Long-term remission after intensive chemotherapy in advanced myelodysplastic syndromes is generally associated with restoration of polyclonal haemopoiesis

The clonality of peripheral blood cells was assessed in eight female patien ts with myelodysplastic syndrome (MDS) by means of the human androgen recep tor gene-based assay (HUMARA). The patients were in complete remission for a median follow-up time of 83 months after intensive chemotherapy. X-chromo some inactivation patterns (XCIPs) indicated polyclonal haemopoiesis in fiv e patients. Two patients had skewed lyonization (i.e. unbalanced XCIPs in b oth granulocytes and T cells) and one patient presented monoclonal granuloc ytes together with polyclonal T cells. We conclude that long-term remission in MDS following intensive chemotherapy is usually associated with polyclo nal haemopoiesis.