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Occupationally induced hypersensitive reactions towards chemical compounds are increasingly observed. In this regard ammonium persulfate (APS) is reported as an inducer of erythema, urticaria, eczema, rhinitis and bronchial asthma. On the basis of these reactions, persulfates obviously show some characteristics of skin-sensitizing as well as respiratory allergens. We measured the effect of APS on the release of inflammatory mediators, i.e. leukotriene B4 (LTB4), from human polymorphonuclear neutrophils (PMN). The effect of the persulfate was analyzed in comparison of the corresponding sulfate. After different cellular activation either with the Ca ionophore A23187, the tripeptide formyl-methionyl-leucyl-phenylalanine (fMLP) or sodium fluoride (NaF) coincubation of PMN with APS led to a diminished generation of LTB4. In addition it was demonstrated that APS decreased the stability of leukotrienes in cell-free systems. However, cells which were preactivated with APS and subsequently washed showed an increase in leukotriene formation after stimulation with fMLP or NaF but not with the Ca ionophore. Thus, the concentration of APS at local tissue sites as well as the occurrence and nature of a secondary cell-activating stimulus finally determine to what extent persulfates will interfere with cellular functions, e.g. mediator suppression or induction, which are then responsible for clinical disease processes.

Leukotrienes are potent lipid mediators involved in acute and chronic inflammatory processes and allergic inflammation. Cetirizine is an H1-receptor antagonist used in the treatment of allergic symptoms. We analyzed the effect of cetirizine on the formation of leukotriene B4 (LTB4) after stimulation of human peripheral blood neutrophils. The inflammatory mediators were analyzed after cellular activation with different stimuli: the Ca ionophore A23187, which bypasses membranous signal transduction elements; the bacterial peptide formyl-methionine-leucyl-phenylalanine (fMLP), which activates cells by binding to a GTP-protein (G-protein)-coupled receptor, and with sodium fluoride (NaF), which directly activates G-proteins. After cellular preincubation with cetirizine, the amounts of LTB4 generated from neutrophil granulocytes decreased significantly when the cells were subsequently stimulated with either fMLP or NaF, in contrast to stimulations with the Ca ionophore. The data provide evidence that cetirizine exerts anti-inflammatory effects apart from H1 antagonism.

The influence of the immunosuppressive substances cyclosporin A (CsA), FK506 and rapamycin on inflammatory mediators from cytokine-primed human leukocytes was studied. The cells were primed with granulocyte/macrophage-colony-stimulating factor, granulocyte-stimulating factor (G-CSF) and interleukin-3 (IL-3), and subsequently stimulated with the chemotactic peptide fMLP. The immunosuppressive agents CsA and FK506 enhanced the release of leukotriene B4 (LTB4) from human neutrophil granulocytes dependent on the priming with G-CSF and IL-3. IL-3-primed neutrophils released up to threefold higher amounts of LTB4 after subsequent stimulation with FK506 and fMLP. In contrast, the immunosuppressant rapamycin inhibited the formation of LTB4 after subsequent stimulation with fMLP. In addition to the well-documented inhibitory effects on lymphocyte function, our results indicate an enhancing effect of the immunosuppressive agents on the cellular inflammatory response of human peripheral blood neutrophils.

Pseudomonas aeruginosa infections are commonly observed in sepsis, burns, as well as cystic fibrosis (CF). Among the professional phagocytes neutrophils and monocytes are recruited by various chemotactic factors from the cellular environment. Although they provide the first line of host defense excessive neutrophil accumulation seems to be a major cause of pathogenesis during P. aeruginosa infection. Interleukin-8 (IL-8) represents one important chemoattractant for professional phagocytes. To evaluate IL-8 releasability by phagocytes in the context of P. aeruginosa infection and especially of CF, we stimulated human polymorphonuclear neutrophilic granulocytes (PMN) and peripheral blood mononuclear cells (PBMC) as a source for monocytes with clinical P. aeruginosa isolates, with mucoid P. aeruginosa strain (CF3M) and its nonmucoid revertant (CF3), and with purified P. aeruginosa mucoid exopolysaccharide (alginate). A significant increase in IL-8 release as compared to unstimulated cells was observed after an incubation time of 90 min for PMN and after 60 min for PBMC which increased (PMN: up to 60-fold; PBMC: up to 40-fold) over time (up to 4 h). In contrast of PBMC, when PMN were studied, intracellular IL-8 exceeded the IL-8 release in unstimulated as well as in stimulated cells by up to 10-fold. All clinical P. aeruginosa isolates, independent of the clinical source, induced IL-8 release from human PBMC and PMN in a dose- and time-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Patients with atopic dermatitis (AD) are frequently colonized with Staphylococcus aureus strains secreting exotoxins such as the staphylococcal enterotoxin B (SEB) and A (SEA). Nonetheless the role of SEB and SEA in AD is yet unknown. We analyzed the responsiveness of peripheral blood mononuclear cells (PBMCs) and isolated T cells from donors with AD and from normal donors to SEB and SEA. PBMCs as well as T cells from normal donors showed a significantly enhanced proliferation after stimulation with enterotoxin B, whereas the 3H-thymidine uptake of the T lymphocytes from patients with AD was markedly suppressed. Furthermore, we show that IFN-gamma mRNA and protein and mRNA for both chains of IL-12 (p35 and p40) are produced in human PBMCs from normal donors upon stimulation with SEB and SEA. In contrast to normal donors T cells from donors with AD predominantly express mRNA for IL-4, IL-5, and only diminished levels for IFN-gamma and IL-12 upon stimulation with SEB and SEA. Furthermore, in contrast to normal donors, PBMCs from donors with AD spontaneously produce high levels of IgE and express increased levels of CD23, the low-affinity receptor for IgE. Nonetheless, the superantigens by themselves, from 0.1 fg up to 1 microgram/10(6) cells, induced neither IgE secretion nor CD23 expression on PBMCs. Moreover, the addition of superantigens to IL-4-treated PBMC cultures diminished or totally suppressed the IL-4-induced IgE synthesis and CD23 expression. No differences were observed between PBMCs from normal donors of donors with AD. Both PBMCs isolated from normal and atopic donors produced high levels of soluble IL-4-receptor (up to 210 +/- 90 pg/ml). Addition of soluble IL-4-receptor to PBMC cultures downregulated the IL-4-induced IgE synthesis and CD23 expression in unstimulated as well as in SEB-stimulated PBMCs from normal donors and donors with AD. Our results suggest that superantigen-producing staphylococcal strains on the skin of patients with AD may modulate and/or amplify allergic inflammation.

The role of platelets in acute and chronic infection has been widely discussed in various disease processes. We studied the effects of two lipolytic enzymes (phospholipase C, lipase) secreted by Pseudomonas aeruginosa strains isolated from cystic fibrosis (CF) patients with regard to 12-hydroxyeicosatetraenoic acid (12-HETE) generation from human platelets. Both phospholipase C (PLC) and lipase were secreted into the culture supernatant at the end of the logarithmic growth phase. Indeed, only culture supernatants obtained from the late logarithmic/early stationary phase of CF strains induced the generation of 12-hydroxyeicosatetraenoic acid (12-HETE) (from 15 +/- 9 to 370 +/- 98 ng, n = 7). Purified P. aeruginosa lipase itself generated only small amounts of 12-HETE from human platelets with a maximum of 30 +/- 7 ng/10(8) platelets at the highest concentration tested (20 nkat). A partially purified culture supernatant from P. aeruginosa strain PAO1 containing phospholipase C and lipase, but lacking glycolipid and protease activities, induced time- and dose-dependently a significant 12-HETE generation from human platelets. Maximal 12-HETE generation was observed at the highest enzyme concentrations tested (PLC: 1.35 nkat, lipase: 3.7 nkat/10(8) platelets). To analyze whether lipase exhibits a modulatory role on PLC-induced 12-HETE generation from human platelets we inhibited lipase activity in the P. aeruginosa partially purified culture supernatant by treatment with the lipase-specific inhibitor hexadecylsulfonylfluoride (AMSF) leaving the activity of PLC unaffected (lipase-free culture supernatant). The capacity of lipase-free culture supernatant to induce 12-HETE generation was diminished by up to 100% depending on the PLC activity.(ABSTRACT TRUNCATED AT 250 WORDS)

We analyzed the role of soluble purified Pseudomonas aeruginosa alginate on Escherichia coli K-12 (pANN5211) as well as on Staphylococcus aureus 121c-induced inflammatory mediator release from human platelets, granulocytes, and basophils. In the presence of alginate (1-4 mg/ml), the mucoid exopolysaccharide of P. aeruginosa, the bacteria-induced inflammatory mediator release was modulated as follows: (1) the E. coli- as well as S. aureus-induced chemiluminescence response from human neutrophils increased 2- to 3-fold and 5- to 6-fold, respectively; (2) the E. coli-induced leukotriene B4 formation from human neutrophils was enhanced (from 29.17 +/- 1.8 up to 36.9 +/- 4 ng/10(7) cells) as was also observed for the E. coli- and S. aureus-induced histamine release (3- to 4-fold) and the 12-hydroxyeicosatetraenoic acid generation from human platelets (2-fold), and (3) prolonged duration of the E. coli-induced increase in CD11b expression was observed. Alginate by itself was inactive. Our results provide evidence that alginate interacts with hemolysin-producing E. coli and S. aureus bacteria and thus leads to a modulation of the cellular response pattern, which leads to the local destruction of the lung in cystic fibrosis.