CD19 and Miyoshi myopathy: Fig. 4 shows the statistically highly significant difference in the numbers of MAGE C1 positive cells in the CD19+ population vs the more mature CD20+ cells (p-value<0.0001). While circulating plasma cells were observed in the PB of all the MM patients, MAGE C1 expression was only apparent in the proliferating plasma cell population if present and corresponded with the expression in the matched BM samples (if applicable) (Fig. 3).