Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Marginal zone B cells”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

Recent advances in our understanding of the biology and pathogenesis of gastric mucosa-associated lymphoid tissue (malt) lymphoma.

The evolution of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a multi-stage process, comprising the sequential development of chronic H. pylori-associated gastritis, low grade and high grade lymphoma. The genesis of MALT lymphoma embodies the mechanisms of both physiological immune responses and the acquisition of genetic abnormalities. The tumour probably originates from an autoreactive MALT marginal zone B cell, which is generated during H. pylori infection. As a consequence of a genotoxic insult induced by H. pylori infection, the progenitor tumour cell may become genetically unstable and develop genetic abnormalities such as the t(11;18) translocation, trisomy three, c-myc and p53 mutations during a phase of expansion, which lead to partial transformation. With the growth help from H. pylori specific T cells, this abnormal B cell clone may undergo clonal expansion and gradually form a low grade MALT lymphoma. Additional genetic abnormalities including the t(1;14) translocation and other uncharacterised events could completely transform this abnormal B cell clone and result in escape from T cell dependency. Finally, further genetic events such as complete inactivation of the tumour suppressor genes p53 and p16, and possible activation of c-myc oncogene by translocation or other undetermined abnormalities can result in high grade transformation

Cell Transformation, Neoplastic↗
PubMed2001

MALT lymphoma originating in breast and uvula.

A case of marginal zone B cell lymphoma of MALT type arising in the uvula and breast is reported. The patient, a 30-year-old woman who delivered a child and lactated in 1997, was suffering from Sjögren syndrome (SS). She was diagnosed with MALT lymphoma after a biopsy of the right breast and uvula. To investigate the relationship of the delivery, lactation and MALT lymphoma, we examined the immunohistochemical analysis of hormone receptors. As a result, lymphoid cells of the breast were stained with anti-progesterone receptor antibodies in the cytoplasm. Consequently, the MALT lymphoma of the uvula appeared to be associated with SS. Moreover, hormones such as progesterone may have influenced the breast involvement of MALT lymphoma in our case.

Adult↗
PubMed2005

Association study of a functional Toll-like receptor 4 polymorphism with susceptibility to gastric mucosa-associated lymphoid tissue lymphoma.

Toll-like receptor 4, as part of innate immune response, is the main receptor for lipopolysaccharide on marginal zone B cells. The rare allele of TLR4 Asp299Gly attenuates receptor signaling and diminishes the inflammatory response. We genotyped 87 patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, 594 Helicobacter pylori positive controls and 358 healthy blood donors to investigate an association of TLR4 Asp299Gly in the development of gastric MALT lymphoma. Heterozygote genotype was significantly less frequent in patients with gastric MALT lymphoma compared to H. pylori-infected controls (4.6% vs. 11.6%, Fischer's exact P=0.019, odds ratio=0.37, 95% confidence interval 0.13-1.03). Because 10% of caucasians are carriers of the rare allele G TLR4 Asp299Gly appears to be only one factor in the genetic susceptibility to gastric lymphoma. Further studies in larger samples are needed to confirm our findings and fully elucidate the role of TLR4 and its genetic variants in the pathophysiology of H. pylori infection and gastric lymphoma.

Adolescent↗
PubMed1999

Ocular adnexal lymphoma-comparison of MALT lymphoma with other histological types.

AIMS: To correlate histological features of ocular adnexal lymphoma using the revised European American lymphoma classification (REAL), with stage of disease at presentation, treatment modalities, and patient outcome. MALT lymphoma defines an extranodal marginal zone B cell lymphoma as outlined in the REAL classification. Comparison groups of patients included those with primary ocular adnexal MALT lymphoma versus primary ocular adnexal lymphomas of other types, MALT lymphoma versus non-MALT lymphomas (primary and secondary), and primary ocular adnexal lymphoma (MALT lymphomas and other types) versus secondary ocular adnexal lymphomas. METHODS: A retrospective review of the National Ophthalmic Pathology Laboratory records identified 20 cases of ocular adnexal lymphoma over a 10 year period which were reclassified using appropriate immunohistochemical stains. Patients' medical records were examined for data including stage of the disease at presentation, mode of treatment, and patient outcome. RESULTS: Among the 20 cases identified 14 had primary ocular adnexal lymphomas. 10 of the primary lymphomas had histological features of MALT lymphoma. One case was a primary ocular adnexal T cell lymphoma, one a follicular centre, follicular B cell lymphoma, and two were large cell B cell lymphomas. Six cases had systemic disease, four large B cell, one follicular centre, follicular B cell, and one mantle cell. A significantly higher proportion of patients with MALT lymphomas had early disease (p = 0.005), initially required local treatment (p = 0.005) and were alive at last follow up (p = 0.001) than those without. Two patients with MALT lymphoma had recurrence of lymphoma which responded to further treatment. CONCLUSIONS: Patients with primary ocular adnexal MALT lymphomas present with localised disease requiring local treatment and have a better outcome compared with patients with other types. As a small percentage of these tumours recur, patients should be followed up indefinitely.

Adult↗
PubMed2007

MALT1, BCL10 and FOXP1 in salivary gland mucosa-associated lymphoid tissue lymphomas.

In view of the certain anatomic site-dependent frequency of chromosomal translocations involved in extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) pathogenesis, 17 salivary gland MALT lymphoma cases were analyzed for MALT1 and FOXP1 translocations. B cell CLL/lymphoma 10 (BCL10) and forkhead box PA (FOXP1) protein expression were studied by immunohistochemistry and translocations identified using fluorescence in situ hybridization (FISH)-specific probes FOXP1, t(11;18)(q21;q21)/API2-MALT1 and t(14;18)(q32;q21)/IgH-MALT1. None of the 11 analyzed cases showed FOXP1 rearrangement or amplification. The t(11;18) was present in five of 13 cases and the t(14;18) in three of 13 cases. MALT1 translocations were mostly mutually exclusive except in a single case. FOXP1 protein expression showed differences in the proportion of tumor cells with nuclear expression but not in their intensity, with the exception of one case where very intense nuclear staining was noted. BCL10 nuclear expression was present in four of 17 cases, two of which lacked t(11;18). Our results suggest that MALT1-specific translocations and FOXP1 rearrangements are not commonly involved in pathogenesis. A case with strong FOXP1 protein expression indicates the possibility that the upregulation of FOXP1 expression is significant in a small subset of salivary gland MALT lymphomas. Also a single case in which both MALT1 translocations were present indicates that these are not always mutually exclusive.

Adaptor Proteins, Signal Transducing↗
PubMed2004

[The expression of API2-MALT1 fusion gene and its influence on the cellular apoptosis and proliferation in gastrointestinal MALT lymphoma].

OBJECTIVE: To investigate the expression of API2-MALT1 fusion gene mRNA and its effect on protein of API2, Caspase3 and Ki67 in gastrointestinal MALT lymphoma (Extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue). METHODS: The mRNA of API2-MALT1 fusion transcript was assayed in 33 archival cases of gastrointestinal MALT lymphoma by RT-PCR and nested PCR. According to the expression of API2-MALT1 mRNA or not, 33 cases of MALT lymphoma were divided into two groups. Ki67, API2 and Caspase3 were detected by immunohistochemical technique and analyzed by the microsoft Image-Pro plus. RESULTS: API2-MALT1 fusion gene mRNA was found in 16 of specimens with gastrointestinal MALT lymphoma. The expression rate was 48.4%. The average area (21177.30 +/- 6171.72) micron 2 and single cell average area (29.81 +/- 7.40) micron 2 of API2 were decreased in the group with the expression of API2-MALT1 mRNA, compared with those in the group without the expression of API2-MALT1 mRNA [(34325.65 +/- 6577.00) micron 2, (37.84 +/- 8.55) micron 2]. The integrated optical density(IOD) of API2 showed no significant difference between the two groups, neither did the expression of Ki67 and Caspase3. CONCLUSION: The expression of API2-MALT1 is related to the down-regulated expression of protein of API2, its effect on apoptosis of MALT lymphoma remains to be detected further. The expression of API2-MALT1 mRNA is unrelated to the cellular proliferation.

Apoptosis↗
PubMed2003

Pulmonary crystal-storing histiocytosis and extranodal marginal zone B-cell lymphoma associated with a fibroleiomyomatous hamartoma.

Crystal-storing histiocytosis (CSH) is a rare disorder occurring in patients with lymphoproliferative diseases, predominantly in cases of multiple myeloma and low-grade B-cell lymphoma. To the best of our knowledge, only three cases of pulmonary CSH have been reported in the English literature and one of them was associated with a low-grade B-cell lymphoma (immunocytoma). We document a case of a 59-year-old man with bilateral lung masses in which a right middle lobe pulmonary lobectomy specimen showed CSH associated with an extranodal marginal-zone B-cell lymphoma. A single nodule showing features of fibroleiomyomatous hamartoma was present in a wedge biopsy specimen from the left lung. Two nodules within the right middle lobe were composed of sheets of histiocytic cells with abundant eosinophilic cytoplasm resembling striated muscle cells. In addition, there were nodular aggregates and a more diffuse infiltrate of small slightly atypical centrocyte-like lymphocytes, as well as bronchial lymphoepithelial lesions. Immunohistochemistry performed on paraffin-embedded sections demonstrated that the histiocytic cells were immunoreactive with the KP-1 (CD68) antibody while the lymphocytic infiltrate was CD20 positive, co-expressed for CD43, and was negative for CD3, CD5, and CD10. Genotypic analysis demonstrated the presence of an immunoglobulin heavy-chain gene rearrangement, indicating the presence of a monoclonal B-cell population. These features were consistent with pulmonary CSH associated with extranodal marginal-zone lymphoma of baltoma type.

Antigens, CD↗
PubMed2003

Small lymphocytic lymphoma, marginal zone B-cell lymphoma, and mantle cell lymphoma exhibit distinct gene-expression profiles allowing molecular diagnosis.

Non-germinal center small B-cell lymphomas represent a heterogeneous group of non-Hodgkin lymphomas, the most frequent histologic subtypes being small lymphocytic lymphoma (SLL), splenic marginal zone B-cell lymphoma (MZL), and mantle cell lymphoma (MCL). In order to identify genomic signatures specific for each disease, we analyzed 128 primary tumors using high-density microarrays. Several clusters of genes significantly discriminated the 3 histologic subtypes. Genes associated with cell adhesion, angiogenesis, and inhibition of apoptosis were up-regulated in SLL. Genes associated with intracellular signaling via the AKT1 pathway were up-regulated in splenic MZL. Genes associated with cell cycle control and multidrug resistance were up-regulated in MCL. Using 44 genes selected within the gene clusters discriminant for the 3 lymphoma subtypes, we generated a class prediction score that allowed us to classify the 3 entities in 96% of the cases, including borderline cases. Whereas specific transcriptional profiles easily distinguished all MZL samples, SLL samples, and most of the MCL samples into separate groups, few MCL cases exhibited MZL-type transcriptional profiles. This study demonstrates that SLL, splenic MZL, and MCL possess specific transcriptional profiles that may be relevant to the pathogenesis and the diagnosis of these histologic subtypes.

Biopsy↗
PubMed2002

The eye's view of antigen presentation.

A form of systemic tolerance is created when antigenic material is placed in the anterior chamber of the eye, an immune privileged site. Termed anterior chamber associated immune deviation (ACAID), this form of tolerance insures that the systemic immune response to eye-derived antigens is devoid of T cells that mediate delayed hypersensitivity and antibodies that fix complement. As a consequence, the eye is spared the disruptive blinding influence of immunogenic inflammation. ACAID arises when antigen is captured by intraocular antigen presenting cells, then carried to the marginal zone of the spleen where, in the presence of natural killer T cells and marginal zone B cells, a microenvironment is created that activates antigen-specific T cells to differentiate into regulatory cells that interfere with the induction of delayed hypersensitivity as well as its expression. Transforming growth factor beta-2 (TGFbeta-2), constitutively present in the aqueous humor of the eye, imposes distinctive properties on antigen presenting cells. Thrombospondin is an early activated gene following TGFbeta-2 treatment and as a consequence the eye-derived antigen presenting cells fail to secrete IL-12 or express CD40. The lack of these potent stimulators of Th1 cell differentiation is central to the induction of ACAID.

Animals↗
PubMed2005

Inhibitory oligodeoxynucleotides - therapeutic promise for systemic autoimmune diseases?

Recent studies have shed new light on a possible link between the innate activation of plasmocytoid dendritic cells and marginal zone B cells and the pathogenesis of systemic lupus erythematosus. Animal studies have identified that this response requires the Toll-like receptor 9 (TLR9). Engagement of the TLR9 by various ligands, including non-canonical CpG-motifs, can cause or aggravate pathogenic autoantibody production and cytokine secretion in lupus. Attempts to neutralize this activity either by blocking the acidification of the endosomal compartment with chloroquine and related compounds, or by preventing the interaction between the CpG-DNA sequences and TLR9 using inhibitory oligonucleotides could be a promising therapeutic option for lupus.

Animals↗
PubMed1993

Comparative in vitro analysis of proliferation, Ig secretion, and Ig class switching by murine marginal zone and follicular B cells.

We have previously demonstrated that activation of murine B cells by dextran-conjugated anti-IgD antibodies may serve as a polyclonal, in vitro model system for studying immune responses to T cell-independent type 2 (TI-2) Ag, as exemplified by the bacterial polysaccharides. Because in vivo Ig responses to TI-2 Ag are mediated primarily by B cells resident in the splenic marginal zone, we wished to determine whether this reflected an intrinsic difference in the responsiveness of marginal zone B cells (MZB) compared with follicular B cells (FB) to this class of Ag. In this report we demonstrate that highly purified MZB, isolated by electronic cell sorting, exhibit a lower proliferative response in vitro in response to unconjugated anti-Ig antibody as well as to dextran- or Sepharose-conjugated anti-IgM or anti-IgD antibodies, whereas they proliferate equal to or better than FB when stimulated by other B cell mitogens including LPS, Salmonella typhimurium mitogen, or anti-CD3-activated CD4+ Th2 cell clone. Despite the different proliferative responses of MZB and FB induced by anti-Ig, Ag receptor cross-linkage stimulates comparable increases in intracellular free calcium concentrations in both of these B cell populations. Furthermore, MZB secrete Ig and undergo Ig isotype switching to a comparable degree, relative to FB, in response to both T cell-dependent and T cell-independent stimuli. This suggests that the compartmentalization of TI-2 responses to the splenic marginal zone rather than the follicular zone reflects something other than the intrinsic responsiveness of the B cells from these two sites.

Animals↗
PubMed2005

Cytogenetic analysis delineates a spectrum of chromosomal changes that can distinguish non-MALT marginal zone B-cell lymphomas among mature B-cell entities: a description of 103 cases.

The purpose of this study was to document the frequency and distribution of karyotypic changes present at diagnosis in 103 non-MALT marginal zone cell lymphoma (MZL) patients. This cytogenetic analysis of a large cohort extends previous observations and allows the identification of new cytogenetic features. Abnormalities identified in more than 15% of patients included +3/+3q (37%), 7q deletions (31%), +18/+18q (28%), 6q deletions (19%), +12/+12q (15%) and 8p deletions (15%). Trisomy 3/3q, 7q deletions, +18 and +12 were seen in different combinations in more than 30% of patients in comparison to 2% in lymphocytic lymphomas/chronic lymphocytic leukemias, 1% in mantle cell lymphomas and 7% in follicular lymphomas. The marked propensity of these abnormalities to be recurrently associated with the same tumoral clone of individual karyotypes allowed the delineation of a cytogenetic profile that may help to distinguish non-MALT MZL among other mature B-cell neoplasms. If +3/3q, +12/+12q, and 6q, 7q and 8p deletions were significantly associated with clinical prognostic factors previously reported to influence survival and time to progression, patients displaying these abnormalities did not experience a significantly shorter time to progression.

Adult↗
PubMed2006

Cutaneous marginal zone B-cell lymphoma in the setting of fluoxetine therapy: a hypothesis regarding pathogenesis based on in vitro suppression of T-cell-proliferative response.

INTRODUCTION: Drugs may be an important cause of atypical lymphocytic infiltration. Oftentimes, these infiltrates are in the context of pseudolymphomata. We report a patient who developed lymphocytoma cutis temporally associated with initiation of fluoxetine therapy that later went on to develop cutaneous marginal zone B-cell lymphoma. The response of peripheral blood lymphocytes to fluoxetine and other drugs was examined in an attempt to ascertain the potential role for drugs in the propagation of these infiltrates. MATERIALS AND METHODS: Routine light microscopic analysis and phenotypic studies were performed on tissue obtained from a skin biopsy. Lymphocyte mitogenic studies were carried out using increasing concentrations of fluoxetine, bupropion, and two anticonvulsants. RESULTS: An initial biopsy was consistent with lymphocytoma cutis. The patient stopped fluoxetine associated with lesional regression. The lesions recurred despite being off fluoxetine; a repeat biopsy was compatible with marginal zone lymphoma. Lymphocyte proliferation assays revealed a suppressive effect on T-lymphocyte proliferation at physiologic concentrations. Other tested drugs did not have a similar suppressive effect. CONCLUSIONS: Fluoxetine may be associated with pseudolymphomata and marginal zone lymphoma. The inhibitory effects on T-lymphocyte function and more specifically T-suppressor function may lead to excessive antigen-driven B-cell proliferation.

Anticonvulsants↗
PubMed2006

Schnitzler syndrome associated with systemic marginal zone B-cell lymphoma.

Schnitzler syndrome is a rare condition defined by chronic urticaria and monoclonal IgM gammopathy. Malignant evolution to Waldenström disease (WD) has been reported in several cases. We report a 49-year-old man who developed a marginal zone B-cell lymphoma (MZL) 3 years after the beginning of Schnitzler syndrome. This is the first report of MZL in association with Schnitzler syndrome. IgM gammopathy is a clue for the diagnosis of Schnitzler syndrome. This condition needs to be closely monitored; it can precede the onset of an authentic lymphoproliferative disorder including WD and rarely MZL.

Cell Transformation, Neoplastic↗
PubMedDate not supplied

Marginal zone B-cell lymphoma of the parotid gland associated with epithelioid granulomas. Report of a case with fine needle aspiration.

BACKGROUND: Although granulomas can occur in association with malignant neoplasms, including some subtypes of lymphoma, they have been described rarely in marginal zone B-cell lymphoma (MZCL). To our knowledge, the cytologic features of this association have not been documented. We present the cytologic findings with fine needle aspiration cytology (FNAC) of an unusual case of MZCL with concomitant granulomas. CASE: An 82-year-old male presented with a mass in the left parotid gland. The lesion was evaluated by FNAC. The smears showed syncytial aggregates of epithelioid histiocytes intermixed with small and medium-sized lymphoid cells containing round to irregular-shaped nuclei and small nucleoli. Some of these cells had a greater amount of cytoplasm and frequently had a plasmacytoid appearance. The lesion was removed, and histopathologic study showed MZCL associated with extensive nonnecrotizing granulomas. CONCLUSION: Granulomatous reactions can be seen in rare cases of MZCL. However, the cytologic features of the lymphoid infiltrate can suggest the possibility of MZCL in the clinical setting of FNAC performed from an extranodal location, such as the parotid gland.

Aged↗
PubMed2006

Primary cutaneous B-cell lymphoma (marginal zone) with prominent T-cell component and aberrant dual (T and B) genotype; diagnostic usefulness of laser-capture microdissection.

The presence of a dominant B- or T-cell clone is an important diagnostic criterion for distinguishing cutaneous lymphomas from lymphoid reactive infiltrates. Rarely, a combined B- and T-cell rearrangement can be detected from a single sample. In such instances, genotypic analysis does not permit differentiation of the coexistence of a T- and B-cell lymphoma from a single clone harbouring a monoclonal rearrangement for both immunoglobulin heavy chain and T-cell receptor genes. We herein report a case of a skin tumour consistent with a dense cutaneous lymphoid infiltrate showing a double prominent B- and T-cell component. A dual B- and T-cell clonality was detected by polymerase chain reaction from whole-tissue DNA sample. Genotypic analysis with DNA, obtained after laser-assisted microdissection from the B-cell population, again showed both T- and B-cell monoclonal rearrangements. Conversely, the microdissected T-cell population did not reveal a clonal pattern. The diagnosis of cutaneous B-cell lymphoma with a dual B- and T-cell genotype was established. This description illustrates the diagnostic usefulness of laser-capture microdissection in cutaneous lymphomas presenting dual genotype.

Aged↗
PubMed2005

Spotlight on the role of hormonal factors in the emergence of autoreactive B-lymphocytes.

Pathogenic autoimmunity requires a combination of inherited and acquired factors. In as much as hormones influence the sexual dimorphism of the immune system, it is possible that they can initiate or accelerate an autoimmune process, and contribute to gender-biased autoimmune disorders. Not only natural hormones, but also endocrine disruptors, such as environmental estrogens, may act in conjunction with other factors to override immune tolerance to self-antigens. In lupus, murine and human studies demonstrate that female sex hormones are implicated in disease pathogenesis. In the B cell compartment, both prolactin and estrogen are immunomodulators that affect maturation, selection and antibody secretion. Their impact may be based on their capacity to allow autoreactive B cells to escape the normal mechanisms of tolerance and to accumulate in sufficient numbers to cause clinically apparent disease. Both hormones lead to the survival and activation of autoreactive B cells, but they skew B cell maturation towards different directions, with prolactin inducing T cell-dependent autoreactive follicular B cells and estrogen eliciting T cell-independent autoreactive marginal zone B cells. Differential modulation of the cytokine milieu by hormones may also affect the development and activation of specific mature B cell subsets. This novel insight suggests that targeted manipulation of these pathways may represent a promising avenue in the treatment of lupus and other gender-biased autoimmune diseases.

Animals↗