Soluble CD16 (sCD16) are soluble part of Fc receptor for IgG which control in mice, proliferation of hybridoma B cells and IgG production. The levels of sCD16 in 165 myeloma patients and 29 patients with MGUS appear significantly different:25a.u./ml versus 144a.u./ml and values of stage I are significantly higher than those of stages II + III.sCD16 might be a prognosis factor in myeloma.