Studies of biological functions in blood cells from individuals with large platelets

The present study was performed to explore differences in the expression of P-selectin and IL-8 production of blood cells in healthy individuals with large size platelets (MI-families) as compared to people having normal size platelets. A positive correlation between LPS-induced IL-8 production per platelet in whole blood and mean platelet volume (MPV) was found in the large platelet group ( R = 0.74, P< 0.05). When the large and normal groups were combined the correlation was nearly, but not quite significant ( R = 0.46, P< 0.06). There was also a positive correlation between sP-selectin and MPV ( R = 0.42, P< 0.05). Furthermore, IL-8 in serum was positively correlated to sP-selectin in serum ( R = 0.68, P< 0.005). sP-selectin baseline values in citrated plasma correlated significantly with values found in serum ( R = 0.72, P< 0.0005), indicating that sP-selectin in blood originates from the platelets rather than from endothelial cells. Significant correlations were also found in both groups between P-selectin and CD40L ( R = 0.44, P< 0.05) and P-selectin and RANTES ( R = 0.44, P< 0.05). A significant correlation was also found between PDGF and RANTES ( R = 0.44, P< 0.05). Our results suggest that larger platelets enhance the production of IL-8 more than normally sized platelets. This phenomenon is probably mediated through P-selectin exposed on platelets.