Cytogenetic study in multiple myeloma at diagnosis: comparison of two techniques.

Cytogenetic studies in multiple myeloma (MM) have been disappointing due to the low mitotic index of plasma cells. Recently the detection of clonal chromosomal abnormalities at diagnosis seemed to be improved by addition of cytokines (IL-6 and GM-CSF) in the culture medium. We performed two parallel total bone marrow cells culture types in 33 stage I, II and III multiple myeloma patients at diagnosis: 3 d without any cytokine, and 4-7 days stimulated with IL-6 and GM-CSF. No clonal chromosomal abnormality was detected in the 12 stage I and II patients either in 3 d or in 4-7 d culture. In stage II patients, abnormalities were observed in 18/21 (85.7%) and in 8/18 (44.4%) in the 3 d culture and the 4-7 d stimulated cultures respectively. Our results suggest that in stage III multiple myeloma at diagnosis, 3 d culture without cytokine may be the better technique to detect clonal chromosomal abnormalities, and, before using cytokines as a reference condition, this 3 d unstimulated culture should be considered.