Design and introduction of a rational mechanical eluting system for leukocyte recovery from leukoreduction filters: A cell differential approach

Evaluation of a New Method of Leukocyte Extractions from the Leukoreduction Filter

This study's purpose was to optimize the leukocyte extraction protocol and evaluate the efficacy of this new protocol. 12BioR blood filters were collected from Tehran Blood Transfusion Center. A twosyringe system and Multi-step rinsing were designed for cell extraction. The final purpose of this optimization was: (1) removed the residual RBCs, (2) reversed the leukocyte trapping process, and (3) remove the microparticles to obtain the high yield of target cells. Finally, Extracted cells were evaluated by Automated Cell count; Samples smear differential cell count, Trypan blue, and Annexin-PI staining. The results showed that on average 11.88 × 108 ± 3.32 leukocytes recovered after indirect washing and that the mean count of granulocytes, lymphocytes, and Monocyte in this sample was 5.24 ± 2.18 × 108, 5.57 ± 1.74 × 108, and 0.56 ± 0.38 × 108 respectively. Also, the mean percent of manual differential cell count after concentration was 42.81%, 41.80%, and 15.82% for granulocytes, lymphocytes, and monocytes respectively. Moreover, viability and apoptosis assay showed > 95% viability in mononuclear cells recovered from LRFs. It is concluded that the use of a double-syringe system and RBC and microparticles removal from leukoreduction filters lead to acceptable viable leukocyte count that can be used in in vitro and in vivo studies.

In-line Leukoreduction Filters; a New Source of Microparticle for Human and Animal Study

INTRODUCTION

The isolation of microparticles (MPs) from leukoreduction filters (LRFs) during cell extraction process introduced LRFs as a precious source of MPs for animal and human study.

METHOD

LRFs were collected from Tehran Blood Transfusion Center. The back-flushing method was used for leukocyte extraction from the LRFs. MPs were isolated through double-step centrifugation. Dynamic light scattering (DLS), electron microscopy (EM), and flow cytometry were performed for the evaluation of MPs size, morphology, and structural properties respectively. Statistical analyses were carried out to evaluation of differences between test and control groups. a p-value less than 0.05 indicates significant differences.

RESULT

DLS analysis showed that the average MP size in the test and control groups was 654.83 nm and 233.68 nm respectively. SEM images showed the spherical, oval, cell fragment, and micro-aggregate particles and TEM images demonstrated the mitochondrial-like body in the MPs. Flow cytometry studies also showed a significant increase in the percent of CD41, and CD14, and a significant decrease in the percent of CD235a in the test group compared to control (P value=0.029, P value=0.035, P value= 0.001 respectively). Moreover, the percentage of CD34 MPs indicated a borderline difference between the two groups (P value= 0.075). Finally count of MPs in the test and control groups was 1202095.34 and 280948.64, respectively and the difference was significant (P value=0.008).

CONCLUSION

It is concluded that LRFs are a potential source of the large volume of various cell MPs with different phenotypical and structural properties for animal and human phase studies. Moreover, the investigation of LRFs as a source of different types of exosomes can shed new light on extracellular vesicle studies.