Assessing deviations for HPCs obtained during COVID-19 (ADHOC): Evaluating impact of the COVID-19 pandemic on cellular therapy products and processes, the BEST collaborative study

BACKGROUND

The success of allogeneic hematopoietic stem cell transplantation is dependent on a world-wide network of collection centers providing donations that predominantly have been infused as fresh cells. The logistics chain that supports the just-in-time delivery model for stem cell and immunotherapy products was severely stressed by the COVID pandemic, and in early 2020 a number of national and international bodies recommended that cells should be cryopreserved at the collection or transplant center to avoid interruptions in their acquisition or delivery to patients who had started conditioning.

STUDY DESIGN

To assess the potential consequences of such pandemic-related deviations to normal practice, we surveyed nine international laboratories to determine if the characteristics or transplant outcomes of allogeneic stem cell donations differed in the immediate periods before and after the switch to routine cryopreservation.

RESULTS

Nine centers on two continents provided data for 72 HSC donations just before, and 71 just after, switching to cryopreservation for allogeneic HSC products. No statistically significant differences between the period before and after cryopreservation were noted for time from product collection to receipt, product temperature at receipt, or CD34⁺ cell viability at receipt. There was an indication of slower absolute neutrophil count recovery after cryopreservation was required (mean time of 15 vs. 17.6 days).

DISCUSSION

While there were no apparent changes to most parameters studied, there was an indication of slower neutrophil engraftment that will need to be examined in larger, longer term studies.

Development of curative therapies for sickle cell disease

Recent advances in managing Sickle Cell Disease (SCD) significantly improved patient survival and quality of life. Disease-modifying drug therapies such as hydroxyurea, L-glutamine, voxelotor, and crizanlizumab reduce pain crises and severe complications. Allogeneic hematopoietic stem cell transplantation using matched-sibling donors is currently the only standard curative option; however, only a small proportion of patients have such donors. Cord blood and haploidentical transplantation with a modified conditioning regimen have expanded the allogeneic donor pool, making the therapy available to more patients. Gene therapy is a promising cure that is currently undergoing clinical trials and different approaches have demonstrated efficacy. Multidisciplinary expertise is needed in developing the best treatment strategy for patients with SCD.

Therapeutic plasma exchange practices in immune thrombocytopenia related hospitalizations: Results from a nationally representative sample

Per the American Society for Apheresis, therapeutic plasma exchange (TPE) is a Category III indication in the management of immune thrombocytopenia (ITP). This nationally representative study evaluates TPE utilization in hospitalized adults with a primary admission diagnosis of ITP. Hospitalizations with ITP as the primary admitting diagnosis were analyzed from the 2010 to 2014 National Inpatient Sample, the largest all-payer inpatient database in the United States. Univariate and multivariable logistic regressions were used to determine clinical outcomes in ITP patients undergoing TPE. Sampling weights were applied to generate nationally representative estimates. From 2010 to 2014, there were a total of 56,149 admissions with a primary admitting diagnosis of ITP, of which 0.66% admissions (n = 372) also coded TPE. Most subjects undergoing TPE were the highest disease severity class: major (34.6%) and extreme severity (31.0%), by all-patients refined diagnoses-related groups severity of illness subclass. After multivariable analysis, underlying severity of illness remained the most significant predictor of TPE (P < .001). ITP admissions with TPE had a high rate of comorbidities (50%) and significantly longer mean length of hospital stay than those without (P < .001). TPE was reported in ~0.6% of hospitalizations with ITP as the primary diagnosis in this nationally representative sample from 2010 to 2014. TPE was performed in patients with the highest severity of underlying illness, and higher rates of comorbidities.

Rotational thromboelastometry in patients with acute respiratory distress syndrome owing to coronavirus disease 2019: Is there a viscoelastic fingerprint and a role for predicting thrombosis?

Objectives

We evaluated rotational thromboelastometry tracings in 44 critically ill coronavirus disease 2019 patients, to determine whether there is a viscoelastic fingerprint and to test the hypothesis that the diagnosis and prediction of venous thromboembolism would be enhanced by the addition of rotational thromboelastometry testing.

Results

Rotational thromboelastometry values reflected an increase in clot strength for the EXTEM, INTEM, and FIBTEM assays beyond the reference range. No hyperfibrinolysis was noted. Fibrinolysis shutdown was present but did not correlate with thrombosis; 32% (14/44) of patients experienced a thrombotic episode. For every 1 mm increase of FIBTEM maximum clot formation, the odds of developing thrombosis increased 20% (95% confidence interval, 0–40%, P = .043), whereas for every 1,000 ng/mL increase in D-dimer, the odds of thrombosis increased by 70% (95% confidence interval, 20%–150%, P = .004), after adjustment for age and sex (AUC 0.96, 95% confidence interval, 0.90–1.00). There was a slight but significant improvement in model performance after adding FIBTEM maximum clot formation and EXTEM clot formation time to D-dimer in a multivariable model (P = .04).

Conclusions

D-dimer concentrations were more predictive of thrombosis in our patient population than any other parameter. Rotational thromboelastometry confirmed the hypercoagulable state of coronavirus disease 2019 intensive care unit patients. FIBTEM maximum clot formation and EXTEM clot formation time increased the predictability for thrombosis compared with only using D-dimer. Rotational thromboelastometry analysis is most useful in augmenting the information provided by the D-dimer concentration for venous thromboembolism risk assessment when the D-dimer concentration is between 1,625 and 6,900 ng/dL, but the enhancement is modest. Fibrinolysis shutdown did not correlate with thrombosis.

Overcoming Drug Interference in Transfusion Testing: A Spotlight on Daratumumab

Daratumumab, a monoclonal antibody therapeutic, is highly efficacious and widely used in all stages of multiple myeloma and amyloidosis and has promising activity in other hematologic disorders. Daratumumab interacts with red blood cells, interfering with pre-transfusion testing. This interference can lead to compromising transfusion safety, extensive blood bank work ups and delays in provision of compatible units. Several methods have been developed to negate daratumumab interference with indirect antiglobulin testing. They are based on i) standard blood bank techniques including dithiothreitol and enzymatic treatment of reagent cells, using reagent red blood cells negative for CD38, ii) blocking CD38 antigens on reagent or donor cells, iii) neutralization of anti-CD38 antibody in patient plasma prior to testing, and iv) extended antigen typing of patient red blood cells in conjunction with provision of phenotypically matched units for transfusion. Implementation of those methods by the blood bank should be a planned effort coordinated with the patient’s clinical team. Timely involvement of blood bank and transfusion services and educational efforts by both blood banks and clinical providers can improve the overall daratumumab safety profile in regard to blood transfusion.

Epidemiology of the Use of Hemostatic Agents in Children Supported by Extracorporeal Membrane Oxygenation: A Pediatric Health Information System Database Study

Objectives: Children supported by extracorporeal membrane oxygenation (ECMO) are at high risk of bleeding. Though practitioners often prescribe blood components and/or medications to prevent or treat bleeding, the utilization of these hemostatic measures in children is not well-understood. We sought to evaluate the use of hemostatic blood products (platelet, plasma and cryoprecipitate transfusions) and medications [aminocaproic acid, tranexamic acid (TXA) and Factor VIIa] in children supported by ECMO. Design: Retrospective observational study using the Pediatric Health Information System (PHIS) database from 2011-2017. Setting: Fifty-one U.S. children's hospitals. Patients: Children (aged 0-18 years) supported by ECMO. Interventions: None. Measurements and Main Results: ECMO was employed in the care of 7,910 children for a total of 56,079 ECMO days. Fifty-five percent of the patients were male with a median (IQR) age of 0 (0-2) years. The median (IQR) length of ECMO was 5 (2-9) days with a hospital mortality rate of 34%. Platelets were transfused on 49% of ECMO days, plasma on 33% of ECMO days and cryoprecipitate on 17% of ECMO days. Twenty-two percent of children received TXA with the majority receiving it on the first day of ECMO and the use of TXA increased during the 6-year period studied (p < 0.001). Seven percent of children received aminocaproic acid and 3% received Factor VIIa. Conclusions: Children supported by ECMO are exposed to a significant number of hemostatic blood products. Antifibrinolytics, in particular TXA, are being used more frequently. Given the known morbidity and mortality associated with hemostatic blood products, studies are warranted to evaluate the effectiveness of hemostatic strategies.

Routine Laboratory Blood Tests Predict SARS-CoV-2 Infection Using Machine Learning

Background

Accurate diagnostic strategies to rapidly identify SARS-CoV-2 positive individuals for management of patient care and protection of health care personnel are urgently needed. The predominant diagnostic test is viral RNA detection by RT-PCR from nasopharyngeal swabs specimens, however the results are not promptly obtainable in all patient care locations. Routine laboratory testing, in contrast, is readily available with a turn-around time (TAT) usually within 1-2 hours.

Method

We developed a machine learning model incorporating patient demographic features (age, sex, race) with 27 routine laboratory tests to predict an individual’s SARS-CoV-2 infection status. Laboratory test results obtained within two days before the release of SARS-CoV-2-RT-PCR result were used to train a gradient boosted decision tree (GBDT) model from 3,356 SARS-CoV-2 RT-PCR tested patients (1,402 positive and 1,954 negative) evaluated at a metropolitan hospital.

Results

The model achieved an area under the receiver operating characteristic curve (AUC) of 0.854 (95% CI: 0.829-0.878). Application of this model to an independent patient dataset from a separate hospital resulted in a comparable AUC (0.838), validating the generalization of its use. Moreover, our model predicted initial SARS-CoV-2 RT-PCR positivity in 66% individuals whose RT-PCR result changed from negative to positive within two days.

Conclusion

This model employing routine laboratory test results offers opportunities for early and rapid identification of high-risk SARS-CoV-2 infected patients before their RT-PCR results are available. It may play an important role in assisting the identification of SARS-COV-2 infected patients in areas where RT-PCR testing is not accessible due to financial or supply constraints.

Routine Laboratory Blood Tests Predict SARS-CoV-2 Infection Using Machine Learning

BACKGROUND

Accurate diagnostic strategies to identify SARS-CoV-2 positive individuals rapidly for management of patient care and protection of health care personnel are urgently needed. The predominant diagnostic test is viral RNA detection by RT-PCR from nasopharyngeal swabs specimens, however the results are not promptly obtainable in all patient care locations. Routine laboratory testing, in contrast, is readily available with a turn-around time (TAT) usually within 1-2 hours.

METHOD

We developed a machine learning model incorporating patient demographic features (age, sex, race) with 27 routine laboratory tests to predict an individual's SARS-CoV-2 infection status. Laboratory testing results obtained within 2 days before the release of SARS-CoV-2 RT-PCR result were used to train a gradient boosting decision tree (GBDT) model from 3,356 SARS-CoV-2 RT-PCR tested patients (1,402 positive and 1,954 negative) evaluated at a metropolitan hospital.

RESULTS

The model achieved an area under the receiver operating characteristic curve (AUC) of 0.854 (95% CI: 0.829-0.878). Application of this model to an independent patient dataset from a separate hospital resulted in a comparable AUC (0.838), validating the generalization of its use. Moreover, our model predicted initial SARS-CoV-2 RT-PCR positivity in 66% individuals whose RT-PCR result changed from negative to positive within 2 days.

CONCLUSION

This model employing routine laboratory test results offers opportunities for early and rapid identification of high-risk SARS-CoV-2 infected patients before their RT-PCR results are available. It may play an important role in assisting the identification of SARS-CoV-2 infected patients in areas where RT-PCR testing is not accessible due to financial or supply constraints.

Thawed solvent/detergent-treated plasma demonstrates comparable clinical efficacy to thawed plasma

BACKGROUND

Thawed Plasma (TP), plasma thawed and refrigerated for up to 5 days, is a commonly transfused plasma product. This pilot study was conducted to determine whether Thawed Solvent/Detergent-treated Plasma stored refrigerated for up to 5-days post-thaw (T-S/D) was as efficacious as TP.

STUDY DESIGN AND METHODS

This single institution retrospective cohort analysis evaluated the efficacy of T-S/D in reversing coagulopathies in comparison to TP. Utilizing the institution's electronic medical records, transfusion data were collected in adult patients who received either TP or T-S/D. The primary outcome was the incidence of subsequent transfusions within 24 hours after first dose of either type of plasma. Secondary outcomes included the number of blood products transfused within 24 hours of first-dose plasma, correction of pre-transfusion coagulation laboratory values, volume transfused, and clinical outcomes.

RESULTS

TP was received by 301 patients and 137 received T-S/D during the first 32 months post-implementation of T-S/D. There was no difference in incidence of subsequent transfusions or number of blood products given. The median pre-INR of both the TP and T-S/D cohorts was 1.9, with a similar decrease in INR of 0.2 and 0.3 (p = 0.36), respectively, post plasma transfusion. There was no difference in correction of PT/aPTT, mortality, transfusion reactions, readmission rates, length of stay, or inpatient deep venous thrombosis. The median volume of T-S/D plasma transfused for the first dose was 126 mL less than TP (p = .0001).

CONCLUSION

T-S/D was as efficacious as TP for the treatment of coagulopathies and the reversal of coagulation laboratory values.

Poor graft function after T cell-depleted allogeneic hematopoietic stem cell transplant

PGF implies persistent cytopenia in the presence of predominant donor chimerism. We examined contributors to PGF in 104 HCT recipients who survived ≥100 days without relapse or major complications. Surrogate parameters for PGF were: Hg <10 g/dl, RBC transfusion dependence, platelet count <20 × 10⁹/L or ANC < 0.5 × 10⁹/L. All patients received T cell depletion with alemtuzumab or ATG. The 2-year OS and PFS probabilities were 66%, 95%CI (56 - 75%) and 51%, 95%CI (41-60%) respectively. Fifty-four patients (52%) met one or more PGF criteria. There was significant association between major ABO incompatibility and platelet <20 × 109/L (OR = 4.7, 95%CI 1.05-21.26, p = .043), acute GVHD and Hg <10 g/dl (OR 3.7, 95%CI 1.4-9.6, p = .005) and CMV viremia and ANC < 0.5 × 10⁹/L (OR 3.0, 95% CI 1.0, 8.7, p = .043). NRM was significantly higher in the PGF group compared to patients with adequate graft function (45.5% vs 16.7%, p = .014).

Association of Perioperative Red Blood Cell Transfusions With Venous Thromboembolism in a North American Registry

Importance

Increasing evidence supports the role of red blood cells (RBCs) in physiological hemostasis and pathologic thrombosis. Red blood cells are commonly transfused in the perioperative period; however, their association with postoperative thrombotic events remains unclear.

Objective

To examine the association between perioperative RBC transfusions and postoperative venous thromboembolism (VTE) within 30 days of surgery.

Design, Setting, and Participants

This analysis used prospectively collected registry data from the American College of Surgery National Surgical Quality Improvement Program (ACS-NSQIP) database, a validated registry of 525 teaching and nonteaching hospitals in North America. Participants included patients in the ACS-NSQIP registry who underwent a surgical procedure from January 1 through December 31, 2014. Data were analyzed from July 1, 2016, through March 15, 2018.

Main Outcomes and Measures

Risk-adjusted odds ratios (aORs) were estimated using multivariable logistic regression. The primary outcome was the development of postoperative VTE (deep venous thrombosis [DVT] and pulmonary embolism [PE]) within 30 days of surgery that warranted therapeutic intervention; DVT and PE were also examined separately as secondary outcomes. Subgroup analyses were performed by surgical subtypes. Propensity score matching was performed for sensitivity analyses.

Results

Of 750 937 patients (56.8% women; median age, 58 years; interquartile range, 44-69 years), 47 410 (6.3%) received at least 1 perioperative RBC transfusion. Postoperative VTE occurred in 6309 patients (0.8%) (DVT in 4336 [0.6%]; PE in 2514 [0.3%]; both DVT and PE in 541 [0.1%]). Perioperative RBC transfusion was associated with higher odds of VTE (aOR, 2.1; 95% CI, 2.0-2.3), DVT (aOR, 2.2; 95% CI, 2.1-2.4), and PE (aOR, 1.9; 95% CI, 1.7-2.1), independent of various putative risk factors. A significant dose-response effect was observed with increased odds of VTE as the number of intraoperative and/or postoperative RBC transfusion events increased (aOR, 2.1 [95% CI, 2.0-2.3] for 1 event; 3.1 [95% CI, 1.7-5.7] for 2 events; and 4.5 [95% CI, 1.0-19.4] for ≥3 events vs no intraoperative or postoperative RBC transfusion; P < .001 for trend). In subgroup analyses, the association between any perioperative RBC transfusion and postoperative VTE remained statistically significant across all surgical subspecialties analyzed. The association between any perioperative RBC transfusion and the development of postoperative VTE also remained robust after 1:1 propensity score matching (47 142 matched pairs; matched OR, 1.9; 95% CI, 1.8-2.1).

Conclusions and Relevance

The results of this study suggest that perioperative RBC transfusions may be significantly associated with the development of new or progressive postoperative VTE, independent of several putative confounders. These findings, if validated, should reinforce the importance of rigorous perioperative management of blood transfusion practices.

Red blood cells donated by smokers: A pilot investigation of recipient transfusion outcomes

BACKGROUND

Current regulations do not require blood collection facilities to ask donors about cigarette smoking, and the prevalence of nicotine and its metabolites in blood products is not well established. Although smokers have higher hemoglobin (Hb) levels, smoking may adversely affect the quality of donated red blood cells through higher carboxyhemoglobin (COHb) content and premature hemolysis.

STUDY DESIGN AND METHODS

Red blood cell (RBC) unit segments from 100 unique donors were tested for nicotine and its metabolite cotinine by mass spectrometry and for COHb spectrophotometrically. Outcomes were evaluated retrospectively in adult non-bleeding patients receiving single RBC units.

RESULTS

Thirteen of 100 RBC segments (13%) were positive for cotinine at levels consistent with current smoking (> 10 ng/mL). The cotinine positive RBCs showed significantly greater COHb content compared to cotinine negative units (median 3.0% vs. 0.8%, p = 0.007). For patients transfused cotinine-positive units, there was no significant change in their vital signs following transfusion and no transfusion reactions were observed. However, patients transfused cotinine-positive units showed significantly reduced hematocrit and hemoglobin increments (median +1.2% and +0.4 g/dL) following transfusion compared to patients receiving cotinine negative units (median +3.6% and +1.4 g/dL) (p = 0.014).

CONCLUSION

Thirteen percent of RBC units tested positive for cotinine at levels consistent with active smoking, accordant with the estimated national smoking rate of 15.5%. Cotinine-positive RBC units had greater COHb content and showed reduced hematocrit and hemoglobin increments following transfusion. These preliminary results should be validated in a larger cohort.

The impact of Daratumumab on transfusion service costs

BACKGROUND

Daratumumab (DARA) is a human IgG1κ monoclonal antibody directed against CD38, approved for the treatment of multiple myeloma. As CD38 is expressed on RBCs, DARA can interfere with pretransfusion testing. DARA interference can be negated by denaturation of CD38 on RBCs with dithiothreitol (DTT) reagents. Because of this interference in pretransfusion testing, our hospital implemented a notification and testing/transfusion algorithm (NATTA) for pretransfusion testing and RBC product provision for DARA patients. This standardized approach combines DTT-based testing with selective genotyping and the provision of phenotypically similar RBCs for patients with clinically significant antibodies.

STUDY DESIGN AND METHODS

We evaluated pretransfusion test results and transfusion requirements for 91 DARA patients in an academic medical center over 1 year to determine the incremental cost of pretransfusion testing and RBC selection. The actual costs for the NATTA approach were compared to a theoretical approach using universal genotyping with a provision of phenotypically similar RBC transfusions.

RESULTS

The annual cost of testing related to DARA after NATTA implementation was $535.76 per patient. The simulated annual cost for the alternative genotyping with provision of phenotypically similar RBC transfusions approach was $934.83 per patient.

CONCLUSION

In our entire cohort of DARA patients, a DTT-based testing algorithm with selective genotyping and provision of phenotypically similar RBCs only for patients with clinically significant antibodies was less expensive than a simulated model of universal genotyping and provision of phenotypically similar RBCs.

Comparison of time to engraftment between autologous patients receiving washed versus non-washed cryopreserved peripheral blood stem cell products

Washing cryopreserved peripheral blood stem cell (PBSC) products can decrease infusion-related adverse reactions but can also result in cell loss and reduced cell viability. To assess the risk and benefit of washing products, we compared the time to neutrophil and platelet engraftment between autologous patients that received washed products (n = 201) and non-washed products (n = 89). The effect of the other variables, including age, gender, diagnosis, transplant dose, method of stem cell mobilization, and growth factor support regimen post-transplant, was assessed. In multivariate analysis, direct thaw and infusion of non-washed products resulted in significantly faster neutrophil engraftment (p = .003) and platelet engraftment (p = .017) than washed products. The mean neutrophil and platelet engraftment times were 1.07 days faster and 2.27 days faster, respectively. In conclusion, direct thaw and infusion of cryopreserved PBSC without washing results in significantly shorter time to recovery of neutrophils and platelets after autologous transplantation.

Validating and implementing the use of an infusion pump for the administration of thawed hematopoietic progenitor cells-a single-institution experience

BACKGROUND

Direct thaw and administration of previously cryopreserved peripheral blood stem cell products is a commonly used practice and should be performed rapidly to reduce cellular damage caused by dimethyl sulfoxide exposure. Cells are typically thawed at the bedside and infused by gravity through a high-flow-rate central venous catheter. An existing nontunneled catheter is occasionally used instead and often results in a slower infusion rate. To ensure expedient and consistent infusions, we validated and implemented the use of an infusion pump for thawed peripheral blood stem cells.

STUDY DESIGN AND METHODS

Validation was performed in two phases: in vitro simulation and in vivo clinical assessment. Total nucleated cell recovery and viability plus progenitor cell viability and potency were compared in vitro between two cryopreserved peripheral blood stem cell units that were either passed through a preset infusion pump or drained by gravity. The infusion rate, adverse events, and engraftment times were retrospectively compared between patients who received infusions by infusion pump (n = 35) and by gravity (n = 38).

RESULTS

No significant differences were observed in vitro between the infusion methods for all measured variables. Overall infusion rates were similar in vivo for both groups but were significantly lower for patients who had nontunneled catheters that delivered the infusion by gravity. The time to neutrophil and platelet engraftment was similar for both groups.

CONCLUSION

This is the first study to assess the use of an infusion pump for stem cell transplant. The use of an infusion pump for peripheral blood stem cell infusion is safe, provides a reliable and consistent infusion method, and can mitigate the effect of the type of venous access line used.

Visualization of macro-immune complexes in the antiphospholipid syndrome by multi-modal microscopy imaging

The antiphospholipid syndrome (APS) is an autoimmune thrombotic condition that is marked by autoantibodies against phospholipid-binding proteins. The mechanism(s) of thrombogenesis has (have) resisted elucidation since its description over thirty years ago. Nevertheless, a defining aspect of the disorder is positivity for clinical laboratory tests that confirm antibody binding to anionic phospholipids. It is remarkable that, to our knowledge, the binding of proteins from plasmas of APS patients to phospholipid has not been previously imaged. We therefore investigated this with high resolution microscopy-based imaging techniques that have not been previously used to address this question, namely atomic force microscopy and scanning electron microscopy. Atomic force microscopy imaging of APS plasmas incubated on an anionic planar phospholipid layer revealed the formation of distinct complex three-dimensional structures, which were morphologically dissimilar to structures formed from control plasmas from healthy patients. Likewise, scanning electron microscopy analysis of phospholipid vesicles incubated with APS plasmas in suspension showed formation of layered macro-immune complexes demonstrated by the significant agglomeration of a complex proteinaceous matrix from soluble plasma and aggregation of particles. In contrast, plasmas from healthy control samples bound to phospholipid vesicles in suspension generally displayed a more flattened, mat-like appearance by scanning electron microscopy. Scanning electron microscopy of plasma samples incubated on planar phospholipid layers and previously imaged by atomic force microscopy, corroborated the results obtained by mixing the plasmas with phospholipids in solution. Analysis of the incorporated proteins by silver stained SDS-polyacrylamide gel electrophoresis indicated considerable heterogeneity in the composition of the phospholipid vesicle-adsorbed proteins among APS patients. To our knowledge, these results provide the first images of plasma-derived APS immune complexes at high resolution, and show their consistent presence and heterogeneous compositions in APS patients. These findings demonstrate how high resolution microscopic techniques can contribute to advancing the understanding of an enigmatic disorder and may lay additional groundwork for furthering mechanistic understanding of APS.

Inverted erythrocyte membranes demonstrate β2GPI-antiphospholipid antibody interactions and membrane crosslinking

INTRODUCTION

The antiphospholipid syndrome (APS) is an acquired autoimmune disorder predisposing patients to thrombosis or pregnancy complications. Since inverted erythrocyte membranes (iEMs) might provide a physiologically relevant source of anionic phospholipids, we studied the interactions of phospholipid-binding proteins and APS antibodies using iEMs.

MATERIALS & METHODS

iEMs were prepared from packed erythrocytes by hypotonic lysis. Phosphatidylserine (PS) exposure was confirmed by annexin A5 (A5) binding using fluorescence microscopy and flow cytometry. Binding of β₂-glycoprotein I (β₂GPI)-IgG immune complexes to iEMs was investigated with gel electrophoresis, western blot and flow cytometry. Functional involvement in coagulation was documented in the thrombin generation assay.

RESULTS

iEMs readily precipitated purified β₂GPI as well as β₂GPI from normal plasma and APS plasma. The plasma of APS patients provided higher levels of IgG binding to iEMs relative to healthy controls. Thrombin generation increased with increasing concentrations of iEMs, documenting that coagulation proteins bound to the exposed phospholipids. The LA effect was also distinguished in thrombin generation when comparing APS patients, as indicated by an increased lag time. Agglutination was observed after incubation with APS patient plasma and this was augmented by anti-human globulin.

CONCLUSIONS

In conclusion, iEMs can provide a more physiological approach than phospholipid vesicle-based tests for investigating APS and are more amenable to standardization than platelet membranes.

A safe therapeutic apheresis protocol in paediatric patients weighing 11 to 25 kg

BACKGROUND AND OBJECTIVES

Erythrocytapheresis and leukapheresis (LPE) of small children are logistically complex and many centres are reluctant to perform these procedures. In children, both sickle cell and leukaemic emergencies demand prompt action to prevent additional morbidity but detailed protocols for small children are lacking, and often are performed using guidelines shown to work in larger patients. We report a 3-year experience with children weighing 11-25 kg at a large academic medical centre.

MATERIALS AND METHODS

All patients were treated with the COBE® Spectra apheresis system; circuit was primed with blood not adjusted for haematocrit and anticoagulant citrate dextrose A was used as anticoagulation. Procedures were performed in the paediatric intensive care unit by apheresis nursing staff.

RESULTS

Twenty-five apheresis procedures in 19 patients were performed; 17 of 19 patients presented with sickle cell-related acute complications and two (2/19) with newly diagnosed acute leukaemia and hyperleucocytosis. None of the patients required medications during the procedures. Vital signs and clinical condition remained stable and did not worsen during or postapheresis. One patient had a delayed haemolytic transfusion reaction 1 week posterythrocytapheresis as he developed alloantibodies as a result of the procedure. All sickle cell patients achieved a target haematocrit of 21-30% and Haemoglobin A of ≥68%. Both leukaemia patients who underwent LPE had no further signs of leukostasis and achieved marked reductions in leucocyte counts.

CONCLUSIONS

Apheresis of children weighing 11-25 kg can be safely performed without increased morbidity. We outline a protocol that can be used to perform apheresis with minimal complications.

A team-based approach to autopsy education: integrating anatomic and clinical pathology at the rotation level

CONTEXT

Pathology residency training programs should aim to teach residents to think beyond the compartmentalized data of specific rotations and synthesize data in order to understand the whole clinical picture when interacting with clinicians.

OBJECTIVE

To test a collaborative autopsy procedure at Montefiore Medical Center (Bronx, New York), linking residents and attending physicians from anatomic and clinical pathology in the autopsy process from the initial chart review to the final report. Residents consult with clinical pathology colleagues regarding key clinical laboratory findings during the autopsy. This new procedure serves multiple functions: creating a team-based, mutually beneficial educational experience; actively teaching consultative skills; and facilitating more in-depth analysis of the clinical laboratory findings in autopsies.

DESIGN

An initial trial of the team-based autopsy system was done from November 2010 to December 2012. Residents were then surveyed via questionnaire to evaluate the frequency and perceived usefulness of clinical pathology autopsy consultations.

RESULTS

Senior residents were the most frequent users of clinical pathology autopsy consultation. The most frequently consulted services were microbiology and chemistry. Eighty-nine percent of the residents found the clinical pathology consultation to be useful in arriving at a final diagnosis and clinicopathologic correlation.

CONCLUSION

The team-based autopsy is a novel approach to integration of anatomic and clinical pathology curricula at the rotation level. Residents using this approach develop a more holistic approach to pathology, better preparing them for meaningful consultative interaction with clinicians. This paradigm shift in training positions us to better serve in our increasing role as arbiters of outcomes measures in accountable care organizations.

Primary intestinal posttransplant T-cell lymphoma

There have been only five reported cases of primary posttransplant T-cell lymphoma. We report the first case associated with the use of sirolimus (Rapamycin, Wyeth-Ayerst, Philadelphia, PA). The patient, receiving prednisone, cyclosporine, and sirolimus treatment, developed ascites, diarrhea, and weight loss 7 months after his second renal transplant. Tissue obtained at laparotomy established the diagnosis of primary T-cell lymphoma. Latent membrane protein-1 for Epstein-Barr virus was negative, but in-site hybridization test for Epstein-Barr-encoded RNA was positive. Despite aggressive chemotherapy, the patient died 8 months posttransplant. This is the sixth reported case of primary intestinal posttransplant T-cell lymphoma, but it is the first case associated with the use of sirolimus. The incidence of posttransplant lymphoproliferative disease in patients receiving sirolimus should be studied.

Cellular requirements for the monoclonal antibody-mediated eradication of an established solid tumor

Following subcutaneous implantation, the murine lymphoma E.G7 [a variant of EL-4, transfected with the chicken ovalbumin (OVA) gene] up-regulates the CD4 molecule. We previously showed that the administration of an anti-CD4 monoclonal antibody (mAb) to EG.7-bearing mice leads to a rapid and complete regression of large established tumors. This tumor regression was shown to require both CD8+ cells and functional Fcgamma receptors (FcgammaR), as it failed to occur in mice depleted of CD8 cells, or mice genetically deficient in FcgammaI/III (gamma-/-mice). Using adoptive transfer, we now show that the FcgammaR+ cells required for this regression are the CD11b+ (phagocytic) cells. Furthermore, experiments using peptide tolerization demonstrated that the critical CD8 CTL population in this model is tumor specific. Analysis of tumors at various stages of regression revealed a massive CD11b+FcgammaR+ and a marginal CD8 infiltration. In the presence of the CTL determinant OVA-8 on tumor cells and of the antitumor mAb, this CD8 infiltration became remarkable, and correlated with tumor regression. These results identify the specific cellular effectors essential for the mAb-mediated tumor regression, and suggest that FcgammaR-activated macrophages induced an expansion of tumor-eliminating CTL in situ.