The 13th workshop of the European Bone Marrow Working Group in Utrecht, The Netherlands, was devoted to studying myelodysplastic syndromes (MDS) and their boundaries. The panel received 44 cases submitted to the 3 invited categories, which included: reactive cytopenias with dysplasia, idiopathic cytopenia of undetermined significance, clonal haematopoiesis of indeterminate potential, idiopathic dysplasia of uncertain significance and overt MDS. For this summary, we have selected 17 cases that highlight difficulties in separating true MDS from other causes of cytopenia and the intricate relationship between clonal haematopoiesis and true MDS. In addition, cases of overt MDS with challenging features were also selected. All cases were stained for p53 expression. Using instructive submitted cases we discuss the following: (1) cytopenia with clonal haematopoiesis not fulfilling MDS criteria, (2) cytopenia and/or dysplasia with germline mutations and/or familial history suggesting an underlying gene defect, (3) MDS based on a recurrent chromosomal abnormality and (4) overt MDS with diagnostic difficulties due to concurrent treatment or disease. The lively discussion in the open forum of the workshop illustrated the need for better integrative understanding of the evolution of acquired genetic abnormalities in haematopoiesis, and the challenge of diagnosing true MDS in cytopenic patients with genetic abnormalities, either germline or acquired.

• Keywords
• Bone marrow, Classification, Cytopenia, Myelodysplastic syndrome, Next-generation sequencing, Workshop,
• MeSH
• Chromosome Aberrations * MeSH
• Adult MeSH
• Genetic Testing MeSH
• Bone Marrow pathology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Myelodysplastic Syndromes classification   diagnosis   genetics   pathology   MeSH
• Sequence Analysis, DNA MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Education MeSH
• High-Throughput Nucleotide Sequencing MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Refractory cytopenia of childhood is the most common type of childhood myelodysplastic syndrome. Because the majority of children with refractory cytopenia have a normal karyotype and a hypocellular bone marrow, differentiating refractory cytopenia from the immune-mediated bone marrow failure syndrome (very) severe aplastic anemia can be challenging. Flow cytometric immunophenotyping of bone marrow has been shown to be a valuable diagnostic tool in differentiating myelodysplastic syndrome from non-clonal cytopenias in adults. Here, we performed the first comprehensive flow cytometric analysis of immature myeloid, lymphoid cells and erythroid cells, and granulocytes, monocytes, and lymphoid cells in bone marrow obtained from a large prospective cohort of 81 children with refractory cytopenia. Children with refractory cyotopenia had a strongly reduced myeloid compartment, but not as severe as children with aplastic anemia. Furthermore, the number of flow cytometric abnormalities was significantly higher in children with refractory cytopenia than in healthy controls and in children with aplastic anemia, but lower than in advanced myelodysplastic syndrome. We conclude that flow cytometric immunophenotyping could be a relevant addition to histopathology in the diagnosis of refractory cytopenia of childhood. (The multi-center studies EWOG-MDS RC06 and EWOG-MDS 2006 are registered at clinicaltrials.gov identifiers 00499070 and 00662090, respectively).

• MeSH
• Anemia, Aplastic diagnosis   immunology   pathology   MeSH
• Antigens, CD immunology   MeSH
• Diagnosis, Differential MeSH
• Child MeSH
• Erythroid Cells immunology   pathology   MeSH
• Granulocytes immunology   pathology   MeSH
• Immunophenotyping * MeSH
• Infant MeSH
• Bone Marrow immunology   pathology   MeSH
• Humans MeSH
• Lymphocytes immunology   pathology   MeSH
• Adolescent MeSH
• Monocytes immunology   pathology   MeSH
• Myelodysplastic Syndromes diagnosis   immunology   pathology   MeSH
• Pancytopenia diagnosis   immunology   pathology   MeSH
• Child, Preschool MeSH
• Flow Cytometry MeSH
• Severity of Illness Index MeSH
• Check Tag
• Child MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Clinical Trial MeSH
• Multicenter Study MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antigens, CD MeSH

Immunosuppressive therapy (IST), consisting of antithymocyte globulin and cyclosporine A, is effective in refractory cytopenia of childhood (RCC), suggesting that, similar to low-grade myelodysplastic syndromes in adult patients, T lymphocytes are involved in suppressing hematopoiesis in a subset of RCC patients. However, the potential role of a T-cell-mediated pathophysiology in RCC remains poorly explored. In a cohort of 92 RCC patients, we prospectively assessed the frequency of T-cell receptor (TCR) β-chain variable (Vβ) domain skewing in bone marrow and peripheral blood by heteroduplex PCR, and analyzed T-cell subsets in peripheral blood by flow cytometry. TCRVβ skewing was present in 40% of RCC patients. TCRVβ skewing did not correlate with bone marrow cellularity, karyotype, transfusion history, HLA-DR15 or the presence of a PNH clone. In 28 patients treated with IST, TCRVβ skewing was not clearly related with treatment response. However, TCRVβ skewing did correlate with a disturbed CD4(+)/CD8(+) T-cell ratio, a reduction in naive CD8(+) T cells, an expansion of effector CD8(+) T cells and an increase in activated CD8(+) T cells (defined as HLA-DR(+), CD57(+) or CD56(+)). These data suggest that T lymphocytes contribute to RCC pathogenesis in a proportion of patients, and provide a rationale for treatment with IST in selected patients with RCC.

• MeSH
• T-Lymphocytes, Cytotoxic immunology   MeSH
• Child MeSH
• Immunosuppression Therapy MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Myelodysplastic Syndromes immunology   pathology   MeSH
• Pancytopenia immunology   MeSH
• Child, Preschool MeSH
• Prospective Studies MeSH
• Receptors, Antigen, T-Cell, alpha-beta immunology   MeSH
• Case-Control Studies MeSH
• T-Lymphocyte Subsets chemistry   MeSH
• Check Tag
• Child MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Receptors, Antigen, T-Cell, alpha-beta MeSH