput, nonsubjective manner, we labeled B. anthracis Sterne 7702 spores prior to infection with an Alexa Fluor 488 amine-reactive dye in a manner that did not alter their germination, growth kinetics, and heat resistance. Using flow cytometry, large numbers of cells exposed to labeled spores were screened to concurrently discriminate infected from uninfected cells and surface-associated from internalized spores. These experiments revealed that spore uptake was not uniform, but instead, highly heterogeneous and characterized by subpopulations of infected and uninfected cells, as well as considerable variation in the number of spores associated with individual cells. Flow cytometry analysis of infections demonstrated that spore uptake was independent of the presence or absence of fetal bovine serum, a germinant that, while routinely used in vitro, complicates the interpretation of the outcome of infections. Two commonly used macrophage cell lines, RAW264.7 and J774A.1 cells, were compared, revealing significant disparity between these two models in the rates of phagocytosis of labeled spores. These studies provide the experimental framework for investigating mechanisms of spore phagocytosis, as well as quantitatively evaluating strategies for interfering with macrophage binding and uptake of spores.