Comparison of manual hematocrit determinations versus automated methods for hematopoietic progenitor cell apheresis products

Process and procedural adjustments to improve CD34+ collection efficiency of hematopoietic progenitor cell collections in sickle cell disease

BACKGROUND

Adequate CD34+ collection efficiency (CE) is critical to achieve target CD34+ cell doses in hematopoietic progenitor cell (HPC) collections. Autologous HPC collection in sickle cell disease (SCD) is associated with unstable collection interfaces and low CD34+ CEs. We hypothesized that variables specific to SCD, activation of blood cells and elevated viscosity, might contribute to these issues and made adjustments to the collection process and procedure to address our hypothesis.

STUDY DESIGN AND METHODS

In two patients with SCD undergoing autologous HPC collection on our clinical trial (NCT02193191), we therefore implemented adjustments to the process and procedure in the following areas: proximity of RBC exchange to HPC collection, the type of anticoagulation, and the packing factor setting.

RESULTS

There was no collection interface instability. Our CD34+ CE1s were high at 70% and 51%, and granulocyte CE, platelet CE, and product granulocyte % were remarkably low. Product hematocrits were not as high as previously reported to be required to obtain adequate CEs. Interestingly, one HPC product showed a hemoglobin S (HbS) of 91% at the same time that the peripheral blood (PB) showed a HbS of 22%.

DISCUSSION

Adjustments to the HPC collection process and procedure were associated with adequate CD34+ CEs and low granulocyte and platelet contamination in HPC products from SCD patients. Given the discrepancy in the percentage of sickle RBCs in the product versus the PB, we hypothesize that CD34+ cells and RBCs may aggregate. Our interventions and hypothesis should be further investigated in larger studies.

A Nomogram for the Rapid Prediction of Hematocrit Following Blood Loss and Fluid Shifts in Neonates, Infants, and Adults

Introduction

There is often a need for a simple means of predicting hematocrit (Hct) following blood loss, administration of intravenous fluids, or fluid shifts. The aim of this study is to introduce a nomogram for the rapid prediction of blood volume and packed red cell volume appropriate for a given patient's body weight and Hct in both the pediatric and adult populations.

Methods

A nomogram for prediction of Hct was created using the following variables: 1) blood volume determined from bodyweight, 2) estimated blood loss, and 3) initial Hct.

Results

Hct was calculated after blood loss, administration of intravenous fluids, or fluid shifts using the pediatric and adult nomograms. Alternatively, the nomograms can be used to back-calculate blood or fluid loss if Hct is known. The nomogram allows for adjustment for measured and insensible fluid losses and fluid administration.

Conclusions 

The nomogram helps to predict the Hct and fluid requirements in neonates, children, and adults with blood loss, fluid administration, and rehydration following dehydration. It allows for the calculation of Hct after fluid shifts in a simple, fast, and portable manner. We believe it can be a useful adjunct to monitor the fluid balance in all patients, especially in resource-limited settings where laboratory equipment may not be available.

Rejuvenation solution as an adjunct cold storage solution maintains physiological haemoglobin oxygen affinity during early-storage period of red blood cells

BACKGROUND

Red blood cell (RBC) units accumulate morphologic and metabolic lesions during storage before transfusion. Pyruvate-inosine-phosphate-adenine (PIPA) solutions (Rejuvesol, Biomet, Warsaw, IN) can be incubated with RBC units to mitigate storage lesions. This study proposes a PIPA treatment process, termed cold 'rejuvenation', using Rejuvesol as an adjunct additive solution, to prevent biomechanical storage lesions while avoiding the 1 h PIPA incubation required with standard PIPA treatment. We compared the efficacy of cold to standard 'rejuvenation' in improving metabolic lesions that occur during cold storage of RBCs, without altering function.

METHODS

Twelve leucoreduced, A-positive RBC units were obtained. Each unit was aliquoted into either control (standard storage), washed (W), standard rejuvenation (SR) or cold rejuvenation (CR) groups, the latter two requiring washing. A volume-adjusted dose of Rejuvesol was instilled into the CR group upon receipt (Day 3). After 15 days of storage, p50, RBC deformability, in-bag haemolysis and mechanical fragility were analysed. 'Any treatment' is defined as W, SR and CR, with comparisons in reference to control.

RESULTS

Higher p50s were seen in rejuvenated groups (>30 mmHg vs. <19 mmHg; P < 0·0001). Any treatment significantly increased elongation index (P = 0·034) but did not significantly increase in-bag haemolysis (P = 0·062). Mechanical fragility was not significantly different between groups (P = 0·055) at baseline, but the control (CTL) group was more fragile after 2 h in a cardiac bypass simulation than any treatment (P < 0·0001).

CONCLUSIONS

This study demonstrates that rejuvenation (standard or cold) prevents the leftward p50 shift of storage lesions without detrimental effect on RBC deformity, in-bag haemolysis or mechanical fragility.

Validation of simple prediction algorithms to consistently achieve CD3+ and postselection CD34+ targets with leukapheresis

BACKGROUND

Cellular therapies using engineered T cells, haploidentical transplants, and autologous gene therapy are increasing. Specified CD3+ or high CD34+ doses are typically required for subsequent manufacturing, manipulation, or CD34+ selection. Simple, practical, and reliable lymphocyte and hematopoietic progenitor cell (HPC) collection algorithms accounting for subsequent CD34+ selection have not been published.

STUDY DESIGN AND METHODS

In this analysis of 15 haploidentical donors undergoing tandem lymphocyte and HPC collections, we validated one-step, practical prediction algorithms (Appendix S1, available as supporting information in the online version of this paper) that use conservative facility-specific collection efficiencies, CD34+ selection efficiency, and donor-specific peripheral counts to reliably achieve the target CD3+ and CD34+ product doses. These algorithms expand on our previously published work regarding predictive HPC collection algorithms.

RESULTS

Ninety-three percent of lymphocyte and 93% of CD34+ collections achieved the final target CD3+ and CD34+ product dose when our algorithm-calculated process volumes were used. Linear regression analysis of our algorithms for CD3+, preselection CD34+, and postselection CD34+ showed statistically significant models with R² of 0.80 (root mean square error [RMSE], 31.3), 0.72 (RMSE, 385.7), and 0.56 (RMSE, 326.0), respectively, all with p values less than 0.001.

CONCLUSION

Because achievement of CD3+ or CD34+ dose targets may be critical for safety and efficacy of cell therapies, these simple, practical, and reliable prediction algorithms for lymphocyte and HPC collections should be very useful for collection facilities.

Effect of Iron Supplementation on the Outcome of Non-Progressive Pulmonary Mycobacterium tuberculosis Infection

The human response to Mycobacterium tuberculosis (Mtb) infection is affected by the availability of iron (Fe), which is necessary for proper immune cell function and is essential for the growth and virulence of bacteria. Increase in host Fe levels promotes Mtb growth and tuberculosis (TB) pathogenesis, while Fe-supplementation to latently infected, asymptomatic individuals is a significant risk factor for disease reactivation. However, the effect of Fe-supplementation on the host immunity during latent Mtb infection remains unclear, due partly to the paucity in availability of animal models that recapitulate key pathophysiological features seen in humans. We have demonstrated that rabbits can develop non-progressive latency similar to infected humans. In this study, using this model we have evaluated the effect of Fe-supplementation on the bacterial growth, disease pathology, and immune response. Systemic and lung Fe parameters, gene expression profile, lung bacterial burden, and disease pathology were determined in the Mtb-infected/Fe- or placebo-supplemented rabbits. Results show that Fe-supplementation to Mtb-infected rabbits did not significantly change the hematocrit and Hb levels, although it elevated total Fe in the lungs. Expression of selected host iron- and immune-response genes in the blood and lungs was perturbed in Mtb-infected/Fe-supplemented rabbits. Iron-supplementation during acute or chronic stages of Mtb infection did not significantly affect the bacterial burden or disease pathology in the lungs. Data presented in this study is of significant relevance for current public health policies on Fe-supplementation therapy given to anemic patients with latent Mtb infection.

Evaluation of two automated cell counters for the analysis of hematopoietic progenitor cell apheresis products

INTRODUCTION

Routine hematology parameters in hematopoietic progenitor cell apheresis products (HPC-A) are usually determined using automated cell counters. These instruments, however, are designed to analyze whole blood samples, that differ considerably from HPC-A in blood cell composition. This study evaluates the performance of two automated cell counters for the analysis of HPC-A.

METHODS

Routine hematology parameters [red blood cells (RBC), hematocrit (HCT), mean corpuscular volume (MCV), white blood cells (WBC), WBC differentiation, and platelets (PLT)] were determined on the Unicel DxH 800 instrument (Beckman Coulter) and the XN-350 instrument (Sysmex). Correlations with the reference methods, intrarun precision, and linearity of the analyses were studied.

RESULTS

Good correlations were found for almost all parameters. However, RBC count was overestimated by XN-350, using the impedance technique, as was neutrophil percentage using DxH 800. Coefficients of variation for intrarun precision were below 10% on both analyzers for all parameters, except for neutrophil percentage (14.7%) and PLT (10%) on DxH 800. Both instruments showed good linearity for all parameters, except for RBC and HCT on DxH 800.

CONCLUSION

With the exception of the measurement of neutrophils on DxH 800 and RBC by the impedance technique on the XN-350, routine hematology parameters in HPC-A can safely be determined using automated cell counters.