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The allograft inflammatory factor-1 in Creutzfeldt-Jakob disease brains.

The allograft inflammatory factor-1 (AIF-1) is a 17-kDa IFN-gamma inducible Ca(2+)-binding EF-hand protein that is encoded within the HLA class III genomic region and is involved in immune dysfunction and smooth muscle cell activation. We used immunohistochemistry double labelling experiments to analyse the spatial distribution and cell-type-specific localization of AIF-1 in the brains of patients who died as a result of sporadic Creutzfeldt-Jakob disease (CJD) and neuropathologically unaltered controls. Significantly more AIF-1 immunoreactive macrophages/microglial cells and, interestingly, neurones were observed in CJD patients compared to controls. Western blotting confirmed more prominent AIF-1 immunoreactive bands of approximately 50 kDa in four CJD patients compared to three controls. Chaotropic SDS-PAGE of the recombinant AIF-1 resulted in almost complete reduction of the 50 kDa band and mass spectrometry revealed only AIF-1-specific tryptic protein fragments suggesting that trimerized AIF-1 is the predominant form in vivo. Finally, we analysed mechanisms of neuronal AIF-1 induction. Following H2O2 challenge, a model of general cell stress, we observed the gradual induction of AIF-1 and, more interestingly, release to the supernatant of SKNSH neurones. Parallel reverse transcriptase polymerase chain reaction and sequencing was used to confirm AIF-1 mRNA expression.

Adult↗

Increased frequency of HLA-DR3 and complotype SCO1 in Mexican mestizo children with amoebic abscess of the liver.

The increase of HLA-DR3 and complotype SCO1 previously found in Mexican mestizo adults with E. histolytica amoebic abscess of the liver, was also found in Mexican mestizo children of either sex with the same disease, when compared to the healthy control population (adults and/or children) of the same ethnic and socioeconomic background. This HLA and complotype pattern was not found in Mexican Mestizo patients with amoebic rectocolitis. No linkage disequilibrium was found between these and the other MHC determinants tested in this survey. Thus, HLA-DR3 and SCO1 may constitute primary, independent risk factors, not for any kind of amoebic tissue invasion (i.e. amoebic rectocolitis), but specifically for amoebic liver abscess, irrespective of age or sex. The possibility of linkage disequilibrium with other factors (i.e. the TNF family) within or close to the MHC that were not tested in this study, is discussed. Children with amoebic liver abscess revealed a significant increase in HLA-DR5, and the absence of HLA-DR6 when compared to adults with amoebic liver abscess, suggesting that at least in this ethnic group these class II HLA traits may contribute to some of the peculiarities of pediatric amoebic liver abscess as opposed to the adult version of this disease. HLA-DR3, SCO1, but also HLA-DR5 and HLA-DR6 have all been associated with certain forms of immune-dysfunction, and may thus contribute to some of the clinical and immunological features of this parasitic disease.

Adolescent↗

Differential immunological aberrations in patients with primary and secondary Sjögren's syndrome.

The aim of the present study was to analyse possible differences in immunological features between patients with primary and secondary Sjögren's syndrome (SS). Ten patients with primary SS and 10 patients with secondary SS also suffering from rheumatoid arthritis, were identified according to established criteria for SS. Ten healthy, age-matched women served as controls. The authors analysed the phenotypic characteristics of lymphocytes in peripheral blood as well as in focal inflammatory infiltrates of minor salivary gland biopsies. Functional analyses of T lymphocytes were performed after stimulation with mitogens and antigen. B cell activity was determined at the single cell level by spontaneous and mitogen induced immunoglobulin production. Serum levels of IL-4, IL-6 and IFN-gamma were also analysed. Patients with primary SS displayed a significantly higher degree of salivary gland inflammation and reduced salivary flow than did patients with secondary SS. Decreased in vitro T cell responses to antigen and mitogens were evident in both patient groups. The CD4/CD8 ratios in both peripheral blood and salivary gland lesions were significantly lower in primary SS compared with secondary SS patients. Polyclonal B cell activation, measured as the frequency of spontaneous immunoglobulin producing cells, was most prominent in primary SS, whereas a diminished response to poke-weed mitogen (PWM), a T cell dependent B cell mitogen, was more pronounced in secondary SS. The results reveal certain immunological aberrations in the whole group of patients with SS. In addition, the authors demonstrated distinct differences in immune dysfunction between patients with primary and secondary SS, indicating that they may constitute separate entities.

Adult↗

The effects of CD40 ligation on peripheral blood mononuclear cell interleukin-12 and interleukin-15 production and on monocyte CD14 surface antigen expression in human immunodeficiency virus-positive patients.

Human immunodeficiency virus (HIV) infection causes dysregulation of surface phenotype, of accessory function and of cytokine production from peripheral blood mononuclear cells (PBMCs). As CD40 ligation induces several functional activities in these cells, this stimulation may partially mimic the situation occurring in vivo during an antigen-driven immune response. The aim of this study was to measure cytokine production and immunophenotypic changes induced by CD40 stimulation of PBMCs from HIV-positive patients. Under these experimental conditions, total and heterodimeric interleukin (IL)-12 production from PBMCs was similar, while IL-10 production was increased in HIV-positive patients compared with controls. On the contrary, CD40 ligation did not induce IL-15 production by PBMCs. Surface CD14 was down-modulated, as a consequence of CD40 stimulation, on monocytes from healthy controls but not on monocytes from HIV-positive patients. These data demonstrate that some of the CD40-mediated signals are disturbed in HIV-positive patients. These disturbances may contribute to the immune dysfunction seen in HIV infection.

Adult↗

Low and nontoxic levels of ionic mercury interfere with the regulation of cell growth in the WEHI-231 B-cell lymphoma.

WEHI-231 is a mouse B-cell line, which is a well-established model for studying signal transduction in B lymphocytes, normally responding to cross-linking of the B-cell receptor (BCR) complex by the rapid upregulation of protein tyrosine kinase activity, followed by increased intracellular calcium and activation of protein kinase C. In WEHI-231, activation of protein kinase C is functionally associated with downregulation of DNA synthesis, followed by the induction of apoptosis. We have found in WEHI-231, that at low and environmentally relevant exposure levels (0.1 microM) mercury is not toxic, but still interferes with signal transduction in that it attenuates the growth inhibitory effects of BCR cross-linking. The molecular target for mercury resulting in attenuation of the BCR-mediated growth inhibitory signal is likely proximal to activation of the BCR complex, as HgCl2 had no effect on the negative growth signal generated downstream by direct activation of protein kinase C with phorbol 12-myristate 13-acetate. Treatment of WEHI-231 cells with high and toxic concentrations of Hg results in a marked increase in protein tyrosine phosphorylation in a great many proteins; whereas treatment of WEHI-231 cells with 0.1 microM mercury is not toxic. Under these conditions mercury selectively perturbed BCR-mediated protein tyrosine phosphorylation of a 75 kDa protein, without grossly affecting tyrosine phosphorylation levels of most other proteins. These data suggest that low levels of mercury, which are not toxic, may still contribute to immune dysfunction by interfering with antigen-receptor-mediated and protein-kinase-dependent signal transduction in lymphocytes.

Animals↗

Ocular toxoplasmosis: more than just what meets the eye.

Toxoplasma gondii is an intracellular parasite whose life cycle may include the man as an intermediate host. Close to a billion people are infected with this parasite worldwide. Ocular lesions may occur in up to 25% of those individuals infected. The infection may occur intra-uterus, through the placenta when the mother is infected during pregnancy. The parasite may also infect adults after the ingestion of contaminated food products, most notably meats or water. We have shown that although congenital and post-natal (acquired) infection results in similar ocular lesions, the immunological mechanisms behind the development of disease are different. On the other hand, contrary to published data obtained in mice, we were unable to find evidence that the T. gondii express superantigen activity for human lymphocytes. Our findings are important because they suggest that superantigen activity is not important as a pathological mechanism in human disease. Our data also suggest that, whereas the ocular lesion caused by infection after birth is the result of an excessive or dysfunctional immune response, the lesions caused by congenital infection may be due to a lack of an appropriate response to the parasite.

Animals↗

Multiple sclerosis in a radiosensitive family with low levels of the ATM protein.

Multiple sclerosis (MS) is a chronic neurological disease of the central nervous system (CNS) characterized by demyelination associated with progressive disability. The mechanisms underlying the pathogenesis of MS remain a mystery. The highly pleiotropic syndrome known as ataxia telangiectasia (A-T) overlaps with MS in that it also presents with demyelination in the CNS. Whether demyelination in MS or in A-T is initiated through neuronal degeneration or immune dysfunction is not yet known. However, unlike MS, the underlying cause of A-T is known to result from mutations in the A-T gene (ATM) that often result in the complete loss of ATM protein and loss/gain of function. ATM is implicated in neurological degeneration, particularly in the cerebellum, cellular apoptosis, immunodeficiency, double stranded deoxyribonucleic acid (DNA) rejoining, VDJ antibody recombination, tumour suppression, particularly T-lymphoid malignancies, signal transduction, cell-cycle control and cellular radiohypersensitivity. In this study, we describe a case of MS in a family with cellular radiosensitivity and abnormally low postinduction levels of the ATM protein. Defective DNA repair/rejoining may impact on autoimmunity.

Adult↗

Sexual dimorphism in the spontaneous recovery from spinal cord injury: a gender gap in beneficial autoimmunity?

Immune cells have been shown to contribute to spontaneous recovery from central nervous system (CNS) injury. Here we show that adult female rats and mice recover significantly better than their male littermates from incomplete spinal cord injury (ISCI). This sexual dimorphism is wiped out and recovery is worse in adult mice deprived of mature T cells. After spinal cord contusion in adult rats, functional recovery (measured by locomotor scores in an open field) was significantly worse in females treated with dihydrotestosterone prior to the injury than in placebo-treated controls, and significantly better in castrated males than in their noncastrated male littermates. Post-traumatic administration of the testosterone receptor antagonist flutamide promoted the functional recovery in adult male rats. These results, in line with the known inhibitory effect of testosterone on cell-mediated immunity, suggest that androgen-mediated immunosuppression plays a role in ISCI-related immune dysfunction and can therefore partly explain the worse outcome of ISCI in males than in female. We suggest that females, which are more prone to develop autoimmune response than males, benefit from this response in cases of CNS insults.

Androgen Antagonists↗

Pneumococcal necrotizing fasciitis in a patient with Type 2 diabetes.

Necrotizing fasciitis (NF) is a rare and often fatal soft-tissue infection involving the superficial fascial layers of the extremities, abdomen or perineum. Progression to septic shock can occur very rapidly with its associated high morbidity and mortality. NF is usually caused by beta haemolytic streptococci; less often a poly-microbial isolate is the cause. It typically occurs in patients with some degree of immune dysfunction. We present a case of severe pneumococcal necrotizing fasciitis in an obese patient with Type 2 diabetes. There was no history of trauma or evidence of diabetes-related complications. The initial presentation was with features of septic arthritis of the left knee, which subsequently progressed to NF. Differentiation from cellulitis is often difficult in the early stages. Invasive pneumococcal infections are extremely rare, with only a few reported in the literature. Moreover, our case highlights the need to consider other differential diagnoses (and to look out for complications) in patients with diabetes, especially if there is little clinical response to the initial treatment.

Adult↗

Longitudinal study of apoptosis in chronic uremic patients.

Uremia is associated with a state of immune dysfunction, increasing infection and malignancy rates. Dysregulation of homeostasis may be directly related to abnormal apoptosis regulation, a process which is crucial for the maintenance of the biologic system. Abnormal apoptosis rates (ARs) have been reported in the literature. We performed a longitudinal study over a 10-week period in three groups of uremic subjects-hemodialysis (HD), peritoneal dialysis (PD), and predialysis chronic renal failure (CRF). Our results showed that ARs were consistent over the observed period. Monocytes extracted from HD and CRF subjects had higher ARs compared to PD and controls (HD: 26.06 +/- 8.82; CRF: 26.96 +/- 12.81; PD: 14.77 +/- 5.87; C: 11.42 +/- 4.60) when placed in culture medium. The plasma of HD and CRF subjects when incubated with U937 cells had a stronger apoptogenic potential compared with PD and controls (HD: 26.08 +/- 11.39; CRF: 24.87 +/- 9.07; PD: 12.13 +/- 4.51; C: 11.69 +/- 4.02). Inflammatory markers (C-reactive protein [CRP], procalcitonin) and cytokines (interleukin [IL]-1beta, IL-2, IL-10) had a generally poor correlation except for tumor necrosis factor (TNF)-alpha (p < 0.001). The phagocytic ability of U937 cells when incubated with the various plasma demonstrated impaired response in the HD and CRF subjects (HD: 27.56 +/- 6.67; CRF: 30.24 +/- 9.08; PD: 36.55 +/- 9.80; C: 40.04 +/- 6.98). These results suggest continuous renal purification, such as in continuous ambulatory peritoneal dialysis (CAPD), may have advantages over intermittent therapies in regulating apoptosis and maintaining biologic function and homeostasis.

Adult↗

Vitamin D analogues.

The plethora of actions attributed to 1,25(OH)2D3 throughout the body have suggested potential therapeutic applications for the treatment of hyperproliferative diseases, immune dysfunction, endocrine disorders, and metabolic bone disease. However, the potent calcemic activity of the natural vitamin D hormone has precluded its use in most cases. New vitamin D analogues are under development that display greater specificity, in most cases, by retaining the therapeutic properties of 1,25(OH)2D3, but with lower calcemic activity. Two analogues have been approved for use in patients: calcipotriol (Dovonex from Leo Pharmaceuticals, Copenhagen, Denmark) for the treatment of psoriasis; and 19-nor-1,25(OH)2D2 (Zemplar from Abbott Laboratories, Abbott Park, IL) for secondary hyperparathyroidism. Many others analogues are currently being tested in preclinical and clinical trials for the treatment of various types of cancer and osteoporosis, and for immunosuppression. The selectivity of the analogues can be attributed to the combined interactions with four proteins: the vitamin D receptor (VDR), the serum vitamin D binding protein (DBP), the vitamin D-24-hydroxylase and to a newly described membrane receptor. Low DBP affinity has been shown to be responsible for the reduced calcemic actions of calcipotriol and 22-oxacalcitriol (OCT), which is being tested for secondary hyperparathyroidism. However, the low calcemic activity of other analogues, including 19-nor-1,25(OH)2D2, involves other, as yet undefined, mechanisms. Understanding of the molecular basis for the selectivity of the vitamin D analogues will allow the design of more effective and safer vitamin D compounds for the treatment of a wide range of clinical disorders.

Humans↗

Therapeutic uses of vitamin D analogues.

The vitamin D endocrine system has been implicated in numerous biological activities throughout the body. The breadth and magnitude of vitamin D activity suggest potential therapeutic applications for the treatment of several diseases and disorders, including hyperproliferative diseases, immune dysfunction, endocrine disorders, and metabolic bone diseases. However, therapy using natural vitamin D hormone, 1,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)) has been precluded in most cases because of the potent calcemic activity shown by this hormone. Newly developed vitamin D analogues with lower calcemic activity have been shown to retain many therapeutic properties of 1,25(OH)(2)D(3). Molecular studies discussed in this article provide insights into the unique target cell specificity afforded by these analogues. In particular, the importance of the nuclear vitamin D receptor (VDR), serum vitamin D-binding protein, 24-hydroxylase, and membrane receptor is noted because analogue selectivity, specificity, and potency are afforded through their molecular interactions. The nuclear VDR has been isolated from a variety of target cells and tissues, suggesting that vitamin D compounds may have therapeutic potential throughout several body systems. Five vitamin D analogues have been approved for use in patients: calcipotriol (Dovonex; Leo Pharmaceuticals, Copenhagen, Denmark) for the treatment of psoriasis, 19-nor-1,25(OH)(2)D(2) (Zemplar; Abbott Laboratories, Abbott Park, IL) for secondary hyperparathyroidism, doxercalciferol (Hectorol; Bone Care Int, Madison, WI) for reduction of elevated parathyroid hormone levels, 22-oxacalcitriol (Maxacalcitol; Chugai Pharmaceuticals, Tokyo, Japan), and alfacalcidol. Several other analogues are currently being tested in preclinical and clinical trials for the treatment of various types of cancer and osteoporosis, as well as immunosuppression. Understanding how analogues exert their selective actions may allow for the design of more effective and safer vitamin D compounds for the treatment of a wide range of clinical disorders.

Humans↗

Vaccination against infectious disease following hematopoietic stem cell transplantation.

Patients undergoing hematopoietic stem cell transplantation (HSCT) experience a prolonged period of dysfunctional immunity associated with an increased risk of bacterial and viral infections. Effective approaches toward vaccinating patients against common pathogens are being explored but are limited by poor levels of responsiveness. Relevant studies examining the nature of reconstitution of cellular and humoral immunity and its impact on vaccination strategies against infectious pathogens are reviewed. Following transplantation, deficiencies in cellular immunity are characterized by the inversion of CD4/CD8 ratios, a decreased proliferative response to mitogens, and the development of anergy to recall antigens as measured by delayed-type hypersensitivity testing. The impact on humoral immunity consists of decreased levels of circulating immunoglobulin, impaired immunoglobulin class switching, and a loss of complexity in immunoglobulin gene rearrangement patterns. In this setting, a loss of protective immunity has been demonstrated against viral and bacterial pathogens previously targeted by childhood vaccination. Infections due to encapsulated bacterial organisms such as Streptococcus pneumoniae and Haemophilus influenzae type B remain prevalent even in the late posttransplantation period. The efficacy of vaccination following HSCT is influenced by the time elapsed since transplantation, the nature of the hematopoietic graft, the use of serial immunization, and the presence of graft-versus-host disease. Strategies to enhance vaccine efficacy include pretransplantation immunization of the stem cell donor and the use of cytokine adjuvants.

B-Lymphocytes↗

The impact of human herpesvirus-6 and -7 infection on the outcome of liver transplantation.

Human herpesvirus (HHV)-6 and -7 are novel members of the beta-herpesvirus family that maintain latency in the human host after primary infection. Reactivation from latency and/or increased degree of viral replication occurs during periods of immune dysfunction. The clinical effect of HHV-6 and HHV-7 reactivation in recipients of liver transplants is now being recognized. Clinical illnesses such as fever, rash, pneumonitis, encephalitis, hepatitis, and myelosuppression have been described in a number of anecdotal reports. Moreover, a growing body of evidence suggests that the more important effect of HHV-6 and HHV-7 reactivation on the outcomes of liver transplantation may be mediated indirectly by their interactions with the other beta-herpesvirus-cytomegalovirus (CMV). Coinfection among these three beta-herpesviruses in clinical syndromes that were classically ascribed to be solely caused by CMV has been shown and has raised substantial interest in the potential role of HHV-6 and HHV-7 as copathogens in the direct and indirect illnesses caused by CMV. This article reviews the current scientific data on the role and the magnitude of impact of HHV-6 and HHV-7 infection on the outcomes of liver transplantation.

Herpesvirus 6, Human↗

Neurology of systemic autoimmune disorders: a pediatric perspective.

Autoimmune disorders can involve patients of any age and organs of any organ system. The central and peripheral nervous systems are frequently among the targets of these diseases. Immune dysfunction often presents in childhood or adolescence. Among the autoimmune disorders that present during childhood and adolescence, systemic lupus erythematosus, dermatomyositis, and Behcet's disease affect the nervous system with some degree of frequency. Furthermore, although juvenile rheumatoid arthritis only rarely affects the nervous system during childhood, it and its adult-onset counterpart may have profound long-term neurological consequences. Both symptomatic and pathophysiologically aimed therapies are important in the treatment of the nervous system sequelae of systemic autoimmune disorders.

Arthritis, Rheumatoid↗

Oncologic emergencies.

Cancer can lead to emergencies either due to the primary disease, or as a result of therapy. Appropriate diagnosis and rapid treatment of these conditions can result in survival of the patient. Whether chemotherapy is implemented or not, the clinician may be presented with a patient in need of emergency stabilization. Common occurring emergencies are related to effects of the cancer, ranging from immune dysfunction due to marrow infiltration to brain herniation due to increased intracranial pressure from neoplasia. Often adverse effects secondary to chemotherapy can cause emergency situations such as sepsis. Prompt diagnosis and treatment may result in a favorable outcome. Addressed in this chapter are commonly occurring emergencies and specific stabilizing treatments.

Animals↗

Controversies in the treatment of pediatric immune thrombocytopenias.

Although pediatric immune thrombocytopenia (ITP) is common, there is no consensus on the optimal approach to therapy. Childhood ITP differs in its clinical course and trigger from adult immune thrombocytopenic purpura. There appear to be two clinical phenotypes among children with ITP: children with polyclonal autoantibody production triggered by an external exposure such as infection, and children with coexistent immune deficiency or dysregulation on a congenital or acquired basis. Treatment implications exist for each group. The first may be best managed by observation and conservative measures; for the latter, treatment could include normal intravenous gammaglobulin concentrate, anti-blood group D antigen (anti-Rh factor), or steroids. Early recognition of the thrombocytopenic child with immune dysfunction versus the normal child with a polyclonal response to a particular environmental antigen will result in better prognosis for both by selecting the appropriate therapy and minimizing long-term side effects.

Child↗

The ratio of 2nd to 4th digit length: a new predictor of disease predisposition?

The ratio between the length of the 2nd and 4th digits is: (a) fixed in utero; (b) lower in men than in women; (c) negatively related to testosterone and sperm counts; and (d) positively related to oestrogen concentrations. Prenatal levels of testosterone and oestrogen have been implicated in infertility, autism, dyslexia, migraine, stammering, immune dysfunction, myocardial infarction and breast cancer. We suggest that 2D:4D ratio is predictive of these diseases and may be used in diagnosis, prognosis and in early life-style interventions which may delay the onset of disease or facilitate its early detection.

Disease↗