Myelodysplastic syndrome: diagnostic implications of cytochemical and immunocytochemical studies

Cytochemical Staining

Historically, the diagnosis and classification of acute leukemia involved morphologic review of blasts in the peripheral blood and bone marrow smears and cytochemical staining. Cytochemical stains, which are enzymatic colorimetric reactions that occur in the cells of interest, were necessary to assign and confirm myeloid and lymphoid lineage. In the current WHO 2008 Classification of leukemia, immunophenotyping and cytogenetic analysis have largely replaced cytochemical staining in the characterization of acute leukemias. Nonetheless, cytochemical testing remains a useful adjunct assay for the proper classification of acute leukemia in a number of diagnostic settings. This chapter reviews the principles of the most common cytochemical stains, their procedures and guides to interpretation, and results in acute myeloid leukemia.

Review of therapeutic options and the management of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a poorly understood group of disorders caused by one or more genetic aberrations in the bone marrow-derived cell line responsible for hematopoiesis. Recent advances in genetic medicine have offered new insights into the epigenesis as well as the prognosis of MDS, but have not resulted in new or improved curative treatment options. Bone marrow transplantation, introduced before the advent of genetic medicine, is still the only potential cure. Advances in other medical and pharmaceutical areas have broadened the scope of supportive care and disease-modifying therapies, and treating physicians now have a broad range of disease management options depending on a patient's likely prognosis. There is now clear evidence that appropriate supportive care and therapeutic intervention can improve progression-free and overall survival of MDS patients.

NAD(P)H: quinone oxidoreductase 1 deficiency conjoint with marginal vitamin C deficiency causes cigarette smoke induced myelodysplastic syndromes

Background

The etiology of myelodysplastic syndromes (MDS) is largely unknown. Exposure to cigarette smoke (CS) is reported to be associated with MDS risk. There is inconsistent evidence that deficiency of NAD(P)H-quinone: oxidoreductase 1 (NQO1) increases the risk of MDS. Earlier we had shown that CS induces toxicity only in marginal vitamin C-deficient guinea pigs but not in vitamin C-sufficient ones. We therefore considered that NQO1 deficiency along with marginal vitamin C deficiency might produce MDS in CS-exposed guinea pigs.

Methodology and Principal Findings

Here we show that CS exposure for 21 days produces MDS in guinea pigs having deficiency of NQO1 (fed 3 mg dicoumarol/day) conjoint with marginal vitamin C deficiency (fed 0.5 mg vitamin C/day). As evidenced by morphology, histology and cytogenetics, MDS produced in the guinea pigs falls in the category of refractory cytopenia with unilineage dysplasia (RCUD): refractory anemia; refractory thrombocytopenia that is associated with ring sideroblasts, micromegakaryocytes, myeloid hyperplasia and aneuploidy. MDS is accompanied by increased CD34(+) cells and oxidative stress as shown by the formation of protein carbonyls and 8-oxodeoxyguanosine. Apoptosis precedes MDS but disappears later with marked decrease in the p53 protein. MDS produced in the guinea pigs are irreversible. MDS and all the aforesaid pathophysiological events do not occur in vitamin C-sufficient guinea pigs. However, after the onset of MDS vitamin C becomes ineffective.

Conclusions and Significance

CS exposure causes MDS in guinea pigs having deficiency of NQO1 conjoint with marginal vitamin C deficiency. The syndromes are not produced in singular deficiency of NQO1 or marginal vitamin C deficiency. Our results suggest that human smokers having NQO1 deficiency combined with marginal vitamin C deficiency are likely to be at high risk for developing MDS and that intake of a moderately large dose of vitamin C would prevent MDS.

The myelodysplastic syndromes: diagnosis and treatment

The myelodysplastic syndromes (MDSs) are common, acquired, clinically challenging hematologic conditions that are characterized by bone marrow failure and a risk of progression to acute leukemia. These disorders can arise de novo, especially in elderly patients or, less often, as a consequence of prior chemotherapy or radiotherapy for an unrelated disease. The MDS classification systems were revised recently and updated. These refined classification and prognostic schemes help stratify patients by their risk of leukemia progression and death; this knowledge can help clinicians select appropriate therapy. Although many treatments for MDS have been proposed and evaluated, at present, only hematopoietic stem cell transplantation offers any real hope for cure, and no available therapy beyond general supportive care offers benefit to more than a minority of patients. However, recent clinical trials enrolling patients with MDS have reported encouraging results with use of newer drugs, including lenalidomide, decitabine, and darbepoetin alfa. Other exciting treatment regimens are being tested. Here, we present a contemporary, practical clinical approach to the diagnosis and risk-stratified treatment of MDS. We review when to suspect MDS, detail how to evaluate patients who may have a form of the condition, explain key features of treatments that are currently available in the United States, and summarize a general, common-sense therapeutic approach to patients with MDS.

Myelodysplasia and the acute myeloid leukaemias

The myelodysplastic syndromes are increasingly recognised clinical entities reflecting a stem cell defect that gives rise to ineffective clonal haematopoiesis. The spectrum extends from relatively indolent refractory anaemia through varying combinations of leucopoenia and thrombocytopenia to acute leukaemia. Diagnosis rests on marrow hypercellularity with dysplastic morphology, apoptosis and, often distinctive cytogenetic defects. Stratification to risk-related protocols range from occasional blood transfusions or erythropoietin through innovative options including thalidomide or amifostine to haematopoietic stem cell transplantation in selected individuals. Acute myeloid leukaemia, conceptually segregated from preleukaemia, is treated differently although accumulating cellular and molecular data favour a more integrated approach. Morphology and immunophenotyping are complemented by molecular genetics. On this basis chemotherapy alone is sufficient in defined sub-groups whereas others benefit by autologous or allogeneic grafting. Attention to demonstrating minimal residual disease is the basis for more specific intervention exemplified by monoclonal antibodies or maturation-inducing agents as with retinoic acid in acute progranulocytic leukaemia

Diagnosis of mastocytosis: value of cytochemistry and immunohistochemistry

The diagnosis of mastocytosis or mast cell disease may be difficult sometimes because of the wide variety of clinical presentation, abnormal morphology of mast cells, and variation in histologic features which may mimic varieties of other diseases. Over the years, several cell type specific cytochemical and immunochemical markers have been used for the identification of hematopoietic cells in order to establish the accurate diagnosis of mastocytosis and their associated hematologic diseases. Cytochemical stain for aminocaproate esterase is the most specific enzyme marker for identification of mast cells on cytologic specimens and the immunohistochemical stain for tryptase and/or c-kit has also been established as a sensitive and specific marker for mast cells in paraffin sections.

Myelodysplastic syndrome: a search for minimal diagnostic criteria

We have evaluated dyshemopoietic features in bone marrow (BM) samples obtained from healthy people aged over 50 without peripheral blood (PB) cytopenia patients and compared them with MDS patients. Control group displayed BM features of dyserythropoiesis and dysgranulopoiesis in up to 15 and 27% of the considered cell elements (P90) respectively, overlapping in part with MDS patients. Interobserver agreement in dyshemopoietic features was highest for BM blast cell and pathological sideroblast counts. An algorithm based on BM blast cell and pathological sideroblast counts that has been verified on 613 patients from different Spanish centers may be of help to improve reproducibility in Myelodysplastic syndrome (MDS) diagnosis.

The diagnostic and prognostic value of bone marrow immunostaining in myelodysplastic syndromes

Immunohistochemistry has been introduced as a means of increasing the diagnostic accuracy of bone marrow biopsy (BMB) in myelodysplastic syndromes (MDS); more recently the possibility of coupling immunostaining with other investigational techniques has broadened the spectrum of applications to the biology and physiopathology of MDS. Using panels of monoclonal antibodies (MoAbs), various histological classifications of MDS have been proposed as an alternative to the FAB criteria. The use of lineage-specific MoAbs has allowed a deeper insight into the dysplastic features of early hematopoietic precursors. The study of various gene products involved in the regulation of cell growth, proliferation and sensitivity to antineoplastic drugs, has revealed significant differences between MDS and morphologically-related disorders, particularly acute myelogenous leukemias (AML); these can be considered markers of a biological difference between the two groups of disorders and deserve consideration when designing therapeutic strategies for MDS. Both an increase in the percentage of cell positivity for the CD34 glycoprotein and a tendency of positive cells towards forming aggregates have been shown to be reliable predictors of leukemic transformation and survival, irrespective of the FAB subtype; furthermore, CD34 positivity has also proved to be a better prognostic factor than the presence of the abnormal localization of immature precursors (ALIP) on BMB. Finally, the simultaneous occurrence of "large" and CD34 positive aggregates can be proposed as a means of recognizing MDS patients with an exceedingly unfavourable prognosis, and who are therefore suitable for early aggressive therapy.

Morphologic characteristics of erythroleukemia (acute myeloid leukemia; FAB-M6): a CALGB study

We have reviewed the clinical, morphologic, immunophenotypic, and cytogenetic features of 52 patients with erythroleukemia (FAB Cooperative Group; AML-M6) studied by the Cancer and Leukemia Group B (CALGB). The purpose of this study was to correlate morphology with the clinical features, immunophenotypes, and karyotypes of neoplastic cells, and with the response to therapy of patients with AML-M6. Thirty-three patients (63%) were male, median age 59 (range 16-81) years, 47 patients (90%) were white, and 42 patients (81%) had a performance status of < 2. Myelodysplastic changes were observed in at least 1 cell lineage in all cases, and in 2 cell lineages in 45 of 52 (86%) cases. Fifty percent or more of cases studied were positive for CD11b, CD13, CD15, CD33, glycophorin-A, and HLA-DR markers. Fourteen of 27 cases (52%) in whom karyotypic analyses were conducted had cytogenetic abnormalities. Five (19%) were simple (< 3 karyotypic abnormalities), while 9 (33%) were complex (> or = 3 abnormalities). We observed either a complete or partial loss of chromosomes 5, 7, or 12p, or the presence of trisomy 8, in 11 of 27 (41%) patients. Cases of AML-M6 were divided into group 1 (14 patients with bone marrow proerythroblasts and basophilic erythroblasts > 25% of all erythroblasts) and group 2 (38 patients with proerythroblasts and basophilic erythroblasts < or = 25% of all erythroblasts). We observed no significant differences between groups 1 and 2 in regard to sex, age, race, performance status, percentage of blood erythroblasts or myeloblasts, percentage of bone marrow erythroblasts, and periodic acid-Schiff (PAS) or myelodysplasia scores. Six of 6 (100%) patients of group 1, and 7 of 21 (33%) patients of group 2, had normal karyotypes (P = .006). Nine of 13 (69%) patients of group 1 and 15 of 33 (45%) patients of group 2 had a complete remission (CR) (P = .2). Eight of 11 (73%) cytogenetically normal patients achieved CR: 5 of 6 (83%) in group 1, and 3 of 5 (60%) in group 2. Five of 12 (42%) cytogenetically abnormal patients achieved CR. No difference in duration of survival (group 1, median = 4.6 months vs. group 2, median = 10.2 months; P = .93) was observed between the 2 groups. We conclude that AML-M6 is typified by multilineage involvement of hematopoietic cells. The morphology of erythroblasts in patients with AML-M6 may correlate with cytogenetic abnormalities and rate of CR.