SOLUBLE CD16 (SCD16), A MARKER OF MALIGNANCY IN INDIVIDUALS WITH MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE (MGUS)

There are no well-defined host markers to determine which patients wit h a diagnosis of monoclonal gammopathy of undetermined significance (M GUS) will progress to multiple myeloma (MRI). in this preliminary stud y we measured plasmatic soluble Fc gamma receptor type III (sFc gamma RIII or sCD16) in 54 individuals with MGUS, 35 patients with multiple myeloma (MM) and 29 healthy controls. We confirmed, through receiver o perating characteristic (ROC) curve analysis, that a low lever of sCD1 6 discriminates MM patients from controls. Indeed, for a sCD16 value o f 1.3 mu g/ml, the sensitivity, as well as the specificity, of this di scrimination were both equal to 83%, i.e. 83% of MM patients had a pla smatic sCD16 value <1.3 mu g/ml compared with only 17% of controls. Mo reover, ROC curve analysis showed that a low sCD16 lever also identifi es among MGUS patients a subgroup of patients who rapidly progress tow ards multiple myeloma: in this comparison, for a sCD16 level of 1.3 mu g/ml, sensitivity and specificity were 70% and 79% respectively. Ther efore a low sCD16 level in MGUS indicated a high likelihood of rapid e volution to MM. In contrast to sCD16, soluble IL-6R did not appear to be discriminant in this study.