Combined immunophenotyping and FISH identifies the involvement of B-cells in 5q-syndrome

The 5q- syndrome is a distinct subtype of myelodysplastic syndrome (MDS) ch aracterized by refractory anemia, deletion of the long arm of chromosome 5, del(5q), as the sole cytogenetic abnormality, and a low frequency of trans formation to acute leukemia. Using combined immunophenotyping and fluoresce nce in situ hybridization (FISH), studies were carried our, on bone marrow smears of three 5q- syndrome cases to identify the cell lineages carrying t he 5q deletion. In all three cases, the granulocytic, monocytic, and erythr oid lineages possessed the del(5q) clonal marker, whereas the T-lymphocytes did not. interestingly, in one case, cells of B-lymphoid lineage also show ed the presence of the del(5q). This is the first report to date showing in volvement of an acquired 5q deletion associated with MDS in B-cells. This r esult suggests chat in some cases, MDS arises in a multipotent cell with a capacity to differentiate into both myeloid and lymphoid cells. (C) 2000 Wi ley-Liss, Inc.