No abstract

The involvement of the alpha4-integrin very late activation antigen 4 and vascular cell adhesion molecule-1 (VCAM-1) in leukocyte trafficking into the airways of ovalbumin (OA)-sensitized and OA-challenged mice was investigated using in vivo administration of anti-alpha4 monoclonal antibodies (mAb) PS/2, R1-2, and M/K-2.7 (MK2), specific for VCAM-1. VCAM-1 was upregulated on endothelial cells in lung tissue after OA inhalation. PS/2, R1-2, or MK2 significantly inhibited the recruitment of eosinophils and lymphocytes into the bronchoalveolar lavage (BAL) fluid and decreased inflammation in the lung tissues. Escalating in vivo doses of PS/2 or MK2 increased circulating levels of rat immunoglobulin G in the plasma. The binding of phycoerytherin-labeled anti-alpha4 mAb to blood T cells from PS/2-treated mice was reduced, implying that alpha4 sites were already occupied. T cells and eosinophils in BAL fluid from mice treated with PS/2 or MK2 were phenotypically different from controls. Selective decreases of alpha4+ T cells in the BAL fluid after PS/2 or MK2 treatment were coupled with changes in CD8+, CD11a, and CD62L expression. The alpha4-integrin and VCAM-1 may have important roles in the antigen-induced recruitment of T cells and eosinophils during OA-induced airway inflammation. The data suggest that these adhesion molecules may be suitable targets for therapeutic intervention in certain conditions of pulmonary inflammation.

The effect has been studied of sodium cromoglycate (SCG) on the activity of ‘C’ fibre sensory nerve endings in the canine lung. Pretreatment with SCG (100 μg/kg i.v.) reduced the excitation of these endings by capsaicin (10 μg/kg i.v.) for approximately 45 min. This property of SCG may explain its ability to suppress certain types of bronchoconstrictor responses in man.

Considerable attention has recently focused on the role of inflammation in the pathophysiology of asthma, with special emphasis on "late-phase" bronchoconstriction and increased airway hyperreactivity after antigen challenge in sensitized subjects. The present report describes the histopathologic changes in guinea-pig lung and trachea at various time intervals after ovalbumin inhalation in nonsensitized (control) and sensitized animals. Bronchoalveolar lavage (BAL) was also used to assess the accompanying accumulation of intraluminal leukocytes. A distinct leukocyte margination, consisting of neutrophils and eosinophils, was observed in the peribronchial vasculature as early as 8 min postchallenge in sensitized guinea pigs. At 6 h, the eosinophils predominated and migrated to the peribronchiolar smooth muscle layer. Between 6 h and 18 h, eosinophils were seen in tracts between the smooth muscle cell layers, accumulating in large numbers in the bronchial mucosal epithelium. This pattern persisted for at least 7 days postchallenge during which eosinophils remained the dominant cell type present. Peribronchiolar accumulation of neutrophils and mononuclear cells was minimal at all time points studied. Intraluminal mucus eosinophilia developed between 18 h and 7 days. A similar pattern of eosinophil infiltration was observed in the tracheal epithelium. Control, nonsensitized, guinea-pig lungs showed minor changes with little or no eosinophil infiltration at any time after antigen challenge. These findings correlated well with the BAL study in which sensitized guinea pigs exhibited a marked delayed increase in eosinophil counts between 18 h and 7 days compared with that in nonsensitized animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Fish oil may be beneficial in the treatment of psoriasis and in RA. We examined the potential benefit of Efamol Marine, a combination of evening primrose oil and fish oil in the treatment of 38 patients with PsA. Patients with PsA were entered in a double-blind placebo controlled study and received either 12 Efamol Marine capsules or 12 placebo capsules daily for 9 months. All patients received placebo capsules for a further 3 months. At month 3 of the study patients were asked to reduce their intake of NSAIDs and maintain that decrease provided there was no worsening of their joint symptoms. Clinical assessments of skin and joint disease severity and activity were performed at 0, 1, 3, 6, 9 and 12 months. All measures of skin disease activity including severity, percentage body affected and itch were unchanged by Efamol Marine. The NSAID requirement remained the same between both treatment groups. In addition, there was no change demonstrated in the activity of arthritis as measured by duration of morning stiffness. Ritchie articular index, number of active joints, ESR and CRP. However, a rise in serum TXB2 was observed in the active group during the placebo phase; in addition a fall in leukotriene B4 production occurred during the active phase period followed by a marked rise during the placebo phase suggesting some laboratory documented anti-inflammatory effect. In conclusion, this study suggests that Efamol Marine may alter prostaglandin metabolism in patients with PsA, although it did not produce a clinical improvement and did not allow reduction in NSAID requirement. A larger dose of essential fatty acid may be needed to produce a clinical benefit.

SUIMMARY1. The ability of histamine, acetylcholine (ACh) and 5-hydroxytryptamine (5-HT) given i.v. and by aerosol to induce reflex bronchoconstriction and to activate lung irritant receptors has been studied in dogs anaesthetized with chloralose. 4. Histamine, 5-HT and ACh given by aerosol and i.v. increased lung irritant receptor discharge. Irrespective of the route of administration, for a given change in RL histamine produced a greater increase in irritant receptor discharge than did ACh or 5-HT, which produced similar increases.5. For a given change in RL, histamine, ACh and 5-HT were more effective in activating lung irritant receptors when given I.v. than by aerosol.6. The mechanisms of irritant receptor activation by histamine, ACh and 5-HT and the relationship between irritant receptor discharge and reflex bronchoconstriction are discussed.

1 Passive lung anaphylaxis (PLA) was investigated in rats sensitized by the intravenous injection of high titre reaginic antiserum prepared in rats. 2 The effect of various pharmacological antagonists on anaphylactic bronchoconstriction in vivo were examined. An antihistamine (mepyramine), a kallikrein inactivator (aprotinin) or a prostaglandin synthesis inhibitor (aspirin) did not inhibit PLA, whereas an anti-5-hydroxytryptamine agent (methysergide) and an anti-slow reacting substance-A agent (FPL, 55712) significantly reduced the response. 3 Isolated perfused lungs taken from sensitized rats released, on challenge with the sensitizing antigen, histamine, 5-hydroxytryptamine, slow reacting substance of anaphylaxis (SRS-A) and prostaglandins, but no rabbit aorta contracting substance (RCS). 4 Disodium cromoglycate inhibited both anaphylactic bronchoconstriction in vivo and the anaphylactic release of mediators in vitro. Inhibition in vivo was dose-related. 5 Mediators from the intestine, the primary shock organ of anaphylaxis in the rat, did not contribute to the lung response. 6 Vagal reflex pathways were found not to be important in PLA in vivo. 7 The relationship between the mediators released following antigen challenge of passively sensitized rat lung in vitro and passive lung anaphylaxis in vivo is discussed.

Cytokines released from CD4+ T lymphocytes contribute to the pathogenesis of asthma by influencing the differentiation and function of eosinophils, the primary effector cells that cause airway epithelial damage. Using a model of ovalbumin (OA)-induced, eosinophil-rich chronic lung inflammation in sensitized mice, we have defined the role of T lymphocytes further by using three-color flow cytometry to characterize the adhesion and activation antigens that may be associated with the migration of these cells into the lung and airway lumen. OA inhalation in OA-sensitized C57BL/6 mice resulted in an early (6 to 24 h) influx of neutrophils into the bronchial lumen as enumerated by bronchoalveolar lavage (BAL), which was followed by a marked accumulation of lymphocytes and eosinophils between 24 to 72 h. Phenotypic analysis of BAL or lung tissue T cells showed that most Thy-1 CD3+ T cells were CD4+ (CD4: CD8 ratio of 3 to 4:1). The majority (90%) of the T cells in lung or BAL fluid expressed alpha beta T-cell receptors (TCR). Only 3 to 7% of the T cells were gamma delta TCR+ even though almost 25% of the T cells were CD4- CD8-. There were very few natural killer (NK) or B cells in BAL fluid compared with 15% B cells in dissagregated lung tissue. In contrast to T cells in spleen, almost all the lung and BAL T cells were of the memory phenotype, as ascertained by the expression of high levels of CD44 and by the absence of L-selectin and CD45RB on the cell surface. Fifty to ninety percent of lung and BAL T cells from vehicle-sensitized or OA-sensitized and challenged mice expressed the adhesion molecules CD11a (LFA-1), CD54 (ICAM-1), and CD49d (VLA-4). The early T-cell activation marker CD69 was upregulated on 30% of the lung and BAL T cells in OA-sensitized mice after antigen inhalation. When BAL fluid T cells from OA-sensitized and challenged mice were analyzed for their coexpression of adhesion and/or activation molecules, 75% of the cells that expressed one of three adhesion molecules, CD54, CD49d, or CD11a, also expressed at least one of the other two antigens. At least 15% of BAL T cells had all three of these molecules on their cell surfaces. The OA-dependent, temporally regulated emigration of T cells into the bronchial lumen after exposure to aerosolized antigen may be correlated with the accumulation of cells that express the memory phenotype with enhanced expression of adhesion molecules.