Multicentric Study Comparison Between Erythropoietin and Erythropoietin Associated to Differentiating Therapy With Acid 13-cis-retinoic and Dihydroxyvitamin D3 in Myelodysplastic Syndromes Without Excess of Blasts

Inclusion Criteria: 1. Age higher than 18; 2. Confirmed diagnosis by osseous biopsy and bone marrow cyto-morphologic counts of blast cells, of Myelodysplastic syndrome without excess of blasts: "refractary anemia", "refractary anemia with rings sideroblasts", "refractary citopenya with multilineage dysplasia", " refractary citopenya with multilineage dysplasia and rings sideroblasts" or "5q-syndrome" without excess of blasts based on WHO classification (appendix). 3. Low or intermediate-1 IPSS (appendix). 4. Hb \< 11g/dl. 5. rEPO serum level \< 500mU/L. 6. Women in menopause from at least one year. 7. Informed consent Exclusion Criteria: 1. Myelodisplastic syndrome with excess of blasts (RAEB). 2. IPSS score intermediate-2 or high (appendix). 3. Forecasted allogeneic bone marrow transplant within 1 year after diagnosis(patients younger than 60 years, transfusion dependents or with serious leuko/thrombocytopenia and HLA compatible family donor).Considering the time needed to perform this procedure, the indication of a transplant from non-consanguineous donor has no contraindication to the inclusion in this protocol of the response to rEPO therapy ± differentiating therapy. 4. Renal failure with creatininemia value greater than 3 times the normal limit. 5. Chronic hepatophaty with bilirubinemia value greater than 3 times the normal limit and/or AST or ALT or ALP values greater than 5 times the normal limit. 6. Presence of second tumor or other serious pathology with life expectancy lower than one year. 7. Presence of neurologic or psychiatric pathologies that make the patient unreliable in the acquisition of drugs. 8. Allergy/intolerance known to use drugs. 9. Pregnant women. 10. Women of childbearing age or in menopause from less than one year. 11. Age \< 18 years old. 12. HIV positive.