ICAM1 and systemic lupus erythematosus: IL-15 enhanced CD54 expression on T cells from SLE patients (4.8 ± 0.9% versus 2.4 ± 0.4%, p < 0.001) and controls (8.3 ± 1.0% versus 3.3 ± 0.6%, p = 0.001) alike.