Chunk #21 — Results and Discussion — Gene expression differences between isolation methods are associated with cellular composition and B-cell manipulation
These findings suggest that the gene expression differences between the PBMCs and PAX are caused by the differences in cellular composition; gas transport is specific for erythrocytes and translation and transcription are physiological responses more important in lymphocytes and monocytes than in granulocytes [6,9]. To explore whether enrichment is derived from the most abundant cell types in the sample, we clustered the differentially expressed transcripts in six groups and correlated the transcripts in each group to the cell counts in whole blood (Figure 6). All three groups up-regulated in the PBMCs showed significant positive correlations with monocyte counts (ρ = 0.20, p = 2.2*10-16; ρ = 0.20, p = 2.7*10-14; ρ = 0.29, p = 5.9*10-7) and platelets (ρ = 0.39, p < 10-16; ρ = 0.42, p < 10-16; ρ = 0.47, p = 6.6*10-7). Only one of these groups was correlated with lymphocytes (ρ = 0.36, p = 1.3*10-7) whereas the two other groups of up-regulated genes were significantly positively correlated with neutrophil count (ρ = 0.20, p = 1.3*10-14; ρ = 0.50, p = 4.1*10-11). Three groups
