That's a good question. I can imagine that there was a time before there was life on Earth, and then clearly there was a time X-hundred thousand years or a million years later when there were things that we would all recognize as biological.
A high count indicates the presence of inflammation in the body. Because white blood cells are calculated by the number of cells per volume of blood, test results can vary between labs. Different labs use different degrees of measurements for the white blood cell count.
Quick Answer. Diseases that cause low white blood cell counts include aplastic anemia, human immunodeficiency virus, leukemia and lupus, according to Mayo Clinic. Other causes include rheumatoid arthritis, Crohn's disease and infections such as tuberculosis, reports MedlinePlus.