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Results for “Immunologic Deficiency Syndromes”

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At least 181 records · Page 10Linked to original sources
PubMed1999

Further characterization of memory T cells existing in a case of CD8 deficiency.

CD8 deficiency is a rare primary immunodeficiency caused by a defect of ZAP-70, which plays a pivotal role in T cell activation. We previously reported the existence of memory phenotype-CD4+ T cells in a case of CD8 deficiency, which demonstrates that activation signals through ZAP-70 are not essential to the phenotypic conversion of T cells from "naive" to "memory." In this study, we further characterized CD45RO+ T cells in a CD8 deficient patient. We showed that the patient's CD45RO+ T cell population had a wide variety of T cell receptor Vbeta-chain gene usage, and contained few clonally expanded T cells, while many clonally expanded T cells were present in the memory T cell population of age-matched healthy children. These results suggest that various kinds of antigens were involved in the differentiation of the patient's T cells, and that the differentiation into memory T cells was not accompanied by profound T cell proliferation. Moreover, our findings confirmed that the patient's CD45RO+CD4+ T cells had acquired effector-cytokine producing ability, indicating that there exists an alternative activation pathway which is independent of ZAP-70 for the acquisition of effector-cytokine producing ability.

CD8 Antigens↗
PubMed1987

Evaluation of foals for immune deficiency disorders.

Currently recognized equine immune deficiency disorders include failure of passive colostral immunoglobulin transfer, combined immunodeficiency, selective IgM deficiency, transient hypogammaglobulinemia, and agammaglobulinemia. Additional equine immune deficiency disorders probably exist. Immune deficiency should be suspected in any horse experiencing persistent or recurrent infections that are not responsive to conventional therapy.

Animals↗
PubMed2001

Cancer vaccines.

Attempts to generate an anticancer immune response in vivo in patients with cancer have taken several forms. Although to date there have been relatively few published studies describing the effects of the approach in hematologic malignancy, that circumstance is expected to change rapidly during the next few years. In solid tumors, it is not known which, if any, of the approaches being explored will be able to produce responses of sufficient effectiveness and duration to be of general clinical value. Despite the documented increase in survival of patients developing an immune response to tumor immunization, no randomized clinical trial has been entirely convincing. As knowledge of the molecular basis of the immune response and of the immune defenses used by cancer cells improves, it is reasonable to expect to see increasing benefits from tumor vaccines, which are likely to complement, long before they replace, conventional therapies.

Antigen Presentation↗
PubMed2001

[The child with recurrent infections: which screening for immunoe deficiency?].

A child with recurrent infections represents a challenge to the pediatrician who must identify, among a large number of repeatedly infected but nevertheless healthy children whose parents need to be reassured, the rare cases of potentially severe immune deficiency. This can be most successfully achieved through the measurement of IgA, IgG, and antibody titers to vaccine (tetanus, diphtheria, Haemophilus influenzae B) and exposure (pneumococcus) antigens. The presence of normal antibody responses makes it possible to rule out underlying immune deficiency in a sensitive and specific manner. Conversely, abnormally weak antibody responses identify the children who have to be referred without delay for further investigation of a potential immune defect. This article indicates for which pediatric patients an immunodeficiency screening should be considered, and how to analyze its results.

Algorithms↗
PubMed1993

Hairy cell leukaemia.

Hairy cell leukaemia is a rare chronic lymphoproliferative disease, characterized by splenomegaly, pancytopenia and recurrent infection. The characteristic 'hairy cells', present in the peripheral blood and bone marrow, are the hallmark of this leukaemia. The disease has a chronic, progressive course, and the majority of patients afflicted by it require therapy. The most common reason to initiate treatment is neutropenia with or without associated infectious complications, or the development of severe thrombocytopenia. Therapeutic options in hairy cell leukaemia include splenectomy, interferon administration, or the use of chemotherapeutic agents such as pentostatin (2'-deoxycoformycin) and 2-chlorodeoxyadenosine. Splenectomy is still indicated in the treatment of young patients with significant splenomegaly and only minimal bone marrow involvement. Interferon treatment induces remission in approximately 90% of patients with hairy cell leukaemia, but complete remission is obtained in only 5-10%. The development of antibodies against interferon was initially considered a major problem, but longer follow-up of patients who developed antibodies has shown that it is transient and does not have a significant impact on the overall response to treatment. Pentostatin induces complete remission in 60-70% of patients and partial remission in 20-40%. 2-Chlorodeoxyadenosine is a very promising drug in the treatment of this rare leukaemia, inducing long-lasting complete remission in approximately 80% of patients. While interferon does not cure the disease, it is possible that a subset of patients treated with pentostatin or 2-chlorodeoxyadenosine are cured. Longer follow-up of these patients will determine whether this is true.

Adult↗
PubMed2000

Leukocyte migration: scent of the T zone.

Recent studies show that the chemokine receptor CCR7 helps T lymphocytes and dendritic cells to navigate into the T-cell zone of lymphoid organs. Furthermore, down-modulation of CCR7 redirects some activated T cells from these zones into other lymphoid tissue compartments.

Animals↗
PubMedDate not supplied

Type I interferons and autoimmunity: lessons from the clinic and from IRF-2-deficient mice.

Type I interferons (IFN-alpha/beta) are produced upon viral and bacterial infections and play essential roles in host defense. However, since IFN-alpha/beta have multiple regulatory functions on innate and adoptive immunity, dysregulation of the IFN-alpha/beta system both in uninfected hosts and during immune responses against infection can result in immunopathologies. In fact, IFN-alpha/beta therapy often accompanies autoimmune-like symptoms. In this regard, we have recently found that mice lacking IFN regulatory factor (IRF)-2, a negative regulator of IFN-alpha/beta signaling, develop spontaneous, CD8(+) T cell-dependent skin inflammation. This unique animal model, together with other animal models, highlights the importance of the mechanism maintaining the homeostasis in the IFN-alpha/beta system even in the absence of infection.

Animals↗
PubMed2001

Immunological memory in CBA and CBA/N mice after vaccination with Mycobacterium bovis (BCG).

In inbred CBA and CBA/N mice immunological memory was induced by subcutaneous injection of Mycobacterium bovis (BCG). Experiments with adoptive transfer of spleen T cells and ionomycin-resistant T cells (memory cells) between CBA and CBA/N mice in various combinations showed that immunological memory was not formed in CBA/N mice, but can be induced by adoptive transfer of cells from CBA mice.

Animals↗
PubMed2002

Lethal T cell immunodeficiency induced by chronic costimulation via CD27-CD70 interactions.

It has been proposed that HIV-1, in addition to directly infecting and killing CD4+ T cells, causes T cell dysfunction and T cell loss by chronic immune activation. We analyzed the effects of chronic immune activation in mice that constitutively expressed CD70, the ligand for the tumor necrosis factor receptor family member CD27, on B cells. CD70 transgenic (CD70 Tg) mice showed a progressive conversion of naive T cells into effector-memory cells, which culminated in the depletion of naive T cells from lymph nodes and spleen. T cell changes depended on continuous CD27-CD70 interactions and T cell antigen receptor stimulation. Despite this hyperactive immune system, CD70 Tg mice died aged 6-8 months from Pneumocystis carinii infection, a hallmark of T cell immunodeficiency. Thus, persistent delivery of costimulatory signals via CD27-CD70 interactions, as may occur during chronic active viral infections, can exhaust the T cell pool and is sufficient to induce lethal immunodeficiency.

Animals↗
PubMed1999

Existence of activated and memory CD4+ T cells in peripheral blood and their skin infiltration in CD8 deficiency.

CD8 deficiency is a rare primary immunodeficiency caused by the defect of a tyrosine kinase, ZAP-70, which transduces signals from the T cell receptor. We report here a case of CD8 deficiency, having CD4+ T cells with a unique phenotype. The patient's T cells did not respond to anti-CD3 stimulation in vitro, suggesting that they were naive. However, many CD4+ T cells with activated and memory phenotypes, which expressed CD45RO+, HLA-DR+ and CD25+, were present in the peripheral blood, and these cells accumulated in the perivascular area of his infiltrative erythematous skin lesions. The patient's T cells could be activated by a high concentration of phytohaemagglutinin (PHA), indicating the presence of an alternate signalling pathway which bypasses ZAP-70 and activates CD4+ T cells in vivo. The origin and role of activated CD4+ T cells in the pathogenesis involved in the skin lesions are discussed.

CD4-Positive T-Lymphocytes↗
PubMed2001

Investigation for immunodeficiency in patients with recurrent ENT infections.

Patients suffering with primary immunodeficiency frequently present to ear, nose, and throat (ENT) clinics, but the diagnosis is rarely made at this time. Early diagnosis of these patients would help to prevent morbidity and even mortality. Normal results from a simple panel of blood tests will exclude the commonest immune deficiencies. An abnormal result from these tests, or a strong suspicion despite normal initial testing, should prompt discussion with an immunologist.

Humans↗
PubMed1997

B cell memory in xid mice is long-lived despite reduced memory B cell frequency.

Brutons tyrosine kinase (Btk) deficient xid mice have a diminished primary T cell dependent immune response, resulting in a reduced memory B cell frequency. Boosting at 35 days post primary immunization, however, generates a normal secondary immune response, indicating a functional memory B cell compartment. The longevity of B cell memory appears to depend on both the presence of antigen and expression of cell survival genes such as bcl-2. Since there is a natural decay in the number of memory B cells over time and since xid B cells have been demonstrated to have reduced Bcl-2 levels, we aimed at determining whether B cell memory of xid mice would be long-lasting. This report demonstrates that memory B cell precursors are detectable in xid mice more than 100 days after primary immunization. Furthermore, a secondary immune response of normal magnitude and kinetics can be generated in xid mice at 150 days after primary immunization indicating that B cell memory is long-lived in xid mice. Thus, although survival of B cell memory is presumably dependent on immunoglobulin (Ig)-mediated interaction with antigen, this interaction does not depend solely on signalling through Btk.

Animals↗
PubMed1999

Immune surveillance against a solid tumor fails because of immunological ignorance.

Many peripheral solid tumors such as sarcomas and carcinomas express tumor-specific antigens that can serve as targets for immune effector T cells. Nevertheless, overall immune surveillance against such tumors seems relatively inefficient. We studied immune surveillance against a s.c. sarcoma expressing a characterized viral tumor antigen. Surprisingly, the tumor cells were capable of inducing a protective cytotoxic T cell response if transferred as a single-cell suspension. However, if they were transplanted as small tumor pieces, tumors readily grew. Tumor growth correlated strictly with (i) failure of tumor cells to reach the draining lymph nodes and (ii) absence of primed cytotoxic T cells. Cytotoxic T cells were not tolerant or deleted because a tumor antigen-specific cytotoxic T cell response was readily induced in lymphoid tissue by immunization with virus or with tumor cells even in the presence of large tumors. Established tumors were rejected by vaccine-induced effector T cells if effector T cells were maintained by prolonged or repetitive vaccination, but not by single-dose vaccination. Thus, in addition to several other tumor-promoting parameters, some antigenic peripheral sarcomas-and probably carcinomas-may grow not because they anergize or tolerize tumor-specific T cells, but because such tumors are immunologically dealt with as if they were in a so-called immunologically privileged site and are ignored for too long.

Animals↗
PubMed1987

Antibody-defective, genetically susceptible CBA/N mice have an altered Salmonella typhimurium-specific B cell repertoire.

CBA/N mice, which express the X-linked immunodeficiency gene xid, are susceptible to Salmonella typhimurium. The basis for this susceptibility is currently unknown. However, previous studies (10) from this laboratory have provided evidence that susceptibility may be due to a defective anti-S. typhimurium antibody response. In that report we hypothesized that the defective antibody response may be a reflection of an altered S. typhimurium-specific B cell repertoire. In the studies described here, we have investigated this hypothesis using a modification of the in vitro splenic focus system. The frequency and characteristics of salmonella-specific B cells in normal, innately resistant, CBA/Ca mice have been compared with those of salmonella-susceptible, anti-S. typhimurium antibody-defective CBA/N mice. The results show that CBA/N mice express no primary or secondary S. typhimurium-specific B cell precursors after stimulation with an acetone-killed and dried (AKD) preparation of S. typhimurium strain TML. However, after three immunizations, the CBA/N tertiary frequency of 15.4 per 10(6) splenic B cells was similar to the primary precursor frequency in immunologically normal CBA/Ca mice, but 23-fold lower than the tertiary precursor frequency in CBA/Ca control mice. Moreover, CBA/N mice had an altered isotype distribution pattern after stimulation with AKD-TML. Greater than 70% of the tertiary CBA/N TML-specific B cells secreted IgG2, in contrast to either nonimmune or primed control mice. In addition, 80% of the CBA/N TML-specific B cells secreted only a single isotype, whereas the majority of B cells from primed normal mice secreted multiple isotypes. Fine specificity analysis of the TML-specific B cells indicated that the array of antigenic determinants to which CBA/N B cells could respond was restricted. Although the majority of primed CBA/Ca and primed CBA/N B cells were specific for LPS, the fine specificity pattern exhibited by CBA/N B cells was similar to that observed in unprimed normal mice, i.e., the vast majority were specific for the O antigen region of the LPS molecule. In contrast, a major portion of the LPS-specific B cells in primed CBA/Ca mice were directed against the KDO/lipid A region of the LPS molecule. Therefore, it appears that CBA/N mice lack or are unable to stimulate the B cell subset that predominates in primed, normal mice. Taken together, these studies indicate that the basis for susceptibility of CBA/N mice to S. typhimurium is multifactorial and suggests that the inability of some animals to respond to some infectious agents may be related to holes in their B cell repertoire.

Animals↗
PubMed1991

Mature murine B and T cells transferred to SCID mice can survive indefinitely and many maintain a virgin phenotype.

To seek information on the potential lifespan of normal B and T lymphocytes, lymph node (LN) cells from unprimed mice were transferred to H-2-identical severe combined immunodeficiency (SCID) hosts. At a population level, the donor B and T cells survived for at least 10 mo post-transfer with no reduction in their numbers. In terms of antibody production, LN-injected SCID mice remained responsive to several different antigens and contained unprimed precursors of memory cells for greater than or equal to 6 mo post-transfer. Most of the B and T cells recovered from LN-injected SCID mice expressed the typical virgin phenotype of mature lymphocytes from young mice. These findings suggest that many of the transferred lymphocytes might have remained in interphase as virgin cells from the time of injection. This did not apply to all of the transferred cells, however, because 20-40% of CD4+ cells from long-term SCID hosts displayed a memory phenotype, 7% incorporated 2-bromodeoxyuridine over 5 d, and total numbers of B and T cells increased gradually (twofold) over a 10-mo period. Collectively, the data favor the view that the pool of mature B and T cells in adult mice is largely self sufficient: some of the cells proliferate, presumably in response to environmental antigens, but many mature cells can remain quiescent for prolonged periods. Input of new cells from the primary lymphoid organs continues, but at a much reduced rate relative to young life.

Animals↗
PubMed1994

MHC-unrestricted immune surveillance of leukemia.

The characteristics of natural killer (NK) cells and their role in immunosurveillance of cancer is reviewed. Evidence derived from in vitro and in vivo experiments is in favor of an important role of NK cells in host resistance to leukemia, as illustrated by studies of untreated patients, patients treated with biological response modifiers and by bone marrow transplantation.

Adult↗