In the coculture experiment with KP/KPP conditioned medium and dendritic cells, the results demonstrated that the effect of PLK1 on MHC-II could be explained by CXCL2, as treatment with Cxcl2 in KP group reduced MHC-II expression and treatment with either SX-682 or neutralization antibodies in KPP group elevated MHC-II level (S5C, S5D, S5E and S5F Fig), which was different from the results in macrophages. Here, CXCL2 is linked to keratosis pilaris.