Biomedical subjects

Conny Höflich

Publications and source records attributed to Conny Höflich.

10 recordsLinked to original sources

PubMed2007

Reduced monocyte CD86 expression in postinflammatory immunodeficiency.

OBJECTIVE: Major surgery, polytrauma, stroke, and pancreatitis frequently lead to a compensatory anti-inflammatory response syndrome that often predisposes patients to lethal infections. This temporary postinflammatory immunodeficiency is characterized by altered function of blood monocytes. These cells show strongly reduced inflammatory and antigen-presentation capacity. Diminished monocyte expression of the major histocompatibility complex class II molecule human leukocyte antigen (HLA)-DR is a well-established diagnostic marker of this immunodeficiency. To further characterize the monocytic cells in this clinical state, we analyzed their expression of CD86, the most important co-stimulatory molecule. DESIGN: Analysis of blood samples that entered the clinical immunologic diagnostics and of cells from an in vitro model of postinflammatory immunodeficiency. SETTING: University laboratory. SUBJECTS: Healthy donors and intensive care unit (ICU) patients at the university hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The expression of HLA-DR on monocytes and of CD86 and CD80 on monocytes and B cells was analyzed by flow cytometry. Messenger RNA expression of CD86 was analyzed in isolated monocytes by real-time polymerase chain reaction on reverse transcribed. The normal range of monocyte CD86 expression in healthy subjects was established to be from 2128 to 5102 surface molecules per cell and was independent of age, gender, and leukocyte and monocyte count. The CD86 expression on monocytes in ICU patients correlated with HLA-DR expression. Approximately 40% of the ICU patients with long-term reduced monocyte HLA-DR expression had a long-term reduction of CD86 expression. Patients in whom the expression of both molecules was diminished had an unfavorable prognosis. The diminished number of CD86 surface molecules on monocytes was associated with reduced CD86 messenger RNA levels in these cells. The expression of CD86 in B cells was not diminished in immunodeficient patients. The expression of CD80 in both monocytes and B-cells was minimal in healthy donors and not clearly changed in patients. CONCLUSIONS: The monocyte CD86 expression may be a helpful diagnostic variable in ICU patients.

Adolescent↗

PubMed2006

Rapid whole blood flow cytometric test to detect ICOS deficiency in patients with common variable immunodeficiency.

BACKGROUND/AIMS: Common variable immunodeficiency (CVID) is the most common primary immunodeficiency. With respect to underlying defects it comprises a heterogeneous group of deficiencies. For some patients, distinct phenotypical abnormalities have been described, e.g. partial CD40L deficiency or complete ICOS deficiency. For the diagnosis of CD40L deficiency, a rapid whole blood flow cytometric method has been described several years ago. We aimed to determine if the same method can be used to diagnose ICOS deficiency. METHODS: Whole blood from 8 healthy volunteers was stimulated for 4 and 20 h with phorbol 12-myristate 13-acetate (PMA) and ionomycin. Induction of ICOS expression was analyzed on CD8-CD3+ lymphocytes using three-color flow cytometry. Blood from a patient with diagnosed ICOS deficiency was also analyzed. RESULTS: Whole-blood stimulation with PMA and ionomycin for 20 h resulted in a significant induction of ICOS expression on CD8-CD3+ lymphocytes in healthy volunteers. Four-hour incubation also demonstrated ICOS upregulation but to a much lower extent. In CD8-CD3+ lymphocytes from an ICOS-deficient patient, no ICOS expression could be induced following 20 h of stimulation. CONCLUSION: ICOS expression can be analyzed using a rapid whole blood flow cytometric test.

Antigens, CD↗

PubMed2006

The evaluation of psoriasis therapy with biologics leads to a revision of the current view of the pathogenesis of this disorder.

Psoriasis is a common chronic, recurring skin disease that is characterised by typical macroscopic and microscopic skin alterations. It is widely accepted that the immune system plays an important role in the pathogenesis of this disorder. Since the early 1990s, the dominant role of a subpopulation of T cells, so-called T1 cells, and their prominent cytokine IFN-gamma has been assumed in the pathogenesis of psoriasis. Surprisingly, the comparison of the therapeutic success of treatments with recombinant proteins directed against defined immunological structures shows that those that directly affect T cells (alefacept, efalizumab, Hu-max-CD4, OKTcdr4a) were clearly less effective than those targeting TNF-alpha (etanercept, adalimumab, infliximab). For this reason, the authors critically re-evaluated the view of psoriasis pathogenesis and postulate that in the majority of patients the T1 cells do not play a dominant role in the clinical, visible stage of this disease.

Biological Products↗

PubMed2005

Monitoring temporary immunodepression by flow cytometric measurement of monocytic HLA-DR expression: a multicenter standardized study.

BACKGROUND: Single-center trials have shown that monocytic HLA-DR is a good marker for monitoring the severity of temporary immunodepression after trauma, major surgery, or sepsis. A new test for measuring monocytic HLA-DR is now available. METHODS: We evaluated a new test reagent set for monocytic HLA-DR expression (BD Quantibritetrade mark HLA-DR/Monocyte reagent; Becton Dickinson) in single-laboratory and interlaboratory experiments, assessing preanalytical handling, lyse-no-wash (LNW) vs lyse-wash (LW) values, reference values, and the effect of use of different flow cytometers and different instrument settings on test variance. RESULTS: For preanalytical handling, EDTA anticoagulation, storage on ice as soon as possible, and staining within 4 h after blood collection gave results comparable to values obtained for samples analyzed immediately after collection (mean increase of approximately 4% in monocytic HLA-DR). Comparison of LNW and LW revealed slightly higher results for LNW ( approximately 18% higher for LNW compared with LW; r = 0.982). Comparison of different flow cytometers and instrument settings gave CVs <4%, demonstrating the independence of the test from these variables and suggesting that this method qualifies as a standardized test. CV values from the interlaboratory comparison ranged from 15% (blood sample unprocessed before transport) to 25% (stained and fixed before transport). CONCLUSIONS: For the BD Quantibrite HLA-DR/Monocyte test, preanalytical handling is standardized. Single-laboratory results demonstrated the independence of this test from flow cytometer and instrument settings. Interlaboratory results showed greater variance than single-laboratory values. This interlaboratory variance was partly attributable to the influence of transport and can be reduced by optimization of transport conditions.

Flow Cytometry↗

PubMed2005

Release of the mitochondrial enzyme carbamoyl phosphate synthase under septic conditions.

To identify sepsis-related dysregulations of protein expression in the liver, we used a baboon model of acute endotoxemia and performed comparative proteome analysis. Treatment with lipopolysaccharide (LPS) was followed by an early but long-lasting (5-48 h) generation of N-terminal fragments of carbamoyl phosphate synthase-1 (CPS-1), an abundant enzyme of the hepatic urea cycle, which is normally located in the mitochondrial matrix. In addition, we developed a new sandwich immunoassay to determine circulating CPS-1 in human and baboons. We found CPS-1 to be induced by LPS and to be released into the circulation of healthy humans and baboons as early as 4 to 5 h after stimulation. Similarly, CPS-1 levels increased after injection of gram-positive bacteria in another baboon model. Enhanced CPS-1 levels were also detected in serum of patients with sepsis. Our data demonstrate fragmentation of CPS-1 in the liver and early increase in circulating CPS-1 levels under septic conditions. We suggest that circulating CPS-1 might serve as a novel serum marker indicating mitochondrial impairment of the liver and/or the small intestine in critically ill patients.

Animals↗

PubMed2004

Altered cell-mediated immunity and increased postoperative infection rate in long-term alcoholic patients.

BACKGROUND: Preoperative alteration of T cell-mediated immunity as well as an altered immune response to surgical stress were found in long-term alcoholic patients. The aim of this study was to evaluate perioperative T cell-mediated immune parameters as well as cytokine release from whole blood cells after lipopolysaccharide stimulation and its association with postoperative infections. METHODS: Fifty-four patients undergoing elective surgery of the aerodigestive tract were included in this prospective observational study. Long-term alcoholic patients (n = 31) were defined as having a daily ethanol consumption of at least 60 g and fulfilling the Diagnostic and Statistical Manual of Mental Disorders for either alcohol abuse or alcohol dependence. The nonalcoholic patients (n = 23) were defined as drinking less than 60 g ethanol/day. Blood samples to analyze the immune status were obtained on morning before surgery and on the morning of days 1, 3, and 5 after surgery. RESULTS: Basic patient characteristics did not differ between groups. Before surgery, the T helper 1:T helper 2 ratio (Th1: Th2) was significantly lower (P < 0.01), whereas plasma interleukin 1beta and lipopolysaccharide-stimulated interleukin 1ra from whole blood cells were increased in long-term alcoholic patients. After surgery, a significant suppression of the cytotoxic lymphocyte ratio (Tc1:Tc2), the interferon gamma:interleukin 10 ratio from lipopolysaccharide-stimulated whole blood cells, and a significant increase of plasma interleukin 10 was observed. Long-term alcoholics had more frequent postoperative infections compared with nonalcoholic patients (54%vs. 26%; P = 0.03). CONCLUSIONS: T helper cell-mediated immunity was significantly suppressed before surgery and possibly led to inadequate cytotoxic lymphocyte and whole blood cell response in long-term alcoholic patients after surgery. This altered cell-mediated immunity might have accounted for the increased infection rate in long-term alcoholic patients after surgery.

Alcoholism↗

PubMed2003

Naturally occurring anti-IFN-gamma autoantibody and severe infections with Mycobacterium cheloneae and Burkholderia cocovenenans.

Recently various genetic defects in immunity mediated by interferon gamma (IFN-gamma) have been described, including mutations in the IFN-gamma receptor 1 (IFN-gammaR1) and receptor 2 (IFN-gammaR2), signal transducer and activator of transcription 1 (STAT 1), and interleukin 12 receptor beta 1 (IL-12Rbeta1), and IL-12 p40 genes. These mutations are associated with the occurrence of severe infections with intracellular pathogens especially nontuberculous mycobacteria and vaccine-associated bacilli Calmette-Guérin (BCG). Here we report data on a previously healthy adult patient primarily presenting with severe infections with Burkholderia cocovenenans and subsequently Mycobacterium cheloneae. We found a strong inhibitory anti-IFN-gamma activity in the patient's plasma and identified a high-affinity neutralizing anti-IFN-gamma autoantibody. Unfortunately, the patient died due to severe sepsis before we knew the nature of the inhibitory activity. The application of alternative therapeutic approaches such as intravenous immunoglobulin or immunoadsorption may have been beneficial in this case. Screening for neutralizing anti-IFN-gamma autoantibodies should supplement testing for IFN-gamma and IL-12 pathway defects in patients with recurrent infections with intracellular pathogens, especially with nontuberculous mycobacteria.

Autoantibodies↗

PubMed2003

Stroke-induced immunodeficiency promotes spontaneous bacterial infections and is mediated by sympathetic activation reversal by poststroke T helper cell type 1-like immunostimulation.

Infections are a leading cause of death in stroke patients. In a mouse model of focal cerebral ischemia, we tested the hypothesis that a stroke-induced immunodeficiency increases the susceptibility to bacterial infections. 3 d after ischemia, all animals developed spontaneous septicemia and pneumonia. Stroke induced an extensive apoptotic loss of lymphocytes and a shift from T helper cell (Th)1 to Th2 cytokine production. Adoptive transfer of T and natural killer cells from wild-type mice, but not from interferon (IFN)-gamma-deficient mice, or administration of IFN-gamma at day 1 after stroke greatly decreased the bacterial burden. Importantly, the defective IFN-gamma response and the occurrence of bacterial infections were prevented by blocking the sympathetic nervous system but not the hypothalamo-pituitary-adrenal axis. Furthermore, administration of the beta-adrenoreceptor blocker propranolol drastically reduced mortality after stroke. These data suggest that a catecholamine-mediated defect in early lymphocyte activation is the key factor in the impaired antibacterial immune response after stroke.

Animals↗

PubMed2003

Downregulation of the epidermal growth factor receptor by human cytomegalovirus infection in human fetal lung fibroblasts.

Epidermal growth factor plays a key role in late fetal lung development and differentiation as well as in regulating surfactant protein A synthesis, which is involved in innate immunity of the lung. Here we show that human cytomegalovirus (HCMV), a known lung pathogen in connatal and postnatal infection of neonates as well as transplant recipients, completely down-regulates EGF receptor (EGF-R) on the surface of human fetal lung fibroblasts. Inhibition of EGF-R synthesis occurs on the transcriptional rather than on the posttranscriptional level. The effect essentially depends on expression of viral immediate early and/or early genes, as binding of ultraviolet light-inactivated virus to the cells had no effect on EGF-R expression. Furthermore, the anti-HCMV drug ganciclovir, which blocks HCMV DNA replication and late gene expression, cannot overcome HCMV-mediated inhibition of EGF-R, suggesting that immediate early or early gene products may be responsible for down-regulation of EGF-R. Interestingly, the glucocorticoid dexamethasone, which is used for its antiinflammatory action to prevent chronic lung disease in preterm infants, promotes HCMV-associated downregulation of the EGF-R by stimulation of viral gene expression. From these data it can be hypothesized that the pathogenesis of HCMV lung infection involves down-regulation of EGF-R and that congenital HCMV infection may cause retardation in lung maturation and surfactant protein synthesis.

Antiviral Agents↗

PubMed2003

Proteasome inhibitors: a novel tool to suppress human cytomegalovirus replication and virus-induced immune modulation.

Recently, we like others, demonstrated that systemic inflammation is the most important mechanism involved in (re)activation of human cytomegalovirus (HCMV) in both immunocompetent patients. By in vitro studies the eukaryotic transcription factor NF-kappaB could be identified as the key mediator of TNF-alpha- and IE1-dependent stimulation of the HCMV IE1/2 enhancer/promoter activity, which is crucial for initiation of viral gene expression during reactivation from latency as well as productive infection. The enzymatic proteasome complex plays a central role in regulating intracellular processes, including the activation of NF-kappaB. As present antiviral strategies target mainly late events in HCMV replication (DNA replication, virus assembly) that do not completely prevent virus mediated immunopathogenesis, we wondered whether proteasome inhibitors might be a novel tool for targeting the interaction between inflammation and HCMV (re)activation. Here, proteasome inhibitors like MG132, PSI, II and III (MG262) have been shown to block both TNF-alpha-associated up-regulation of the HCMV IE1/2 enhancer/promoter in monocytic cells in an in vitro transient transfection system and HCMV replication in permissive embryonal fibroblasts. Importantly, ganciclovir-resistant HCMV strains are sensitive to proteasome inhibitors. The effect of proteasome inhibitors on HCMV replication was found to be specific as replication of other herpes viruses, like HSV-1 and HSV-2, under identical experimental conditions was not influenced. Inhibition of HCMV replication correlated with a delayed and significantly reduced expression of IE proteins, particularly of the IE2 protein, suggesting that MG132 blocks HCMV replication at an immediate early stage of infection. Early and late protein synthesis as shown exemplary for the pp52 (DNA-binding protein) and p68 (structural protein) protein production and viral DNA synthesis were also inhibited. Suppression of HCMV replication could be correlated with an increased cytosolic accumulation of IkappaB as well as a reduced NF-kappaB binding activity in nuclear extracts of MG132-treated cells, which mainly regards NF-kappaB p50. MG132 also reduced the immune modulatory activity of the virus by abrogating virus-induced up-regulation of cellular ICAM-1. These data suggest that short-term therapy with proteasome inhibitors might be an alternative strategy to prevent (re)activation, replication and immune modulatory activity of HCMV in patients with systemic inflammation.

Chemokine CCL5↗