Double-stranded RNA excess in hematologic diseases: clinical implications

Evaluation of double-stranded RNA by flow cytometric analysis is an important parameter for discriminating quantitatively between human tumoral and normal cells. We studied double-stranded RNA (ds-RNA) measurements using propidium-iodide after DNase treatment in bone marrow and in peripheral blood cells from patients with acute lymphoblastic leukemia, acute myeloid leukemia, chronic myeloid leukemia and multiple myeloma. The highest incidence of ds-RNA excess (greater than 30%) was observed in patients with acute leukemia (75%), while those displaying it in complete remission phase were 20-25% and in relapse about 80%. A high incidence was also noted in patients with chronic myeloid leukemia in blastic crisis (100%) and in patients with multiple myeloma with heavy tumor stage myeloma (78%). We never observed an elevated ds-RNA excess in the control group, formed by normal peripheral blood lymphocytes. Indeed the specificity of this tumor marker is attested to not only by its high levels in various hematologic malignancies, but also by its absence in normal cells. Hence the importance of its clinical implications in malignant hematologic diseases is confirmed.