Double-Spin Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Lymphocyte Rich With Notable Concentrations of Other White Blood Cell Subtypes

Purpose: To comprehensively characterize a double-spin leukocyte-rich platelet-rich plasma (LR-PRP) formulation and to compare it with whole blood (WB) by quantitatively assessing platelet and WB cell subtype concentrations in each. Methods: Prospective human ex vivo analysis with 12 healthy adult men with ages ranging from 25 to 31 was performed in a controlled laboratory setting. The main outcome measure was the leukocyte profile of human LR-PRP. Results: In LR-PRP, lymphocytes were the predominant WB cell type (11.94 ± 2.97 × 10³ cells/μL) followed by neutrophils (3.72 ± 1.28 × 10³ cells/μL). The mean cumulative percentage of granulocytes was 23% ± 8% and agranulocytes was 77% ± 18%. There was a significant difference observed between granulocyte and agranulocyte percentage within both WB (P =.004, [95% CI: (7%,31%)]) and LR-PRP (P <.0001, [95% CI: (42%,66%)]) groups. In addition, there was a significant difference observed between the WB and LR-PRP granulocyte percentages (P <.0001, [95% CI: (29%,43%)]) and between the WB and LR-PRP agranulocyte percentages (P <.0001, [95% CI: (30%,42%)]). Conclusions: Our study found that LR-PRP is predominantly lymphocyte rich with notable concentrations of other WB cell subtypes, including neutrophils, monocytes, eosinophils, basophils, and large unstained cells. While these subtypes are not routinely reported, they may play a role in modulating the local inflammatory environment. We also found significant differences in WB cell subtype concentrations between WB and LR-PRP. Clinical Relevance: PRP has been routinely used in many clinical practices without clear indications for its use and lacks standardization in its formulation. This study provides a comprehensive characterization of a broadly used PRP, LR-PRP, and further characterizes subtypes of WBC cells present in LR-PRP that have not been previously reported. Comprehensively reporting these subtypes in clinical trials of PRP is crucial to understanding how these cells participate in PRP's therapeutic potential. This type of data can help standardize future PRP formulations and improve patient outcomes.