Peripheral blood lymphoagglutination and platelet satellitism in marginal zone lymphomas

Abstract Abstract 2698 Background: Splenic marginal zone lymphoma (SMZL) is a small B cell neoplasm whose molecular pathogenesis is still unknown. It has a relatively indolent course, but a fraction of the cases may show an aggressive behavior. The lack of comprehensive molecular analysis for SMZL precludes the development of targeted therapy. Here we studied the mutational status of 6 SMZL samples using Whole Exome Next Generation Sequencing. Methods: Genomic DNA was extracted from splenic tumor or peripheral blood samples and oral mucosa as the corresponding non-tumor control. Whole exome sequencing was performed at CNAG (Barcelona, Spain) following standard protocols for high-throughput paired-end sequencing on the Illumina HiSeq2000 instruments (Illumina Inc., San Diego, CA). The variant calling was performed using an in house written software calling potential mutations showing a minimum independent multi-aligner evidence. Results: We performed paired-end-76pb whole exome sequencing on 6 SMZL samples and the corresponding normal counterpart. Three of the samples corresponded to CD19 isolated cells from peripheral blood, while other three corresponded to spleen freshly frozen tissue. The mean coverage obtained was 104.07 (82.46–119.59) with a mean of 91.41% (90.41–93.73) of bases with at least 15× coverage. After filtering, 237 substitutions and 21 indels where obtained. No recurrent variation was found. Six of the variations found here were already described in other malignancies. Variations were classified into silent (75), missense (147), nonsense (8), and essential splice (5), according to their potential functional effect, and into tolerated (54) and deleterious (76) according to the “variant effect predictor” tool of Ensembl Genome Browser. Whole exome sequencing permitted us to identify variations in several genes of TLR/NFkB pathway (Myd88, Peli3), BCR (Myd88, Arid3A) or signal transduction (ARHGAP32), essential pathways for B-cell differentiation. These variations and other involving selected genes, such as the Bcl6 repressor BCOR, were validated by capillary sequencing. These results were confirmed and expanded in a second series of 10 new cases by exome sequencing. Conclusions: SMZL samples contain somatic mutation involving genes regulating BCR signaling, TLR/NFKB pathways and chromatin remodeling. Disclosures: No relevant conflicts of interest to declare.

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Neutrophil Platelet Satellitism Revisited: Sidedness and Domain of Neutrophil Associated Platelet Aggregates.

Blood ◽

10.1182/blood.v114.22.4469.4469 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4469-4469

Author(s):

Cannon Milani ◽

Fred J. Schiffman ◽

Peter J. Quesenberry

Keyword(s):

Peripheral Blood ◽

Conflicts Of Interest ◽

Incidental Finding ◽

Natural Antibodies ◽

Polymorphonuclear Neutrophils ◽

Platelet Glycoprotein ◽

Clear Correlation ◽

Platelet Aggregates ◽

Platelet Satellitism

Abstract Abstract 4469 Platelet Satellitism surrounding polymorphonuclear neutrophils has been observed almost exclusively in EDTA-treated blood at room temperature. The mechanism underlying this phenomenon is not fully understood. In a PubMed search of the English language medical literature, there are only 44 reported cases involving the phenomenon of Platelet Satellitism. We report a case of platelet rosetting around neutrophils in a 78-year old woman with incidental thrombocytopenia. Her isolated thrombocytopenia was not mediated by any form of immunosuppression, medications, hypersplenism, intravascular consumption, or diminished platelet production. A diagnosis of Pseudothrombocytopenia was made based upon her peripheral blood smear revealing platelet aggregates displaying sidedness in relation to her neutrophils. Platelet Satellitism is postulated to represent an immunologic phenomenon caused by the presence of natural antibodies in which the platelets aggregate around polymorphonuclear neutrophils. The reasons behind why certain individuals possess agglutinating antibodies that lead to platelet clumping, and others have antibodies that cause platelet satellitism is unknown. A proposed mechanism is natural antibodies directed against different epitopes on the platelet GPIIb-IIIa complex. The reported frequency of platelet Satellitism is much lower than that of EDTA platelet clumping (approximately 1:30,000 blood counts) according to the reviewed literature. Platelet Satellitism to polymorphonuclear neutrophils was initially documented by Field and MacLeod in 1963, and has since been reported as an incidental finding in peripheral blood smears when EDTA was used as an anticoagulant. The process by which platelets bind and form rosettes around polymorphonuclear leukocytes is due to activation of EDTA-dependent antiplatelet and antineutrophil IgG autoantibodies directed against the platelet glycoprotein IIb/IIIa complex and Fc receptors of neutrophils. Further, it is theorized that a non-immunologic cause may play in role in which adherence is induced by thrombospondin or the alpha-granule protein of other platelets. In rare instances, platelets may aggregate around monocytes or basophils. Our retrospective review underscores the importance of recognizing the principle of Pseudothrombocytopenia due to EDTA-induced Platelet Satellitism. This entity is in vitro phenomena which has no clinical bearing in terms of a predisposition to increased mucous membrane bleeding. As in other literature cases, a clear correlation between the presence of IgG antibodies and a specific clinical situation, disease, or use of drugs could not be demonstrated. Therefore, these antibodies, which are present in some normal individuals, might occur naturally. Due to the exposure of certain antigenic structures present on EDTA-modified platelets and neutrophils, they may manifest themselves by triggering the Platelet Satellitism phenomenon. Disclosures: No relevant conflicts of interest to declare.

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Disseminated Gastric MALT Lymphoma with Monoclonal Gammopathy, t(11;18)(q21;q21), and Subsequent Development of T-Large Granular Lymphocytic Leukemia: A Case Report and Review of the Literature

Case Reports in Medicine ◽

10.1155/2015/953297 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Riad Akoum ◽

Wassim Serhal ◽

Hussein Farhat

Keyword(s):

Bone Marrow ◽

B Cell ◽

Malt Lymphoma ◽

Peripheral Blood ◽

Marginal Zone ◽

Granular Cell ◽

Gastric Malt Lymphoma ◽

Review Of The Literature ◽

Malt Type Lymphoma ◽

Hodgkin's Lymphomas

Background. Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a well-characterized entity that may share clinical and morphological findings with other low-grade non-Hodgkin’s lymphomas. Dissemination of MALT-type lymphoma to bone marrow and peripheral blood simultaneously with the presence of T-large granular cell leukemia (T-LGL) has rarely been reported.Case Presentation. This is the case of a 42-year-old male who presented with a gastric MALT-type lymphoma, disseminated to the bone marrow and the peripheral blood with high serum IgM levels and t(11;18)(q21;q21). The morphological, immunophenotypical and, immunohistochemical studies of the successive bone marrow and peripheral blood samples had revealed the coexistence of two distinct lymphoma cell populations: a B-cell, marginal zone type population expressing CD19, CD20, CD22, CD79b, IgM, and kappa light chain, and a T-large granular cell population, developed after treatment with rituximab expressing CD3, CD8, CD5, CD7, and CD45.Conclusion. Based on the analysis of this unusual case we performed an extensive review of the literature to elucidate the relationship between T-LGL and B-cell lymphomas and to emphasize the importance of paraprotein analysis at diagnosis of gastric MALT lymphoma.

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