Low-density blood cells from patients with refractory anemia with excess of blasts (RAEB) and RAEB in transformation (RAEB-T) release a high molecular weight inhibitory substance that reduces the entry of normal progenitor cells of granulocytes and macrophages (CFU-GM) into the S-phase. Out of 20 patients with refractory anemia (RA and RAS) only 3 were positive. One patient with CMML was negative. Serial examination of 3 patients (two RA and one CMML) revealed that the production of the inhibitory activity preceded the development of the disease into RAEB, RAEB-T, or AML. With one exception, the inhibitory activity in positive cases was neutralized by antiserum against human placental ferritin.

Institute of Hematology and Blood Transfusion Prague Czechoslovakia

Neutralization of inhibitory activity derived from cells of MDS patients and ML-2 cell line by monoclonal antibodies against H and L-subunit-rich ferritins