CD28 and Miyoshi myopathy: PCs are characterized by the expression at high level of two main markers, CD38 and CD138; however, MM PCs may be recognized because they could express markers such as CD56, CD28, CD200 and CD117, and, compared with normal PCs, generally are CD45−low, CD19−, CD27−, and CD81−.All together, these markers, in addition to the clonal restriction of MM PCs to just one of two immunoglobulin light chains, κ or λ, contribute to easily discriminating normal from clonal MM PCs (24).