Rowley et al. have reported that the postmortem examination of KD patients revealed the invasion of many mononucleoses, CD8 positive T-cells, and IgA producing plasma cells (17), proposing a hypothesis that viruses invading mainly from the respiratory apparatus stimulate CD8 positive T-cells and B cells in the organ lymph nodes and differentiate them into IgA producing plasma cells, with these cell groups giving rise to vasculitis (Figure 1D). Here, CD8A is linked to vasculitis.