Safe peripheral blood stem cell collection in patients less than 10 kg: A single-center review.

INTRODUCTION: Peripheral blood stem cell collection (PBSCC) is well-documented in adults and pediatric patients with larger total blood volume (TBV). However, very little data are available for the successful PBSCC of pediatric patients weighing less than 10 kg. Here, we highlight our institutional approach to PBSCC in this smaller-sized patient population. METHODS: Our protocol, including blood prime, was reviewed for PBSCC for bone marrow transplantation (BMT) in 18 children weighing 4.5-9.9 kg who safely underwent 37 PBSCC procedures at a single institution, Children's Hospital Colorado, between September 2016 and February 2022. RESULTS: We attained the individualized collection goals in all 18 patients with an average yield of 17.03 million CD34+ cells/kg of patient body weight (range: 0.84-67.45 million/kg). The average collection efficiency of the procedures was 41.5% (range: 23.0%-71.5%). We performed all 37 procedures safely and without complication. The estimated average TBV was 587 mL (range: 351-765 mL), the average blood volume processed was 596 mL (range: 351-756 mL), and the average TBVs processed was 2.5 (range: 1-4). CONCLUSION: PBSCC in patients ranging from 4.5 to 9.9 kg is safe and effective for collecting peripheral blood stem cells for BMT.

Perceptions on acceptability and reported consumption of marijuana by blood donors prior to donation in the recreational use state of Colorado, USA.

BACKGROUND AND OBJECTIVES: Blood donor opinions and behaviours regarding marijuana use are not well known nor is the potential impact to the blood supply. We sought to assess opinions and frequency of marijuana use in proximity to blood donation via a survey of blood donors at a hospital-based blood collection site in a state where recreational marijuana use has been legal since 2012. MATERIALS AND METHODS: Blood donors at least 18 years of age who donated between 2014 and 2019 were surveyed electronically, with all responses kept anonymous to encourage engagement and accurate reporting. RESULTS: Overall response rate was 8.03% (12,186 surveys sent with 979 responses). Of responding donors, 23.5% indicated that they felt that consuming various forms of marijuana was acceptable prior to blood donation. Marijuana use <72 h prior to blood donation was reported in all demographic groups surveyed except age 18-24 years. Of donors who reported daily marijuana use, 47.4% indicated >20 donations and 52.6% indicated apheresis platelet donation. CONCLUSION: Nearly one quarter of responding blood donors feel that marijuana use is acceptable prior to blood donation, and nearly every demographic group surveyed indicated use of marijuana <72 h prior to donation. These results suggest the need for additional research to determine if marijuana-related metabolites in collected blood products negatively impact recipients, particularly vulnerable populations such as children and pregnant women. These results may inform whether changes in donor screening or testing for marijuana use are warranted.

Blood counts in children with Down syndrome.

BACKGROUND: Children with Down syndrome (DS) are more likely to have hematologic and immunologic abnormalities compared to their typically developing peers, but normal ranges have not been defined. The goal of this study was to create references for complete blood counts (CBCs) in patients with DS. METHODS: A retrospective investigation of 355 (male = 196, 55.2%; mean age = 6.49 years, SD = 5.07) healthy pediatric patients with DS who received a CBC between 2011 and 2017 as part of their medical care at a single, large, pediatric teaching hospital. Control data on 770 healthy patients without DS were included. Descriptive statistics were performed on demographic and clinical characteristics. Kruskal-Wallis H tests, nested analysis-of-variance tests, and t-tests were run to determine the significant associations. RESULTS: Age-related normative curves for healthy children with DS outlining 2.5th, 25th, 50th, 75th, and 97.5th percentiles are provided for total white blood count, hemoglobin concentration, hematocrit, mean corpuscular volume, and platelet, absolute neutrophil, absolute lymphocyte, eosinophil, monocyte, and basophil counts. Statistical differences were found between children with and without DS receiving care at the same hospital based on matched age/sex groups. CONCLUSIONS: This study demonstrates that patients with DS have different reference ranges for multiple blood counts compared to those without DS, creating a new resource for pediatricians to refer to when evaluating CBCs in this population.

Development and Validation of a Multiplex Microsphere Immunoassay Using Dried Blood Spots for SARS-CoV-2 Seroprevalence: Application in First Responders in Colorado, USA.

Serological testing of large representative populations for antibodies to SARS-CoV-2 is needed to estimate seroprevalence, transmission dynamics, and the duration of antibody responses from natural infection and vaccination. In this study, a high-throughput SARS-CoV-2 multiplex microsphere immunoassay (MMIA) was developed for the receptor binding domain (RBD) and nucleocapsid (N) that was more sensitive than enzyme-linked immunosorbent assay (ELISA) (98% versus 87%). The MMIA was then applied and validated in 264 first responders in Colorado using serum and dried blood spot (DBS) eluates, compared to ELISA, and evaluated for neutralizing antibodies. Four percent (11/264) of first responders were seropositive in July to August 2020. Serum and DBS were highly correlated for anti-RBD and anti-N antibodies (R = 0.83, P < 0.0001 and R = 0.87, P < 0.0001, respectively) by MMIA. The MMIA accurately predicted SARS-CoV-2 neutralizing antibodies using DBS (R = 0.76, P = 0.037). On repeat antibody testing 3 months later, anti-RBD IgG decreased less rapidly than anti-N IgG measured by MMIA, with a median change in geometric median fluorescence intensity of 62% versus 79% (P < 0.01) for anti-RBD and anti-N IgG, respectively. This novel MMIA using DBS could be scalable for rapid and affordable SARS-CoV-2 serosurveillance in the United States and globally.

A New SARS-CoV-2 Dual-Purpose Serology Test: Highly Accurate Infection Tracing and Neutralizing Antibody Response Detection.

Many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology tests have proven to be less accurate than expected and do not assess antibody function as neutralizing, correlating with protection from reinfection. A new assay technology measuring the interaction of the purified SARS-CoV-2 spike protein receptor binding domain (RBD) with the extracellular domain of the human angiotensin-converting enzyme 2 (hACE2) receptor detects these important antibodies. The cPass surrogate virus neutralization test (sVNT), compared directly with eight SARS-CoV-2 IgG serology and two live-cell neutralization tests, gives similar or improved accuracy for qualitative delineation between positive and negative individuals in a fast, scalable, and high-throughput assay. The combined data support the cPass sVNT as a tool for highly accurate SARS-CoV-2 immunity surveillance of infected/recovered and/or vaccinated individuals as well as drug and convalescent-phase donor screening. The data also preview a novel application for the cPass sVNT in calibrating the stringency of live-cell neutralization tests and its use in longitudinal testing of recovered and/or vaccinated patients.

Presence and short-term persistence of SARS-CoV-2 neutralizing antibodies in COVID-19 convalescent plasma donors.

BACKGROUND: In March 2020, the Food and Drug Administration (FDA) approved use of COVID-19 convalescent plasma (CCP) as an investigational new drug for treatment of COVID-19. Since then, collection of CCP from COVID-19-recovered patients has been implemented in donor centers nationwide. Children's Hospital Colorado rapidly put into practice a CCP collection protocol, necessitating development and implementation of assays to evaluate SARS-CoV-2 antibodies in CCP units. STUDY DESIGN AND METHODS: We evaluated 87 units of CCP collected from 36 donors over two to four sequential donations using both antigen-binding assays for SARS-CoV-2 nucleoprotein and spike antigens and a live virus focus reduction neutralization test (FRNT50 ). RESULTS: Our data show that the majority of donors (83%) had a FRNT50 titer of at least 80, and 61% had a titer of at least 160, which met the FDA's criteria for acceptable CCP units. Additionally, our data indicate that analysis of antibodies to a single SARS-CoV-2 antigen is likely to miss a percentage of seroconverters; however, these individuals tend to have neutralizing antibody titers of less than 80. There was considerable variability in the short-term, sustained antibody response, measured by neutralizing antibody titers, among our donor population. CONCLUSION: The correlation of neutralizing activity and antigen-binding assays is necessary to qualify CCP for therapeutic use. Since SARS-CoV-2 antibody levels decline in a percentage of donors, and such a decline is not detectable by current qualitative assays implemented in many laboratories, robust, quantitative assays are necessary to evaluate CCP units best suited for therapeutic infusion in COVID-19 patients.

Platelet transfusion for patients with cancer.

BACKGROUND: Platelet transfusion is a critical and often necessary aspect of managing cancer. Low platelet counts frequently lead to bleeding complications; however, the drugs used to combat malignancy commonly lead to decreased production and destruction of the very cell whose function is essential to stop bleeding. The transfusion of allogeneic platelet products helps to promote hemostasis, but alloimmunization may make it difficult to manage other complications associated with cancer. METHODS: The literature relating to platelet transfusion in patients with cancer was reviewed. RESULTS: Platelet storage, dosing, transfusion indications, and transfusion response are essential topics for health care professionals to understand because many patients with cancer will require platelet transfusions during the course of treatment. The workup and differentiation of non-immune-mediated compared with immune-mediated platelet refractoriness are vital because platelet management is different between types of refractoriness. CONCLUSIONS: A combination of appropriate utilization of platelet inventory and laboratory testing coupled with communication between those caring for patients with cancer and those providing blood products is essential for effective patient care.

Platelets from blood diversion pouches (DPs) are a suitable alternative for functional, bioenergetic, and metabolomic analyses.

BACKGROUND: The collection of the first blood flow into a diversion pouch (DP) has become widely adopted in blood donation systems to reduce whole-blood unit contamination from skin bacteria. The strict control of pre-analytical variables, such as blood collection and proper anticoagulant selection, is critical to diminish experimental variability when studying different aspects of platelet biology. We hypothesize that the functional, mitochondrial, and metabolomic profiles of platelets isolated from the DP are not different from the ones isolated from standard venipuncture (VP), thus representing a suitable collection method of platelets for experimental purposes. MATERIALS AND METHODS: Whole blood from the blood DP or VP was collected. Platelets were subsequently isolated and washed following standard protocols. Platelet function was assessed by flow cytometry, light transmission aggregometry, clot retraction, and under flow conditions using the total thrombus formation analyzer (T-TAS). Mitochondrial function and the platelet metabolome profiles were determined by the Seahorse extracellular flux analyzer (Agilent, Santa Clara, CA, USA) and ultra-high-pressure liquid chromatography-mass spectrometry metabolomics, respectively. RESULTS: Platelets isolated from VP and the DP have similar functional, mitochondrial, and metabolic profiles with no significant differences between both groups at baseline and upon activation by any of the assays mentioned above. DISCUSSION: The findings of our study support the use of platelets from the DP for performing functional and metabolic studies on platelets from a wide range of blood donors. The DP may serve as an alternative blood collection method to standard VP, allowing the study of diverse aspects of platelet biology, such as age, sex, race, and ethnicity, in many eligible individuals for blood donation.

Cellular Therapy in Pediatric Hematologic Malignancies.

Advances in cellular therapies for pediatric patients have created many opportunities for improved survival with reduced morbidity. This article reviews current cellular therapies in pediatric hematological malignancy, including the most updated practices in hematopoietic stem cell transplant and the use of chimeric antigen receptor (CAR) therapy in T cells. Hematopoietic stem cell transplant has evolved with improvements in chemotherapy regimens, immunosuppression, and donor-matching options. Novel therapies in development which will likely further improve the options for patients are reviewed including Natural Killer, Regulatory T-cells and αß depletion.

Evaluation of a multiplexed coronavirus antigen array for detection of SARS-CoV-2 specific IgG in COVID-19 convalescent plasma.

Mitigation of the COVID-19 pandemic requires an understanding of the antibody response to SARS-CoV-2. However, throughout the development of SARS-CoV-2 IgG antibody assays during the past year, cross-reactivity to other coronaviruses remained a question. To address these issues, we evaluated IgG in COVID-19 convalescent plasma samples for reactivity against three SARS-CoV-2 antigens including full-length spike, receptor binding domain, and the proximal extracellular fusion domain, and spike antigens from other coronaviruses (SARS-CoV, MERS-CoV, hCoV-HKU1, hCoV-OC43, hCoV-229E and hCoV-NL63) using the VaxArray Coronavirus SeroAssay which is a multiplexed antigen assay developed by InDevR Inc. These results were compared to two commercial SARS-CoV-2 IgG ELISAs targeting either the SARS-CoV-2 nucleocapsid or spike antigens and a live virus focus reduction neutralizing antibody test (FRNT). The VaxArray platform showed high specificity for detection of SARS-CoV-2 IgG, evident from lack of reactivity to SARS-CoV-2 antigens despite significant reactivity to endemic coronavirus antigens in pre-pandemic samples. SARS-CoV-2 IgG positive samples reacted weakly to SARS-CoV spike but not to MERS-CoV. While the VaxArray platform had overall comparable results to the spike and nucleocapsid IgG ELISAs, results were more similar to the spike antigen ELISA and the platform displayed a higher sensitivity and specificity than both ELISAs. Samples with FRNT titers below 1/23 reported negative on VaxArray, while positive samples on VaxArray had significantly higher neutralizing antibody titers. These results suggest that the VaxArray Coronavirus SeroAssay performs with high sensitivity and specificity for the detection of SARS-CoV-2 IgG, and positive results on the platform indicate SARS-CoV-2 neutralizing activity.

Analysis of COVID-19 convalescent plasma for SARS-CoV-2 IgG using two commercial immunoassays.

Coronavirus Disease 2019 (COVID-19) convalescent plasma (CCP) was approved by the FDA for use in severe cases of COVID-19 under an emergency Investigational New Drug (IND) protocol. Eligibility criteria for CCP donors includes documentation of evidence of COVID-19 either by viral RNA detection at the time of illness or positive SARS-CoV-2 IgG after recovery if diagnostic testing for COVID-19 was not performed at the time of illness. In addition to analysis of CCP, analysis of SARS-CoV-2 IgG provides information for possible past exposure and may support diagnosis when SARS-CoV-2 PCR is negative and clinical suspicion for COVID-19 is high. Furthermore, assays with high sensitivity and specificity for SARS-CoV-2 IgG are critical for understanding community exposure rates to SARS-CoV-2. Currently, there are several assays that test for antibodies to SARS-CoV-2 using a variety of methods, including point-of-care lateral flow-based devices, high throughput immunoassay analyzers, and manual methods such as ELISA. These assays target a number of SARS-CoV-2 antigens, including the nucleocapsid protein (N), full length spike protein (S), S1 subunit, or receptor binding domain (RBD) of the S protein. Given the heterogeneity among methods for, and antigenic targets used in SARS-CoV-2 antibody assays, it is necessary for careful evaluation of these assays prior to implementation for clinical use. We compared two assays that had received the CE mark of regulatory approval and that used either the N antigen or S1-RBD antigen as the target for analysis of a large set of CCP samples. Our data indicates that sensitivity and specificity vary between these assays and that more than one antigenic target may be required to improve the sensitivity and specificity of IgG detection to SARS-CoV-2.

A 5-hour-old male neonate with cyanosis.

Methemoglobin (MetHb) is a form of hemoglobin in which heme iron is oxidized and unable to bind oxygen; its normal basal production is counteracted by an efficient MetHb-reduction pathway. The causes of methemoglobinemia are classified as congenital or acquired. Shortly after his birth, the 5-hour-old male Caucasian neonate, whose case we present herein, developed central cyanosis that was unresponsive to supplemental oxygen. Oxygen saturation as determined via pulse oximetry was normal. In contrast, blood gas testing by multiwave CO-oximetry indicated decreased fractional oxyhemoglobin and an elevated MetHb fraction. The patient was subsequently diagnosed with a congenital cytochrome b5 reductase deficiency. This case emphasizes causes of methemoglobinemia and differences among analytical methods used to measure oxygen status when MetHb is present.

Optimal use of fresh frozen plasma.

Fresh frozen plasma contains a number of therapeutically useful substances, most notably coagulation factors. As with any transfusion, there are risks associated with plasma transfusion. Ironically, the risk of viral transmission (human immunodeficiency virus or hepatitis), although widely publicized, is extremely small. On the other hand, less well-known, noninfectious complications are common. Indeed, these noninfectious complications are the most significant cause of morbidity and mortality following transfusion. Although certain patients undeniably benefit from plasma transfusion, the benefit for many patients is less clear. This review will discuss indications for plasma transfusion, the associated risks, and special considerations for plasma administration.

B1 and TRPV-1 receptor genes and their relationship to hyperalgesia following spinal cord injury.

STUDY DESIGN: Laboratory investigation of pain behavior following spinal cord injury. OBJECTIVE: To explore changes in the spinal cord expression of nociceptive genes following spinal cord injury (SCI) as they relate to the manifestation of pain behavior in rats. SUMMARY OF BACKGROUND DATA: Neuropathic pain following SCI is common, disabling, and largely untreatable. In peripheral nerve injury models, bradykinin B1 and vanilloid 1 (TRPV-1) receptor activity is associated with neuropathic pain behavior. We sought to examine the role of these gene products in SCI-mediated pain. METHODS: Rats were subjected to SCI using the MASCIS impactor. Animals were tested preinjury and at regular intervals postinjury for the appearance of thermal hyperalgesia using a hind limb withdrawal latency test. The expression of B1 and TRPV-1 genes was assessed using real-time polymerase chain reaction. Immunohistochemistry was used to localize the B1 and TRPV-1 receptors within the spinal cord. RESULTS: Greater than twofold increases in the expression of the B1 and TRPV-1 genes were detected in the injured region of the spinal cord in animals exhibiting hyperalgesia compared with animals with SCI that did not display hyperalgesia. Immunohistochemical staining revealed that both receptor types were largely localized to the dorsal horn. Staining for TRPV-1 receptors decreased while that for B1 receptors increased in all of the injured animals when compared with sham-operated controls. CONCLUSION: B1 and TRPV-1 receptor genes are overexpressed in the injured spinal cord of animals manifesting thermal hyperalgesia following SCI compared with similarly injured animals without hyperalgesia. This finding is consistent with past work regarding the role of these receptors in nociception and indicates that ongoing modifiable processes are occurring in the spinal cord that lead to clinical pain syndromes.