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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum levels of the soluble form of the low-affinity receptor for IgE (FcERII, CD23) (sCD23) are elevated in autoimmune conditions associated with hypergammaglobulinaemia and B cell hyperactivity. Very high levels of sCD23 are found in patients with B-chronic lymphatic leukaemia (B-CLL) who are, however, frequently hypogammaglobulinaemic. We therefore compared the serum levels of sCD23 in healthy controls (n = 33) with three conditions associated with hypogammaglobulinaemia (HGG) and varying B cell numbers: X-linked agammaglobulinaemia (XLA, n = 12), common variable immunodeficiency (CVI, n = 20) and B-chronic lymphatic leukaemia (n = 33). Serum levels of sCD23 showed a significant correlation with the CD19+ B cell count in both normals and patients with CVI (r = 0.65, P < 0.0001). Amongst the different clinical groups, serum levels of sCD23 were increased in the order XLA < CVI < normals < CLL (medians 2.5, 7.7, 11.1 and 540, respectively; P < 0.001 for all comparisons except CVI versus normals P < 0.03 in a one-tailed test). In the CVI group, serum sCD23 was lowest amongst four patients with low B cell numbers. There was no overlap in sCD23 between patients with XLA and this subgroup of CVI patients. Serum sCD23 is, therefore, derived predominantly from B cells, and is significantly related to the peripheral blood B cell count.
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PMID:Serum soluble CD23 in patients with hypogammaglobulinaemia. 805 Jan 71

The gene which causes X-linked agammaglobulinemia, btk, has recently been identified as a cytoplasmic tyrosine kinase expressed almost exclusively in B cells, and at all stages of B-cell differentiation. To assess the possibility of involvement of this gene in childhood B-cell malignancies, cells from 23 pediatric patients with B-cell acute lymphoblastic leukemia were examined for expression and alteration of the Btk protein and also for mutations in the btk gene. Btk proteins, similar in both molecular weight and quantity to those seen in unaffected individuals, were detected in whole cell lysates from the blasts of 12/12 patients indicating that no abnormal protein was present. cDNAs from the leukemic blasts of all 23 patients were screened with specific primers covering the coding region of the btk cDNA for mutations using single strand conformation polymorphism (SSCP) analysis. No mutations were found but a nucleotide polymorphism was identified in 4/23 patients at the 3' end of btk. Although the sample size in this study was relatively small, these data suggest that btk does not appear to play a critical role in childhood B-cell leukemias.
Leukemia 1994 Apr
PMID:Expression of the X-linked agammaglobulinemia gene, btk in B-cell acute lymphoblastic leukemia. 815 53

Bruton's tyrosine kinase (Btk) is a non-receptor protein tyrosine kinase (PTK) that is expressed in all haemopoietic lineages except mature T cells and plasma cells. Despite the broad range of expression. mutations that inactivate this molecule affect primarily the development of the B-cell lineage. As a PTK, Btk could potentially be involved directly or indirectly in the processes that relate to the malignant transformation of all the cell lineages where this molecule is expressed. Previous studies have failed to demonstrate mutations in patients with B-cell origin acute lymphoblastic leukaemia (ALL). We have utilized a recently developed method that enables the rapid and convenient detection of mutations at the cDNA level, namely, the non-isotopic RNase cleavage assay (NIRCA) to analyse Btk sequences from 27 patients with different types of acute myeloid leukaemia (AML). The only alteration that we observed was a polymorphism at position 2031. This polymorphism has already been seen in previous studies. Furthermore, using the same methodology, we identified the Btk mutations in six XLA (X-linked agammaglobulinaemia) patients. Our results, although they do not exclude the involvement of Btk mutations in the development or progression of some type of AML, nevertheless suggest that such mutations do not constitute a major co-factor in the development of myeloid malignancies.
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PMID:Absence of Bruton's tyrosine kinase (Btk) mutations in patients with acute myeloid leukaemia. 975 52

Bruton's tyrosine kinase (BTK) is a member of the Src-related Tec family of protein tyrosine kinases. Mutations in the btk gene have been linked to severe developmental blocks in human B-cell ontogeny leading to X-linked agammaglobulinemia. Here, we provide unique biochemical and genetic evidence that BTK is an inhibitor of the Fas/APO-1 death-inducing signaling complex in B-lineage lymphoid cells. The Src homology 2, pleckstrin homology (PH), and kinase domains of BTK are all individually important and apparently indispensable, but not sufficient, for its function as a negative regulator of Fas-mediated apoptosis. BTK associates with Fas via its kinase and PH domains and prevents the FAS-FADD interaction, which is essential for the recruitment and activation of FLICE by Fas during the apoptotic signal. Fas-resistant DT-40 lymphoma B-cells rendered BTK-deficient through targeted disruption of the btk gene by homologous recombination knockout underwent apoptosis after Fas ligation, but wild-type DT-40 cells or BTK-deficient DT-40 cells reconstituted with wild-type human btk gene did not. Introduction of an Src homology 2 domain, a PH domain, or a kinase domain mutant human btk gene into BTK-deficient cells did not restore the resistance to Fas-mediated apoptosis. Introduction of wild-type BTK protein by electroporation rendered BTK-deficient DT-40 cells resistant to the apoptotic effects of Fas ligation. BTK-deficient RAMOS-1 human Burkitt's leukemia cells underwent apoptosis after Fas ligation, whereas BTK-positive NALM-6-UM1 human B-cell precursor leukemia cells expressing similar levels of Fas did not. Treatment of the anti-Fas-resistant NALM-6-UM1 cells with the leflunomide metabolite analog alpha-cyano-beta-methyl-beta-hydroxy-N-(2, 5-dibromophenyl)propenamide, a potent inhibitor of BTK, abrogated the BTK-Fas association without affecting the expression levels of BTK or Fas and rendered them sensitive to Fas-mediated apoptosis. The ability of BTK to inhibit the pro-apoptotic effects of Fas ligation prompts the hypothesis that apoptosis of developing B-cell precursors during normal B-cell ontogeny may be reciprocally regulated by Fas and BTK.
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PMID:Bruton's tyrosine kinase as an inhibitor of the Fas/CD95 death-inducing signaling complex. 988 May 44

Bruton's tyrosine kinase (Btk) is required for normal B cell development and signal transduction through cell surface molecules, and its defects lead to X-linked immune deficiency in mice and X-linked agammaglobulinemia in humans. In this report, we will describe the identification and characterization of a molecule, BAM11, which binds to the pleckstrin homology domain of Btk. A sequence homology search revealed that BAM11 has 89% homology, at the amino acid level, to human LTG19/ENL, that was originally identified as one of the fusion partners involved in chromosomal translocations of 11q23, MLL/ALL-1/HRX, in leukemia cells. Deletion mutants demonstrated that the region of BAM11 required for binding to Btk was localized between amino acid residues 240 and 256. Forced expression of a truncated form of BAM11 (amino acids 246-368) inhibited IL-5-induced proliferation by 50%, whereas forced expression of full-length BAM11 in Y16 cells did not affect the IL-5 responsiveness. We have also shown that BAM11 (amino acids 246-368) inhibited the kinase activity of Btk. These results suggest that the binding of BAM11 to Btk plays a regulatory role in the Btk signal transduction pathway. A cell fractionation study and analysis using EGFP-fused Btk protein demonstrated that a proportion of Btk is present within the nucleus.
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PMID:Identification and characterization of a molecule, BAM11, that associates with the pleckstrin homology domain of mouse Btk. 1100 57

The main topic of this article is B cell development and differentiation, with a special focus on the mechanisms and molecules that regulate the expression of humoral immunity. Molecular epidemiological analysis was performed on the genes responsible for the X-linked agammaglobulinemia (XLA) phenotype of the majority of Italian patients and their distinct mutations were characterized. Mutations in Bruton's tyrosine kinase (BTK), a member of Tec Family of protein tyrosine kinases, have been found to be mainly responsible for XLA disease. The exact function of BTK in signal transduction is not yet known; thus, the specific role of BTK in receptor-dependent calcium signaling and the pro-antiapoptotic regulatory activity was addressed by transfecting RAMOS-1, a BTK-deficient human Burkitt's/B cell leukemia line with wild-type and mutant constructs. This work may provide clues about critical sites in the molecule and give support for gene therapy as a potential successful approach to XLA. Another aspect of this research is the identification and dissection of the molecular events that are likely to be directly related to the ability to express various isotypes of immunoglobulin with differing function and certain B cell immunodeficiency, mainly common variable disease and non-X-linked hyperIgM. B cell development and maturation steps in different compartments of the immune system are tracked by the analysis of cell-surface molecules and components of the signal transduction pathways, i.e. CD40, CD30, CD27, CD38, CD22 and CD24. A few components involved in B cell development, maturation and differentiation and their specific functional role are at least partially known, but these are far from fitting into an understandable pathway at present.
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PMID:Insight into B cell development and differentiation. 1517 20

X-linked agammaglobulinemia (XLA) is the most common primary immunodeficiency (PID) in man and caused by mutations in the Bruton's tyrosine kinase (BTK) gene. XLA is characterized by a B-cell differentiation arrest in bone marrow, absence of mature B cells and immunoglobulins (Igs), and recurrent bacterial infections. We used self-inactivating lentiviral vectors expressing codon-optimized human BTK under the control of three different ubiquitous or B cell-specific promoters. Btk-/- mice engrafted with transduced cells showed correction of both precursor B-cell and peripheral B-cell development. Lentiviral vectors containing the wildtype BTK sequence did not correct the phenotype. All treated mice with codon-optimized BTK exhibited the recovery of B1 cells in the peritoneal cavity, and of serum IgM and IgG3 levels. Calcium mobilization responses upon B-cell receptor stimulation as well as in vivo responses to T cell-independent antigens were restored. Viral promoters overexpressing BTK >100-fold above normal resulted in erythro-myeloid proliferations independent of insertional mutagenesis. However, transplantation into secondary Btk-/- recipients using cellular promoters resulted in functional restoration of peripheral B cells and IgM levels, without any adverse effects. In conclusion, transduction of human BTK corrects B-cell development and antigen-specific antibody responses in Btk-/- mice, thus indicating the feasibility of lentiviral gene therapy for XLA, provided that BTK expression does not vastly exceed normal levels.
Leukemia 2010 Sep
PMID:Correction of B-cell development in Btk-deficient mice using lentiviral vectors with codon-optimized human BTK. 2057 53

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency characterized by marked reduction in all classes of serum immunoglobulins and the near absence of mature CD19(+) B-cells. Although malignancy has been observed in patients with XLA, we present the first reported case of acute myeloid leukemia (AML) in a patient with XLA. We also demonstrate the complete correction of the XLA phenotype following allogeneic hematopoietic cell transplantation for treatment of the patient's leukemia.
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PMID:Successful hematopoietic cell transplantation in a patient with X-linked agammaglobulinemia and acute myeloid leukemia. 2590 May 77

Kawasaki disease (KD) has features that appear supporting an infectious cause with a secondary deranged inflammatory/autoimmune response. The association of KD in adults with human immunodeficiency virus infection and the presence of KD in patients with immunodeficiency disorders support the infectious theory. We present four KD patients associated with immunodeficiencies: one with X-linked agammaglobulinemia, one with HIV infection, and two with leukemia; one of these patients also had Down syndrome. We did a literature search to find out all reported cases of immunodeficiency with KD in children. In immunodeficiency disorders, the inability of the immune system to eradicate the pathogens coupled to an exaggerated inflammatory response, especially in chronic granulomatous disease, may lead to the development of KD. The study of patients with immunodeficiencies complicated with KD may shed light into the etiopathogenesis of the disease.
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PMID:Kawasaki disease and immunodeficiencies in children: case reports and literature review. 3131 87

Patients with primary immunodeficiency are at increased risk for malignancy, especially hematologic neoplasms. This paper reports a unique case of a 47-year-old man with X-linked agammaglobulinemia who presented with progressive asymptomatic violaceous papules and plaques on his face, hands, and trunk for 1 year. Skin biopsies revealed deep, nodular infiltrates of histiocytes and CD8-positive lymphocytes, with a CD4:CD8 ratio of 1:10. Laboratory studies showed cytopenias. Flow cytometry in the skin, blood, and bone marrow (BM) showed a CD3+/CD8+/CD57+ large granular lymphocyte population. BM biopsy showed 30% involvement with these atypical T-cells. T-cell gene rearrangement studies of skin, blood, and BM revealed identical T-cell clones. He was diagnosed with T-large granular lymphocyte leukemia (T-LGLL) with an associated CD8+ cutaneous lymphoproliferation. Skin involvement was suspected to represent infiltration by T-LGLL. However, co-existence of two lymphoproliferative disorders (LPDs), T-LGLL and CD8+ granulomatous LPD, remains a possibility. In general, cutaneous infiltrates associated with LGLL are rare and poorly understood. It has been suggested that they are markers of poor prognosis. Our case report describes skin, blood, and BM findings in an immunosuppressed patient with T-LGLL in detail. These findings have not yet been reported and their significance requires further investigation.
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PMID:CD8-positive cutaneous lymphoproliferation associated with large granular lymphocyte leukemia in a patient with X-linked agammaglobulinemia. 3288 80


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