CD4 and plasma cell myeloma: Analysis of CD4 T cells showed a significantly higher proportion of naïve/stem cell memory (SCM) phenotype in HDs (30.8 ± 7.7%) compared with newly diagnosed multiple myeloma (11.1 ± 2.4%, P < 0.05) or patients with relapsed multiple myeloma (6.0 ± 1.5%, P < 0.05; Fig. 1E).