Thiol-mediated redox regulation of intestinal lamina propria T lymphocytes.

Intestinal lamina propria T lymphocytes (LP-Ts) have a markedly low proliferative potential both in vivo and in vitro. Here, we have identified that the capacity of antigen-presenting cells to release cysteine upon receptor-ligand interactions represents a critical parameter for proliferation of LP-Ts. The availability of cysteine is limiting for the intracellular production of glutathione, which in turn is essential for cell cycle progression. When cysteine is provided either directly or by addition of the reducing agent 2-mercaptoethanol to cystine-containing culture medium, proliferation of LP-T is fully restored. Importantly, coculture with peripheral blood monocytes that easily take up cystine, reduce cystine, and secrete cysteine also restores reactivity of LP-Ts to T cell receptor/CD3 stimulation. In marked contrast, lamina propria macrophages lack this capacity to elaborate cysteine, and thereby secure physiological unresponsiveness to antigen exposure in the intestinal microenvironment. The well-documented local recruitment of blood monocytes in inflammatory bowel disease (IBD) may thus represent an important parameter underlying hyperresponsiveness of T cells, an essential component of the pathogenesis of IBD.

Functional characterisation of decoy receptor 3 in Crohn's disease.

AIMS: Both epithelial barrier dysfunction and apoptosis resistance of immune cells contribute to the pathogenesis of Crohn's disease. The soluble decoy receptor 3 (DcR3) acts in an anti-apoptotic manner by neutralising the death ligand CD95L. Here, we investigated the possible involvement of DcR3 in Crohn's disease. METHODS: The epithelial fraction of human small intestinal mucosa samples was obtained by laser microdissection. Expression of DcR3 was examined by global gene expression profiling, quantitative reverse transcription polymerase chain reaction, immunoblot analysis, and immunohistochemistry. DcR3 concentrations in the serum of patients with Crohn's disease were measured by enzyme-linked immunosorbent assay. Apoptosis assays were performed to study the effects of DcR3 in intestinal epithelial cells and lamina propria T cells. RESULTS: DcR3 is over-expressed in the epithelial layer of ileum specimens in patients with Crohn's disease, both at actively inflamed and non-active sites. DcR3 serum levels are significantly elevated in patients with active and non-active Crohn's disease as compared to healthy controls. The expression of DcR3 in intestinal epithelial cells is induced by tumour necrosis factor alpha. Increased DcR3 expression is associated with activation of nuclear factor kappa B (NF-kappaB) and results in protection of intestinal epithelial cells and lamina propria T cells from CD95L-induced apoptosis. CONCLUSIONS: DcR3 may promote inflammation in Crohn's disease by inhibiting CD95L-induced apoptosis of epithelial and immune cells as well as by inducing NF-kappaB activation.

Adrenal insufficiency is a contraindication for omalizumab therapy in mast cell activation disease: risk for serum sickness.

Omalizumab is an effective therapeutic humanized murine IgE antibody in many cases of primary systemic mast cell activation disease (MCAD). The present study should enable the clinician to recognize when treatment of MCAD with omalizumab is contraindicated because of the potential risk of severe serum sickness and to report our successful therapeutic strategy for such adverse event (AE). Our clinical observations, a review of the literature including the event reports in the FDA AE Reporting System, the European Medicines Agency Eudra-Vigilance databases (preferred search terms: omalizumab, Xolair®, and serum sickness) and information from the manufacturer's Novartis database were used. Omalizumab therapy may be more likely to cause serum sickness than previously thought. In patients with regular adrenal function, serum sickness can occur after 3 to 10 days which resolves after the antigen and circulating immune complexes are cleared. If the symptoms do not resolve within a week, injection of 20 to 40 mg of prednisolone on two consecutive days could be given. However, in MCAD patients whose adrenal cortical function is completely suppressed by exogenous glucocorticoid therapy, there is a high risk that serum sickness will be masked by the MCAD and evolve in a severe form with pronounced damage of organs and tissues, potentially leading to death. Therefore, before the application of the first omalizumab dose, it is important to ensure that the function of the adrenal cortex is not significantly limited so that any occurring type III allergy can be self-limiting.

[Surgical interventions in patients with systemic mast cell activation disease : Recommendations for perioperative management]. / Chirurgische Eingriffe bei Patienten mit systemischer Mastzellaktivierungserkrankung : Empfehlungen für das perioperative Management.

BACKGROUND: Systemic mast cell activation disease (MCAD, prevalence 5-10%) is a multifactorial, polygenic disease with multisystemic symptoms that is characterized by an unregulated increased release of mast cell mediators and an accumulation of activated mast cells potentially in all organs and tissues. Due to the high prevalence of the disease, physicians involved in surgical, anesthesiological and interventional procedures are often unknowingly faced with MCAD patients experiencing unexpected preoperative, intraoperative and postoperative complications, if no mast cell-specific treatment regimens have been applied. OBJECTIVE: The findings from a literature search, consensus recommendations of the various international expert groups and extensive own experience in the treatment of MCAD patients enable an empirical and evidence-based care of MCAD patients in association with invasive procedures. RESULTS AND CONCLUSION: Due to the high prevalence of MCAD in the population, it can be assumed that patients with MCAD are correspondingly frequently represented in the surgical patient collective. When MCAD-specific peculiarities are preventively considered in the anesthesiological and surgical procedures in patients with proven or suspected mast cell disease, MCAD patients should not be classified as being at risk.

Up-regulation of the phosphoinositide 3-kinase pathway in human lamina propria T lymphocytes.

Human intestinal lamina propria T lymphocytes (LPT), when investigated ex vivo, exhibit functional properties profoundly different from those of peripheral blood T lymphocytes (PBT). One prominent feature represents their enhanced sensitivity to CD2 stimulation when compared to PBT. Given that LPT are hyporesponsive to T cell receptor (TCR)/CD3 stimulation, an alternative activation mode, as mimicked by CD2 triggering in vitro, may be functional in mucosal inflammation in vivo. This study provides insight into signalling events associated with the high CD2 responsiveness of LPT. When compared to PBT, LPT show an increased activation of the phosphoinositide 3/protein kinase B/glycogen synthase kinase 3beta (PI3-kinase/AKT/GSK-3beta) pathway in response to CD2 stimulation. Evidence is provided that up-regulation of this pathway contributes to the enhanced CD2-induced cytokine production in LPT. Given the importance of TCR-independent stimulation for the initiation of intestinal immune responses analysis of signalling pathways induced by 'co-stimulatory' receptors may provide valuable information for therapeutic drug design.

Soluble thrombomodulin--a marker of reperfusion injury after orthotopic liver transplantation.

Thrombomodulin is an endothelial cell membrane protein that is released into the blood in soluble forms (soluble thrombomodulin [sTM]) in response to endothelial cell damage. We evaluated intraoperative sTM as a marker of reperfusion injury in 29 liver transplant recipients using an ELISA. Preoperative sTM levels were significantly elevated, as compared with healthy control subjects (75 +/- 61 ng/ml vs. 17 +/- 10 ng/ml; P < 0.001) and remain unchanged at the end of the anhepatic phase (58 +/- 40 ng/ml). There is an increase to 194 +/- 182 ng/ml 3 min after reperfusion (P < 0.001). Post-reperfusion sTM levels correlate significantly with the early liver enzyme release (aspartate transaminase) (P < 0.001). Patients with pronounced reperfusion injury (postreperfusion arterial sTM > 138 ng/ml, n = 16) present significantly higher maximum aspartate transaminase levels within the first 24 postoperative hr, as compared with patients with less reperfusion injury (arterial sTM < 138 ng/ml, n = 12) (P = 0.001). Released sTM is derived from the graft, since patients with pronounced reperfusion injury present significantly higher sTM levels in the hepatic vein 3 min after reperfusion compared with the portal vein (P < 0.001) and artery (P = 0.025), respectively. In patients with higher reperfusion injury, we found significantly more adherent intrasinusoidal granulocytes in the liver biopsy taken 1 hr after reperfusion (P = 0.006), indicating an interrelation of endothelial damage and the important phenomenon of "leukocyte sticking" in reperfusion injury. Thus the postreperfusion increase of sTM as a marker of reperfusion injury correlates with the early liver enzyme release and the accumulation of intrasinusoidal granulocytes.

Prolonged allograft survival but no tolerance induction by modulating CD28 antibody JJ319 after high-responder rat heart transplantation.

BACKGROUND: Allograft rejection depends on T cell immune responses requiring antigen recognition and costimulatory signals through accessory T cell receptors, including CD28. Inhibition of CD28 signaling with a CTLA-4-immunoglobulin (Ig) fusion protein has resulted in immunosuppression and occasional T cell anergy in mouse transplant models, but not in rats. Because this approach also inhibits a potentially tolerizing signal through CTLA-4, selective blockade of CD28 ligation might induce more profound immunosuppression and transplant tolerance. METHODS: The effects of escalating doses of the rat CD28 monoclonal antibody JJ319 on allograft survival were studied after vascularized heterotopic heart transplantation in a high responder strain combination (DA to Lewis). CD28 antigen modulation and circulating antibody levels were monitored by flow cytometry. RESULTS: CD28 antibody JJ319 markedly prolonged cardiac graft survival compared with untreated controls (7 days, range: 6-8). A strictly dose-dependent increase in median graft survival time was demonstrated with a maximum of 36 days (range: 30-40; p <0.001) after the administration of 8 x 1 mg JJ319 i.p. (days -1 to +6 before/after transplantation). However, indefinite graft survival and tolerance could not be induced by JJ319 treatment. At the maximal dose, flow cytometry showed complete down modulation of the CD28 receptor for 10-14 days without T cell depletion in close temporal relation to antibody presence in serum. In vitro, CD28-modulated T cells showed significantly reduced responses to activation. CONCLUSIONS: CD28 antibody JJ319 induces profound immunosuppression after rat heart transplantation, however without development of transplant tolerance. The underlying mechanism seems to be receptor modulation during primary alloantigen recognition. While still potentially applicable clinically, there are no qualitative or quantitative differences to the treatment with CTLA-4/lg or the blockade of CD2 or LFA-1, as reported elsewhere. Thus, a CD28-modulating approach seems not to allow therapeutic exploitation of a tolerizing signal delivered by CTLA-4 but may still be clinically applicable, especially in combined immune interventions.

[Perspectives of immunosuppressive therapy]. / Perspektiven der immunsuppressiven Therapie.

The goal of immunosuppressive therapy in organ transplantation is the achievement of transplant-specific immune tolerance. Elucidation of the molecular basis of the functions of human lymphocytes is a step towards the development of novel, more specific and less harmful measures for clinical immune intervention.

[Effect of blood transfusions on rate of recurrence of Crohn disease]. / Der Einfluss von Bluttransfusionen auf die Rezidivrate bei Morbus Crohn.

The effect of perioperative blood transfusions on recurrence has been investigated in 261 patients with Crohn's disease who underwent a "curative" operation since 1981. Reoperations were necessary with a rate of approximately 3% per year. By Kaplan-Meier-analysis no difference could be detected between 120 patients with transfusion and 141 without (p = 0.407, log rank test). Statistical analysis of potentially interfering covariables revealed a significant effect of age and type of operation on postoperative recurrences. Even after stratification for these parameters it was impossible to confirm the protective influence of transfusions reported by others. However, in some subgroups there was a trend towards an association of blood transfusions with earlier reoperations.

[Surgical interventions in patients with mast cell activation disease. Aspects relevant for surgery using the example of a cholecystectomy]. / Chirurgische Eingriffe an Patienten mit Mastzellüberaktivitätserkrankung. Operationsrelevante Aspekte am Beispiel einer Cholezystektomie.

BACKGROUND: Systemic mast cell activation disease (MCAD) is characterized by an increased and unregulated release of mast cell mediators which can evoke a multifaceted clinical picture often resembling irritable bowel syndrome or fibromyalgia. Because of the considerable prevalence (~ 17 %) of MCAD surgeons are frequently unwittingly confronted with MCAD patients in whom unexpected intraoperative and postoperative complications may occur. Therefore, knowledge of the particular requirements is of relevance for surgical treatment of MCAD patients. OBJECTIVE: The present paper outlines a concept of surgical treatment of MCAD patients based on the literature which is illustrated by a case report on emergency laparoscopic cholecystectomy. CONCLUSIONS: Due to the high prevalence of MCAD in the general population it can be assumed that the frequency in the surgical patient population is similar. If a patient has MCAD, specific characteristics should be taken into account in the surgical procedure to avoid increased operative and complication risks resulting from MCAD.

Molecular characterisation of non-absorptive and absorptive enterocytes in human small intestine.

BACKGROUND AND AIMS: Perturbation of differentiation of the crypt-villus axis of the human small intestine is associated with several intestinal disorders of clinical importance. At present, differentiation of small intestinal enterocytes in the crypt-villus axis is not well characterised. SUBJECTS AND METHODS: Expression profiling of microdissected enterocytes lining the upper part of crypts or the middle of villi was performed using the Affymetrix X3P arrays and several methods for confirmation. RESULTS: A total of 978 differentially expressed sequences representing 778 unique UniGene IDs were found and categorised into four functional groups. In enterocytes lining the upper part of crypts, cell cycle promoting genes and transcription/translation related genes were predominantly expressed, whereas in enterocytes lining the middle of villi, high expression of cell cycle inhibiting genes, metabolism related genes, and vesicle/transport related genes was found. CONCLUSION: Two types of enterocytes were dissected at the molecular level, the non-absorptive enterocyte located in the upper part of crypts and the absorptive enterocyte found in the middle of villi. These data improve our knowledge about the physiology of the crypt-villus architecture in human small intestine and provide new insights into pathophysiological phenomena, such as villus atrophy, which is clinically important.

[Abdominal trauma]. / Das Abdominaltrauma.

Blunt abdominal trauma is much more frequent than penetrating abdominal trauma in Europe. As a consequence of improved quality of computed tomography, even complex liver injuries are increasingly being treated conservatively. However, missed hollow viscus injuries still remain a problem, as they considerably increase mortality in multiply injured patients. Laparoscopy decreases the rate of unnecessary laparotomies in perforating abdominal trauma and helps to diagnose injuries of solid organs and the diaphragm. However, the sensitivity in detecting hollow viscus injuries is low and the role of laparoscopy in blunt abdominal injury has not been defined. If intra-abdominal bleeding is difficult to control in hemodynamically unstable patients, damage control surgery with packing of the liver, total splenectomy, and provisional closure of hollow viscus injuries is of importance. Definitive surgical treatment follows hemodynamic stabilization and restoration of hemostasis. Injuries of the duodenum and pancreas after blunt abdominal trauma are often associated with other intra-abdominal injuries and the treatment depends on their location and severity.

[Desmosis coli in adults. Differential diagnosis of chronic constipation]. / Desmosis coli im Erwachsenenalter. Ein Beitrag zur Differenzialdiagnose der chronischen Obstipation.

Desmosis coli is a disturbance of the intramural connective tissue mesh network of the colonic wall which can lead to a hypoperistalsis syndrome with chronic constipation in the absence of any anomaly of the vegetative gut innervation. The condition typically occurs in infants and adolescents; however, as an incomplete form, desmosis coli can also cause chronic constipation in adults, as demonstrated in this case report.

Prolonged allograft survival by the inhibition of costimulatory CD2 signals but not by modulation of CD48 (CD2 ligand) in the rat.

The CD2 receptor is an important costimulatory molecule in T cell activation. Its ligand CD48 in rodents is supposed to be a homologue of human CD58, because of its similarities in structure and distribution. We evaluated the immunosuppressive activity of CD2/CD48-directed therapy in vitro and in vivo for the efficacy in prolonging rat heart allograft survival in a high responder transplant model. CD2-directed monoclonal antibody (mAb) therapy significantly prolonged median survival time to 45 days (P < 0.001). Suppression was mediated by down-modulation of CD2 below 20% on lymph node cells without considerable cell depletion. In contrast, CD48 mAb could not prolong graft survival. Rejection occurred in the presence of complete CD48 modulation and, therefore, despite disruption of the CD2-CD48 interaction. CD48 mAb failed to inhibit lymphocyte activation via a mitogenic pair of CD2 mAbs and inhibited mixed lymphocyte reaction (MLR) only by an unspecific mechanism. In conclusion, our results suggest a negative regulatory signal transduction by inhibitory CD2 mAbs and argue against a pivotal role of mere disruption of the CD2-CD48 interaction in CD2-mediated immunosuppression.