T Cell Response After SARS-CoV-2 Vaccination in Immunocompromised Patients with Inflammatory Bowel Disease.

BACKGROUND: Vaccination is a promising strategy to protect vulnerable groups like immunocompromised inflammatory bowel disease [IBD] patients from an infection with SARS-CoV-2. These patients may have lower immune responses. Little is known about the cellular and humoral immune response after a SARS-CoV-2 vaccination in IBD patients. METHODS: Totals of 28 patients with IBD and 27 age- and sex-matched healthy controls were recruited at Jena University Hospital. Blood samples were taken before, after the first, and in a subgroup of 11 patients after second dose of a SARS-CoV-2 vaccination. Cellular immune response, including IFN-γ and TNF-α response and antibody titres, were analysed. RESULTS: Overall, 71.4% of the IBD patients and 85.2% of the controls showed levels of anti-SARS-CoV-2 antibodies above the cutoff of 33.8 BAU/ml [p = 0.329] after the first dose. Even in the absence of SARS-CoV-2 antibodies, IBD patients showed significant T cell responses after first SARS-CoV-2 vaccination compared with healthy controls, which was not influenced by different immunosuppressive regimens. Associated with the vaccination, we could also detect a slight increase of the TNF production among SARS-CoV-2-reactive TH cells in healthy donorsn [HD] and IBD patients. After the second dose of vaccination, in IBD patients a further increase of humoral immune response in all but one patient was observed. CONCLUSIONS: Already after the first dose of a SARS-CoV-2 vaccination, cellular immune response in IBD patients is comparable to controls, indicating a similar efficacy. However, close monitoring of long-term immunity in these patients should be considered.

[Research consortium Neuroimmunology and pain in the research network musculoskeletal diseases]. / Forschungsverbund Neuroimmunologie und Schmerz (Neuroimpa) im Forschungsnetz Muskuloskelettale Erkrankungen.

BACKGROUND: The research consortium Neuroimmunology and Pain (Neuroimpa) explores the importance of the relationships between the immune system and the nervous system in musculoskeletal diseases for the generation of pain and for the course of fracture healing and arthritis. MATERIAL AND METHODS: The spectrum of methods includes analyses at the single cell level, in vivo models of arthritis and fracture healing, imaging studies on brain function in animals and humans and analysis of data from patients. RESULTS: Proinflammatory cytokines significantly contribute to the generation of joint pain through neuronal cytokine receptors. Immune cells release opioid peptides which activate opioid receptors at peripheral nociceptors and thereby evoke hypoalgesia. The formation of new bone after fractures is significantly supported by the nervous system. The sympathetic nervous system promotes the development of immune-mediated arthritis. The studies show a significant analgesic potential of the neutralization of proinflammatory cytokines and of opioids which selectively inhibit peripheral neurons. Furthermore, they show that the modulation of neuronal mechanisms can beneficially influence the course of musculoskeletal diseases. DISCUSSION: Interventions in the interactions between the immune system and the nervous system hold a great therapeutic potential for the treatment of musculoskeletal diseases and pain.

Bacterial load of conditioned pressure ulcers is not a predictor for early flap failure in spinal cord injury.

OBJECTIVES: Pressure ulcers impose a major lifetime medical problem to patients with high-grade spinal cord injury (SCI). For patients with stages 3-4 pressure ulcers, plastic surgery is often the only remaining treatment option. Despite considerable flap failure rates of around 30%, only sparse knowledge exists on predictors for flap failure. Hence, identification of predictors for flap failures is needed. METHODS: We prospectively enrolled 38 SCI patients with stages 3-4 pressure ulcers scheduled for plastic surgery. Preoperative wound swabs, intraoperative tissue samples and postoperative drainage liquids were microbiologically analyzed. In multivariable logistic regression analyses, bacterial loads of deep tissue cultures of intraoperative samples as well as other clinical variables were analyzed with respect to the prediction of flap failures. RESULTS: The flap failure rate was 27.5%. Bacterial loads of deep tissue cultures were not predictive for flap failure, neither was the colonization with a specific bacterial strain. We observed a considerable fluctuation of microbiological environment from initial swab cultures, intraoperative samples and postoperative drainage fluids. Antibioprophylaxis was sufficient in only 75% of deep tissue cultures and 69% of drainage fluids. Insufficient antibioprophylaxis was associated with a higher flap failure rates (odds ratio 6.3, confidence interval 1.2-41.0). CONCLUSION: After inpatient wound conditioning, bacterial load analysis of intraoperative wound tissue cultures is ineffective in order to predict flap failure rates in SCI patients with stages 3-4 pressure ulcers after flap surgery. Instead, insufficient antibioprophylaxis might be a factor contributing to flap failure.

[Regulatory T cells and rheumatic diseases]. / Regulatorische T-Zellen und rheumatische Erkrankungen.

BACKGROUND: Regulatory T cells (Treg) are crucial for the maintenance of immunological peripheral tolerance by controlling the activation and expansion of autoreactive cells; therefore, they make a decisive contribution to the prevention and control of autoimmune diseases. OBJECTIVES: The aims of this article are to summarize the history and role of Treg in science and medicine, to provide a brief introduction to the development and function, to explain how failures in Treg biology contribute to the development of autoimmune disease, to explain their specific role in particular rheumatic diseases and to provide an introduction to the therapeutic use of Treg in autoimmune diseases. METHODS: Relevant original literature and review articles were analyzed and the results are summarized in this article. RESULTS: Disorders in Treg biology can contribute to the development of rheumatic diseases in various ways. In addition, their capability to suppress autoimmunity renders Treg an attractive target for the treatment of rheumatic diseases. CONCLUSIONS: The concept of Treg-mediated immunoregulation has evolved into an independent field of research in immunology and medicine. First translational approaches and clinical studies confirmed the therapeutic efficacy of Treg in the treatment of autoimmune syndromes.

Tim-3 is differently expressed in genetically susceptible C57BL/6 and resistant BALB/c mice during oral infection with Toxoplasma gondii.

Tim-3 has opposing roles in innate and adaptive immunities. It not only dampens CD4+ and CD8+ T cells responses but also enhances the ability of macrophages to eliminate intracellular pathogens. After peroral infection with 100 cysts of Toxoplasma gondii genetically susceptible C57BL/6 mice develop an unchecked Th1 response associated with the development of small intestinal immunopathology. Here we report that upon infection with T. gondii, both susceptible C57BL/6 and resistant BALB/c mice exhibit increased frequencies of Tim-3+ cells in spleens and mesenteric lymph nodes. The number of Tim-3+ cells was significantly higher in C57BL/6 than in BALB/c mice. Tim-3 was expressed by macrophages, dendritic, natural killer, as well as CD4+ and CD8+ T cells. Highest frequencies of Tim-3+ cells were observed at the peak of Th1 responses (day 7 post infection) concurrent with the development of ileal immunopathology. Infected Tim-3-deficient BALB/c mice did not develop ileal immunopathology nor did their parasite loads differ from those in wildtype BALB/c mice. Thus, although Tim-3 is markedly upregulated upon infection and differentially regulated in susceptible and resistant mice upon infection with T. gondii, the absence of Tim-3 is not sufficient to overcome the genetic resistance of BALB/c mice to the development of Th1-driven small intestinal immunopathology.

Spinal cord injury: association with axonal peripheral neuropathy in severely paralysed limbs.

BACKGROUND AND PURPOSE: Pressure sores are a major health problem in spinal cord injury (SCI). In this population pressure damage to peripheral nerves was not thoroughly investigated so far. However, intact peripheral nerves and innervated muscles are a prerequisite for the effectiveness of supportive therapies like functional electrical stimulation (FES). METHODS: We assessed electroneurographic (ENG) data of lower limbs in SCI individuals admitted to our hospital due to severe pressure sores. Our centers prospectively acquired ENG data of the European Multicenter study about SCI (EMSCI) patients served as early control. RESULTS: In the pressure sore cohort (n = 15) all patients were sensory-motor complete (American Spinal Cord Injury Association Impairment Scale A). Most patients (10/15) suffered from a severe axonal sensory-motor polyneuropathy in paralysed legs with absent compound muscle action potentials (CMAPs) of tibial/peroneal nerves as well as absent sensory nerve action potentials of sural nerves. The onset of this polyneuropathy dates within the first year after incident SCI and was mainly associated with increasing sensory-motor completeness as demonstrated by a significant CMAP drop of our centers EMSCI-ENG data on serial tibial nerve recordings in 275 patients. CONCLUSIONS: Severe SCI is associated with an early-onset axonal polyneuropathy in paralysed limbs to which pressure damage might contribute. Because intact peripheral nerves are required for: (i) maintenance of motor function in centrally impaired muscles; and (ii) effectiveness of supportive therapies like FES, ENG-monitoring could serve as a low invasive screening method for peripheral nerve integrity in patients with SCI to initiate pressure relief procedures early enough.

[Bad memories: understanding and removal of pathogenic consequences of immunological memory in inflammatory rheumatic diseases. The IMPAM consortium]. / Schlechte Erinnerungen: pathogene Konsequenzen des immunologischen Gedächtnisses bei entzündlich rheumatischen Erkrankungen verstehen und beseitigen. Das IMPAM-Konsortium.

The Research Consortium IMPAM (IMprinting of the PAthogenic Memory for rheumatic inflammation) has recently been funded by the Federal Ministry of Education and Research in Germany. Within this consortium ten different research groups, coordinated by the German Rheumatism Research Center (DRFZ) and the University Hospital Jena, will examine the molecular dialogue between immune system memory cells and mesenchymal cells in chronic rheumatic diseases, such as rheumatoid arthritis or ankylosing spondylitis. The consortium's aim is to understand and modulate these interactions therapeutically, such that the pathogenic imprinting of proinflammatory memory cells can be extinguished and the anti-inflammatory capacity of the patients' regulatory cells can be restored.

[Osteoimmunology - IMMUNOBONE - Understanding the interaction between bone and immune system]. / Osteoimmunologie - IMMUNOBONE - Das Wechselspiel zwischen Knochen und Immunsystem verstehen. Schwerpunktprogramm 1468.

The special program "Osteoimmunology" under the leadership of the Universities of Erlangen, Jena, Gießen and Münster, is investigating in 27 projects clarification approaches on the causes of inflammatory rheumatic diseases, such as rheumatoid arthritis and ankylosing spondylitis with the aim of developing new forms of treatment. The molecular mechanisms involved in bone damage and the interaction between the immune system and bone and cartilage are topics of research.

Lack of IL-4 receptor expression on T helper cells reduces T helper 2 cell polyfunctionality and confers resistance in allergic bronchopulmonary mycosis.

T helper (Th)1 and Th2 cells play decisive roles in the regulation of resistance vs. susceptibility to pulmonary cryptococcosis. To study the function of interleukin (IL)-4 receptor (IL-4R) on Th cells in pulmonary cryptococcosis, we infected mice specifically lacking IL-4Rα on CD4(+) T cells (Lck(Cre)IL-4Rα(-/lox) mice) and IL-4Rα(-/lox) controls. Lck(Cre)IL-4Rα(-/lox) mice developed enhanced resistance accompanied by reduced pulmonary allergic inflammation and diminished production of the Th2 cytokines IL-4, IL-5, and IL-13 as compared with IL-4Rα(-/lox) mice. Polyfunctional antigen-specific Th2 cells producing simultaneously two or three Th2 cytokines were reduced in infected Lck(Cre)IL-4Rα(-/lox) mice, pointing to a critical role of polyfunctional Th2 cells for disease progression. Reduced Th2 polyfunctionality was associated with fewer pulmonary alternatively activated macrophages. This work is the first direct evidence for a critical contribution of the IL-4R on Th cells to Th2-dependent susceptibility during allergic bronchopulmonary mycosis. Moreover, the data demonstrate that the quality of the Th2 response has an impact on type 2 inflammation. The analysis of polyfunctional Th2 cells may be useful for monitoring the course of the disease.

[Th1, Th17 and Th1+17 cells]. / Th1-, Th17- und Th1+17-Zellen.

T helper cells contribute to the induction and maintenance of rheumatic inflammation through the secretion of cytokines. The analysis of Th1 cells expressing interferon-γ, Th17 cells expressing interleukin-17 and the newly described Th1+17 cells could give insight into the pathophysiological mechanisms of rheumatic diseases. This could lead to the development of novel, targeted therapeutic strategies.

[Intestinal microbiota as regulator of the immune system]. / Darmflora als Regulator des Immunsystems.

The intestinal microbiota contributes to the regulation of the intestinal immune system and protection against intestinal infections. Recent studies revealed that the locally restricted intestinal microbiota affects systemic immunity and influences the induction of autoimmunity.

[Biologics. Magic bullets - magic effects - magic costs? New therapeutics and their effects]. / Biologika. Magic bullets - magic effects - magic costs? Neue Therapien und ihre (Aus-)Wirkungen.

Biologics and especially therapeutic monoclonal antibodies have an ever increasing impact in the therapy of inflammatory and malignant diseases. They allow a selective blockade of cytokines, receptors and other molecules. This review summarizes the immunological background, the current state and future trends in the development of these therapeutic agents.

Histamine modulates γδ-T lymphocyte migration and cytotoxicity, via Gi and Gs protein-coupled signalling pathways.

BACKGROUND AND PURPOSE: The biogenic amine, histamine plays a pathophysiological regulatory role in cellular processes of a variety of immune cells. This work analyses the actions of histamine on γδ-T lymphocytes, isolated from human peripheral blood, which are critically involved in immunological surveillance of tumours. EXPERIMENTAL APPROACH: We have analysed effects of histamine on the intracellular calcium, actin reorganization, migratory response and the interaction of human γδ T cells with tumour cells such as the A2058 human melanoma cell line, the human Burkitt's Non-Hodgkin lymphoma cell line Raji, the T-lymphoblastic lymphoma cell line Jurkat and the natural killer cell-sensitive erythroleukaemia cell line, K562. KEY RESULTS: γδ T lymphocytes express mRNA for different histamine receptor subtypes. In human peripheral blood γδ T cells, histamine stimulated Pertussis toxin-sensitive intracellular calcium increase, actin polymerization and chemotaxis. However, histamine inhibited the spontaneous cytolytic activity of γδ T cells towards several tumour cell lines in a cholera toxin-sensitive manner. A histamine H(4) receptor antagonist abolished the histamine induced γδ T cell migratory response. A histamine H(2) receptor agonist inhibited γδ T cell-mediated cytotoxicity. CONCLUSIONS AND IMPLICATIONS: Histamine activated signalling pathways typical of chemotaxis (G(i) protein-dependent actin reorganization, increase of intracellular calcium) and induced migratory responses in γδ T lymphocytes, via the H(4) receptor, whereas it down-regulated γδ T cell mediated cytotoxicity through H(2) receptors and G(s) protein-coupled signalling. Our data suggest that histamine activated γδ T cells could modulate immunological surveillance of tumour tissue.

[Effector function plasticity of T helper lymphocytes]. / Plastizität der Effektorfunktionen von T-Helfer-Lymphozyten.

T helper (Th) cells are grouped into functionally different subsets (considered hitherto distinct and stable) according to their cytokine production. However, a number of recent findings show a much higher degree of Th cell plasticity and interconvertibility than previously assumed. Therefore, Th effector functions might be subject to therapeutic modulation even in late stages of immunopathological diseases.

Self-tolerance in the immune privileged CNS: lessons from the entorhinal cortex lesion model.

Upon peripheral immunization with myelin epitopes, susceptible rats and mice develop T cell-mediated demyelination similar to that observed in the human autoimmune disease multiple sclerosis (MS). In the same animals, brain injury does not induce autoimmune encephalomyelitis despite massive release of myelin antigens and early expansion of myelin specific T cells in local lymph nodes, indicating that the self-specific T cell clones are kept under control. Using entorhinal cortex lesion (ECL) to induce axonal degeneration in the hippocampus, we identified possible mechanisms of immune tolerance after brain trauma. Following ECL, astrocytes upregulate the death ligand CD95L, allowing apoptotic elimination of infiltrating activated T cells. Myelin-phagocytosing microglia express MHC-II and the costimulatory molecule CD86, but lack CD80, which is found only on activated antigen presenting cells (APCs). Restimulation of invading T cells by such immature APCs (e.g. CD80 negative microglia) may lead to T cell anergy and/or differentiation of regulatory/Th3-like cells due to insufficient costimulation and presence of high levels of TGF-beta and IL-10 in the CNS. Thus, T cell -apoptosis, -anergy, and -suppression apparently maintain immune tolerance after initial expansion of myelin-specific T lymphocytes following brain injury. This view is supported by a previous metastatistical analysis which rejected the hypothesis that brain trauma is causative of MS (Goddin et al., 1999). However, concomitant trauma-independent proinflammatory signals, e.g., those evoked by clinically quiescent infections, may trigger maturation of APCs, thus shifting a delicate balance from immune tolerance and protective immune responses to destructive autoimmunity.