BD FastImmune kit for intracellular cytokines

I will study intracellular cytokine (IFN-g, IL-4) production in T cells 
for clinical trials.  The plan is to collect and freeze PBMC in 
different time points, then thaw the cells and stimulate the cells with 
antigen on same day for cytokine detection.  BD offers FastImmune 
intracellular cytokine kits (IFN-g or IL-4/CD69/CD4/CD3) for whole 
blood.	Based on the information from its FastImmune CFC Handbook, it 
seems the FastImmune kit can also be used on frozen PBMC.  I would like 
to know if you have the (postive or negative) experience in using the 
kits on frozen PBMC, and experience in using the kits for on whole blood 
(stimulation/BFA, lyse/fix, permeablization, staining on one day) then 
freeze the cells at -80C for later analysis.

Thank you,

Dianna Wu
BMS