CD81, CD63, and CD9 signals on CSF EVPs were significantly decreased in the viral disease group (p = 0.005, p = 0.0151, and p = 0.0050, respectively; Figures 5A-C) compared to the non-viral disease group, although this trend is likely heavily influenced by the HAM patient CSF EVPs (open blue circles). Here, CD9 is linked to viral infectious disease.