Nine immunophenotypes have been identified that provide protection against the development of MVP, including the expression of CD45 on CD33 bright HLA DR+, HLA DR on myeloid DC, CD19 on IgD− CD38−, CD14+ CD16+ monocyte ACs, CD86+ plasmacytoid DCs ACs, HLA DR on B cells, Sw mem, SSC-A on B cells, and CD45 on CD14+ monocytes (Figure 3). This evidence concerns the gene CD19 and familial mitral valve prolapse.