Normal variation of bone marrow B-cell precursors according to age - reference ranges for studies in myelodysplastic syndromes in Brazil

Multiparameter flow cytometry in the evaluation of myelodysplasia: Analytical issues: Recommendations from the European LeukemiaNet/International Myelodysplastic Syndrome Flow Cytometry Working Group

Multiparameter flow cytometry (MFC) is one of the essential ancillary methods in bone marrow (BM) investigation of patients with cytopenia and suspected myelodysplastic syndrome (MDS). MFC can also be applied in the follow-up of MDS patients undergoing treatment. This document summarizes recommendations from the International/European Leukemia Net Working Group for Flow Cytometry in Myelodysplastic Syndromes (ELN iMDS Flow) on the analytical issues in MFC for the diagnostic work-up of MDS. Recommendations for the analysis of several BM cell subsets such as myeloid precursors, maturing granulocytic and monocytic components and erythropoiesis are given. A core set of 17 markers identified as independently related to a cytomorphologic diagnosis of myelodysplasia is suggested as mandatory for MFC evaluation of BM in a patient with cytopenia. A myeloid precursor cell (CD34⁺ CD19^- ) count >3% should be considered immunophenotypically indicative of myelodysplasia. However, MFC results should always be evaluated as part of an integrated hematopathology work-up. Looking forward, several machine-learning-based analytical tools of interest should be applied in parallel to conventional analytical methods to investigate their usefulness in integrated diagnostics, risk stratification, and potentially even in the evaluation of response to therapy, based on MFC data. In addition, compiling large uniform datasets is desirable, as most of the machine-learning-based methods tend to perform better with larger numbers of investigated samples, especially in such a heterogeneous disease as MDS.

Immunophenotypic changes in juvenile myelomonocytic leukaemia after treatment with hypomethylating agent: Do they help to evaluate dept of response?

5-Azacitidine has been used before stem cell transplantation in juvenile myelomonocytic leukaemia (JMML) patients. Recently, we have described immunophenotypic features in JMML at diagnosis. Here, our aim was to examine the changes in the immunophenotypic features during azacitidine treatment, correlating it with clinical response. Patients treated with 5-azacitidine were evaluated at diagnosis and after three and six cycles of medication. Among 32 patients entering the study, 28 patients were examined after three cycles and 25 patients after six. Patients showed a reduction in CD34/CD117⁺ cells: median 3.35% at diagnosis, 2.8% after three cycles and 1.63% after six. B-cell progenitors were decreased at diagnosis and decreased after treatment. Monocytes decreased: 11.91% to 6.4% and 4.18% respectively. Complete response was associated with increase in classical monocytes. T lymphocytes, reduced at diagnosis, increased in patients responding to 5-azacitidine. Immunophenotypic aberrancies including expression of CD7 in myeloid progenitors remained after treatment. This feature was associated with a worse response to treatment, as well as presence of NF1. Immunophenotyping was feasible in all patients. Clinical response was associated with a decrease of myeloid progenitors and monocytes and a rise in T lymphocytes although phenotypic aberrancies persisted. The largest effect was observed after three cycles.

A simple score derived from bone marrow immunophenotyping is important for prognostic evaluation in myelodysplastic syndromes

Immunophenotyping of bone marrow (BM) precursors has been used as an ancillary diagnostic tool in myelodysplastic syndromes (MDS), but there is no general agreement about which variables are the most relevant for prognosis. We developed a parsimonious prognostic model based on BM cell populations well-defined by phenotype. We analyzed 95 consecutive patients with primary MDS diagnosed at our Institution between 2005 and 2012 where BM immunophenotyping had been performed at diagnosis. Median follow-up: 42 months (4-199). Median age: 67 years (33-79). According to IPSS-R, 71 cases were low or intermediate risk. Flow variables significant in the univariate Cox analysis: "%monocytes/TNCs", "% CD16⁺ monocytes/TNCs", "total alterations in monocytes", "% myeloid CD34⁺ cells", "number of abnormal expressions in myeloblasts" and "% of B-cell progenitors". In the multivariate model remained independent: "% myeloid CD34⁺ cells", B-cell progenitors" and "% CD16⁺ monocytes/TNCs". These variables were categorized by the extreme quartile risk ratio strategy in order to build the score: % myeloid CD34⁺ cells" (≥ 2.0% = 1 point), B-cell progenitors" (< 0.05% 1 point) and "CD16⁺ monocytes/TNCs" (≥ 1.0% 1 point). This score could separate patients with a different survival. There was a weak correlation between the score and IPSS-R. Both had independent prognostic values and so, the flow score adds value for the prognostic evaluation in MDS.

Diagnostic significance of flow cytometry scales in diagnostics of myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes (MDS) can present a challenge for clinicians. Multicolor flow cytometry (MFC) can aid in establishing a diagnosis. The aim of this study was to determine the optimal MFC approach for MDS.

METHODS

The study included 102 MDS (39 low-grade MDS), 83 cytopenic patients without myeloid neoplastic disorders (control group), and 35 healthy donors. Bone marrow was analyzed using a six-color MFC. Analysis was conducted according to the "Ogata score," "Wells score," and the integrated flow cytometry (iFC) score.

RESULTS

The respective sensitivity and specificity values were 77.5% and 90.4% for the Ogata score, 79.4% and 81.9% for the Wells score, and 87.3% and 87.6% for the iFC score. Specificity was not 100% due to deviations of MFC parameters in the control group. Patients with paroxysmal nocturnal hemoglobinuria (PNH) had higher levels of CD34⁺ CD7⁺ myeloid cells than donors. Aplastic anemia and PNH were characterized by a high proportion of CD56⁺ cells among CD34⁺ precursors and neutrophils. The proportion of MDS-related features increased with the progression of MDS. The highest number of CD34⁺ blasts was found in MDS with excess blasts. MDS with isolated del(5q) was characterized by a high proportion of CD34⁺ CD7⁺ cells and low granularity of neutrophils. In 39 low-grade MDS, the sensitivities were 53.8%, 61.5%, and 71.8% for Ogata score, Wells score, and iFC, respectively.

CONCLUSION

The results support iFC as a useful diagnostic tool in MDS.

Immunophenotypic characteristics of juvenile myelomonocytic leukaemia and their relation with the molecular subgroups of the disease

The diagnosis of juvenile myelomonocytic leukaemia (JMML) is based on clinical, laboratory and molecular features but immunophenotyping [multiparametric flow cytometry (MFC)] has not been used routinely. In the present study, we describe the flow cytometric features at diagnosis with special attention to the distribution of monocytic subsets and the relation between MFC and molecular subgroups. MFC was performed with an eight-colour platform based on Euroflow. We studied 33 JMML cases. CD34⁺ /CD117⁺ /CD13⁺ cells >2% was found in 25 cases, and 51·5% presented an aberrant expression of CD7. A decrease of CD34⁺ /CD19⁺ /CD10⁺ cells was seen in eight cases and in four they were absent. The granulocytic population had a decreased side scatter in 29 cases. Bone marrow monocytic precursors were increased in 28 patients, with a decrease in classical monocytes (median 80·7%) and increase in CD16⁺ (intermediate and non-classical). A more pronounced increase in myeloid CD34⁺ cells was seen in patients with Neurofibromatosis type 1 (NF1) and tyrosine-protein phosphatase non-receptor type 11 (PTPN11), with aberrant CD7 expression in four of six and 10/12 patients respectively. Thus, JMML shows an immunophenotypic profile similar to myelodysplastic syndromes, and a different monocyte subset distribution when compared with chronic MML. MFC proved to be an important diagnostic tool that can help in differential diagnosis with other clonal diseases with monocytosis.

The prognostic significance of hematogones and CD34+ myeloblasts in bone marrow for adult B-cell lymphoblastic leukemia without minimal residual disease

This study was aimed to dissect the prognostic significances of hematogones and CD34+ myeloblasts in bone marrow for adult B-cell acute lymphoblastic leukemia(ALL) without minimal residual disease(MRD) after the induction chemotherapy cycle. A total of 113 ALL patients who have received standardized chemotherapy cycle were analyzed. Cases that were not remission after induction chemotherapy or have received stem cell transplantation were excluded. Flow cytometry was used to quantify the levels of hematogones and CD34+ myeloblasts in bone marrow aspirations, and the patients were grouped according to the levels of these two precursor cell types. The long-term relapse-free survival(RFS) and recovery of peripheral blood cells of each group after induction chemotherapy were compared. The results indicated that, after induction chemotherapy, patients with hematogones ≥0.1% have a significantly longer remission period than patients with hematogones <0.1% (p = 0.001). Meanwhile, the level of hematogones was positively associated with the recovery of both hemoglobin and platelet in peripheral blood, while CD34+ myeloblasts level is irrelevant to the recovery of Hb and PLT in peripheral blood, level of hematogones and long-term prognosis. This study confirmed hematogones level after induction chemotherapy can be used as a prognostic factor for ALL without MRD. It is more applicable for evaluation prognosis than CD34+ myeloblasts.