CD130 rather than CD126 expression is associated with disease activity in multiple myeloma

We analysed the expression of both components of IL-6R, CD126 the ligand bi nding protein and CD130 the signal transducing protein, on plasma cells fro m MGUS and multiple myeloma (MM) cases using flow cytometry. CD126 was dete ctable in 50% of either MGUS or MM patients without any change of expressio n during disease progression. In contrast, CD130 expression was up-regulate d during tumoural expansion (43% of MM patients at diagnosis versus 88% at relapse), Finally, combining CD126 and CD130 expression we found a signific ant increase of the percentage of CD126(+) CD130(+) patients at relapse, un derlying the crucial role of IL-6 response in the late stage of MM.