IL2 and infection: PNL can have great influences on the body because of trauma, pain, infection, inflammation, and so forth, so stress response may lead to the elevation of inflammatory factors, such as the acute phase C-reactive protein (CRP), cytokines interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-2 (IL-2), interleukin-10 (IL-10), and TNF-α [3, 4].