Though the US Food and Drug Administration (FDA) stopped requiring informed consent on the risk of lymphocyte reduction for platelet donors in 2007, frequent platelet collection may lead to long-term CD4+ and CD8+ T-cell lymphopenia in healthy platelet donors, according to a study published in Blood.
The prospective, single center, cross-sectional study evaluated immune cell counts in apheresis platelet donors. A total of 60 donors were recruited and assigned to a preselected group based on the number of plateletpheresis sessions they had had in the prior year. One group was established for donors with 1 to 2 sessions, another for 3 to 19 sessions, and the third group for 20 to 24 sessions.
For the study, plateletpheresis was carried out using the Trima Accel® automated blood collection system, which sequesters lymphocytes in its leukoreduction system chamber and does not return them to the donor; it is the only machine type that has been used at the study center since 2006. Donor age increased with donation frequency (P =.0003) but sex was balanced across the donation groups. Low T-lymphocyte counts were associated with increased session numbers. CD4+ T-lymphocyte counts were below 200 cells/μL in 0% (0/20) of donors in the 1 to 2 sessions group, 10% (2/20) of donors in the 3 to 19 sessions group, and 30% (6/20) of donors in the 20 to 24 sessions group (P =.019). Similarly, CD8+ T-lymphocyte counts were below 125 cells/μL in 0% (0/20) of donors in the 1 to 2 sessions group, 20% (4/20) of donors in the 3 to 19 sessions group, and 55% (11/20) of donors in the 20 to 24 sessions group (P <.001). The differences remained significant in models accounting for age.
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Immunophenotyping revealed that naive CD4+ T-lymphocyte (P =.017) and T-helper 17 (P =.024) percentages decreased, whereas CD4+ (P =.007) and CD8+ (P =.002) effector memory and T-helper 1 (P =.024) and T-regulatory cell (P <.001) percentages increased across groups.
All donors appeared to be in good health. Furthermore, while T-cell counts were reduced, their antigen receptor diversity was not. Therefore, the researchers concluded that the lymphopenias appear not to be harmful to donor health.
Reference
1. Gansner JM, Rahmani M, Jonsson AH, et al. Plateletpheresis-associated lymphopenia in frequent platelet donors [published online November 14, 2018]. Blood. doi: 10.1182/blood-2018-09-873125
