In RA SF, CD4+ [55], CD41+ [25], CD66+ [28, 55] and CD14+ [28, 55] EVs were found abundant, whereas glycophorin A [28, 55], CD4+ [28], CD61+ [28, 55], CD8+ [28, 55], and CD20+ [28, 55] EVs were low. Here, CD4 is linked to rheumatoid arthritis.