Preferential egress of PB from the lymphoid compartment. (A) Cell harvesting scheme (left). The mean numbers of harvested cells are reported and represented by the size of the corresponding pie chart (right; n = 3 independent donors). The frequencies of the major lymphocyte subsets are represented by the different slices in the pie charts. A zoomed-in view of the two upper pie charts is provided for clarity. (B) Representative example of B cell phenotyping on cells recovered from the upper and lower LO chip compartments (left plots, top and bottom rows, respectively). Frequencies of PB in CD19⁺ B cells, spike-specific B cells in CD19⁺ cells, and PB in the spike-specific B cell subset are reported for the upper perfusion compartment (upper) and the lower tissue-like compartment (lower) in the graphs (right; n = 3). Each color represents an independent donor. Differences were evaluated with a Wilcoxon matched pairs test; ns, not significant.