The effect of plerixafor on autologous stem cell mobilization, cell viability, and apheresis challenges.

OBJECTIVE: The aim of this study was to determine the efficacy of plerixafor for hematopoietic stem cell (HSC) mobilization prior to autologous stem cell transplantation (aSCT) for patients with multiple myeloma (MM) and various lymphomas, using an oncologist-guided HSC collection goal and markers of cell viability. METHODS: A retrospective chart review of all aSCT patients at Yale New Haven Hospital between 2017 and 2021 who met diagnostic criteria for MM, non-Hodgkin, or Hodgkin lymphoma (n = 382) was undertaken. Logistic regression evaluated plerixafor's effect on meeting the individual's HSC goal. The use of t-tests determined plerixafor's relationship to HSC yield and analysis of variance testing assessed its effect on cell viability. RESULTS: Mobilization with granulocyte colony-stimulating factor (G-CSF) and plerixafor (odds ratio [OR] = 0.08; P < .05) relative to G-CSF alone was negatively associated with meeting the individual's HSC goal. Diffuse large B-cell lymphoma in patients mobilized with plerixafor yielded fewer HSCs than those without plerixafor (t = -2.78; P = .03). Mobilization regimen (P = .13) had no association with HSC viability. Mobilization failure with plerixafor was rare but occurred in patients with multiple risk factors, including exposure to several rounds of HSC-affecting chemotherapy. CONCLUSION: Plerixafor is effective across multiple diagnoses using an oncologist-driven HSC collection endpoint. Its association with mobilization failure is likely attributable to its use in patients predicted to be poor mobilizers.

A multi-institutional survey of apheresis services among institutions in the United States.

INTRODUCTION: Apheresis practices in the United States (US) have not been comprehensively characterized to date. This study aimed to address this gap by evaluating apheresis therapy through a national survey. METHODS: A multi-institutional survey was conducted between April and July 2023. The survey, comprising 54 questions, focused on institutional demographics, procedures, equipment, staffing, training, and impacts of the Coronavirus Disease 2019 (COVID-19) pandemic. Responses from 22 institutions, primarily academic medical centers, were analyzed. RESULTS: Therapeutic plasma exchange (TPE) was the most common procedure, followed by hematopoietic progenitor cell collection (HPC-A) and red blood cell exchange (RCE). CAR-T cell collections were widespread, with some institutions supporting over 30 protocols concurrently. Most sites used the Spectra Optia Apheresis System, were managed by a transfusion medicine service, and employed internal apheresis providers. Insufficient staffing levels, exacerbated by the COVID-19 pandemic, were common and most often addressed using overtime. DISCUSSION: The survey highlighted the ubiquity of TPE, expanding cellular collections and staffing challenges. The role of apheresis in supporting cellular therapy, particularly in newly developing cell and gene therapies and clinical trials, was evident. Staffing issues during the pandemic emphasized the need for innovative recruitment strategies. CONCLUSION: This nationwide survey provides the most comprehensive analysis to date of apheresis practices in large US academic centers.

Therapeutic plasma exchange for hyperviscosity syndrome in IgA multiple myeloma.

Hyperviscosity syndrome (HVS) is defined as the symptomatic presentation of increased blood thickness due to various clinical conditions such as hypergammaglobulinemia. HVS secondary to immunoglobulin (Ig)A multiple myeloma has been infrequently reported. Although the efficiency of IgM or IgG removal by therapeutic plasma exchange (TPE) is well described, the efficiency of IgA removal by TPE is not as well known. Here, we describe a case of HVS due to IgA myeloma in a patient who received 2 TPE treatments, with subsequent symptomatic improvement as well as decrease in IgA and viscosity levels.

Transfusion Support of Patients with Myelodysplastic Syndromes.

Patients with MDS often suffer from anemia, and less often thrombocytopenia, and thus are a frequently transfused population. Red blood cell (RBC) transfusion may be used to improve functional capacity and quality of life in this population, while platelet transfusion is typically used to decrease bleeding risk. Despite the frequency of transfusion in patients with MDS, there are few well-defined guidelines for RBC and platelet transfusion support in this patient population. Transfusion is not without risk-patients with MDS who are frequently transfused may develop alloantibodies to RBC antigens, which can lead to hemolytic transfusion reactions and delays in obtaining compatible RBCs. Regular communication between clinicians and blood bank physicians is crucial to ensure that patients with MDS receive the most appropriate blood products.

Immunity in the balance: Fatal disseminated adenovirus infection in a patient undergoing plasma exchange and immunosuppressive chemotherapy for anti-glomerular basement membrane disease.

Anti-glomerular basement membrane (anti-GBM) disease (formerly known as Goodpasture's syndrome) is a rare autoinflammatory condition that affects the renal and/or pulmonary capillaries. The standard therapeutic regimen for anti-GBM disease involves therapeutic plasma exchange (TPE), cyclophosphamide, and corticosteroids to rapidly remove and inhibit autoantibody production and reduce organ inflammation. Herein we report an 82-year-old female who developed anti-GBM disease but expired despite therapy, secondary to multi-organ failure in the setting of disseminated adenovirus disease. We discuss the utility and potential adverse effect of daily TPE for a protracted course (ie, 10-14 days), the recommended TPE intensity in the 2023 American Society for Apheresis guidelines, updated from every-other-day TPE in the 2019 guidelines, despite no new data. We also highlight the potential for unusual infections to occur in these patients due to the profound immunosuppression, and discuss the importance of balancing immunosuppression to treat the disease with close surveillance of any potential opportunistic infections.

Optimizing Donor Chimerism Threshold for Next-Generation Sequencing Monitoring of Measurable Residual Disease Post-Allogeneic Stem Cell Transplantation for Myeloid Neoplasms.

Next-generation sequencing (NGS) is used to monitor genetically measurable residual disease (gMRD) following allogeneic stem cell transplantation (aSCT). It is unknown whether an upper limit of chimerism exists such that gMRD NGS testing can be safely forgone. We reviewed 61 patients with acute myeloid leukemia and 24 patients with myelodysplastic syndrome who had at least 1 NGS panel before and after aSCT between 2016 and 2020. Donor chimerism was quantified. Logistic regression characterized which factors predicted gMRD. Receiver operating characteristic (ROC) curves were used to determine the optimal chimerism threshold for which gMRD would not be detected. Data from an additional 22 patients with follow-up NGS testing in 2022 were also analyzed to validate our proposed threshold. A: s expected, donor chimerism was a significant predictor of gMRD (odds ratio, .38; 95% confidence interval, .10 to .62; P = .02). Age, sex, conditioning regimen, presence of a related donor, and diagnosis were not associated with gMRD. A chimerism threshold of 92.5% optimized sensitivity (97.7%) and specificity (95.4%) such that values >92.5% strongly predicted the absence of gMRD (area under the ROC curve [AUC], .986). The validation cohort demonstrated similarly strong predictive capability (AUC, .974) with appropriate sensitivity (100%) and specificity (90.9%). NGS monitoring of gMRD is redundant at chimerism values greater than a more conservative threshold of 92.5% after aSCT.

Alloimmunization following antigen-negative red blood cell transfusion.

BACKGROUND: Red blood cell (RBC) alloimmunization can occur secondary to transfusion or pregnancy. It is observed most frequently among patients with hemoglobinopathies and myeloid neoplasms. Although previous antigen exposure is generally required for alloimmunization, some alloantibodies may develop naturally without prior exposure. Other alloantibodies may become evanescent, only to reemerge at a detectable titer following a stimulatory event. In a minute fraction of cases, 'non-naturally occurring' alloantibodies may appear without a known antigenic stimulus. METHODS AND MATERIALS: All testing (antibody detection tests and identification, antigen phenotyping, and crossmatching) was performed using the same method and reagents, but occurred at two hospitals within the Yale New Haven Hospital delivery network, and was performed by technologists utilizing different instruments and reagent lots. RESULTS: We present two cases of seemingly de novo alloimmunization (anti-E and anti-K), and one case of re-emergence of a known, previously evanescent alloantibody (anti-K) following transfusion of RBCs that were antigen-negative for the corresponding antibodies. CONCLUSION: While the exact mechanism underlying the development and/or re-emergence of RBC alloantibodies in the absence of antigenic stimulation remains unclear, these cases highlight this unusual phenomenon, underscoring the general immunogenicity, as well as the potential consequences, of RBC transfusion and reiterates the importance of concluding an alloantibody specificity, even in the absence of known transfusion of RBCs with a particular antigen.

Association of iron infusion reactions with ABO blood type.

OBJECTIVES: We sought to determine risk factors for iv iron infusion-related reactions (IRR), and identify strategies for iron repletion after IRR. METHODS: We conducted a retrospective chart review of patients treated in the classical hematology clinic at Yale Cancer Center (n = 330 consecutive patients) from 2016 to 2021, who received iv ferumoxytol (60.3%), iron sucrose (14.8%), or iron dextran (10.9%). RESULTS: The iv iron IRR was noted in 58 (17.6%) patients, 62.1% of whom had previously tolerated iv iron. The severity of IRR was mild in 22, moderate in 23, and severe in 11 patients. Most (72.4%) patients who experienced IRR tolerated a subsequent iv iron infusion. On multivariable analysis, a history of non-medication allergies was associated with greater odds of IRR (odds ratio [OR] 2.12, 95% confidence interval (CI): 1.16-3.87, p = .01). No patients with type AB blood, and few with type A blood (n = 6), had IRR; compared to type A or AB together, patients with type B (OR 5.00, 95% CI: 1.56-16.06, p = .007) or type O (OR 3.71, 95% CI: 1.44-9.55, p = .007) blood had greater odds of IRR. CONCLUSIONS: This study highlights a possible association of blood type with iv iron IRR; prospective studies with larger patient numbers are warranted to explore this association.

Automated analysers underestimate atypical basophil count in myeloid neoplasms.

INTRODUCTION: Recent data suggest basophils can adopt an atypical appearance in myeloid disorders including myeloproliferative neoplasms (MPNs) and myeloproliferative/myelodysplastic disease. We hypothesized that automated analysers may not accurately quantitate basophils in myeloid neoplasms based on scatter properties. This study examined basophil counts and properties in myeloid disorders by automated cell analyser, manual differential, and flow cytometry. METHODS: Patients with myeloid neoplasms and control patients with no myeloid disorder diagnosis at a tertiary care centre were identified. Basophil percentage was compared for automated analyser counts (Sysmex XN9000), manual differential, and flow cytometry. Basophil scatter properties in MPNs were examined using flow cytometry. RESULTS: Thirty-one patients with myeloid neoplasms were included: 58% were male, mean age was 70.2 (±20.7) years, 32% had a diagnosis of chronic myeloid leukaemia with the remaining patients divided among various other forms of myeloid disease (including: essential thrombocythemia, polycythemia vera, unclassifiable MPN, myelodysplastic syndromes). For these patients, mean basophil percentage by automated analyser was significantly lower than manual differential (2.7 ± 2.9 vs. 7.1 ± 4.6, respectively, p < 0.001). No significant difference was found between automated versus manual differential for basophils in control subjects (p = 0.373). For myeloid neoplasm patients, mean basophil percentage was not significantly different between manual differential and flow cytometry (p = 0.116); mean basophil percentage by automated analyser was significantly lower than flow cytometry (2.7 ± 2.9 vs. 5.3 ± 3.7, respectively, p = 0.003). CONCLUSION: Automated analysers underestimate basophil counts in patients with myeloid neoplasms. Manual differential and flow cytometry are recommended for more accurate quantitation and characterization of aberrant basophils.

Therapeutic plasma exchange for peripheral neuropathy associated with trisulfated heparan disaccharide IgM antibodies: A case series of 17 patients.

BACKGROUND: Small fiber neuropathy (SFN) can be associated with autoantibodies, including those of IgM class with specificity for the trisulfated heparan disaccharide (TS-HDS) antigen. We hypothesized that, as an IgM autoantibody-mediated disorder, TS-HDS-associated SFN symptoms may be reduced with therapeutic plasma exchange (TPE). STUDY METHODS: This was an observational analysis of all patients referred for TPE from 2018 to 2020 following laboratory confirmation of SFN with TS-HDS autoantibodies; a loading course of 3 to 5 procedures over 2 weeks was completed, with some patients returning for monthly procedures. The following data were collected: demographics, symptoms and duration, TS-HDS levels, skin biopsy results, reported responses to TPE, and TPE-associated adverse events. RESULTS: Of the 17 subjects, 12 (71%) were female and the mean age was 57.5 years (range 27-94). The most common reported symptom was lower extremity paresthesia (88% of subjects). The mean number of TPE procedures completed per subject was 9 (range 3-18), with 71% (12/17) reporting symptomatic improvement or slowed disease progression. About 15% of procedures were associated with an adverse event, with vasovagal reactions being the most common; 53% of patients had at least one adverse event. CONCLUSIONS: Given a reported symptomatic response rate of more than 70%, TPE may be a treatment option for individuals with autoimmune-mediated SFN associated with increased titers of TS-HDS IgM autoantibodies. Since TPE-associated adverse events appear common in this population, close monitoring during procedures is warranted.

Autologous hematopoietic stem cell product contaminated with Salmonella due to occult salmonellosis in an asymptomatic donor.

Recent advancements in infectious disease testing methods and pathogen reduction technologies have greatly reduced the incidence of microbial contamination of allogeneic blood products. Despite this significant reduction, contamination of autologous cellular therapy products remains a challenging issue, as many of these mitigation strategies are not feasible for such products. Most microorganisms isolated from cellular therapy products are Gram-positive normal skin flora, and studies have demonstrated that adverse effects are infrequent when these contaminated products are infused. However, no prior report has documented an autologous hematopoietic stem cell (HSC) or other cellular therapy product contaminated with Salmonella bacteria-a pathogenic Gram-negative organism. We present the first known case of Salmonella contaminating an HSC product secondary to occult salmonellosis in the donor, and discuss the implications of this contaminating organism and the therapeutic dilemma posed by this scenario.

Transfusion practices for pediatric oncology and hematopoietic stem cell transplantation patients: Data from the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III (REDS-III).

BACKGROUND: To evaluate transfusion practices in pediatric oncology and hematopoietic stem cell transplant (HSCT) patients. STUDY DESIGN AND METHODS: This is a multicenter retrospective study of children with oncologic diagnoses treated from 2013 to 2016 at hospitals participating in the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III. Transfusion practices were evaluated by diagnosis codes and pre-transfusion laboratory values. RESULTS: A total of 4766 inpatient encounters of oncology and HSCT patients were evaluated, with 39.3% (95% confidence interval [CI]: 37.9%-40.7%) involving a transfusion. Red blood cells (RBCs) were the most commonly transfused component (32.4%; 95% CI: 31.1%-33.8%), followed by platelets (22.7%; 95% CI: 21.5%-23.9%). Patients in the 1 to <6 years of range were most likely to be transfused and HSCT, acute myeloid leukemia, and aplastic anemia were the diagnoses most often associated with transfusion. The median hemoglobin (Hb) prior to RBC transfusion was 7.5 g/dl (10-90th percentile: 6.4-8.8 g/dl), with 45.7% of transfusions being given at 7 to <8 g/dl. The median platelet count prior to platelet transfusion was 20 × 109 /L (10-90th percentile: 8-51 × 109 /L), and 37.9% of transfusions were given at platelet count of >20-50 × 109 /L. The median international normalized ratio (INR) prior to plasma transfusion was 1.7 (10-90th percentile: 1.3-2.7), and 36.3% of plasma transfusions were given at an INR between 1.4 and 1.7. DISCUSSION: Transfusion of blood components is common in hospitalized pediatric oncology/HSCT patients. Relatively high pre-transfusion Hb and platelet values and relatively low INR values prior to transfusion across the studied diagnoses highlight the need for additional studies in this population.

Optimization of repeat plerixafor dosing for autologous peripheral blood stem-cell collection.

INTRODUCTION: Peripheral CD34+ cells may be mobilized using filgrastim alone or in combination with chemotherapy. The addition of plerixafor can be efficacious, though guidelines for repeat dosing are lacking. MATERIAL AND METHODS: This quality improvement project was initiated to generate guidelines for repeat plerixafor dosing after retrospective evaluation of data in adult patients undergoing autologous peripheral blood stem cell mobilization and collection. RESULTS: Analysis included 195 patients: 119 (61 %) with multiple myeloma and 76 (39 %) with lymphoma. Patients given at least one dose of plerixafor (n = 109) were further divided: Group 1) (A) goal of 3 × 10E6/kg and day 1 peripheral blood CD34+ count < 30 × 10E6/L, vs (B) ≥ 30 × 10 E6/L; Group 2) (A) goal of 6 × 10E6/kg and day 1 peripheral blood CD34+ count < 50 × 10E6/L or < 50 % of collection goal after day 1, vs (B) ≥ 50 % of collection goal after day 1. Ninety five percent of cases in Group 1B and 88 % of cases in Group 2B did not receive additional plerixafor doses and all of them achieved their collection goals. In contrast, those in Groups 1A and 2A required additional plerixafor dosing and some mobilizations/collections were futile. CONCLUSION: Based on these data, with consideration of collection goal, peripheral blood CD34+ count, and CD34+ cell bag count on collection day 1, we have generated institutional guidelines for collection initiation and repeat plerixafor dosing. Long term, we predict these guidelines will optimize pharmacy, apheresis, and stem cell processing resources while improving the patient experience.

Behind the scenes with basophils: an emerging therapeutic target.

Though basophils were originally viewed as redundant blood 'mast cells', the implementation of flow cytometry has established basophils as unique leukocytes with critical immunomodulatory functions. Basophils play an active role in allergic inflammation, autoimmunity, and hematological malignancies. They are distinguishable from other leukocytes by their characteristic metachromatic deep-purple cytoplasmic, round granules. Mature basophils are phenotypically characterized by surface expression of IL-3Rα (CD123); IL-3 drives basophil differentiation, degranulation, and synthesis of inflammatory mediators including type 2 cytokines. Basophil degranulation is the predominant source of histamine in peripheral blood, promoting allergic responses. Basophils serve as a bridge between innate and adaptive immunity by secreting IL-4 which supports eosinophil migration, monocyte differentiation into macrophages, B-cell activation, and CD4 T-cell differentiation into Th2 cells. Further, basophilia is a key phenomenon in myeloid neoplasms, especially chronic myeloid leukemia (CML) for which it is a diagnostic criterion. Increased circulating basophils, often with aberrant immunophenotype, have been detected in patients with CML and other myeloproliferative neoplasms (MPNs). The significance of basophils' immunoregulatory functions in malignant and non-malignant diseases is an active area of research. Ongoing and future research can inform the development of immunotherapies that target basophils to impact allergic, autoimmune, and malignant disease states. This review article aims to provide an overview of basophil biology, identification strategies, and roles and dysregulation in diseases.

Evaluation of Positive B- and T-Cell Gene Rearrangement Studies in Patients With Negative Morphology, Flow Cytometry, and Immunohistochemistry.

CONTEXT.­: The significance of positive immunoglobulin (IG) or T-cell receptor (TCR) gene rearrangement studies in the context of otherwise normal ancillary findings is unknown. OBJECTIVE.­: To examine long-term hematologic outcomes of individuals with positive gene rearrangement studies with otherwise unremarkable blood or bone marrow studies in parallel. DESIGN.­: Data from patients who underwent IG or TCR gene rearrangement testing at the authors' affiliated Veterans Affairs Hospital January 1, 2013 to July 6, 2018 were extracted from medical records. Date of testing, specimen source, and morphologic, flow cytometric, immunohistochemical, and cytogenetic characterization of the tissue source were recorded. Gene rearrangement results were categorized as test positive/phenotype positive (T+/P+), test positive/phenotype negative (T+/P-), test negative/phenotype negative (T-/P-), or test negative/phenotype positive (T-/P+) based on comparison to other studies and/or final diagnosis. Patient records were reviewed for subsequent diagnosis of hematologic malignancy for patients with positive gene rearrangements but no other evidence for a disease process. RESULTS.­: A total of 136 patients with 203 gene rearrangement studies were analyzed. For TCR studies, there were 2 T+/P- and 1 T-/P+ results in 47 peripheral blood assays, as well as 7 T+/P- and 1 T-/P+ results in 54 bone marrow assays. Regarding IG studies, 3 T+/P- and 12 T-/P+ results in 99 bone marrow studies were identified. None of the 12 patients with T+/P- TCR or IG gene rearrangement studies later developed a lymphoproliferative disorder. CONCLUSIONS.­: Positive IG/TCR gene rearrangement studies in the context of otherwise negative bone marrow or peripheral blood findings are not predictive of lymphoproliferative disorders.

Monocytic Acute Myeloid Leukemias with KM2TA Translocations to Chromosome 17q that May Clinically Mimic Acute Promyelocytic Leukemia.

OBJECTIVE: Acute promyelocytic leukemia (APL) with variant RARA translocation, eg, t(11;17), is not sensitive to all-trans retinoic acid and requires distinct chemotherapy. However, there are some leukemic entities that may mimic aspects of the clinical and/or laboratory picture of APL and cause confusion because of karyotype nomenclature. Therefore, recognition of such entities may be of therapeutic and prognostic significance. METHODS: We present 2 cases of acute myeloid leukemia (AML) with t(11;17) that were clinically concerning for APL based primarily on clinical presentation but were ultimately diagnosed as AML with monocytic differentiation. RESULTS: Both leukemias harbored KMT2A translocations, one located near but not involving RARA and the other with SEPT9. CONCLUSION: In leukemias that clinically and/or immunophenotypically mimic APL, identification of specific gene translocations can lead to the correct diagnosis and may carry therapeutic/prognostic implications.

The Development and Implementation of a Novel Electronic Consult System by a Laboratory Medicine Service: Experience From the First 2 Years of Use.

CONTEXT.­: A novel electronic consult (e-consult) system for a pathology and laboratory medicine service (PLMS) was implemented in 2015 at a high-complexity Veterans Administration health care facility. Consults were previously made through direct provider communication without documentation in the medical record. OBJECTIVE.­: To evaluate the utilization trends of the laboratory e-consult system at the Department of Veterans Affairs Connecticut facility during the first 2 years since inception. DESIGN.­: E-consultation involves pathology and laboratory medicine resident review followed by attending pathologist review and cosignature. E-consults to the pathology and laboratory medicine service from 2015 to 2017 were reviewed to record type of consult, requesting department, patient location, and turnaround time. RESULTS.­: The pathology and laboratory medicine service received 351 e-consults from 2015 to 2017. The volume varied by subsection: hematology and coagulation (215 of 351; 61%), chemistry (109 of 351; 31%), blood bank (19 of 351; 6%), and microbiology/virology (8 of 351; 2%). Hematology and coagulation consults were entirely for peripheral blood smear review (215 of 215; 100%). Chemistry consults were placed for toxicology/drugs of abuse (81 of 109; 74%), test utilization (17 of 109; 16%), or nontoxicology (11 of 109; 10%). Three services placed the majority of consults: primary care (279 of 351; 80%), hematology/oncology (39 of 351; 11%), and psychiatry (27 of 351; 8%). The median turnaround time for completion of e-consults was 1.2 days. Since e-consult implementation, the mean number of consults increased from 8.6/mo in 2015 to 18.1/mo in 2017, peaking in the last quarter of analysis in 2017 with a mean of 25.3 consults/mo. CONCLUSIONS.­: This novel e-consult system improved accessibility to and documentation of answers to laboratory questions and increased the visibility of the pathology and laboratory medicine service. Future goals include development of outcomes-based measures to better assess the clinical impact of e-consults.