Whole-cell MALDI-TOF MS based identification of biomarkers specific for pan-monocyte and CD16+ monocytes. A) Smoothed mass spectra quadruplicates obtained from resting pan-monocytes (n = 8, 32 red spectra) overlaid with those obtained from CD16+ monocytes (n = 7, 28 green spectra). m/z peaks significantly over-represented in pan-monocytes (left overlay plot) or CD16+ monocytes (right overlay plot) are indicated. B) Scatter-plot of quadruplicate’s averaged mass peak intensities from pan-monocytes and CD16+ monocytes from individual donor are shown for the peak at 9296.1 m/z (left) and 9720.3 m/z (right). The two-way ANOVA with Bonferroni post-tests correction was used with a significance at p < 0.001.