Immunosuppressive treatments for myelodysplastic syndromes.

The myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem cell disorders, while, immunological abnormalities are frequently observed in patients with MDS. Several reports revealed that about 10% of MDS patients have clinical autoimmune disorders like skin vasculitis, rheumatic disease, or autoimmune hemolytic anemia. Furthermore, serological immunological abnormalities like hyper- or hypogammaglobulinemia, positivities of antinuclear antibody, positivities of direct Coombs test, or inverted CD4/8 ratios were found in 18-65% of patients with MDS. Recently immunosuppressive therapies including prednisolone, antithymocyte globulin, and cyclosporin A (CsA) are used to treat cytopenia in some patients with MDS. We examined the efficacy of CsA in 50 patients with MDS. Hematologic improvement was observed in 30 (60%) patients especially for erythroid lineage. There were significantly more responders with good karyotype or DRB1*1501 than with intermediate/poor karyotypes or with other HLA types. MDS with erythroid hypoplasia is a rare form of MDS, and has not yet been clearly defined. We reported four patients with MDS with erythroid hypoplasia who had morphological evidence of myelodysplasia and low percentage of erythroid precursors. Rearrangements of the TCR-beta and -gamma genes were seen in these patients using Southern blot and PCR analysis. Also they had skewed TCR usages using TCR repertoire analysis. Their anemia drastically improved with CsA therapy. We have to establish the clinical usefulness of immunosuppressive therapy in MDS patients and simple tools for revealing T-cell mediated myelosuppression in the individual patients for decision-making.