We hypothesized that analysis of single nucleotide polymorphism arrays (SNP-A) and new molecular defects may provide new insight in the pathogenesis of systemic mastocytosis (SM). SNP-A karyotyping was applied to identify recurrent areas of loss of heterozygosity and bidirectional sequencing was performed to evaluate the mutational status of TET2, DNMT3A, ASXL1, EZH2, IDH1/IDH2 and the CBL gene family. Overall survival (OS) was analyzed using the Kaplan-Meier method.
View Article and Find Full Text PDFLoss of heterozygosity affecting chromosome 7q is common in acute myeloid leukemia and myelodysplastic syndromes, pointing toward the essential role of this region in disease phenotype and clonal evolution. The higher resolution offered by recently developed genomic platforms may be used to establish more precise clinical correlations and identify specific target genes. We analyzed a series of patients with myeloid disorders using recent genomic technologies (1458 by single-nucleotide polymorphism arrays [SNP-A], 226 by next-generation sequencing, and 183 by expression microarrays).
View Article and Find Full Text PDFBackground: While lenalidomide (LEN) shows high efficacy in myelodysplastic syndromes (MDS) with del[5q], responses can be also seen in patients presenting without del[5q]. We hypothesized that improved detection of chromosomal abnormalities with new karyotyping tools may better predict response to LEN.
Design And Methods: We have studied clinical, molecular and cytogenetic features of 42 patients with MDS, myeloproliferative neoplasms (MPN), MDS/MPN overlap syndromes and secondary acute myeloid leukemia (sAML) without del[5q] by metaphase cytogenetics (MC) who underwent therapy with LEN.
Purpose: Interstitial deletions of chromosome 5q are common in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), pointing toward the pathogenic role of this region in disease phenotype and clonal evolution. The higher level of resolution of single-nucleotide polymorphism array (SNP-A) karyotyping may be used to find cryptic abnormalities and to precisely define the topographic features of the genomic lesions, allowing for more accurate clinical correlations.
Patients And Methods: We analyzed high-density SNP-A karyotyping at diagnosis for a cohort of 1,155 clinically well-annotated patients with malignant myeloid disorders.
Background: A combination of horse anti-thymocyte globulin and cyclosporine produces responses in 60-70% of patients with severe aplastic anemia. We performed a phase II study of rabbit anti-thymocyte globulin and cyclosporine as first-line therapy for severe aplastic anemia.
Design And Methods: Twenty patients with severe aplastic anemia treated with rabbit anti-thymocyte globulin were compared to 67 historical control cases with matched clinical characteristics treated with horse anti-thymocyte globulin.
In aplastic anemia (AA), contraction of the stem cell pool may result in oligoclonality, while in myelodysplastic syndromes (MDS) a single hematopoietic clone often characterized by chromosomal aberrations expands and outcompetes normal stem cells. We analyzed patients with AA (N = 93) and hypocellular MDS (hMDS, N = 24) using single nucleotide polymorphism arrays (SNP-A) complementing routine cytogenetics. We hypothesized that clinically important cryptic clonal aberrations may exist in some patients with BM failure.
View Article and Find Full Text PDFSingle nucleotide polymorphism arrays (SNP-As) have emerged as an important tool in the identification of chromosomal defects undetected by metaphase cytogenetics (MC) in hematologic cancers, offering superior resolution of unbalanced chromosomal defects and acquired copy-neutral loss of heterozygosity. Myelodysplastic syndromes (MDSs) and related cancers share recurrent chromosomal defects and molecular lesions that predict outcomes. We hypothesized that combining SNP-A and MC could improve diagnosis/prognosis and further the molecular characterization of myeloid malignancies.
View Article and Find Full Text PDFDeletion of the long arm of chromosome 20 is a common abnormality associated with myeloid malignancies. We characterized abnormalities of chromosome 20 as defined by metaphase cytogenetics (MC) in patients with myeloid neoplasms to define commonly deleted regions (CDR) and commonly retained regions (CRR) using genome-wide, high resolution single nucleotide polymorphism array (SNP-A) analysis. We reviewed the MC results of a cohort of 1,162 patients with myeloid malignancies, including myelodysplastic syndromes (MDS), MDS/myeloproliferative neoplasia (MDS/MPN), and acute myeloid leukemia (AML).
View Article and Find Full Text PDFPurpose: Cytogenetics is the primary outcome predictor in acute myeloid leukemia (AML). Metaphase cytogenetics (MC) detects an abnormal karyotype in only half of patients with AML, however. Single nucleotide polymorphism arrays (SNP-A) can detect acquired somatic uniparental disomy (UPD) and other cryptic defects, even in samples deemed normal by MC.
View Article and Find Full Text PDFChromosomal abnormalities are frequent in myeloid malignancies, but in most cases of myelodysplasia (MDS) and myeloproliferative neoplasms (MPN), underlying pathogenic molecular lesions are unknown. We identified recurrent areas of somatic copy number-neutral loss of heterozygosity (LOH) and deletions of chromosome 4q24 in a large cohort of patients with myeloid malignancies including MDS and related mixed MDS/MPN syndromes using single nucleotide polymorphism arrays. We then investigated genes in the commonly affected area for mutations.
View Article and Find Full Text PDFTwo types of acquired loss of heterozygosity are possible in cancer: deletions and copy-neutral uniparental disomy (UPD). Conventionally, copy number losses are identified using metaphase cytogenetics, whereas detection of UPD is accomplished by microsatellite and copy number analysis and as such, is not often used clinically. Recently, introduction of single nucleotide polymorphism (SNP) microarrays has allowed for the systematic and sensitive detection of UPD in hematologic malignancies and other cancers.
View Article and Find Full Text PDFUsing metaphase cytogenetics (MC), chromosomal abnormalities are found in only a proportion of patients with myelodysplastic syndrome (MDS). We hypothesized that with new precise methods more cryptic karyotypic lesions can be uncovered that may show important clinical implications. We have applied 250K single nucleotide polymorphisms (SNP) arrays (SNP-A) to study chromosomal lesions in samples from 174 patients (94 MDS, 33 secondary acute myeloid leukemia [sAML], and 47 myelodysplastic/myeloproliferative disease [MDS/MPD]) and 76 controls.
View Article and Find Full Text PDFObjectives: Using metaphase cytogenetics (MC), chromosomal defects can be detected in 40% to 60% of patients with myelodysplastic syndromes (MDS); cytogenetic results have a major impact on prognosis. We hypothesize that more precise methods of chromosomal analysis will detect new/additional cryptic lesions in a higher proportion of MDS patients.
Methods: We have applied single nucleotide polymorphism microarrays (SNP-A) to perform high-resolution karyotyping in MDS to determine gene copy number and detect loss of heterozygosity (LOH).
The development of laboratory tests for the diagnosis and monitoring of graft-vs-host disease (GVHD) is hampered by a lack of knowledge of minor histocompatibility Ags triggering alloresponses. We hypothesized that the unique molecular structure of the TCR could be used as a marker for the unidentified Ags and exploited for molecular monitoring of GVHD posttransplant. To identify alloreactive T cell clones, we performed in vitro allostimulation cultures for a cohort of patients undergoing hemopoietic stem cell transplantation and determined the sequence of the CDR3 of immunodominant alloreactive clones; 10 corresponding clonotypes restricted to activated T cells were identified.
View Article and Find Full Text PDFObjective: Unbalanced chromosomal aberrations are common in myelodysplastic syndromes and have prognostic implications. An increased frequency of cytogenetic changes may reflect an inherent chromosomal instability due to failure of DNA repair. Therefore, it is likely that chromosomal defects in myelodysplastic syndromes may be more frequent than predicted by metaphase cytogenetics and new cryptic lesions may be revealed by precise analysis methods.
View Article and Find Full Text PDFObjective: In allogeneic hematopoietic stem cell (HSCT) transplantation, recovery of the T cell receptor (TCR) repertoire depends upon the composition of the graft and is modulated by peri-transplant immunosuppression, viral infections, and graft-vs-host disease (GVHD). We hypothesized that after allogeneic HSCT, molecular analysis of the TCR repertoire can be used to identify and quantitate immunodominant T cell clones that may play a role in GVHD or other clinical events.
Methods: We utilized a rational strategy for the analysis of the expanded CTL clones.
Stem cell transplantation (SCT) constitutes a major challenge to the immune system. Long-term impairment of immunity against various common infectious stimuli leads to increased susceptibility to infectious diseases; in contrast, an immune response against the recipient may cause the devastating graft-versus-host disease (GvHD). Recovery of the immune system (both qualitative and quantitative) after SCT is perhaps the most important factor in determining the clinical outcome.
View Article and Find Full Text PDFObjective: Similar immune mechanisms have been suggested to operate in aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH), and the presence of PNH clones in AA may indicate that an immune reaction directed against hematopoietic stem cells may be responsible for the immune selection pressure leading to PNH evolution. We previously described expansions of selective cytotoxic T-lymphocyte (CTL) clones in AA patients.
Materials And Methods: We applied a molecular analysis of the T-cell receptor repertoire to study the characteristics of CTL response in patients with various forms of PNH.
Large granular lymphocytic (LGL) leukemia is a clonal lymphoproliferative disorder of CTL associated with cytopenias resulting from an immune and cytokine attack on hemopoietic progenitor cells. Extreme clonality of CTL expansions seen in LGL leukemia makes it an ideal model to study the role of the T cell repertoire in other less-polarized immune-mediated disorders. Complementarity-determining region 3 (CDR3) of the TCR is a unique Ag-specific region that can serve as a molecular marker, or clonotype, of the disease-specific T cells.
View Article and Find Full Text PDFA broad array of antibodies directed against the variable (V) region of the T-cell receptor (TCR) beta (V beta) chain has become available in a directly conjugated multicolor format that permits assessment of 19 of 25 V beta families, covering 70% of the normal circulating T-cell repertoire. These antibodies were used to detect expanded T-cell populations in 43 peripheral blood samples submitted for suspected T-cell malignancy. Of 43 samples, 27 were diagnosed as follows: T-cell large granular lymphocyte leukemia, 14 samples; Sézary syndrome, 4 samples; T-cell prolymphocytic leukemia, 5 samples; or T-cell non-Hodgkin lymphoma or T-cell lymphoproliferative disorder not otherwise specified, 4 samples.
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