Clinical and laboratory features associated with myeloperoxidase expression in pediatric B-lymphoblastic leukemia.

BACKGROUND: B-lymphoblastic leukemia (B-ALL) is the most common childhood malignancy, and its diagnosis requires immunophenotypically demonstrating blast B cell lineage differentiation. Expression of myeloperoxidase (MPO) in B-ALL is well-described and it has been recognized that a diagnosis of mixed phenotype acute leukemia should be made cautiously if MPO expression is the sole myeloid feature in these cases. We sought to determine whether MPO expression in pediatric B-ALL was associated with differences in laboratory, immunophenotypic, or clinical features. METHODS: We reviewed clinical, diagnostic bone marrow flow cytometry, and laboratory data for all new B-ALL diagnoses at our pediatric institution in 5 years. Cases were categorized as MPO positive (MPO+) or negative (MPO-) using a threshold of ≥20% blasts expressing MPO at intensity greater than the upper limit of normal lymphocytes on diagnostic bone marrow flow cytometry. RESULTS: A total of 148 cases were reviewed, 32 of which (22%) were MPO+. MPO+ B-ALL was more frequently hyperdiploid and less frequently harbored ETV6-RUNX1; no MPO+ cases had KMT2A rearrangements or BCR-ABL1. Although not significantly so, MPO+ B-ALL was less likely than MPO- B-ALL to have positive end-of-induction minimal residual disease studies (9.4 and 24%, respectively), but relapse rates and stem cell transplantation rates were similar between groups. Aberrant expression of other more typically myeloid markers was similar between these groups. CONCLUSION: In our study cohort, MPO+ B-ALL showed minimal residual disease persistence less often after induction chemotherapy but otherwise had similar clinical outcomes to MPO- B-ALL, with similar rates of additional myeloid antigen aberrancy.

Feasibility of manual white blood cell counts as a predictor of neonatal sepsis in a low-resource setting.

BACKGROUND: Manual white blood cell (WBC) differential counts as a predictor for neonatal sepsis development in a low-resource setting have not been thoroughly evaluated. We hypothesized that manual differentiation (specifically immature:total [I:T] neutrophil ratios) would be feasible and useful as an adjunct to predict early-onset neonatal sepsis (EONS). Secondarily, we hypothesized that vaccination with bacillus Calmette-Guérin (BCG) and oral polio vaccine (OPV) could alter WBC differential counts and thus might reduce its predictive performance. METHODS: We performed a prospective cohort study within a randomized trial, randomizing healthy, high-risk newborns admitted to the nursery at the national hospital in Guinea-Bissau 1:1 to BCG+OPV at admission or at discharge (usual practice). Thin capillary blood films were prepared at 2 d of age in a subset of 268 neonates. WBC counts were assessed by microscopy and neonates were followed up for sepsis development within 2 weeks. RESULTS: Ninety-eight percent (264/268) of smears provided interpretable reads. Of the 264 children, 136 had been randomized to receive BCG+OPV prior to sampling; the remaining 128 were vaccinated at discharge. The I:T ratio (average 0.017) was lower among children who did not develop clinical sepsis but did not predict sepsis (p=0.70). Only three children had an I:T ratio >0.2 (associated with a higher probability of clinical sepsis in previous studies) but did not develop sepsis. Immunization did not alter WBC composition. CONCLUSIONS: Manual WBC differentials are feasible in low-resource settings. WBC differentials are not affected by standard newborn immunization. However, the I:T ratio had no value in predicting subsequent development of sepsis.

Educating the next frontier of transfusionists: a transfusion camp pilot program for nurse practitioners.

BACKGROUND: Blood transfusion is common and potentially lifesaving but is associated with risk and overuse. Nurse practitioners (NPs) in multidisciplinary care teams are increasingly expanding their scope of practice to transfusion medicine (TM). Resources aimed at NPs are lacking, and little is known about NP TM knowledge. Thus, we developed a pilot TM curriculum for NP credentialing and assessed its impact. METHODS: NP leads and TM directors adapted the successful Canadian Transfusion Camp for medical postgraduate trainees into a 3-day curriculum for NPs. Two modalities were used to assess the pilot: 1) a participant demographics survey and needs assessment; and 2) the validated BEST-TEST knowledge assessment exam administered before and after the course. RESULTS: Of the 23 volunteer participants, the majority reported prescribing blood products within the last year, primarily red blood cells. Minimal opportunities to undertake continuing medical education in TM were identified. NPs often used preprinted order forms, consultation with physicians sharing care, or local fact sheets to guide transfusion; rather than TM physician consultation or guidelines. Exam scores significantly improved after the course (before, 35.2% vs. after, 50.3%; p = 0.005), suggesting average initial knowledge being below medical postgraduate trainee-level improving to postgraduate trainee level. Questions on appropriate transfusion triggers and correct recipient identification were most correctly answered; and responses to transfusion reaction questions required improvement. CONCLUSIONS: Our needs assessment suggests that TM resources for NPs are relevant but lacking. Our initiative supports the generalizability, scalability, and effectiveness of the Transfusion Camp program. Further implementation, refinement, and future impact assessments are required.

Microparticle content of platelet concentrates is predicted by donor microparticles and is altered by production methods and stress.

In circulation, shedding of microparticles from a variety of viable cells can be triggered by pathological activation of inflammatory processes, by activation of coagulation or complement systems, or by physical stress. Elevated microparticle content (MPC) in donor blood might therefore indicate a clinical condition of the donor which, upon transfusion, might affect the recipient. In blood products, elevated MPC might also represent product stress. Surprisingly, the MPC in blood collected from normal blood donors is highly variable, which raises the question whether donor microparticles are present in-vivo and transfer into the final blood component, and how production methods and post-production processing might affect the MPC. We measured MPC using ThromboLUX in (a) platelet-rich plasma (PRP) of 54 apheresis donors and the corresponding apheresis products, (b) 651 apheresis and 646 pooled platelet concentrates (PCs) with plasma and 414 apheresis PCs in platelet additive solution (PAS), and (c) apheresis PCs before and after transportation, gamma irradiation, and pathogen inactivation (N = 8, 7, and 12 respectively). ThromboLUX-measured MPC in donor PRP and their corresponding apheresis PC samples were highly correlated (r = 0.82, P = .001). The average MPC in pooled PC was slightly lower than that in apheresis PC and substantially lower in apheresis PC stored with PAS rather than plasma. Mirasol Pathogen Reduction treatment significantly increased MPC with age. Thus, MPC measured in donor samples might be a useful predictor of product stability, especially if post-production processes are necessary.

Could Microparticles Be the Universal Quality Indicator for Platelet Viability and Function?

High quality means good fitness for the intended use. Research activity regarding quality measures for platelet transfusions has focused on platelet storage and platelet storage lesion. Thus, platelet quality is judged from the manufacturer's point of view and regulated to ensure consistency and stability of the manufacturing process. Assuming that fresh product is always superior to aged product, maintaining in vitro characteristics should preserve high quality. However, despite the highest in vitro quality standards, platelets often fail in vivo. This suggests we may need different quality measures to predict platelet performance after transfusion. Adding to this complexity, platelets are used clinically for very different purposes: platelets need to circulate when given as prophylaxis to cancer patients and to stop bleeding when given to surgery or trauma patients. In addition, the emerging application of platelet-rich plasma injections exploits the immunological functions of platelets. Requirements for quality of platelets intended to prevent bleeding, stop bleeding, or promote wound healing are potentially very different. Can a single measurable characteristic describe platelet quality for all uses? Here we present microparticle measurement in platelet samples, and its potential to become the universal quality characteristic for platelet production, storage, viability, function, and compatibility.

Should intraoperative cell-salvaged blood be used in patients with suspected or known malignancy?

PURPOSE: Intraoperative cell salvage (ICS) is used as an alternative to allogeneic blood transfusion in an attempt to avoid or minimize the risks associated with allogeneic blood. Intraoperative cell salvage is generally avoided in surgeries where malignancy is confirmed or suspected due to concern for potential metastasis or cancer recurrence. The application of post-processing methods for ICS is hypothesized to eliminate this potential risk. The purpose of this narrative review is to examine the in vitro experimental evidence as it pertains to the removal of tumour cells from ICS blood and to review the clinical studies where ICS blood has been used in patients with malignancy. SOURCE: A search of the English literature for relevant articles published from 1973 to 2012 was undertaken using MEDLINE and Cochrane databases. Bibliographies were cross-referenced to locate further studies. PRINCIPAL FINDINGS: Leukoreduction filters are an effective method for removal of malignant cells from ICS blood. Small non-randomized clinical studies to date do not show evidence of an increased rate of metastasis or cancer recurrence. Although a theoretical risk of disease recurrence persists, the decision to use autologous ICS blood must be weighed against the known risks of allogeneic blood transfusion. CONCLUSION: Transfusion of autologous blood harvested via ICS should be considered a viable option for reduction or avoidance of allogeneic product during many oncologic surgeries and may be a lifesaving option for those patients who refuse allogeneic blood products.

Temporal trends in the treatment of severe traumatic hemorrhage.

BACKGROUND: This study examined the evolution of damage control resuscitation (DCR) and outcomes in severe traumatic hemorrhage (STH) at a large Canadian trauma center. METHODS: This was a retrospective cohort study of trauma patients admitted to a level 1 trauma center between 2005 and 2010, who received 10 or more units of packed red blood cells within 24 hours of admission. Demographic and clinical findings were compared between survivors and nonsurvivors. RESULTS: Forty-five patients were included. Twenty-five percent of patients were coagulopathic at admission. Early crystalloid use declined over the study period. The mean 24-hour fresh-frozen plasma:platelets:packed red blood cells ratio was 1:1:2. Hemorrhage-related mortality was 69%. No pedestrians survived STH. A total of 1,032 blood product units were used in the first day for nonsurvivors. CONCLUSIONS: Principles of DCR crept into clinical practice even before the implementation of a formal STH protocol. DCR appeared to reduce the intensive care unit length of stay but not mortality. STH is associated with heavy use of blood bank resources and high mortality rates. Futility of resuscitative efforts may be predictable by mechanism and early physiological markers.

Platelet quality measured with dynamic light scattering correlates with transfusion outcome in hematologic malignancies.

BACKGROUND: A clinically meaningful test for platelet (PLT) quality could improve the transfusion management of patients. The aim of this pilot study was to determine whether a new measure of PLT quality and function based on dynamic light scattering (DLS) correlates with transfusion outcome. STUDY DESIGN AND METHODS: For a total of 160 transfusions, the pretransfusion, 1 hour posttransfusion, and 24-hour posttransfusion PLT counts were routinely measured in 49 patients (31 male, 18 female; age 46 +/- 15 years) with hematologic malignancies. The corrected count increments (CCIs) at 1 hour (PLT recovery) and 24 hours (PLT survival) were calculated and used as the transfusion outcome measures. The ThromboLUX score (LightIntegra Technology, Inc., Vancouver, BC, Canada; range, 0-40; cutoff, 12) and the PLT morphology score of the PLT concentrates were determined and compared to transfusion outcome. RESULTS: The CCIs and ThromboLUX scores were normally distributed and showed a strong correlation (n = 96, in the mixed regression model the adjusted coefficient is R = 0.6292, p < 0.0001), while other variables such as product type, age, and microscopic PLT morphology score were not correlated with transfusion outcome (p > 0.05). Importantly, 12 of 96 transfusions with poor PLT quality were clinically ineffective, that is, did not adequately increase the PLT counts in the recipients. One patient died after receiving three consecutive ineffective PLT transfusions with a low ThromboLUX score. CONCLUSION: In this pilot study, the ThromboLUX score strongly correlated with transfusion outcome (PLT recovery and survival) independent of clinical and product issues.

Past and future approaches to assess the quality of platelets for transfusion.

No automated test exists to routinely measure platelet quality. Currently, the short, 5-day shelf life of platelet concentrates is largely dictated by the risk associated with bacterial contamination and not by platelet quality. With the implementation of bacterial testing and pathogen inactivation, platelet quality will become the major determinant for the shelf life of platelet concentrates. However, extended use of platelet concentrates stored beyond 5 days will require quality testing. In addition, high platelet quality would be expected to result in improved clinical efficacy, determined by count increment, improved hemostasis, and lower risk for adverse reactions in recipients. No in vitro quality test has yet demonstrated a good correlation with clinical efficacy or improved hemostasis. This review focuses on those tests of platelet quality that are based on platelet morphology. These include visual inspection of swirling, microscopic morphology score, measurement of light transmission through platelet concentrates, and platelet light scattering techniques. Recently, a new test for platelet quality has been introduced that uses dynamic light scattering. The advantages and remaining challenges for dynamic light scattering before it can become a routine platelet quality test are discussed.