The soluble release profile by activated T cells is altered by valproic acid, ATRA and cytarabine – a two-ways hierarchical cluster analysis. PBMCs derived from 7 healthy individuals were cultured with the T cell activating signal anti-CD3 plus anti-CD28 for 4 days before supernatants were harvested and cytokine levels determined. The cells were then cultured in drugfree control cultures and together with ATRA 1 μM, valproic acid 500 and 100 μM, and cytarabine 0.01, 0.35, 1 and 44 μM, and each drug was also tested in dual or triple combinations as indicated at the top of the figure. The overall results are presented in detail in Additional file 1: Table S1-S4. The results from a two-ways hierarchical cluster analysis including FasL, TRAIL, HSP70 and HSP90 together with 20 cytokines are presented in the figure. We investigated the levels of (i) the immunoregulatory cytokines IFNγ and TNFα; (ii) the growth factors G-CSF, GM,-CSF, VEGF and bFGF; (iii) the chemokines CCL2-5 and CXCL5; and (iv) the interleukins IL1α, IL1β, IL1RA, IL2, IL4-6, IL8, IL10 and IL17. The cytokines formed 4 main clusters as indicated on the left margin of the figure. The analysis included the 19 single drug/drug combinations used throughout the study and the various drugs/drug combinations formed three main clusters.