Low-dose Anti-thymocyte Globulin Inhibits Human B-cell Differentiation into Antibody-Secreting Cells.

Anti-thymocyte globulin (ATG) is used in the treatment of acute organ rejection. We studied in vitro the effect of low-dose ATG on B-cell activation and differentiation to antibody-secreting cells, as this may have an effect on B cell-driven autoimmune diseases, such as pemphigus vulgaris. Immunoglobulin production was analysed in the supernatants of peripheral blood mononuclear cells (PBMC) and CD19+ B cells from healthy donors and from patients with different autoimmune diseases. B-cell proliferation, viability and differentiation were analysed using flow cytometry. Differentiation of B cells to immunoglobulin G (IgG) secreting cells was significantly reduced by ATG, but not by control unspecific IgG from non-immunized rabbits (rIgG). B-cell viability was not altered by sub-depleting concentrations of ATG. In contrast, B-cell proliferation was enhanced by ATG. When PBMC from patients with autoimmune diseases were studied, specific autoantibodies could be detected in 1 out of 10 patients. In this patient, who had pemphigus vulgaris, ATG not only decreased total IgG, but decreased also specific anti-desmoglein-3. In conclusion, these data suggest that ATG at low concentrations inhibits B-cell differentiation and function.

Tolerability and clinical outcome of coseasonal treatment with Escherichia coli strain Nissle 1917 in grass pollen-allergic subjects.

BACKGROUND: Nonpathogenic Escherichia coli strain Nissle 1917 (EcN) has immunomodulatory properties and can act on different cells which are important for the allergic immune response. Herein, we investigated the efficacy and tolerability of EcN in subjects with grass pollen-dependent allergic rhinoconjunctivitis. METHODS: Grass pollen-allergic subjects were randomly allocated to receive EcN in a double-blind, placebo-controlled manner. The treatment was performed from 2 months before onset until the end of one grass pollen season (in total: 6 months). The clinical symptom score and the intake of symptomatic medications were assessed. A skin prick test and grass pollen-specific immunoglobulin (Ig) E and IgA were evaluated before and after treatment. RESULTS: Our results show that coseasonal treatment with EcN in grass pollen-allergic subjects was not superior to placebo as assessed using the symptom-medication score (p = 0.257). Interestingly, an increase [median (range)] in grass pollen-specific IgA was detectable in the EcN group [20,556 LU/ml (1,812-60,800)] versus placebo [5,246 LU/ml (944-50,467)] (p = 0.048). CONCLUSIONS: The results indicate that 6 months of coseasonal nonspecific immunomodulation by EcN is not sufficient to achieve clinical efficacy in grass pollen-allergic subjects. Future approaches in which such immunomodulators are combined with an allergen-specific protocol might enhance the clinical efficacy of the allergen-specific treatment.

Isolation and phenotypic characterization of mucosal nasal lymphocytes by direct ex vivo analysis.

Cellular inflammation of the nasal mucosa demonstrates a local immune response which plays an important role in allergic rhinitis. The aim of the present study was to characterize nasal mucosal lymphocytes regarding their activation and differentiation state by direct ex vivo flowcytometric analysis. Lymphocytes from the inferior turbinates were isolated by a mechanical method of preparation and, for comparison, from peripheral blood by Ficoll gradient centrifugation. Patients suffering from rhinitis or difficulty in nasal breathing were divided into an allergic (pollen-allergy, n = 13) and non-allergic group (n = 24). Expression of different T- and B-cell markers was determined by flowcytometric analysis. CD4+ T-cells from the nasal mucosa exhibited a memory phenotype (CD45RO+, 97%), were highly activated (CD69+, 43-73%), and showed low expression of the cutaneous lymphocyte antigen (CLA+, 5%). Nasal CD20+ B-lymphocytes expressed significantly higher levels of mIgE and lower levels of CD23 and CD80 than peripheral B-cells. Subsets of CD80+ (4%) and CD86+ (6%) CD20+ B-lymphocytes were identified in the nasal mucosa. No significant differences between allergic and non-allergic individuals were determined. As expected, the data show profound phenotypical differences between circulating peripheral blood and nasal mucosal lymphocytes. Activated memory lymphocytes are present in the nasal mucosa from allergic, but also non-allergic patients and may indicate to a significant role of a local inflammatory state without systemic criteria for allergy. In our study, we show that direct ex vivo isolation of lymphocytes is practicable method and offers a new technique to examine the local nasal allergic immune response using a multiparametric phenotypical analysis.

Multi-residue pesticide analysis (gas chromatography-tandem mass spectrometry detection)-Improvement of the quick, easy, cheap, effective, rugged, and safe method for dried fruits and fat-rich cereals-Benefit and limit of a standardized apple purée calibration (screening).

Some steps of the QuEChERS method for the analysis of pesticides with GC-MS/MS in cereals and dried fruits were improved or simplified. For the latter, a mixing vessel with stator-rotor-system proved to be advantageous. The extraction procedure of dried fruits is much easier and safer than the Ultra Turrax and results in excellent validation data at a concentration level of 0.01mg/kg (116 of 118 analytes with recoveries in the range of 70-120%, 117 of 118 analytes with RSD <20%). After qualifying problematic lipophilic pesticides in fat-rich cereals (fat content >7%), predominantly organochlorines showed recoveries of <70% in quantification when the standard QuEChERS method with water was used. A second extraction was carried out analogous to the QuEChERS method, however, without the addition of water. With this simple modification, the problematic lipophilic pesticides, which had been strongly affected by the fat content of the commodities, could be determined with recoveries above 70% even at a concentration level of 0.01mg/kg. Moreover, a GC-MS/MS screening method for 120 pesticides at a concentration level of 0.01mg/kg was established by employing analyte protectants (ethylglycerol, gulonolactone, and sorbitol). The use of only one standardized calibration, made of an apple purée extract in combination with analyte protectants, allowed for a qualitative and quantitative analysis of 120 pesticides in different matrix extracts (tomato, red pepper, sour cherries, dried apples, black currant powder, raisins, wheat flour, rolled oats, wheat germ). The analyte protectants leveled the differences in the matrix-induced protection effect of the analyzed extracts over a wide range. The majority of the pesticides were analyzed with good analytical results (recoveries in the range of 70-120% and RSD <20%).

Differential immunomodulating effects of inactivated probiotic bacteria on the allergic immune response.

Bacterial stimulation plays an important role in modulating the allergic immune response. The aim of this study was to investigate the effects of inactivated probiotic Lactobacillus acidophilus and non-pathogenic Escherichia coli strain Nissle on the phenotype and function of T- and B-cells. Peripheral blood mononuclear cells from patients with grass-pollen allergy (n=10) and non-allergic patients (n=19) were co-stimulated with inactivated bacteria and grass-pollen allergen. Expression of CD23, CD80, CD86 and CD69 were analysed, and the intracellular production of interleukin-4 and interferon-gamma was measured by direct ex vivo flow cytometry after stimulation. Both bacteria induced a significant up-regulation of CD69 expression on T-lymphocytes (p=0.001). CD23 expression was significantly increased following stimulation with allergen (p=0.008), but reduced after stimulation with Lactobacillus and significantly reduced with E. coli plus allergen (p=0.029). CD80 expression was reduced after stimulation with Lactobacillus in the allergic group only (p=0.021). By contrast, CD86 expression was significantly increased after stimulation with Lactobacillus (p=0.049) and distinctly increased with E. coli in both groups (p=0.001). The cytokine patterns of CD69-positive T-lymphocytes from allergic patients showed a TH2-dominated response after allergen stimulation (interferon-gamma/interleukin-4-ratio 0.2), directed into a T-helper1-like response by stimulation with both types of bacteria (interferon-gamma/interleukin-4-ratios 1.5-2.0 in both groups). These data show that both types of bacteria modulate the allergic immune response by the alteration of CD23 and co-stimulatory molecule expression. Regarding cytokine production, the data suggest a differential response to both bacteria depending on the atopic state, but a clear promotion of T-helper1-dominated response in allergic donors.