I did an experiment where I administrated LPS in WT and KO animals. I wanted to know if the KOs have a different immune response than WTs. As targets I used several cytokines and complement system genes. I wanted to assess if the expression of certain cytokines correlates with the expression of the complement genes in each group. What value would be appropriate to use from my qPCR analysis to do this correlation? dCT? ddCT? I thought about using the dCT since the ddCT is "normalized" to the control group.