Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclosporine (CsA) is a potent immunosuppressive agent primarily affecting T-lymphocyte function. Patients receive CsA following organ transplantation to prevent rejection. These patients are at high risk for developing Epstein-Barr virus (EBV)-induced lymphoproliferative disease (LPD) or B-cell lymphoma (BCL). Severe Combined Immunodeficient (SCID) mice reconstituted with human peripheral blood leukocytes (PBL) develop fatal B-cell lymphomas of human origin following latent or active infection with EBV. This model was utilized to determine the role of CsA in the development of human BCL. SCID mice were reconstituted with PBL, latently or actively infected with EBV, and treated with CsA. Following active EBV infection, mice developed human BCL with or without CsA treatment. In contrast, treatment with CsA prevented the development of BCL in mice latently infected with EBV. This suggests a T-cell interaction with latently infected B-cells which is perturbed by CsA. Further understanding of this interaction and the occurrence of human BCL may allow the development of strategies to prevent, detect, or treat malignancies associated with immunosuppression.
 ...
PMID:Effects of cyclosporine on human B-cell lymphoma development in vivo. 134 Dec 39

Infection of human B cells by Epstein-Barr virus (EBV) causes transformation to immortalized lymphoblastoid cells capable of continuous proliferation. To identify biochemical changes induced by EBV infection of B cells, we have utilized isogenic EBV-positive and -negative B cell lymphoma lines as a model to determine whether EBV induces protein tyrosine phosphorylation. By utilizing two different methods, immunoblotting with phosphotyrosine antibodies and phosphoamino acid analysis, it was shown that the presence of EBV in these cells was reversibly associated with increased phosphorylation of a 50 kilodalton cytosolic protein on tyrosine residues. The characteristics of this protein were not consistent with any known EBV-encoded protein that is expressed in latency, and thus it likely represents a cellular protein that is phosphorylated by an endogenous tyrosine kinase. These results suggest that EBV induces protein tyrosine phosphorylation in human B cells, and this may represent an important event in the transformation of B lymphocytes by EBV.
 ...
PMID:Conversion of a human B cell lymphoma line by Epstein-Barr virus is associated with increased tyrosine phosphorylation of a 50 kilodalton cytosolic protein. 165 26

The pathogenesis of non-Hodgkin's lymphoma (NHL) in HIV-infected individuals is currently poorly understood; however, recent molecular studies have subdivided these lymphomas into distinct molecular pathologic entities. Similar to endemic and sporadic Burkitt's lymphoma, monoclonal B-lymphoma subsets were found to be infected with Epstein-Barr virus (EBV) or have c-myc gene rearrangements, suggesting a role for EBV infection or chromosomal translocation in a subset of AIDS NHLs. Similar to lymphomas that occur in immunosuppressed transplant patients, EBV-positive polyclonal lymphomas also have been described. Unique to HIV-infected patients, however, is the subset of polyclonal B-cell lymphoma with no evidence for EBV infection. Based on these molecular studies, it is apparent that the AIDS NHLs represent a heterogeneous set of diseases with a number of pathogenic processes involved in lymphomagenesis.
 ...
PMID:Molecular pathogenesis of AIDS-associated non-Hodgkin's lymphoma. 202 96

Epstein-Barr virus (EBV), a human herpesvirus, is strongly linked with two relatively rare forms of B-cell lymphoma and with a much more prevalent epithelial malignancy, undifferentiated nasopharyngeal carcinoma (NPC). The availability of suitable culture systems has allowed detailed analysis of EBV-induced growth transformation in B lymphocytes, but little is known about the virus--epithelial cell interaction or about the possible effector role of viral proteins in the pathogenesis of NPC. Here we describe an experimental system to monitor the effects of introduced viral or cellular genes upon human epithelial cell growth and differentiation. We transfected a human epithelial cell line, which retains several features of normal keratinocyte behaviour in vitro, with the EBV gene encoding latent membrane protein (LMP), one of only two viral proteins known to be expressed in NPC cells in vivo. LMP expression was accompanied by changes in the epithelial cell surface phenotype, mimicking surface changes observed in NPC cells, and by severe impairment of the cellular response to differentiation signals. The ability of LMP to inhibit terminal differentiation indicates a mechanism whereby EBV infection of squamous epithelium could contribute to the multi-step pathogenesis of NPC.
 ...
PMID:Epstein-Barr virus latent membrane protein inhibits human epithelial cell differentiation. 215 28

Prevention of EBV-associated lymphoproliferative diseases in immune deficient individuals is preferred; however, standard therapy for the B cell lymphomas has been successful. Chemotherapy must be given cautiously lest further immune compromise result in opportunistic infections. Recently, Acyclovir has decreased morbidity of patients with acute infectious mononucleosis in immune competent persons. In contrast, immunodeficient patients with X-linked lymphoproliferative (XLP) syndrome do not seem to respond favorably. Hence, a prospective study is underway using prophylactic immunoglobulin containing (EBV)-specific antibodies. The mortality rate is 85% following EBV infection in XLP due to fatal infectious mononucleosis associated with fulminant hepatitis and virus-associated hemophagocytic syndrome, acquired hypogammaglobulinemia or malignant B cell lymphoma. We can detect XLP by noting failure of switching from IgM to IgG antibody production on secondary challenge with bacteriophage phi X174. Also, linkage studies with the XLP locus using restriction fragment length polymorphisms are being done to detect affected males pre-EBV infection. Our rationale for prevention of phenotypes of XLP is based on observations that infants in tropical Africa and males with XLP do not develop EBV-induced diseases while neutralizing maternal antibodies are present. An EBV vaccine will be used, when available, in seronegative males with XLP. Prevention of acquired immune deficiency by screening blood for human immune deficiency virus, encouraging prudent life styles, development of specific immunosuppressive agents, development of new antiviral agents (i.e., DHPG), and identification of high risk seronegative patients offer possibilities for preventing life-threatening EBV-induced diseases.
 ...
PMID:Prevention and treatment of Epstein-Barr virus (EBV)-associated lymphoproliferative diseases in immune deficient patients. 243 95

Hairy cell leukemia is a preplasmacytic B cell leukemia which is not EBV associated, although elevated titers of Epstein-Barr virus (EBV) antibodies have been seen in this leukemia and chronic lymphocytic leukemia. Hairy cells are not readily susceptible to EBV infection in vitro, even though they are EBV receptor-positive B cells. We have observed a 59-year-old patient who after 9 years of hairy cell leukemia developed a well-differentiated IgG-kappa monoclonal B cell lymphoma without further evidence of hairy cell leukemia. Pathologically, the lymphoma showed plasmacytic differentiation, and in the patient's serum, a 2 g/dl monoclonal IgG-kappa component was present. DNA extracted from the lymphomatous lymph node hybridized with DNA fragments of a reiterated sequence of EBV, IR1. The transformation, with no chemotherapy involved, from a preplasmacytic leukemia into a lymphoplasmacytic lymphoma with monoclonal gammopathy may be related to the entry of EBV into these cells. Studies at the molecular level may help understand mechanisms of malignant transformation or interconversion in lymphoproliferative disorders of the B cell type.
 ...
PMID:Transformation of hairy cell leukemia to EBV genome-containing aggressive B cell lymphoma. 282 16

Twenty cases of Epstein-Barr virus (EBV)-associated lymphoproliferative syndrome (LPS), defined by the presence of EBV nuclear antigen and/or EBV DNA in tissues, were diagnosed in 1467 transplant recipients in Pittsburgh from 1981-1985. The frequency of occurrence in pediatric transplant recipients was 4% (10/253), while in adults it was 0.8% (10/1214) (P less than .0005). The frequency of LPS in adults declined after 1983 coincidental with the introduction of cyclosporine monitoring. However there was no apparent decline of LPS in children. We describe these ten pediatric cases and one additional case of LPS in a child who received her transplant before 1981. The frequency of EBV infection in 92 pediatric liver recipients was 63%. Of these subjects, 49% were seronegative and 77% of those acquired primary infection. Of 11 cases of pediatric EBV-associated LPS, 10 were in children who had primary infection shortly before or after transplantation. These results reinforce the importance of primary EBV infection in producing LPS, which was previously shown in adults. Children are at greater risk because they are more likely to be seronegative for EBV and to acquire primary infection. Three clinical types of LPS were recognized in children. The first (5 cases) was a self-limited mononucleosislike syndrome. The second syndrome (4 cases) began similarly, but then progressed over the next two months to widespread lymphoproliferation in internal organs and death. The third type (2 cases) was an extranodal intestinal monoclonal B cell lymphoma, occurring late after primary infection.
 ...
PMID:The frequency of Epstein-Barr virus infection and associated lymphoproliferative syndrome after transplantation and its manifestations in children. 283 28

A 12-year-old boy with severe combined immunodeficiency who had been kept in a gnotobiotic environment since birth received bone marrow from a histoincompatible sibling in an attempt to reconstitute immunologic function. To prevent graft versus host disease, the donor's marrow was treated in vitro with monoclonal antibody and complement to remove alloreactive T cells. Eighty days after transplantation, the patient had a systemic illness characterized by fever, thrombocytopenia, gastrointestinal pain, and bleeding; he died on the 124th post-transplantation day. Postmortem examination revealed multiple tumor-like B-cell proliferations, recipient in origin, in numerous organs. Epstein-Barr virus (EBV) was isolated from the patient's pharyngeal secretions; EBV nuclear antigen was found in spontaneously transformed peripheral-blood lymphocytes, inflammatory cells from peritoneal fluid, and bone marrow cells; and EBV genomes were discovered in all tumor tissues. The donor's serum showed evidence of past EBV infection. Analysis of cellular immunoglobulin and immunoglobulin gene DNA from the tumors indicated both monoclonal and oligoclonal B-cell proliferations. These findings provide evidence for the evolution of EBV-induced polyclonal activation of B cells to oligoclonal B-cell proliferation and finally to monoclonal B-cell lymphoma.
 ...
PMID:Epstein-Barr virus-associated B-cell proliferations of diverse clonal origins after bone marrow transplantation in a 12-year-old patient with severe combined immunodeficiency. 298 67

Epstein-Barr virus (EBV) infects virtually everyone by adulthood, and a lifelong latency is maintained. It infects children silently, whereas the majority of adolescents have infectious mononucleosis (IM). Children who have IM before 5 years of age are often heterophil negative; EBV-specific antibodies are required for diagnosis. On rare occasions the symptoms of IM may persist in a chronic or recurrent form, and fatal infectious mononucleosis occurs rarely. Depending on the type and degree of immune deficiency and the time the EBV infection occurs in the life cycle, various atypical outcomes can occur. Children with primary immune deficiency can have fatal or chronic IM, malignant B cell lymphoma, virus-associated hemophagocytic syndrome, aplastic anemia, or acquired hypogammaglobulinemia. The various outcomes of the EBV infections are likely governed by the immune response of the individual. The increased frequency of B cell neoplasms in immunodeficient patients is likely due, in part, to EBV. Individuals with acquired immune deficiency disorders such as AIDS or allograft recipients may develop malignant B cell lymphomas which tend to be polyclonal, but which may progress through stages of oligoclonality to monoclonality. This conversion likely results from specific reciprocal chromosomal translocations such as t(8;14), which is seen in Burkitt's lymphoma. Detection of EBV in immunodeficient patients is achieved by EBV-specific antibody studies or isolation of virus by obtaining spontaneous lymphoblastoid cell lines from peripheral blood, isolating virus from throat washings, or identifying EBV genome by molecular hybridization techniques. Prevention of primary immune deficiency by early detection and genetic counseling and monitoring of patients for occurrence of EBV infection may lead to early treatment. Acyclovir and immunoglobulin therapy can be of value in some patients with active EBV infection.
 ...
PMID:Epstein-Barr virus: the spectrum of its manifestations in human beings. 303 69

AIDS (acquired immune deficiency syndrome) and ARC (AIDS-related complex) are associated with a spectrum of lymphoproliferative disorders ranging from lymphadenopathy syndrome (LAS), an apparently benign polyclonal lymphoid hyperplasia, to B cell non-Hodgkin's lymphoma (B-NHL), i.e., malignant, presumably monoclonal B cell proliferations. To gain insight into the process of lymphomagenesis in AIDS and to investigate a possible pathogenetic relationship between LAS and NHL, we investigated the clonality of the B or T lymphoid populations by Ig or T beta gene rearrangement analysis, the presence of rearrangements involving the c-myc oncogene locus, and the presence of human immunodeficiency virus (HIV) sequences in both LAS and B-NHL biopsies. Our data indicate that multiple clonal B cell expansions are present in a significant percentage of LAS (approximately 20%) and B-NHL (60%) biopsies. c-myc rearrangements/translocations are detectable in 9 of our 10 NHLs, but not in any of the LAS cases. However, only one of the B cell clones, identified by Ig gene rearrangements carries a c-myc gene rearrangement, suggesting that only one clone carries the genetic abnormality associated with malignant B cell lymphoma. Furthermore, the frequency of detection of c-myc rearrangements in AIDS-associated NHLs of both Burkitt and non-Burkitt type suggest that the biological alterations present in AIDS favor the development of lymphomas carrying activated c-myc oncogenes. Finally, our data show that HIV DNA sequences are not detectable in LAS nor in NHL B cell clones, suggesting that HIV does not play a direct role in NHL development. Taken together, these observations suggest a model of multistep lymphomagenesis in AIDS in which LAS would represent a predisposing condition to NHL. Immunosuppression and EBV infection present in LAS can favor the expansion of B cell clones, which in turn may increase the probability of occurrence of c-myc rearrangements leading to malignant transformation.
 ...
PMID:Multiple monoclonal B cell expansions and c-myc oncogene rearrangements in acquired immune deficiency syndrome-related lymphoproliferative disorders. Implications for lymphomagenesis. 349 Nov 76


1 2 3 4 5 6 7 8 9 10 Next >>