Increased platelet protein expression of CD58, CD69, IFITM1 and PRKRA in SLE patients. Surface (CD58, CD69) or intracellular (IFITM1, PRKRA) protein levels were measured on platelets from healthy controls and systemic lupus erythematosus (SLE) patients by flow cytometry. The values are expressed as percentage of cells being positive compared with an antibody isotype control. The lines represent the median-value in each group.