The myelodysplastic syndromes pose important clinical and scientific chal lenges which in recent years have attracted growing interest within haemato oncology and molecular genetics. Their potential as a model for the study of human leukaemogenesis makes this one of the most exciting fields in contemporary haematology. Rapid progress towards understanding these disorders had created the need for international interdisciplinary communi cation. In order to fulfil this need the First International Symposium on Myelodysplastic Syndromes was organized in Innsbruck, Austria, in June 1988. The substantial number of excellent speakers and of participants manifested the great international interest on the topic. The present volume consists of the contributions of most of the speakers at this Symposium. We wish to thank all those who submitted their manus cripts. G. ]. Mufti Franz Schmalzl Contents Classification and Cytopathology of Myelodysplastic Syndromes The Classification of Myelodysplastic Syndromes J. M. Bennett . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Classification of Myelodysplastic Syndromes in Clinical Practice: of Subtypes Frequency G. Flandrin . . . . . . . . . . . . .: . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Pathogenesis of Anaemia in the Myelodysplastic Syndrome A. Jacobs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Immunological Abnormalities in the Myelodysplastic Syndrome T. J. Hamblin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Pediatric Experiences in Myelodysplastic Syndrome H. Gadner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Myelodysplastic Syndromes in Childhood: Description of 11 Cases E. T. van't Veer-Korthof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 The Value of Cytochemical Investigations in the Diagnosis of the Myelodysplastic Syndromes F. Schmalzl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Enzyme Cytochemical Studies in Myelodysplastic Syndromes A. De Pasquale and D. Quaglino . . . . . . . . . . . . . . . . . . . . . . . . ."