Expression of BLyS in primary myeloma cells. Immunohistochemical analysis of BLyS expression in normal bone marrow, MM bone marrow (MM 1-3), Jurkat, or BLyS-transfected Jurkat cells was performed with the anti-BLyS mAb from R&D Systems as described in “Materials and methods.” These results are representative of 3 normal and 10 MM samples. Original magnification, ×200.