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At least 631 records · Page 35Linked to original sources
PubMed1999

[Desensitization of allergy to hymenoptera venoms].

Hyposensitization (immunotherapy) of hymenoptera venom allergy has been practised for 70 years. About 20 years ago the use of ineffective whole-body extracts was abandoned, as effective therapy with preparations of bee venom and wasp venom became available. The diagnosis of hymenoptera venom allergy is based on history, skin tests and determination of venom specific IgE-antibodies in the serum. Only rarely other tests are needed (histamine or leukotriene release tests, immunoblot, specific IgG antibodies). To achieve a definite diagnosis, all findings have to be considered carefully, as "false positive" and "false negative" results can occur in all test systems. Hyposensitization is indicated in all patients with systemic IgE-mediated immediate type reactions, only in children with exclusive skin symptoms it may not be needed. Contraindications of hyposensitization are to be considered. Allergen preparations for subcutaneous injection are available as aqueous preparations or as aluminium hydroxide-adsorbed depot extracts. Various rush or conventional treatment protocols are used to reach the maintenance dose of usually 100 micrograms venom/four weeks. The most frequent side effects are large local reactions, which are observed in almost all patients. Systemic anaphylactic side effects also occur in up to 40%, in most cases the symptoms are mild. To identify patients who are not protected by the usual maintenance dose, a sting challenge test with a living insect should be performed. By this, about 80 to 100% of the patients are found to be protected from systemic symptoms, and in those still reacting an increased dose of 200 micrograms (or even higher) eventually induces protection. Hyposensitization may be stopped if it lasted at least for 3 to 5 years, if systemic side-effects did not occur and if the patient has tolerated a sting challenge or a field-sting without systemic symptoms. In patients intensely exposed to hymenoptera or in those with an increased risk of severe reactions, longer treatment has to be considered.

Anaphylaxis↗
PubMed1985

Immunological complications in multiple sclerosis patients receiving interferon.

In a prospective, placebo-controlled study designed to test the efficacy of human alpha interferon (IFN) in the treatment of multiple sclerosis, we monitored several immunological functions. Interferon was shown to have many effects on the immune system, including activation of natural killer cells in vivo and elevation of serum immunoglobulin and cerebrospinal fluid IgG ratios. Furthermore, all patients who received IFN developed antibody titers to a protein contaminant (molecular weight, 27 kilodaltons) in the IFN preparation. This antibody was associated with an elevation in serum concentrations of C1q- and Raji-binding immune complexes in 6 of 12 patients. Some of these 12 patients developed symptoms suggestive of immune complex disease. IFN had pronounced effects on the immune system of these patients.

Antibodies↗
PubMed2002

Protective immunosurveillance of the central nervous system by Listeria-specific CD4 and CD8 T cells in systemic listeriosis in the absence of intracerebral Listeria.

The invasion of the CNS by pathogens poses a major risk for damage of the highly vulnerable brain. The aim of the present study was to analyze immunological mechanisms that may prevent spread of infections to the CNS. Intraperitoneal application of Listeria monocytogenes to mice induced infection of the spleen, whereas pathogens remained absent from the brain. Interestingly, Listeria-specific CD4 and CD8 T cells homed to the brain and persisted intracerebrally for at least 50 days after both primary and secondary infection. CD4 and CD8 T cells resided in the leptomeninges, in the choroid plexus, and, in low numbers, in the brain parenchyma. CD4 and CD8 T cells isolated from the brain early after infection (day 7) were characterized by an activated phenotype with spontaneous IFN-gamma production, whereas at a later stage of infection (day 28) restimulation with Listeria-specific peptides was required for the induction of IFN-gamma production by CD4 and CD8 T cells. In contrast to splenic T cells, T cells in the brain did not exhibit cytotoxic activity. Adoptively transferred T cells isolated from the brains of Listeria-infected mice reduced the bacterial load in cerebral listeriosis. The frequency of intracerebral Listeria-specific T cells was partially regulated by the time of exposure to Listeria and cross-regulated by CD4 and CD8 T cells. Collectively, these data reveal a novel T cell-mediated pathway of active immunosurveillance of the CNS during bacterial infections.

Adoptive Transfer↗
PubMed1994

Molecular pathology of AIDS-related lymphomas. Biologic aspects and clinicopathologic heterogeneity.

A high frequency of lymphoma in human immunodeficiency virus-infected individuals has been reported since the outbreak of the acquired immunodeficiency syndrome (AIDS) epidemic in 1982. AIDS-associated non-Hodgkin's lymphoma (AIDS-NHL) is almost invariably derived from B cells and is classified as high- or intermediate-grade NHL, according to the working formulation. Two main histologic types are recognized, including small noncleaved cell lymphoma (SNCCL) and diffuse large cell lymphoma (DLCL). Pre-existing host factors putatively involved in lymphoma development include disrupted immunosurveillance, deregulated cytokine production, chronic antigen stimulation, and infection by Epstein-Barr virus (EBV). These alterations are associated with the development of multiple oligoclonal expansions which correspond to the clinical phase known as persistent generalized lymphadenopathy (PGL). The appearance of a true AIDS-NHL is characterized by the presence of a monoclonal B-cell population displaying several genetic lesions, including monoclonal EBV infection, c-MYC and BCL-6 rearrangements, RAS mutations, p53 inactivation, and 6q deletions. These genetic lesions cluster into two distinct molecular pathways, which specifically associate with the different histologic subtypes of AIDS-NHL, i.e., AIDS-SNCCL and AIDS-DLCL. The presence of distinct genetic pathways for AIDS-SNCCL and AIDS-DLCL correlate with a number of clinical features which distinguish these two groups of tumors, including differences in the age of onset, CD4 counts at the time of presentation, time elapsed since HIV infection, and clinical outcome.

Chromosomes, Human, Pair 8↗
PubMed1999

Restoration of normal interleukin-2 production by CD4+ T cells of human immunodeficiency virus-infected patients after 9 months of highly active antiretroviral therapy.

The present study investigated immune restoration in patients at intermediate stages of human immunodeficiency virus (HIV) disease after initiation of highly active antiretroviral therapy (HAART). A progressive increase in both memory and naive CD4+ T cells was observed from the first weeks of therapy, concomitant with a decrease in the expression of activation markers on CD8+ T cells. The early-activation marker CD69 remained, however, overexpressed on T cells after suboptimal stimulation in vitro, indicative of persistent immune activation. The percentage of interleukin (IL)-2-producing CD4+ T cells significantly increased from 9 months of HAART. In most patients, CD4+ T cells recovered an ability to produce IL-2 on stimulation, similar to that of HIV-seronegative controls. Reversal of T-cell anergy may be a key event in immune restoration for achieving long-term clinical benefit with HAART.

Adult↗
PubMed2000

An extended lymphocytotoxicity test for patients treated with lymphocytotoxic antibodies.

BACKGROUND AND OBJECTIVES: After organ transplantation, HLA antibodies (HLA-Ab) stimulated by transplant or transfusion are usually indistinguishable from passive therapeutic lymphocytotoxic antibodies (LyAb), e.g. antilymphocyte globulin (ALG), antithymocyte globulin (ATG) and OKT3, by standard lymphocytotoxicity tests (LCTs). Herein, an extended technique capable of distinguishing between these two types of antibodies is described. MATERIALS AND METHODS: Serum samples from 11 patients who received therapeutic antibodies were screened for HLA-Ab by LCTs. The administered LyAb were murine OKT3 (n = 2), equine ALG (n = 3), rabbit ATG (n = 2), and combinations of ALG and OKT3 (n = 1), ATG and ALG (n = 1), and ATG and OKT3 (n = 2). To discriminate between therapeutically applied antibodies and active HLA alloimmunization, the sera were preincubated with species-specific anti-Fc IgG, thus blocking the therapeutic antibodies. RESULTS: The sera of all patients treated showed strong positive lymphocytotoxic reactions [panel reactive antibodies (PRA) 50-100%]. After incubation with the corresponding Fc antibodies, in 9 of the 11 samples the amount of PRA decreased to the level present before transplantation (0-18%). In the remaining cases, new-onset alloimmunization was detected. CONCLUSION: This extended LCT allows the screening of serum samples for active HLA-Ab even in the presence of therapeutic LyAb.

Adolescent↗
PubMed1997

Immunologic consequences of blood transfusion and their clinical manifestations.

Aspects of clinical immunology, in the context of transfusion medicine, became highlighted in the last decade as a consequence of the accelerating expansion of basic immunology, immunogenetics and molecular biology. In addition sophisticated new technologies, which were capable of producing pure and safe blood products, attracted more attention to research and monitor the consequences of transfusion. These technologies also had obvious effects on supportive hematological therapy. The transfusion of blood components follows the rules of organ transplantation: when there is a mismatch between the donor and the recipient, the transfusion has the potential to induce various kinds of immune response against alloantigens. Antigen-compatible transfusions that involve major and rare blood groups are in almost all cases mismatched with respect to various polymorphic systems expressed on the cellular blood components. These include histocompatibility leukocyte antigens (HLA), tissue-specific and differentiation alloantigens, and, in the case of plasma, immunoglobulins, complement components, heat shock proteins, and shedded soluble membrane alloantigens. Clinical manifestations of alloimmune responses are typically deleterious. For example, immediate antigen-antibody binding and its consequences as secondary activations are paralleled by the nonhaemolytic febrile reaction, HLA sensitization can lead to a state of platelet refractoriness and inconvenient clinical symptoms. In certain immunogenetic situations and in immunodeficient patients graft-versus-host disease can be induced by blood products that contain live lymphocytes. Leukocyte filtration techniques are widely used to avoid most but not all of these harmful side effects of blood component therapy. In contrast to these harmful side effects in certain immunogenetic conditions, alloantigens that are expressed on various blood products can elicit an advantageous suppression of the immune response in the recipient. In the context of kidney transplantation this is termed the 'beneficial transfusion effect', and typically results in the prolongation of the graft's survival. In cases of recurrent habitual abortion and IgG therapy associated with certain autoimmune diseases, immunization with leukocytes specifically takes advantage of this phenomenon. To date the beneficial transfusion effect is not fully understood. In certain cases of malignancies or gastrointestinal surgeries this suppression of immune regulation that is induced by transfusion can worsen the clinical state either by permitting the spread of the tumor or by allowing severe infections to proceed unchecked. In conclusion it is imperative to monitor the immunological consequences of transfusion in order to deter the disadvantageous side effects. Taking advantage of the 'beneficial transfusion effect' may also provide a new means for immune therapy using the various blood products.

Blood Cells↗
PubMed1996

Differential immune responses to fetal intracameral spinal cord and cortex cerebri grafts.

While the central nervous system (CNS) has been characterized as an immunologically privileged site, there are also several reports describing immunological reactions within the CNS. A certain degree of immunological privilege has also been ascribed to the anterior chamber of the eye. We have used the intraocular transplantation model to study immunological reactions in transplants of embryonic neural tissue. Outbred Sprague-Dawley rats and inbred Fisher rats were used. Pieces of rat parietal cortex or the cervical spinal cord were prepared from embryonic day 14 and implanted into the eye chambers of adult rats of the same strain. Following intraocular maturation, grafts were analysed using antibodies against: major histocompatibility complex (MHC) class I, MHC class II; rat antigens CD4, CD8, CD11b; T-cell receptor; rat antigen ED1; and glial fibrillary acidic protein. Using this set of markers for immunological reactions, transplants were scored on a blind basis. We found no significant differences in immunological scores between transplants obtained from different litters of fetuses of the outbred animals. Grafting in the outbred strain led to increased numbers of immunologically reactive cells in the grafts. This was not seen in grafts in the inbred strain. Spinal cord transplants led to a significantly higher degree of cytotoxic immunity-related cells expressing MHC class II as well as CD4-positive cells. There was a positive correlation between ED1 negativity and well-developed ramified microglia. From these results we conclude also that well-developed intraocular CNS tissue grafts do contain cellular evidence of immunological events and that different areas of the CNS may provoke different degrees of response. Reactive microglial proliferation appears to be one of the most sensitive ways to monitor the immunological condition of grafted CNS tissue.

Animals↗
PubMed2005

The tumor suppressor TSLC1/NECL-2 triggers NK-cell and CD8+ T-cell responses through the cell-surface receptor CRTAM.

The tumor suppressor in lung cancer-1 (TSLC1) gene is frequently silenced in human lung carcinomas, and its expression suppresses tumorigenesis in nude mice. TSLC1 encodes a cell-surface protein called Necl-2 that belongs to the Nectin and Nectin-like (Necl) family of molecules. Necl-2 mediates epithelial cell junctions by homotypic contacts and/or heterotypic interactions with other Nectins and Necls. Thus, it inhibits tumorigenesis by ensuring that epithelial cells grow in organized layers. Here, we demonstrate that natural killer (NK) cells and CD8+ T cells recognize Necl-2 through a receptor known as class I-restricted T-cell-associated molecule (CRTAM), which is expressed only on activated cells. CRTAM-Necl-2 interactions promote cytotoxicity of NK cells and interferon gamma (IFN-gamma) secretion of CD8+ T cells in vitro as well as NK cell-mediated rejection of tumors expressing Necl-2 in vivo. These results provide evidence for an additional mechanism of tumor suppression mediated by TSLC1 that involves cytotoxic lymphocytes. Furthermore, they reveal Necl-2 as one of the molecular targets that allows the immunosurveillance network to distinguish tumor cells from normal cells.

Animals↗
PubMed1990

The safety and pharmacokinetics of recombinant soluble CD4 (rCD4) in subjects with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex. A phase 1 study.

STUDY OBJECTIVE: To evaluate the safety and pharmacokinetics of recombinant, soluble human CD4 (rCD4) in subjects with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex. The protein rCD4 binds to envelope protein, gp120, of the human immunodeficiency virus (HIV) and blocks HIV infection of CD4 lymphocytes in vitro. DESIGN: Phase 1 trial with dose escalation. SETTING: Two university-affiliated hospital clinics. SUBJECTS: Of 42 subjects enrolled, 29 had AIDS and 13 had AIDS-related complex. INTERVENTIONS: The rCD4 was administered by rapid intravenous infusion on day 1, followed by a 3-day washout, then once a day for 10 days, followed by a 7-day washout, and then three times a week for 8 weeks. Doses of 1, 10, 30, 100, and 300 micrograms/kg body weight per day of rCD4 were administered intravenously to 6 subjects at each dose level. Twelve additional patients received 300 micrograms/kg.d of rCD4: 6 by intramuscular and 6 by subcutaneous injection. All subjects were monitored for toxicity. Immunologic and virologic variables were also monitored. MEASUREMENTS AND MAIN RESULTS: Administration of rCD4 was not associated with important toxicity as determined by clinical monitoring or by serum chemistry, hematologic, or immunologic variables. No subjects required dose reduction or discontinuation of therapy due to rCD4-related toxicity. No consistent or sustained changes in CD4 lymphocyte populations or HIV antigen levels were observed. The volume of distribution of rCD4 was small, and clearance remained constant over the dose range studied. The bioavailability of intramuscular injection and subcutaneous injection was 51% and 45%, respectively. CONCLUSIONS: At the dose levels used in this study, rCD4 appears safe and well tolerated. Serum concentrations of rCD4 were achieved that were comparable to concentrations shown to have antiviral activity in vitro. Further studies are indicated to determine whether rCD4 or related molecules will be useful in treating HIV infection.

AIDS-Related Complex↗