Necrotizing cutaneous cryoglobulinemic vasculopathy.
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
J P Dutz
Publications and source records attributed to J P Dutz.
Lymphocytic vasculitis in X-linked lymphoproliferative disease.
Systemic vasculitis is an uncommon manifestation of X-linked lymphoproliferative disease (XLP), a disorder in which there is a selective immune deficiency to Epstein-Barr virus (EBV). The molecular basis for XLP has recently been ascribed to mutations within SLAM-associated protein (SAP), an SH2 domain-containing protein expressed primarily in T cells. The authors describe a patient who died as a result of chronic systemic vasculitis and fulfilled clinical criteria for the diagnosis of XLP. Sequencing of this patient's SAP gene uncovered a novel point mutation affecting the SH2 domain. The patient presented with virus-associated hemophagocytic syndrome (VAHS) and later had chorioretinitis, bronchiectasis, and hypogammaglobulinemia develop. He further developed mononeuritis and fatal respiratory failure. Evidence of widespread small and medium vessel vasculitis was noted at autopsy with involvement of retinal, cerebral, and coronary arteries as well as the segmental vessels of the kidneys, testes, and pancreas. Immunohistochemical analysis using antibodies to CD20, CD45RO, and CD8 revealed that the vessel wall infiltrates consisted primarily of CD8(+) T cells, implying a cytotoxic T-lymphocyte response to antigen. EBV DNA was detected by polymerase chain reaction (PCR) in arterial wall tissue microdissected from infiltrated vessels further suggesting that the CD8(+) T cells were targeting EBV antigens within the endothelium. The authors propose that functional inactivation of the SAP protein can impair the immunologic response to EBV, resulting in systemic vasculitis.
CD8 Antigens↗
The pathophysiology of photosensitivity in lupus erythematosus.
The strong association between photosensitivity and lupus erythematosus has led to the suggestion that abnormal photoreactivity participates in the pathogenesis of cutaneous lesions. In this review we discuss the evidence for abnormal cutaneous reactivity to sunlight in lupus and speculate on the cellular, molecular and genetic factors that may underlie this abnormality.
Humans↗
Neonatal beta-cell apoptosis: a trigger for autoimmune diabetes?
In neonatal rodents, the beta-cell mass undergoes a phase of remodeling that includes a wave of apoptosis. Using both mathematical modeling and histochemical detection methods, we have demonstrated that beta-cell apoptosis is significantly increased in neonates as compared with adult rats, peaking at approximately 2 weeks of age. Other tissues, including the kidney and nervous system, also exhibit neonatal waves of apoptosis, suggesting that this is a normal developmental phenomenon. We have demonstrated that increased neonatal beta-cell apoptosis is also present in animal models of autoimmune diabetes, including both the BB rat and NOD mouse. Traditionally, apoptosis has been considered a process that does not induce an immune response. However, recent studies indicate that apoptotic cells can do the following: 1) display autoreactive antigen in their surface blebs; 2) preferentially activate dendritic cells capable of priming tissue-specific cytotoxic T-cells; and 3) induce the formation of autoantibodies. These findings suggest that in some circumstances physiological apoptosis may, in fact, initiate autoimmunity. Initiation of beta-cell-directed autoimmunity in murine models appears to be fixed at approximately 15 days of age, even when diabetes onset is dramatically accelerated. Taken together, these observations have led us to hypothesize that the neonatal wave of beta-cell apoptosis is a trigger for beta-cell-directed autoimmunity.
Animals↗
Crusted scabies in association with human T-cell lymphotropic virus 1.
BACKGROUND: Human T-cell lymphotropic virus I (HTLV- 1) infection can lead to myelopathy/tropical spastic paresis and adult T-cell leukemia/lymphoma (ATLL). Infection with HTLV-1 has also been associated with clinically significant immunosuppression. Crusted scabies, also known as Norwegian scabies, is an uncommon presentation of scabies that may occur in conjunction with immunosuppression. Although crusted scabies has been reported in association with HTLV-1 infection, to our knowledge it has never been described in association with HTLV-1 associated myelopathy. OBJECTIVE: The aim is to describe a case of HTLV-1 associated myelopathy and concomitant crusted scabies. METHODS: This article includes a case report and a literature review. CONCLUSIONS: Crusted scabies is reported in association with HTLV-1 infection with or without concomitant ATLL. Crusted scabies should be considered in the differential diagnosis of a generalized cutaneous eruption in an HTLV-1 positive patient. Patients with crusted scabies from an HTLV-1 endemic population should be rested for a possible HTLV-1 infection. These patients may be at increased risk of progressing to ATLL.
Adult↗
Immunosuppressive agents in dermatology. An update.
Azathioprine, cyclophosphamide, methotrexate, and cyclosporine are the immunosuppressive agents most commonly used by dermatologists. Azathioprine has a relatively good safety profile and is therefore often preferred for the treatment of chronic eczematous dermatitides and bullous disorders. Awareness of the role of genetic polymorphisms in its metabolism can increase the efficacy and safety of this drug. Cyclophosphamide is an antimetabolite that has a more rapid onset of immunosuppressive effect than azathioprine, but has significant short-term and long-term toxicity. It is of use in fulminant, life-threatening cutaneous disease. Methotrexate is an antimetabolite that has significant anti-inflammatory activity. Despite its hepatotoxicity, its role in inflammatory dermatoses is broadening. Likewise, the role of cyclosporine is being expanded. This drug has potent T-cell inhibitory effects secondary to interference with intracellular signal transduction. Given the evidence for cumulative renal toxicity, it currently has a role in the short-term treatment of refractory psoriasis and atopic dermatitis, as well as in select inflammatory dermatoses. Familiarity with disease-specific clinical efficacy, side-effect profile, and dosage allows the successful and judicious use of these drugs in dermatologic disorders.
Azathioprine↗
A comparative study of calcipotriol and anthralin for chronic plaque psoriasis in a day care treatment center.
Eighteen patients with symmetric plaque-type psoriasis were recruited for an open, controlled, bilateral half-body comparison study to evaluate the efficacy of calcipotriol/tar/UVB vs. anthralin/tar/UVB in a day care treatment setting. No patient had been on systemic antipsoriatic agents for at least 3 months prior to enrolment. One half-body was arbitrarily assigned to treatment with gradually increasing concentrations of anthralin as tolerated. The other half-body received calcipotriol ointment twice daily. Both sides received UVB and additional coal tar distillate in accordance with our standard day care regimen. Patients who were admitted to the day care program attended the clinic for UVB, anthralin, and calcipotriol on weekdays for two consecutive weeks. Anthralin was applied to psoriatic plaques on one side in the following fashion: anthralin 0.1% with salicylic acid 3% in zinc oxide paste on days 1 and 2; anthralin 0.2% with salicylic acid 3% in zinc oxide paste on days 3-5; anthralin 1% with salicylic acid 3% in hydrophilic petrolatum for 60 min on days 8-10 to thicker lesions; and anthralin 2% with salicylic acid 3% in hydrophilic petrolatum for 60 min on day 11 to thicker lesions. On the contralateral side, calcipotriol ointment 0.05 microgram/mL (Leo Pharmaceuticals, Ajax, Ontario) was applied to lesions twice daily. No anthralin or calcipotriol was applied on weekends. All patients applied coal tar oil 50% (Doak Oil Forte, Trans CanaDerm, St-Laurent, Québec, equivalent to 5% coal tar distillate) with salicylic acid 5% in hydrophilic petrolatum to their lesions at home in the evenings and on weekends. UVB (FSX72T12 lamps, National Biologic Corporation, Twinsburg, Ohio) was administered twice daily on weekdays in increasing doses as tolerated (to erythema) prior to the application of the topical medications. No trial medications were applied to the face, scalp, or genital regions. For clinical evaluation, the standard Psoriasis Activity and Severity Index (PASI) score was modified by splitting the score for area under 10%; the modified score (mPASI) for an area of coverage of 1%-4% was 0.5 and for an area of 5%-9% was 1. The head and neck area was excluded from the analysis since neither anthralin nor calcipotriol was used at these sites. Each half-body was considered to represent 100% in the area score determination. The maximum modified score for each side was 64.8 (vs. 72 in the standard PASI scoring system). Clinical evaluations were completed at days 0 (baseline), 3, 7, 10, and 42. The primary end-point was day 10. On day 10, patients were asked to compare the calcipotriol ointment to the anthralin on a five-point scale in terms of efficacy and irritancy and to state their future preferred treatment modality. Following discharge from day care, patients were continued on outpatient UVB and tar treatments three times weekly and asked to return for a repeat clinical assessment after 4 weeks (day 42). Blood samples taken prior to treatment and at day 10 were analyzed for serum calcium. Comparisons of treatment efficacy were based on changes in the mPASI scores from onset of treatment to day 10, as well as on the corresponding percentage changes. Analyses were carried out using the Wilcoxon test. Subjective patient comparisons of effectiveness and irritancy, as well as patient preference, were tested for equiprobability using the chi-square goodness-of-fit test with an examination of the adjusted residuals.
Administration, Topical↗
CD45 enhances positive selection and is expressed at a high level in large, cycling, positively selected CD4+CD8+ thymocytes.
T-cell development is arrested at the CD4+CD8+ (DP; double-positive) stage of thymocyte development in CD45 null mice. However, the mechanism by which CD45 participates in the positive selection of T cells remains to be investigated. In this report we describe a DP thymocyte population that associates positive selection with expression of high levels of CD45, CD4 and CD8. DP thymocytes of this phenotype are large, cycling cells and represent approximately 20% of DP thymocytes in normal mice. In mice expressing a transgenic T-cell receptor (TCR) specific for the male antigen presented by H-2Db (H-Y TCR), the up-regulation of TCR, CD5 and CD69 in this large DP population occurred in a major histocompatibility complex (MHC)-restricted manner. To investigate further the role of CD45 in positive selection, we determined whether thymocytes that expressed a transgenic CD45RO molecule under the control of the proximal lck promoter can influence the positive selection of T cells in H-Y TCR transgenic mice. It was found that in female H-Y TCR transgenic mice, MHC-restricted positive selection of CD4- CD8+ H-Y TCR+ thymocytes was enhanced by increased CD45RO expression. Thus, CD45 increases the efficacy of positive selection of CD4- CD8+ thymocytes that express H-Y TCR.
Animals↗
Pathogenetic mechanisms and treatment of cutaneous lupus erythematosus.
The mechanisms of cutaneous lupus erythematosus are under active investigation, and important advances have been made. Humoral mechanisms are likely important in subacute cutaneous lupus erythematosus, the cutaneous subset most associated with the Ro antibody. Many advances have been made in understanding the various Ro epitopes and the specificities of the Ro antibody response. Lupus mice experiments have provided insight into the contributing roles of various T-cell subsets. Variations in cytokine production related to genetic polymorphisms and induction by ultraviolet light combined with alterations in selectins and adhesion molecules contribute to the accumulation of inflammatory cells in cutaneous lupus erythematosus. It is important to institute aggressive systemic therapy when there is widespread scarring disease. Antimalarial agents continue to be first-line systemic drugs, and our understanding of the use of combination antimalarial agents and proper dosing limits problems with toxicity and improves efficacy. Other therapies, including thalidomide, are helpful for patients with resistant disease.
Animals↗
Fas (CD95)-independent regulation of immune responses by antigen-specific CD4-CD8+ T cells.
Antigen-activated T cells of the CD4(+)CD8(-) phenotype are susceptible to antigen receptor-stimulated cell death. This form of apoptotic cell death has been shown to be dependent on the expression of the Fas (CD95) antigen and can occur via an autocrine mechanism involving the concomitant up-regulation of Fas and its ligand on activated T cells. Mutation in genes encoding Fas (Ipr) and the Fas ligand (gld) contribute to the development of an autoimmune syndrome similar to systemic lupus erythematosus in mice. These observations led to the suggestion that the Fas signaling pathway is an important regulator of immune responses in vivo. Here we evaluated the importance of the Fas pathway in regulating immune responses by male antigen-specific CD4(-)CD8(+) T cells. We found that the in vivo elimination of these activated cells was independent of Fas expression by these cells. However, the elimination of these activated cells was inhibited by the transgenic expression of Bcl-2, a protein that inhibits multiple forms of apoptotic cell death. The transgenic Bcl-2 protein also inhibited the death of male antigen-activated cells following IL-2 deprivation. Cell death resulting from IL-2 deprivation occurred efficiently in male antigen-activated Fas- cells. We propose that the rapid deletion of male antigen-activated Fas- cells in vivo is due to limiting amounts of IL-2 that are available in the microenvironment of the activated cells at the peak of the response.
Animals↗
Distinct differentiative stages of CD4+CD8+ thymocyte development defined by the lack of coreceptor binding in positive selection.
Cortical CD4+CD8+ thymocytes mature into CD4+ or CD8+ thymocytes through a process termed positive selection. To better define differentiative stages of CD4+CD8+ thymocyte development in positive selection, we performed a phenotypic analysis of CD4+CD8+ thymocytes from H-Y mice mated to various genetic backgrounds. We have previously shown that coordinate binding of the H-Y TCR and the CD8 coreceptor to the restricting Db MHC class I molecule is required for the efficient positive selection of this TCR. In this study we have used TCR, CD5, and CD45 expression levels as markers for thymocyte maturation. Lack of CD8/Db interaction was achieved by introducing a mutation that abrogates CD8 binding in the alpha 3 domain of Db. We found that the absence of coreceptor ligation prevented TCR up-regulation in CD4+CD8+ thymocytes and resulted in a developmental arrest characterized by low levels of TCR and CD45. We have previously shown that deletion of CD4+CD8+ thymocytes expressing the H-Y TCR is facilitated by CD8 coreceptor ligation. Here we show that expression of the deleting ligand in the absence of coreceptor ligation caused CD5 up-regulation without concomitant TCR or CD45 up-regulation in CD4+CD8+ thymocytes. In a beta 2-microglobulin null background, introduction of the H-Y TCR caused the majority of CD4+CD8+ thymocytes to express an unusually low level of of the CD5 activation marker, suggesting that a low-affinity or noncognate TCR/MHC interaction may be required for initial CD5 up-regulation to intermediate levels. Collectively, these observations favor a maturational process in positive selection in which CD5 up-regulation precedes CD45 and TCR up-regulation.
Animals↗
A mutation in the alpha 3 domain of Db that abrogates CD8 binding does not affect presentation of an immunodominant H-Y peptide.
The peptidic nature of the male (H-Y) antigen, a model minor histocompatibility antigen in H-2b mice, has recently been demonstrated. In this study we show that the H-Y peptide, which is recognized by PM-1, a Db-restricted cytotoxic T-lymphocyte (CTL) clone, is absent in male H-2d spleen cells but present in male H-2d spleen cells that also express a transgenic Db molecule under its endogenous promoter. This result indicates that both the H-Y and the Db gene products are essential and sufficient for production of the Db-restricted H-Y peptide. By comparing the ability of the PM-1 clone and bulk CTL generated in a secondary mixed lymphocyte culture to recognize H-Y peptidic material eluted from affinity-purified Db molecules and separated by reversed-phase high-performance liquid chromatography (HPLC), we provide evidence that there is an immunodominant H-Y epitope that is presented by the Db molecule. Furthermore, the presentation of this epitope is not affected by a mutation in the alpha 3 domain of Db (asp227 to lys227), which abrogates CD8 binding, since similar amounts of H-Y peptide were eluted from affinity-purified wild-type or mutant Db molecules. However, the generation of the H-Y epitope is dependent on the presence of beta 2-microglobulin, since it is absent in male H-2b mice that lack a functional beta 2-microglobulin gene. The implications of these findings on T-cell development are discussed.
Animals↗
A cytotoxic T lymphocyte clone can recognize the same naturally occurring self peptide in association with a self and nonself class I MHC protein.
The alloreactive CD8+ cytotoxic T lymphocyte (CTL) clone 2C was previously shown to recognize complexes made up of the class I MHC (MHC-I) molecule Ld and an octapeptide (LSPFPFDL, termed p2Ca) isolated from tissues of H-2d mice. Because peptide p2Ca has also been found in BALB.B (H-2b) mice, the strain from which clone 2C originated, the question arises as to whether these T cells can recognize peptide p2Ca in association with a self MHC protein of the H-2b haplotype. Here we show that 2C CTL do indeed recognize peptide p2Ca in association with Kb on the surface of H-2b cells or on transfected cells expressing Kb, but that an approximately 1000-fold higher concentration of this peptide is required to sensitize Kb+ than Ld+ target cells for lysis by 2C cells. However, the peptide's binding to Kb was not much weaker than to Ld, with only an approximately 10-fold difference in the respective equilibrium constants. These results predict that the T cell receptor (TcR) of clone 2C has a much lower intrinsic affinity for p2Ca-Kb complexes than for p2Ca-Ld complexes, and they provide some quantitative limits on the requirements for triggering T cell-mediated autoimmune reactivity.
Amino Acid Sequence↗
A role for calcineurin in degranulation of murine cytotoxic T lymphocytes.
The immunosuppressive drugs cyclosporin A (CsA) and FK506 bind to distinct families of intracellular proteins, cyclophilins, and FK506 binding proteins (FKBP) respectively, termed immunophilins. Immuno-suppressant-immunophilin complexes bind to and inhibit the activity of calcineurin, a calcium-dependent serine/threonine phosphatase. CsA is known to inhibit degranulation in CTL as assessed by N benzyloxylcarbonyl-L-lysine thiobenzyl ester-esterase release assays. We have investigated whether calcineurin phosphatase activity is involved in this degranulation. Both CsA and FK506 are shown to inhibit N benzyloxylcarbonyl-L-lysine thiobenzyl esteresterase release in murine CTL clones induced either by cognate target or by PMA and the calcium ionophore A23187. Inhibition is concentration dependent and is observed at drug concentrations that specifically inhibit cellular calcineurin. The FK506-binding immunophilin FKBP12, as well as calcineurin, are shown to be present in these cells by immunoblotting analysis. Rapamycin, a macrolide antibiotic thought to compete with FK506 for binding to common FKBP receptor sites, antagonizes the effects of FK506 on both degranulation and calcineurin activity. Neither the degranulation nor the effect of the immunosuppressants is affected by the protein synthesis inhibitor cycloheximide. These observations suggest a role for calcineurin in CTL degranulation. Thus, in addition to its previously described role in lymphokine gene activation, calcineurin also appears to be involved in T cell activation processes which do not require protein synthesis.
Animals↗
Effects of cognate peptides on cytolytic and proliferative activities of cloned cytotoxic T lymphocytes.
When a cognate peptide is added to a culture of the corresponding clone of CD8+ cytotoxic T lymphocytes (CTLs) having the appropriate major histocompatibility complex (MHC) each cell can serve as both an antigen-presenting target cell and as a responding CTL. Under these circumstances many of the cells die. The extent of cell death is greatly diminished by Ca2+ chelation (by Mg2 EGTA) and by mAbs to CD8 and to LFA-1. Cell death is also blocked by cyclosporin A and FK-506, but not by inhibitors of protein synthesis and gene transcription (cyclohexamide and actinomycin D respectively). In contrast to the stimulatory effect on cytolytic activity, proliferation of recently stimulated CTLs is profoundly inhibited by the cognate peptide, as well as by conventional target cells that are specifically recognized and lysed by the CTLs. The inhibition of proliferation is transient and is followed by enhanced DNA synthesis of surviving CTLs. Cognate peptides also elicit fragmentation of CTL DNA, and this effect is likewise decreased by cyclosporin A and FK-506. Thus the addition of a target, either in the form of a synthetic cognate peptide that associates with MHC proteins on intact CTLs or other cells, or in the form of a conventional target cell, can simultaneously stimulate cytolytic activity and inhibit the proliferative activity of mature CTLs.
Amino Acid Sequence↗
Mortality in systemic sclerosis (scleroderma).
Two hundred and thirty-seven patients with systemic sclerosis were followed prospectively in a scleroderma clinic. The overall 3, 6, and 9-year survival rates were 86, 76 and 61 per cent respectively. Renal, cardiac and pulmonary disease, and older age at enrollment were adverse prognostic factors associated with reduced survival. There were no significant differences in survival between males and females or in patients with restricted compared to those with diffuse skin thickening. Death from systemic sclerosis was most frequently due to pulmonary hypertension, with fewer than expected deaths from renal or cardiac causes. Twenty-eight per cent of deaths were due to causes unrelated to systemic sclerosis, most commonly cancer and ischaemic heart disease, and in older patients.
Coronary Disease↗
T cell receptor genes in rheumatoid arthritis.
Explore the source record for details and available documents.
Animals↗