From the hematoma fluid samples, the pro-inflammatory cytokines IL-1β, IL-2, IL-7, CCL2, CXCL9, TNF-α and IL-12, together with the anti-inflammatory IL-1RA, were related strongly to the first factor, while the pro-inflammatory cytokines IL-6, IL-2R and CXCL10, together with the anti-inflammatory IL-5, IL-10 and IL-13, were strongly related to the second factor. The gene discussed is IL2; the disease is hematoma.