Investigation of changes in exosomes profile during storage period of erythrocyte suspensions

Abstract

This study aimed to investigate the relationship of exosomes in erythrocyte suspension (ES) with leukoreduction and storage period. In this study, we expected to obtain new information about the immunomodulatory effect of allogeneic blood transfusion. Whole blood from healthy donors (10) were transferred to two separate blood bags by an equal amount converted into ES. One of the bags was passed through the leukocyte filter to obtain reduced leukocyte and non-reduced ESs and divided into four equal blood bags. Flow cytometry was used to identify and quantify exosomes in the samples on the 0th, 14th, 28th, and 42nd days at 4 degrees C. The exosomes were first coated with anti-CD9 antibodies with carboxylates beads and exosome volumes were determined by BCA Protein Assay to determine the amount of exosome-containing samples to be bound by beads and investigated by flow cytometry. Exosomes which were derived from Th, NK, NK-T cells were not detected in our study. There were no significant differences in exosome profiles between NL-ES and LR-ES groups. Statistically significant results (in comparison with the 0th day) were found as below. Exosomes that were derived from; T lymphocytes, decrease in LR-ES groups at 42nd-day samples (P < 0.05). Tc lymphocytes, decrease in NL-ES groups at 14th day and 42nd-day samples (P < 0.05). B lymphocytes, a decrease in NL-ES groups at the sample of 28th and 42nd-days (P < 0.05). MDSC and G-MDSC, decrease in both NL-ES groups and LR-ES groups at the sample of 14th, 28th, and 42nd-days (P < 0.05). Our results suggest that exosomes in erythrocyte suspensions are not affected by the leukoreduction procedure. Exosomes which can freely pass from leukocyte filters may be the main cause of the insufficiency of leukoreduction to prevent TRIM.