Furthermore, all switched memory B cells from the MM cohort showed increased expression of CD28, Bcl-6, IRF-4, and CD329, while switched memory B cell clusters differed in the expression of FGFR3 (SM1, SM3); Sox2 and CD24 (SM1); RARα2 and CD44 (SM2); and CD362, Nanog, KLF-4, CD319, and CD81 (SM2–3) expression (Figure 4B). Here, CD81 is linked to Miyoshi myopathy.