is there anyone who study PDL1expression in PB lymphocytes by flow cytometry in healthy controls and in pathological cases ( cancer)
Oddly, we found that healthy controls express more PDL1 than patients with cancer. Any explanation?
1. I assume (in healthy people) that you don't want your PB lymphocytes to be easily activated.
2. A cancer patient is already in disarray and maybe the PB lymphocytes have been affected by the state of the individual. Less PDL1 in PB lymphocytes does not mean that they will be more activated towards cancer targets. They might not even recognize the cancer antigen and may be more towards other cofounding diseases/factors. Also... it depends on the cancer. So this difference might only exist between healthy individuals and whatever cancer patient group you are studying.
3. By itself. PDL1 cannot explain mechanism. At most, you can use it as a biomarker.
Hi Daniela,
PD-L1 can be constitutively expressed in peripheral lymphocytes from healthy and cancer patients, some issues to consider are:
The panel you are using for analyzing PD-L1 expression and whether you included the corresponding flow cytometry controls.
The parameter you are using to evaluate PD-L1 expression (% or MFI)
If you are running paired samples from cancer and healthy subjects at the same time in the flow cytometer.
Is the distribution of lymphocytic populations similar between cancer and healthy donors? If there is a reduction in one particular population, this might account for a reduced expression of this molecule
Are you stimulating the cells to evaluate the expression of PD-L1? Some stimuli might be too aggressive for lymphocytes from cancer patients and cause cell death.
I hope this helps.
Thanks for your answers. They were very helpful
Controls (FMO) are performed and samples are running in paralel several times. No stimuli was used and we use percentage as expression parameter. Results in the cancer group is in line with previous publications and I agree that the only conclusion is that it could be used as a biomarker if results are confirmed.
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