For the active treatment group following treatment (4th assessment), CD4 was negatively correlated with CD4 on QoL total (r = − 0.62, p = 0.010, Fig. 3 upper) and Zung depression (r = − 0.51, p = 0.026; Fig. 3 lower), in that higher CD4 was associated with poorer QoL and more depression. The gene discussed is CD4; the disease is major depressive disorder.