Biomedical subjects

Michael Kurrer

Publications and source records attributed to Michael Kurrer.

12 recordsLinked to original sources

PubMed2006

IL-21 receptor signaling is integral to the development of Th2 effector responses in vivo.

Interleukin 21 (IL-21) is a member of the common gamma-chain family of cytokines, which influence a broad spectrum of immunologic responses. A number of studies have examined the function of IL-21, but its specific role in Th1/Th2-cell differentiation and related effector responses remains to be clarified. Thus, we generated IL-21R-deficient mice and have investigated the role of IL-21R signaling using a series of in vivo experimentally induced disease models. We first addressed the role of IL-21R signaling in Th2 immune responses by examining allergic airway inflammation, and Nippostrongylus brasiliensis and Heligmosomoides polygyrus antihelminth responses. In each of these systems, IL-21R signaling played a clear role in the development of Th2 responses. Comparatively, IL-21R signaling was not required for the containment of Leishmania major infection or the development of experimental autoimmune myocarditis, indicative of competent Th1 and Th17 responses, respectively. Adoptive transfer of T cells and analysis of IL-21R+/+/IL-21R-/- chimera mice revealed that IL-21R-signaling was central to Th2-cell survival or migration to peripheral tissues. Overall, our data show IL-21 plays a crucial role in supporting polarized Th2 responses in vivo, while appearing superfluous for Th1 and Th17 responses.

Animals↗

PubMed2006

The osteopontin - CD44 pathway is superfluous for the development of autoimmune myocarditis.

Osteopontin (OPN) and CD44 have been implicated in the development of autoimmune diseases, including arthritis and multiple sclerosis, as well as chronic inflammatory diseases, such as atherosclerosis and colitis. To investigate their roles in autoimmune myocarditis induced by immunization with heart alpha-myosin (MyHC-alpha), a mouse model of human cardiomyopathy, we analyzed mice lacking OPN or CD44v6/v7, a CD44 isoform that binds OPN. Both, OPN(-/-) and CD44v6/v7(-/-) mice developed myocarditis with the same prevalence and severity as BALB/c wild-type controls. Furthermore, treatment of BALB/c mice with a pan-neutralizing anti-CD44 antibody did not affect the disease outcome. Consistently, expansion of MyHC-alpha-specific autoimmune CD4(+) T cells and MyHC-alpha autoantibody responses from either CD44v6/v7(-/-) mice or OPN(-/-) mice was indistinguishable from their wild-type controls. Thus, OPN and CD44v6/v7 are merely spectators rather than protagonists in autoimmune myocarditis.

Animals↗

PubMed2006

Potential predictive patterns of minimal residual disease detected by immunohistochemistry on bone marrow biopsy specimens during a long-term follow-up in patients treated with cladribine for hairy cell leukemia.

CONTEXT: Minimal residual disease (MRD) in patients treated for hairy cell (HC) leukemia as assessed by immunohistochemistry has not been included routinely in evaluation of treatment results. OBJECTIVE: To assess the presence of persistent HCs after treatment, as detected by immunohistochemistry, and to evaluate the correlation between the level of MRD and clinical outcome. DESIGN: Percentages of DBA.44-positive HCs were assessed on 116 biopsy specimens from 17 patients. The patients had a median follow-up of 55.4 months. RESULTS: Minimal residual disease was seen in 3 patterns. Group 1 (7 patients) had MRD levels ranging from "rare scattered suspicious HCs" to less than 1%. The MRD levels were stable throughout follow-up, and all patients remained in complete remission. Group 2 (6 patients) had MRD levels ranging from 1% to 5%, and 3 patients were in complete remission at 77.9, 63.8, and 108.0 months. Another patient showed evidence of disease activity (partial remission) at 47.6 months. Two other patients relapsed at 12.3 months and at 25.7 months, respectively, with greater than 1% HCs. Group 3 (4 patients) had MRD levels greater than 5%. Three patients relapsed at 11.3, 12.1, and 29.6 months, respectively, with greater than 5% HCs. The fourth patient had MRD levels of 5% at 14.6 months and 2% at 20.0 months but was subsequently lost to follow-up. CONCLUSIONS: Quantitative assessment of MRD may be of value in identifying patients at risk for relapse of hairy cell leukemia.

Antineoplastic Agents↗

PubMed2005

WHO-EORTC classification for cutaneous lymphomas.

Primary cutaneous lymphomas are currently classified by the European Organization for Research and Treatment of Cancer (EORTC) classification or the World Health Organization (WHO) classification, but both systems have shortcomings. In particular, differences in the classification of cutaneous T-cell lymphomas other than mycosis fungoides, Sezary syndrome, and the group of primary cutaneous CD30+ lymphoproliferative disorders and the classification and terminology of different types of cutaneous B-cell lymphomas have resulted in considerable debate and confusion. During recent consensus meetings representatives of both systems reached agreement on a new classification, which is now called the WHO-EORTC classification. In this paper we describe the characteristic features of the different primary cutaneous lymphomas and other hematologic neoplasms frequently presenting in the skin, and discuss differences with the previous classification schemes. In addition, the relative frequency and survival data of 1905 patients with primary cutaneous lymphomas derived from Dutch and Austrian registries for primary cutaneous lymphomas are presented to illustrate the clinical significance of this new classification.

Humans↗

PubMed2005

Quantification and characterization of myosin peptide-specific CD4+ T cells in autoimmune myocarditis.

Characterization of autoantigen-specific CD4+ T cells at the single cell level is crucial for understanding the immunopathological mechanisms underlying autoimmune diseases. Cardiac myosin heavy chain (myhca) is the major autoantigen associated with autoimmune myocarditis both in humans and in experimental autoimmune myocarditis (EAM) in mice. In the current study, we evaluated two methods for the enumeration and phenotypic characterization of myhca-specific CD4+ T cells during the course of EAM. Both enzyme-linked immunospot (ELISPOT) and cytokine flow cytometry (CFC) assays were suitable for the detection and characterization of myhca-specific Th cells during acute myocardial inflammation and the late healing phase of the disease. Cytokine production of myhca-specific Th cells was restricted to interferon-gamma (IFNgamma). Only trace amounts of the Th2 cytokines IL-4 and IL-5 could be detected. Concomitant surface marker analysis in the CFC assay revealed the prototypical effector phenotype of myhca-specific Th1 cells during the acute phase of the disease. Taken together, the combination of both methods appears to be most appropriate for a comprehensive ex vivo single cell analysis of Th cells in heart-specific autoimmune disorders.

Animals↗

PubMed2005

WHO/EORTC classification of cutaneous lymphomas 2005: histological and molecular aspects.

UNLABELLED: The new WHO/EORTC classification for cutaneous lymphomas comprises mature T-cell and natural killer (NK)-cell neoplasms, mature B-cell neoplasms, and immature hematopoietic malignancies. It reflects the unique features of lymphoproliferative diseases of the skin, and at the same time it is as compatible as possible with the concepts underlying the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. This article reviews the histological, phenotypical, and molecular genetic features of the various nosological entities included in this new classification. These findings always have to be interpreted in the context of the clinical features and biologic behavior. AIM: To review the histological, phenotypical and molecular genetic features of the various nosological entities of the new WHO/EORTC classification for cutaneous lymphomas. METHODS: Extensive review of the literature cited in Medline and own data of the authors. RESULTS: The WHO/EORTC classification of cutaneous lymphomas comprises mature T-cell and NK-cell neoplasms, mature B-cell neoplasms and immature hematopoietic malignancies. It reflects the unique features of primary cutaneous lymphoproliferative diseases. CONCLUSION: This classification is as much as possible compatible with the concept of the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. The histological, phenotypical and molecular genetic features always have to be interpreted in the context of the clinical features and biologic behavior.

Europe↗

PubMed2005

Soluble hemoglobin-haptoglobin scavenger receptor CD163 as a lineage-specific marker in the reactive hemophagocytic syndrome.

Reactive hemophagocytic syndrome (RHS) is a disease of overwhelming macrophage activity triggered by infection, malignancy or autoimmune disorders. Currently used laboratory markers for the quantitative assessment of monocyte/macrophage activation lack lineage-restricted expression patterns and thus specificity. Serum levels of the macrophage specific scavenger receptor CD163 were determined by enzyme-linked immunosorbent assay (ELISA) and were found to be highly increased in patients with RHS (median 39.0 mg/L). Significantly lower levels were determined in patients with sepsis (median 9.1 mg/L), acute mononucleosis (median 8.2 mg/L), Leishmania infection (median 6.7 mg/L) and healthy controls (median 1.8 mg/L). Follow-up of patients with a relapsing course of the disease revealed close correlations of sCD163 with clinical disease activity, serum ferritin and other markers of macrophage activity. Large sinusoidal accumulations of CD163 expressing macrophages actively engaged in phagocytosis of blood cells were detected in spleen sections of RHS patients. Our data suggests sCD163 to be a macrophage-specific marker in patients with disorders of inappropriate macrophage activation.

Adolescent↗

PubMed2005

Interleukin-1 is responsible for acute lung immunopathology but increases survival of respiratory influenza virus infection.

Interleukin-1alpha (IL-1alpha) and IL-1beta are proinflammatory cytokines, which induce a plethora of genes and activities by binding to the type 1 IL-1 receptor (IL-1R1). We have investigated the role of IL-1 during pulmonary antiviral immune responses in IL-1R1(-/-) mice infected with influenza virus. IL-1R1(-/-) mice showed markedly reduced inflammatory pathology in the lung, primarily due to impaired neutrophil recruitment. Activation of CD4(+) T cells in secondary lymphoid organs and subsequent migration to the lung were impaired in the absence of IL-1R1. In contrast, activation of virus-specific cytotoxic T lymphocytes and killing of virus-infected cells in the lung were intact. Influenza virus-specific immunoglobulin G (IgG) and IgA antibody responses were intact, while the IgM response was markedly reduced in both serum and mucosal sites in IL-1R1(-/-) mice. We found significantly increased mortality in the absence of IL-1R1; however, lung viral titers were only moderately increased. Our results demonstrate that IL-1alpha/beta mediate acute pulmonary inflammatory pathology while enhancing survival during influenza virus infection. IL-1alpha/beta appear not to influence killing of virus-infected cells but to enhance IgM antibody responses and recruitment of CD4(+) T cells to the site of infection.

Animals↗

PubMed2004

Requirement of JNK2 for scavenger receptor A-mediated foam cell formation in atherogenesis.

In vitro studies suggest a role for c-Jun N-terminal kinases (JNKs) in proatherogenic cellular processes. We show that atherosclerosis-prone ApoE-/- mice simultaneously lacking JNK2 (ApoE-/- JNK2-/- mice), but not ApoE-/- JNK1-/- mice, developed less atherosclerosis than do ApoE-/- mice. Pharmacological inhibition of JNK activity efficiently reduced plaque formation. Macrophages lacking JNK2 displayed suppressed foam cell formation caused by defective uptake and degradation of modified lipoproteins and showed increased amounts of the modified lipoprotein-binding and -internalizing scavenger receptor A (SR-A), whose phosphorylation was markedly decreased. Macrophage-restricted deletion of JNK2 was sufficient to decrease atherogenesis. Thus, JNK2-dependent phosphorylation of SR-A promotes uptake of lipids in macrophages, thereby regulating foam cell formation, a critical step in atherogenesis.

Animals↗

PubMed2003

The IL-1 receptor 1 is critical for Th2 cell type airway immune responses in a mild but not in a more severe asthma model.

IL-1 alpha and IL-1 beta are potent pro-inflammatory cytokines that regulate many physiological systems by binding and signaling to the same receptor termed IL-1 receptor type 1 (IL-1R1). We have investigated the role of IL-1 for pulmonary immune responses in models of allergic asthma using IL-1R1-deficient (IL-1R1(-/-)) mice. In a model of mild asthma, based on repeated sensitization of mice with low doses of ovalbumin in the absence of any adjuvant and multiple intranasal challenges, the pulmonary eosinophilic inflammation and goblet cell hyperplasia were strongly reduced in IL-1R1(-/-) as compared to control BALB/c mice. Moreover, priming of CD4(+) T cells in bronchial lymph nodes and their recruitment to the lung was affected in IL-1R1(-/-) mice associated with impaired antibody responses including IgG, IgE, and IgA. In contrast, sensitization of mice in the presence of alum adjuvant, a more severe asthma model, rendered the IL-1 pathway dispensable for the development of pulmonary allergic Th2 responses, as eosinophilic inflammation, antibody responses, and CD4(+) T cell priming in lymph nodes were comparable between IL-1R1(-/-) and wild-type mice. These results suggest a critical role of IL-1/IL-1R1 for development of allergic Th2 responses, but its requirement can be overcome by using alum as adjuvant for sensitization.

Animals↗

PubMed2003

Autoimmunity seen through the SEREX-scope.

Autoantibodies can be detected in autoimmune diseases with a long prodromal phase and may serve as early indicators of disease activity. Autoantibody-based screening methods are therefore potent tools for the identification of target antigens. The SEREX method (serological identification of antigens by recombinant expression cloning) has been developed for the serological definition of immunogenic tumor antigens. Recent studies indicate that the SEREX approach may also be utilized for the analysis of complex immune responses involved in autoimmune diseases.

Animals↗

PubMed2003

Endogenous deoxyribonucleic Acid (DNA) damage in human tissues: a comparison of ethenobases with aldehydic DNA lesions.

Two types of endogenous DNA lesions, ethenobases [1,N(6)-ethenoadenine (epsilonA), 3,N(4)-ethenocytosine (epsilonC)] and aldehydic DNA lesions (ADLs), were measured in several tissues (liver, lung, kidney, colon, colon mucosa, cerebellum, and gray and white matter of the cerebrum) obtained postmortem during autopsy examinations of 12 individuals (6 males, 6 females; ages, 58-87 years). Issues relating to changes in levels of DNA damage with disease and after death were addressed. The extent of DNA damage in autopsy samples was not associated with the length of the postmortem interval and was similar to levels observed in surgery samples, suggesting that endogenous, steady-state levels of etheno adducts and of ADLs are relatively stable during the hours immediately after death. In this limited series of samples, and with a few possible exceptions, the disease status before death was not associated with increased endogenous DNA damage in the affected tissue. DNA ethenobases were lowest in the cerebellum (median molar ratios: epsilonA/A = 1.0 x 10(-8); epsilonC/C = 1.9 x 10(-8)) and highest in the gray matter (epsilonA/A = 2.9 x 10(-8); epsilonC/C = 4.8 x 10(-8)) and white matter (epsilonA/A = 2.4 x 10(-8); epsilonC/C = 5.2 x 10(-8)) of the cerebrum. In other tissues, median values were 1.2-1.9 x 10(-8) for epsilonA/A and 2.0-3.3 x 10(-8) for epsilonC/C. There was a good correlation between the levels of epsilonA and epsilonC (r = 0.80, P < 0.0001). Levels of ADLs were similar in the liver, lung, kidney, and white matter of the cerebrum (median values: 5.7-7.9 ADLs/10(6) nucleotides), higher in the colon (11.3 x 10(-6)) and gray matter of the cerebrum (9.0 x 10(-6)) and lower in the cerebellum (3.7 x 10(-6)). There was no correlation between levels of ethenobases and amounts of ADLs (epsilonA versus ADLs: r = 0.12, P = 0.33; epsilonC versus ADLs: r = 0.024, P = 0.85). Although there was an interindividual variability in the extent of endogenous DNA damage (4-fold for epsilonA and epsilonC, 2-fold for ADLs), which may be determined, in part, by the capacity to repair DNA and may be related to the pathology or treatment of the patients, these results suggest that the cerebrum contains higher endogenous DNA damage than the other tissues. These data are in line with previous studies showing that brain tissues are more susceptible to oxidative stress and lipid peroxidation than other tissues.

Aged↗