Change ThreadPriority in Unity?

When I write this:

Thread.CurrentThread.Priority = System.Threading.ThreadPriority.AboveNormal;

It does not change anything, the ThreadPriority is still set to "lowest" ?

When I make some new WorkerThreads I really want to set them to a lower priority than my main Unity thread. But the lowest I can set them is to "Lowest" ?! which is the same as Unity's mainThread?