Study of markers of inflammation: blood will be withdrawn in 5 ml EDTA tube. After extraction, the tube will be centrifuged, and plasma collected in eppendorf tubes and frozen at -70°C until cytokines determination. The content of TNF-alpha, IL-1 beta and IL-6 in the plasma samples will be measured by ELISA. Each sample will be analyzed in duplicate using ELISA kits "R & D Systems" following the specifications that commercial supplier.