Figure 2.

CD4⁺ and CD8⁺ T-cell frequencies and phenotype in cannabis users and nonusers. Multiparameter flow cytometry was used to identify the frequency and phenotype of CD4⁺ and CD8⁺ T cells within total peripheral blood mononuclear cells of cannabis-using and nonusing individuals. A, Representative staining demonstrating CD4⁺ and CD8⁺ T-cell populations. Cells were identified by first excluding doublets using forward and side scatter properties, gating on total leukocytes as determined by CD45 expression, and removing dead cells with an Aqua Live/Dead viability dye. The frequency of T cells was then determined by gating on CD3⁺ cells and identifying CD4⁺- and CD8⁺-expressing T cells within this subset. Pooled data shows the percentage of CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells in all individuals. B and C, Frequency of human leukocyte antigen (HLA)-DR⁺CD38⁺-expressing CD4⁺ (B) and CD8⁺ (C) T cells. Pooled data is accompanied by a representative flow plot showing gating for the indicated marker. In all plots, individuals are classified as noncannabis users or cannabis users stratified by moderate or heavy cannabis use as determined by plasma quantities of 11-nor-carboxy-tetrahydrocannabinol. Each individual is represented by a single point. Horizontal bars indicate the median value. The statistical significance of differences between each of the cannabis-using groups and the noncannabis users was determined using the Mann-Whitney test.