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Preferential decrease in thymus dependent lymphocytes during storage at 4 C in anticoagulant
Insights
Human lymphocytes, specifically thymus-derived (T) cells, rapidly decrease in number when stored at 4°C. This study investigates the impact of storage conditions on T cell viability in blood products.
Area of Science:
- Immunology
- Transfusion Medicine
- Cell Biology
Background:
- Human lymphocytes are crucial for immune function.
- Storage conditions significantly impact cell viability and function.
- Thymus-derived (T) lymphocytes are particularly sensitive to cold storage.
Purpose of the Study:
- To quantify the decrease in T lymphocytes during cold storage of blood products.
- To compare T cell loss in leukocyte concentrates (LCs) versus whole blood.
- To investigate the influence of anticoagulant and storage duration on T cell numbers.
Main Methods:
- Human lymphocytes were stored at 4°C as leukocyte concentrates (LCs) or whole blood in citrate-phosphate-dextrose (CPD).
- Cells were analyzed using Ficoll-Hypaque (F-H) density gradients.
- T and B lymphocyte populations were determined by cell counting and flow cytometry.
Main Results:
- Stored LCs showed a rapid decline in T cells (<10% within 72 hours), with a corresponding increase in B cells.
- LCs exposed to air showed an even faster T cell reduction.
- Whole blood samples exhibited significant T cell loss (to 20% within 24 hours) under similar storage conditions.
Conclusions:
- Cold storage at 4°C leads to a substantial and rapid loss of T lymphocytes in both LCs and whole blood.
- The observed T cell decrease is likely influenced by anticoagulant, storage duration, and blood components.
- Findings highlight the vulnerability of T cells to standard blood storage protocols.
Abstract:
Human lymphocytes stored at 4 C either as leukocyte concentrates (LCs) in citrate-phosphate-dextrose (CPD) or as whole blood anticoagulated with CPD show a rapid and marked decrease in the relative and absolute numbers of thymus derived (T) lymphocytes. Determinations were made on cells recoverable on a Ficoll-Hypaque (F-H) gradient. In evacuated LCs, the relative percentage of T cells dropped to less than 10 per cent within 72 hours with a concomitant increase in the relative percentage of bone marrow derived (B) cells to 80 per cent or more. LCs opened to the air and subsequently stored at 4 C displayed an even more precipitous decline in the relative percentage of T cells, reaching a 10 per cent level within 72 hours. The relative percentage of T cells in CPD-anticoagulated whole blood samples stored at 4 C displayed similar decreases, reaching 20 per cent levels within 24 hours. The change in the relative percentage of T cells at the Ficoll-Hypaque interface was shown to reflect a decrease in the total numbers of T cells placed on the F-H gradient with time, since determinations of T and B cell numbers in NH4Cl-treated whole blood showed a 65 to 80 per cent decrease in the numbers of T cells within 24 hours in anticoagulated whole blood held at 4 C. Thus, it may be inferred that the T cell decrease is mediated via some interaction of anticoagulant, storage time, and some component(s) present in both LCs and whole blood.