![]() Antigens that are useful in detecting MDS on myeloid progenitors, maturing myeloid populations, and monocytic populations include but are not limited to CD5, CD7, CD10, CD11b, CD13, CD14, CD16, CD33, CD34, CD38, CD56, CD117, and HLA-DR. Detection of the multiple characteristic abnormalities depends on incorporation of large numbers of antibodies in a multiparameter four-color (or greater) panel. In addition, maturing myeloid or monocytic forms may show aberrant patterns of antigen expression (e.g., an aberrant pattern of CD11b or CD13 versus CD16 ) or an increase or decrease in intensity of a normally expressed antigen. 5-7, A and B), paralleling the decreased cytoplasmic granularity seen in dysplastic neutrophils. Maturing granulocytic forms may show decreased SSC ( Fig. The types of abnormality seen on myeloid blast typically fall into one of the following categories: (1) Abnormal intensity of antigen expression (2) dyssynchronous expression of mature and immature antigens (3) homogeneous expression of an antigen normally expressed at varying levels during maturation and (4) expression of a non–lineage-specific antigen (e.g., expression of CD5, CD7, or CD56 on myeloid blasts). In addition, identifying MDS by flow cytometry is best approached by considering several populations (e.g., myeloid progenitors, maturing myeloid forms, monocytic forms, erythroid forms). No single MDS-specific immunophenotype exists rather, it is a difference from normal that characterizes MDS. Such changes in antigen expression can be detected by FCM and may be seen in a variety of lineages ranging from myeloid blasts to maturing granulocytic, monocytic, and erythroid forms. Similarly, this ineffective hematopoiesis leads to alterations in the highly conserved and predictable patterns of antigen expression accompanying normal maturation. In MDS, normal hematopoiesis is rendered ineffective, leading to dysplastic changes that alter normal morphology. Normal hematopoiesis is characterized by conserved changes in the appearance of cells that are predictable, orderly, and accompany different stages of maturation. 128 In addition, the 2008 WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues recognized the utility of FCM in the evaluation of MDS. 125-127 This is reflected in the inclusion of FCM in the minimal diagnostic criteria for MDS developed at a 2006 international working conference. For this reason, FCM is increasingly being used in diagnostic evaluation of potential MDS cases in an attempt to increase sensitivity and specificity of diagnosis. Jaffe MD, in Hematopathology, 2017 Myelodysplastic SyndromesĪlthough bone marrow morphology with concurrent cytogenetic study remains the gold standard for the diagnosis of myelodysplastic syndromes (MDSs), a significant number of patients have blood and bone marrow findings that make diagnosis and classification difficult.
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