SERUM STEM-CELL FACTOR CONCENTRATION IN PATIENTS WITH MYELODYSPLASTICSYNDROMES

Stem cell factor (SCF) is characterized by its capacity to synergize d ramatically with other haemopoietic growth factors in in vitro erythro id, myeloid, and lymphoid progenitor culture systems. We have measured serum SCF concentrations by enzyme immunoassay in 8 5 patients with m yelodysplasia (MDS). Serum samples were taken in 1988-89 and in 1991-9 2 and stored at -20-degrees-C. Mean serum SCF concentration in the MDS patients was 2.81 ng/ml (range 0.6-8.0). This was significantly lower (P= 0.0001) than the values for 234 normal subjects; mean 3.30 ng/ml (range 1.3-8.0). No significant relationship between SCF concentration and peripheral blood counts. bone marrow parameters, red cell transfu sion status, survival or FAB subtype was found, although a trend of de creasing SCF concentration from refractory anaemia through sideroblast ic anaemia and chronic myelomonocytic leukaemia to refractory anaemia with excess blasts was seen. The reduced SCF serum concentration in so me patients with myelodysplasia suggests a rationale for therapy with recombinant SCF in these patients.