Effects of protein kinase C and phospholipase C inhibitors on IgE-dependent and IgE-independent basophil histamine release.

OBJECTIVE AND DESIGN: This study was aimed to evaluate the effects of two protein kinase C (PKC) inhibitors (staurosporine and chelerythrine) and one phospholipase C (PLC) inhibitor (U73122) on basophil histamine release induced by anti-IgE, N-formyl-methionyl-leucyl-phenylalanine (FMLP), IL-3 and GM-CSF. METHODS: Leukocytes were suspended in solutions containing physiological or low Na+ concentrations, since IL-3 and GM-CSF were shown to induce histamine release only when the inhibitory effect of extracellular Na+ has been removed. After incubation with PKC and PLC inhibitors, the stimuli were added and histamine release was measured by an automated fluorometric method. RESULTS: Staurosporine and chelerythrine exerted a significant inhibitory effect on histamine release induced by anti-IgE, IL-3 and GM-CSF at concentrations much higher than those required to inhibit PKC. FMLP-induced histamine release in a physiological Na+-containing medium was not significantly modified by staurosporine, although it was reduced by high concentrations of chelerythrine. A slight inhibition by high concentrations of staurosporine was found when basophils were suspended in a low Na+ medium. U73122 exerted a significant and dose-dependent inhibitory effect on basophil histamine release induced by anti-IgE, FMLP, IL-3 and GM-CSF. CONCLUSION: These results suggest that a prodegranulatory role of PKC in basophil histamine release induced by anti-IgE, FMLP, IL-3 and GM-CSF is unlikely; conversely, it is conceivable that PLC has a role in signal transduction and histamine release induced by the above stimuli.

Inhibition of basophil histamine release by tyrosine kinase and phosphatidylinositol 3-kinase inhibitors.

It has been demonstrated that tyrosine kinase (TK) and phosphatidylinositol 3-kinase (PI3-K) are involved in IgE-mediated stimulation of human basophils; conversely, little is known about the biochemical pathways activated by IL-3 and GM-CSF. The aim of this study was to evaluate the effects of TK and PI3-K inhibitors on basophil histamine release induced by anti-IgE, IL-3 and GM-CSF. Since IL-3 and GM-CSF cause histamine release from normal human basophils only when the inhibitory effect of extracellular Na(+) has been removed, peripheral blood leukocytes were suspended in isotonic solutions containing either 140 mM NaCl or 140 mM N-methyl-D-glucamine(+). After stimulation with anti-IgE, IL-3 or GM-CSF, histamine release was measured by an automated fluorometric method. The effects of preincubation with four different TK inhibitors (AG-126, genistein, lavendustin A, tyrphostin 51) and one PI3-K inhibitor (wortmannin) were evaluated. AG-126, genistein and lavendustin A exerted a significant dose-dependent inhibitory effect on basophil histamine release induced by anti-IgE (either in high or in low Na(+) medium), IL-3 and GM-CSF. Among the TK inhibitors, lavendustin A exerted the most potent activity, followed by AG-126 and genistein. Tyrphostin 51 caused a weak inhibition of histamine release induced by IL-3, GM-CSF and anti-IgE in a low Na(+) medium, but not in a physiological Na(+)-containing medium. The PI3-K inhibitor wortmannin exerted the most effective inhibitory activity on the histamine release induced by the three agonists. The combined effects of lavendustin A and wortmannin were less than additive, suggesting that TK and PI3-K are involved in the same activation pathway in human basophils. These results suggest a possible role of TK and PI3-K in basophil histamine release induced by anti-IgE, IL-3 and GM-CSF. TK and PI3-K are indeed potential therapeutic targets for antiallergic drugs.

Favourable outcome of a case of pulmonary Langerhans' cell histiocytosis.

Pulmonary Langerhans' cell histiocytosis and eosinophilic granuloma are the terms used to describe a Langerhans' cell granulomatous interstitial lung disease of unknown aetiology, occurring predominantly in smokers and involving primarily lungs, bones, skin and lymph nodes. In this report a patient with fever, fatigue, dyspnoea, nocturnal perspiration and thoracic pain is described. The high-resolution computed tomography of the chest and histological examination of lung biopsies suggested the diagnosis of pulmonary Langerhans' cell histiocytosis. The disease was limited to the lung, since further investigations did not show any other localization. The patient had a good clinical outcome with avoidance of smoking and steroid therapy. The computed tomography scan follow-up showed a partial resolution of pulmonary lesions.

Nasal response to a single antigen challenge in patients with allergic rhinitis - inflammatory cell recruitment persists up to 48 hours.

BACKGROUND: Allergen challenge in some patients with respiratory allergy is followed by an early and a late reaction. OBJECTIVE: To evaluate the duration of mediator release and inflammatory cell recruitment during the late antigen-induced nasal response. METHODS: Eight patients with seasonal allergic rhinitis due to grass pollen underwent local challenge with the relevant allergen, a non-relevant allergen (Parietaria judaica), and nebulized saline solution. Nasal lavages were performed at baseline and 6, 24, 48, 72 h after challenge. Eosinophil cationic protein (ECP), leukotriene C4 (LTC4), leukotriene B4 (LTB4) myeloperoxidase (MPO) and prostaglandin D2 (PGD2) levels were radioimmunoassayed and histamine concentration was measured by an automated fluorometric method. RESULTS: Nasal challenge with the relevant antigen induced a response 6 h after stimulation, which subsided within 24 h. Eosinophilia, observed in the nasal lavages collected from 6 to 24 h after this challenge, was accompanied by ECP release. Neutrophilia were found in the nasal lavages collected from 6 to 24 h after challenge. The increase in neutrophil number correlated with MPO levels and LTB4 concentrations, but not with the intensity of nasal obstruction. Antigen challenge also induced significant recruitment of mononuclear cells 48 h after provocation. The challenge significantly raised histamine, but not PGD2, levels in the nasal lavages collected 6 h after provocation. A trend towards an increase in LTC4 levels in the nasal lavages collected 6 h after specific antigen challenge was also found. Nasal challenge with a non-relevant allergen or with saline solution did not cause either inflammatory cell recruitment or mediator release. CONCLUSION: Nasal challenge with the relevant antigen can induce a late response characterized by local accumulation of eosinophils, neutrophils and mononuclear cells persisting for 48 h and accompanied by release of ECP, MPO, LTB4 and histamine. These results indicate that a single antigen challenge in patients with allergic rhinitis causes prolonged inflammatory alterations which may contribute to the development of airway hyperreactivity.

Expression of cytokine mRNA in bronchoalveolar lavage cells from atopic asthmatics before late antigen-induced reaction.

Recently, much attention has been given to the possible role of lymphocytes and their soluble products in causing and maintaining allergic inflammation. The aim of this study was to assess the production of mRNAs for interleukins (IL) in bronchoalveolar lavage (BAL) cells obtained from allergic asthmatics after challenge with the relevant allergen in the period between early and late reactions. We evaluated BAL fluid cells obtained from six asthmatic subjects and four nonatopic controls. Challenge was performed with the relevant allergen. BAL fluid cells were obtained by fiberoptic bronchoscopy and bronchoalveolar lavage. To detect mRNA encoding each cytokine in BAL cells we used a reverse transcriptase polymerase chain reaction method. We evaluated IL-1 alpha, -2, -4, -5, -6, -13, and granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon-gamma (IFN-gamma). mRNAs for IL-1 alpha, -2, -4, -5, and IFN-gamma were detected in all of the atopic subjects; mRNAs for IL-6 and GM-CSF were found in five asthmatics; and mRNA for IL-13 was found in one patient only. In contrast, no mRNAs for IL-2, -4, -5, -6, -13, and GM-CSF were detected in the nonatopic healthy controls; mRNA for IL-1 alpha was found in one out of four normal subjects; and mRNA for IFN-gamma was evidenced in two of four subjects. The cellular environment in BAL fluids from allergic asthmatics before the clinical appearance of the late airway reaction shows an unrestricted expression of mRNA for cytokines. The local cytokine milieu could have an important role in the modulation of bronchial inflammation and in the appearance of allergic symptoms.

Prevalence and clinical significance of antiphospholipid antibodies to noncardiolipin antigens in systemic lupus erythematosus.

The specificity and immunoglobulin isotype distribution of antiphospholipid (aPL) antibodies have been evaluated in 68 patients with systemic lupus erythematosus (SLE) by ELISA which employed a panel of 7 different PL antigens. A total of 49 patients (72%) were positive for aPL antibodies of different isotypes and directed to one or more PL epitopes. Prevalence of IgG anticardiolipin (aCL, 37%) was similar to that of the other negatively charged PLs phosphatidylserine (PS, 35%), phosphatidylinositol (PI, 35%), phosphatidylglycerol (PG, 35%) and phosphatidic acid (PA, 40%); prevalence reduced to 9-12% and 7-16% respectively for IgM and IgA isotypes to the same antigens. aPL antibodies to the zwitterionic PLs phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were also observed, though their prevalence was lower than that demonstrated for negatively charged PLs. Of the 36 SLE patients who were aCL negative (53%), 17 (25% of all patients and 47% of aCL-negative patients) were positive for aPL antibodies of different isotypes to one or more non-CL epitopes. During a mean follow-up period of 30 months, 10 patients had deep vein thrombosis (DVT) with a total of 21 events. By chi 2 test, a significant correlation was found between DVT and IgG aCL (p = 0.03) and between this event and the presence of lupus anticoagulant (LA) antibody (p = 0.04). However, stronger correlations were demonstrated between DVT and IgA aCL (p = 0.007), IgG anti-PS (p = 0.02), and IgA anti-PC, -PI and -PG (p = 0.02, 0.003 and 0.02, respectively), whereas no correlation was found between thrombotic events and aPL antibodies with PE and PA specificities.(ABSTRACT TRUNCATED AT 250 WORDS)