When you experience inflammation, the blood cells that are fighting pathogens in your body are white blood cells, also known as leukocytes.
These blood cells function by allowing more blood flow into the affected area, and maybe raising the temperature of your body, so as to cleanse it of any infection or pathogens that are there to make you feel sick. It's a good thing to have many leukocytes, but not too many because that can lead to leukemia.