Hello, I had a question for you.

My blood samples are going to be taken from a hospital in Tehran, and the number of samples is 25, and they are from children with acute lymphoblastic leukemia. After all the samples are collected, they will be transferred to another city within seven months for qPCR and RNA extraction from PBMC and then cDNA synthesis. I need to store my samples in Tehran for a long time, and after 7 months, when all 25 blood samples are collected, I will transfer them to the destination city and then perform RNA extraction.

In this case, can I use RNA shield and store it at -70C for a year? And will it not cause any problems for my cells?

Finally, after seven months, can I have a proper extraction with a proper amount of RNA?

And how should I clean the blood from RNA shield after thawing the sample?

Do I need to separate PBMC in Tehran before adding this solution?

How should I calculate the ratio of RNA SHIELD to blood?

Do you have a better suggestion for storing PBMC and preserving RNA for the long term?

Also, I don't have the conditions to use liquid nitrogen.