When sorted primary bone marrow plasma cells taken from patients with myeloma (n = 7) were co-cultured with CD4+CD25- T-cells from healthy donors, a significant generation of TReg cells was seen (1.2%±0.31 vs 12.02±4.4, n = 7; p = 0.004), similar to the HMCL, U266B (1.2%±0.31 vs 21.9%±5.6, n = 7; p<0.0001; Figure 1F). Here, CD4 is linked to plasma cell myeloma.