I have had a low white blood count for about 16 -18 years. It was found on a random blood test. I have been through a work-up in 2 medical systems (Mayo and Marshfield clinic systems in Eau Claire) because I changed jobs, had to change insurance and had to change doctors. Both systems eventually called it idiopathic, don’t know the cause. I haven’t found anything that improves the count, it doesn’t bother me. I just monitor it with a blood test every 6 months to be sure there is no major change. Ironically, in my 3 bouts with PMR, my white count goes up while on prednisone. I can’t remember the mechanism, but my primary care doctor says this is typical with prednisone. I did read about an auto-immune leukopenia and wonder if I have it, but not diagnosed with it. I do not know any dietary, supplements , etc that can bring WBC’s up.