CLONAL INVOLVEMENT OF EOSINOPHILS IN THERAPY-RELATED MYELODYSPLASTIC SYNDROME WITH EOSINOPHILIA, TRANSLOCATION T(1-7) AND LUNG-CANCER

We report a therapy-related MDS (RAEB) patient with eosinophilia, unba lanced translocation der(7)t(1;7) (q12;q22) and lung cancer. We observ ed no increase in cytokine levels in serum or in the conditioned mediu m (CM) of peripheral T cells cultured with or without IL-2. When bone marrow (BM) cells were cultured with GM-CSF, IL-3 and SCF in a semisol id system, the colonies were exclusively eosinophilic. Cytogenetic ana lysis of the colony cells identified the same chromosome abnormality i n all metaphases to that of BM cells, Suspension and clonogenic colony assay of BM cells cultured with various cytokines showed predominant eosinophilic growth and differentiation with GM-CSF, but not with the other cytokines examined. These findings, together with mild morpholog ical abnormalities of eosinophils, indicate clonal involvement of eosi nophils in the myelodysplastic syndrome (MDS) clone, and that the eosi nophilia was derived from the neoplastic clone with the translocation and was not associated with the patient's lung cancer.