Galectin-9 enhances cytokine secretion, but suppresses survival and degranulation, in human mast cell line

Galectin-9 (Gal-9), a lectin having a β-galactoside-binding domain, can induce apoptosis of Th1 cells by binding to TIM-3. In addition, Gal-9 inhibits IgE/Ag-mediated degranulation of mast cell/basophilic cell lines by binding to IgE, thus blocking IgE/Ag complex formation. However, the role of Gal-9 in mast cell function in the absence of IgE is not fully understood. Here, we found that recombinant Gal-9 directly induced phosphorylation of Erk1/2 but not p38 MAPK in a human mast cell line, HMC-1, which does not express FcεRI. Gal-9 induced apoptosis and inhibited PMA/ionomycin-mediated degranulation of HMC-1 cells. On the other hand, Gal-9 induced cytokine and/or chemokine production by HMC-1 cells, dependent on activation of ERK1/2 but not p38 MAPK. In addition, the lectin activity of Gal-9 was required for Gal-9-mediated cytokine secretion by HMC-1 cells. These observations suggest that Gal-9 has dual properties as both a regulator and an activator of mast cells.

Two tracheal BALT lymphoma patients successfully treated with chemotherapy including rituximab

Bronchus-associated lymphoid tissue (BALT) lymphoma of the trachea, an important differential diagnosis for tracheal tumors, is a rare disease with characteristic bronchoscopic findings. In this study, we reviewed 2 cases of patients who were symptomatic at the time of diagnosis, with tumors in the trachea and left main bronchus, putting them at high risk for asphyxia. Chemotherapies including rituximab were administered, and complete remission was confirmed in both cases. Because tracheal tumors often have a pernicious course, it might be beneficial to initiate a chemotherapeutic treatment regimen instead of adopting the "wait-and-see" approach in patients with symptomatic tracheal BALT lymphoma.

Effect of lifestyle on asthma control in Japanese patients: importance of periodical exercise and raw vegetable diet

Background

The avoidance of inhaled allergens or tobacco smoke has been known to have favorable effects on asthma control. However, it remains unclear whether other lifestyle-related factors are also related to asthma control. Therefore, a comprehensive study to examine the associations between various lifestyle factors and asthma control was conducted in Japanese asthmatic patients.

Methods

The study subjects included 437 stable asthmatic patients recruited from our outpatient clinic over a one-year period. A written, informed consent was obtained from each participant. Asthma control was assessed using the asthma control test (ACT), and a structured questionnaire was administered to obtain information regarding lifestyle factors, including tobacco smoking, alcohol drinking, physical exercise, and diet. Both bivariate and multivariate analyses were conducted.

Results

The proportions of total control (ACT = 25), well controlled (ACT = 20-24), and poorly controlled (ACT < 20) were 27.5%, 48.1%, and 24.5%, respectively. The proportions of patients in the asthma treatment steps as measured by Global Initiative for Asthma 2007 in step 1, step 2, step 3, step 4, and step 5 were 5.5%, 17.4%, 7.6%, 60.2%, and 9.4%, respectively. Body mass index, direct tobacco smoking status and alcohol drinking were not associated with asthma control. On the other hand, younger age (< 65 years old), passive smoking, periodical exercise (> 3 metabolic equivalents-h/week), and raw vegetable intake (> 5 units/week) were significantly associated with good asthma control by bivariate analysis. Younger age, periodical exercise, and raw vegetable intake were significantly associated with good asthma control by multiple linear regression analysis.

Conclusions

Periodical exercise and raw vegetable intake are associated with good asthma control in Japanese patients.

[A case of an asthma patient receiving omalizumab during pregnancy]

We describe the first report in Japan of a woman who received omalizumab during pregnancy and delivery. Her asthma was so severe that she had been taking systemic corticosteroids since 22 years old, but asthma was poorly controlled. She had been pregnant seven times before, but almost every time asthma control had worsened and spontaneous abortion resulted, so she had only one child. She confirmed that she was not intending to become pregnant, and initiated use of omalizumab in August 2009. However, pregnancy was identified after she had taken the drug 3 times. We explained the risks in detail, but the patient wanted to keep taking omalizumab, as her asthma control was improved and she thought she could continue the pregnancy. We therefore decided to continue with omalizumab therapy. In October, she caught a cold and experienced asthma exacerbation. Despite the risk, she decided to suspend omalizumab therapy after taking the drug 7 times, as she was not feeling any benefit from therapy. Threat of abortion was identified in February 2010, so a 544-g female baby was delivered at 26 weeks gestation by Cesarean section. The baby had to be hospitalized in the neonatal intensive care unit because of low birth weight, but she has been developing and growing without handicap. We report this case as the first known case of pregnancy and delivery for a woman receiving omalizumab in Japan. Omalizumab may be safe to use in pregnant women with difficult-to-control asthma.

The pharmacokinetics and long-term therapeutic effects of gefitinib in patients with lung adenocarcinoma harboring the epidermal growth factor receptor(EGFR)mutation

INTRODUCTION

The relationship between the pharmacokinetics and long-term antitumor activity of gefitinib in patients with epidermal growth factor receptor(EGFR)mutation-positive lung adenocarcinoma has not yet been clarified in clinical practice. The present study assessed the correlation between the pharmacokinetics and long-term therapeutic effects of gefitinib in patients with lung adenocarcinoma harboring the EGFR-activating mutation.

METHODS

Fifteen patients with lung adenocarcinoma harboring the EGFR mutation were administered 250 mg of gefitinib daily. Blood samples were collected prior to the first administration of gefitinib and after 1, 4, 6, 8, and 24 h. Plasma concentrations of gefitinib were measured via liquid chromatography mass spectrometry, and the peak plasma concentration(Cmax)and area under the plasma concentration time curve from 0 to 24 h(AUC 0-24)of gefitinib were determined. The correlations between these pharmacokinetic variables and the objective responses, including progression-free survival(PFS)and overall survival(OS), were retrospectively analyzed.

RESULTS

The Cmax of gefitinib in patients with a partial response(PR)was significantly lower than that of patients with stable disease(SD)(median Cmax: 278 vs 588 ng/mL, p<0.05 ). However, the Cmax of gefitinib did not correlate with longer PFS. Conversely, a significant negative correlation was found between the AUC 0-24 of gefitinib and longer survival(r=-0.545, p<0.05 ).

CONCLUSIONS

It may be possible that a high concentration of gefitinib is not necessary to achieve long-term therapeutic effects in patients with lung adenocarcinoma harboring the EGFR mutation.

Increased risk of nontuberculous mycobacterial infection in asthmatic patients using long-term inhaled corticosteroid therapy

BACKGROUND AND OBJECTIVE

The risk of pneumonia is increased among COPD patients using inhaled corticosteroids (ICS). However, there is uncertainty regarding the association between long-term use of ICS and exacerbations of respiratory tract infections among asthmatic patients.

METHODS

A case-control nested cohort study was performed to assess the association of asthma with nontuberculous mycobacterium (NTM) infection.

RESULTS

Among this cohort of 464 asthmatic patients, 14 experienced complications due to NTM infections, of which eight were caused by Mycobacterium avium-intracellulare complex, three by M. kansasii, one by M.terrae and the remaining two by unclassifiable scotochromogens. Asthmatic patients with NTM infections were older (67.1 ± 8.6 vs 58.8 ± 12.3 years, P < 0.01) and had more severe airflow limitation (FEV(1) %, 60.6 ± 10.3 vs 72.3 ± 18.3, P < 0.03) than those without NTM infections. All except one had received ICS treatment for more than 5 years, and 12 of the 14 patients used inhaled fluticasone propionate daily (four patients at a dose of 400 µg/day and eight patients at a dose >800 µg/day).

CONCLUSIONS

These findings suggest that the risk of NTM infection may be greater in asthmatic patients who are older, have more severe airflow limitation and receive higher doses of ICS therapy.

[Efficacy of combination therapy with EGFR-TKI and cytotoxic drug in lung adenocarcinoma already treated with EGFR-TKI]

OBJECITVE: To assess the efficacy of combination therapy with EGFR-TKI and a cytotoxic drug in lung adenocarcinoma already being treated with EGFR-TKI.

METHODS

Eight patients with adenocarcinoma who were treated with combination therapy of EGFR-TKI and a cytotoxic drug between April 2008 and December 2010 were retrospectively evaluated for response rate, disease-control rate, progression-free survival(PFS), time-to-treatment-failure(TTF)and overall survival(OS).

RESULTS

Among the 7 patients with tumor samples available, EGFR-mutations were detected in six.The median number of prior therapy regimens received by the patients was 5.All the patients had been treated before with both gefitinib and erlotinib.Among 8 patients, six showed stable disease, including three patients intolerant because of severe hematological toxicities, and 2 with progressive disease.The disease-control rate was 75%, and median TTF, PFS, and OS were 42 days, 84 days, and 495 days, respectively.

CONCLUSION

Combination therapy with EGFR-TKI and a cytotoxic drug after the failure of EGFR-TKI may be a useful therapeutic option for selected patients.

[Clinical study concerning anti-inflammatory effect of fixed dose therapy by budesonide/formoterol combination inhaler for moderate persistent asthmatics]

BACKGROUND

The clinical usefulness of fixed dose maintenance therapy using a combination inhaler containing budesonide and formoterol (FBC) has already been established, still evidence concerning anti-inflammatory effect by maintenance therapy with fix-dosed FBC, in comparison with other ICS and LABA combination therapy including salmeterol/fluticasone combination inhaler, is lacking.

METHODS

Moderate persistent adult asthmatics who has received combination therapy of ICS (200∼500 μg/day FP equivalent) and LABA (salmeterol 100 μg/day) for more than 6 months and under well-control conditions by asthma control test (ACT) have been recruited. FeNO, as a marker of airway inflammation, ACT score, and the results of spirometry have been evaluated after switching to maintenance therapy by FBC 640/18 μg/day for 8 weeks.

RESULTS

The fixed dosed FBC therapy resulted in superior primary outcome, as compared with previous ICS/LABA combination therapy, as assessed by measuring FeNO, 44.0±26.5 to 31.3± 15.4 ppb (p<0.01, paired-t test). ACT score also improved significantly, 22.22±1.57 to 23.88±1.57 (p<0.01). The number of patients who used SABA more than once a week has decreased 13 to 0 with FBC treatment.

CONCLUSION

The airway anti-inflammatory effect by 8 weeks maintenance therapy with fix-dosed FBC 640/18 μg/day (2 puffs twice a day) has been strongly suggested.

Paracrine IL-33 stimulation enhances lipopolysaccharide-mediated macrophage activation

Background

IL-33, a member of the IL-1 family of cytokines, provokes Th2-type inflammation accompanied by accumulation of eosinophils through IL-33R, which consists of ST2 and IL-1RAcP. We previously demonstrated that macrophages produce IL-33 in response to LPS. Some immune responses were shown to differ between ST2-deficient mice and soluble ST2-Fc fusion protein-treated mice. Even in anti-ST2 antibody (Ab)-treated mice, the phenotypes differed between distinct Ab clones, because the characterization of such Abs (i.e., depletion, agonistic or blocking Abs) was unclear in some cases.

Methodology/Principal Findings

To elucidate the precise role of IL-33, we newly generated neutralizing monoclonal Abs for IL-33. Exogenous IL-33 potentiated LPS-mediated cytokine production by macrophages. That LPS-mediated cytokine production by macrophages was suppressed by inhibition of endogenous IL-33 by the anti-IL-33 neutralizing mAbs.

Conclusions/Significance

Our findings suggest that LPS-mediated macrophage activation is accelerated by macrophage-derived paracrine IL-33 stimulation.

Cough challenge tests involving mechanical stimulation of the cervical trachea in patients with cough as a leading symptom

BACKGROUND AND OBJECTIVE

Challenge tests involving chemical stimulation by inhalation of capsaicin or citric acid are currently used to assess cough sensitivity. We investigated the clinical usefulness of cough challenge tests based on mechanical stimulation.

METHODS

A total of 347 patients (126 men and 221 women) were enrolled in the study, including 161 patients with asthma, 116 with cough-variant asthma, 27 with acute upper respiratory tract viral infections, 25 with acute bronchitis, four with pneumonia, three with chronic bronchitis and 11 with cough of unknown aetiology. Three modes of mechanical stimulation were assessed: the cervical trachea was compressed softly with the fingers several times (tracheal compression test); the trachea was stretched by retroflexion of the neck for 5 s (tracheal stretch test); and a vibrating tuning fork was placed on the cervical trachea for 20 s (tuning fork test). The relationships between phonation-induced cough and the results of these tests were assessed.

RESULTS

The cough detection rate was 27.7% with the tracheal compression test, 39.8% with the tracheal stretch test and 36.9% with the tuning fork test. An itchy sensation with or without cough was noted by about 50% of subjects undergoing each of the tests. Provocation of cough and an itchy sensation during each test was significantly more frequent in subjects with phonation-induced cough. Tests were usually negative after improvement of the cough with treatment.

CONCLUSIONS

Mechanical stimulation of the cervical trachea is a feasible cough challenge test that may be useful for evaluating disease activity.

Human basophils and cytokines/chemokines

Basophils comprise the smallest population in human peripheral blood leukocytes. The role of basophils in the pathogenesis of allergic diseases has long been obscure, although their accumulation and activation in tissues have suggested their potential importance. Recent advances in the field of basophil biology have indicated that cytokines and chemokines are the primary regulators of basophil functions. In addition, various functions of these cells seem differently modulated. The evidence strongly supports the notion that basophils exposed to these substances and allergens will behave as unique effector cells that presumably play proinflammatory roles in type I allergic reactions.

An IL-1 cytokine member, IL-33, induces human basophil activation via its ST2 receptor

Basophils are thought to play pivotal roles in allergic inflammation through rapid release of chemical mediators in addition to sustained production of Th2 cytokines, including IL-4. A newly identified cytokine, IL-33, has been recognized as one of the key cytokines enhancing Th2-balanced immune regulation through its receptor, ST2. The present study was conducted to elucidate whether IL-33 acts directly on, and affects the functions of, human basophils. Real-time PCR analysis showed that basophils express transcripts for ST2. The expression levels were significantly higher compared with eosinophils and neutrophils, and treatment with IL-33 significantly up-regulated basophil ST2 mRNA expression. Expressions of IL-4 and IL-13 mRNA were also up-regulated by IL-33, and there was also enhanced secretion of IL-4 protein. IL-33 increased the surface levels of basophil CD11b expression and enhanced basophil adhesiveness. Although IL-33 failed to directly induce degranulation or attract basophils, it exerted priming effects on basophils. It enhanced degranulation in response to IgE-crosslinking stimulus and also enhanced basophil migration toward eotaxin without changing surface CCR3. Also, IL-33 synergistically enhanced IL-4 production and CD11b expression by IL-3-stimulated basophils. Neutralization using Ab specific for ST2 significantly diminished the enhancing effects of IL-33 on both basophil CD11b expression and migration toward eotaxin, indicating that IL-33 signals via ST2 expressed on basophils. This study revealed that IL-33 potently regulates migration and activation of human basophils. IL-33 may be a key cytokine in the pathogenesis of Th2-dominant inflammation by acting not only on lymphocytes but also on effector cells such as basophils.

Interleukin-33 enhances adhesion, CD11b expression and survival in human eosinophils

Eosinophils are important effector cells in allergic diseases, but the mechanisms regulating their biological functions remain obscure. Interleukin-33 (IL-33) is a recently identified cytokine of the IL-1 family, and it reportedly accelerates the production of Th2-associated cytokines and promotes tissue inflammation. However, the action of IL-33 on effector cells such as eosinophils has remained unclear. In this study, we investigated the effects of IL-33 on eosinophil activation, assessed in terms of the cells' adhesiveness, expression of CD11b and apoptosis. Adhesiveness was quantified by measuring eosinophil peroxidase content of adherent eosinophils, and expression of CD11b was measured by flow cytometry. Apoptosis was determined by flow cytometry based on the ability of cells to bind annexin V. Real-time PCR analysis showed that eosinophils expressed mRNA for ST2, a putative receptor for IL-33. IL-33 at 1-100 ng/ml enhanced the adhesiveness and CD11b expression of eosinophils even more potently than IL-5. IL-33 maintained the viability of eosinophils. Treatment with neutralizing antibodies to ST2 eliminated the effects of IL-33 on eosinophil CD11b expression and cell survival. However, IL-33 did not elicit degranulation or leukotriene C4 synthesis in eosinophils. These findings indicate that IL-33 potently induces eosinophil adhesion and CD11b expression and enhances eosinophil survival. The IL-33-ST2 pathway might be an important regulator of eosinophil biology in the pathogenesis of Th2-biased allergic diseases.

IL-33 can promote survival, adhesion and cytokine production in human mast cells

IL-33 is a recently identified member of the IL-1 family of molecules, which also includes IL-1 and IL-18. IL-33 binds to the receptor, T1/ST2/IL-1R4, and can promote cytokine secretion by Th2 cells and NF-kappaB phosphorylation in mouse mast cells. However, the effects of these molecules, especially IL-33, in human mast cells are poorly understood. Expression of the receptors for IL-1 family molecules, specifically, IL-1R1, IL-18R and T1/ST2, was detectable intracellularly in human umbilical cord blood-derived mast cells (HUCBMCs) by flow cytometry, but was scarcely detectable on the cells' surface. However, IL-1beta, IL-18 or IL-33 induced phosphorylation of Erk, p38 and JNK in naïve HUCBMCs, and IL-33 or IL-1beta, but not IL-18, enhanced the survival of naive HUCBMCs and promoted their adhesion to fibronectin. IL-33 or IL-1beta also induced IL-8 and IL-13 production in naïve HUCBMCs, and enhanced production of these cytokines in IgE/anti-IgE-stimulated HUCBMCs, without enhancing secretion of either PGD(2) or histamine. Moreover, IL-33-mediated IL-8 production by HUCBMCs was markedly reduced by the p38 MAPK inhibitor, SB203580. In contrast to findings with mouse mast cells, IL-18 neither induced nor enhanced secretion of the mediators PGD(2) or histamine by HUCBMCs. Our findings identify previously unknown functions of IL-33 in human mast cells. One of these is that IL-33, like IL-1beta, can induce cytokine production in human mast cells even in the absence of stimuli of FcepsilonRI aggregation. Our findings thus support the hypothesis that IL-33 may enhance mast cell function in allergic disorders and other settings, either in the presence or absence of co-stimulation of mast cells via IgE/antigen-FcepsilonRI signals.

IL-33 induces IL-13 production by mouse mast cells independently of IgE-FcepsilonRI signals

The IL-1-related molecules, IL-1 and IL-18, can promote Th2 cytokine production by IgE/antigen-FcepsilonRI-stimulated mouse mast cells. Another IL-1-related molecule, IL-33, was identified recently as a ligand for T1/ST2. Although mouse mast cells constitutively express ST2, the effects of IL-33 on mast cell function are poorly understood. We found that IL-33, but not IL-1beta or IL-18, induced IL-13 and IL-6 production by mouse bone marrow-derived, cultured mast cells (BMCMCs) independently of IgE. In BMCMCs incubated with the potently cytokinergic SPE-7 IgE without specific antigen, IL-33, IL-1beta, and IL-18 each promoted IL-13 and IL-6 production, but the effects of IL-33 were more potent than those of IL-1beta or IL-18. IL-33 promoted cytokine production via a MyD88-dependent but Toll/IL-1R domain-containing adaptor-inducing IFN-beta-independent pathway. By contrast, IL-33 neither induced nor enhanced mast cell degranulation. At 200 ng/ml, IL-33 prolonged mast cell survival in the absence of IgE and impaired survival in the presence of SPE-7 IgE, whereas at 100 ng/ml, IL-33 had no effect on mast cell survival in the absence of IgE and reduced mast cell survival in the presence of IgE. These observations suggest potential roles for IL-33 in mast cell- and Th2 cytokine-associated immune responses and disorders.

TIM-1 and TIM-3 enhancement of Th2 cytokine production by mast cells

Members of the T-cell immunoglobulin- and mucin-domain-containing molecule (TIM) family have roles in T-cell-mediated immune responses. TIM-1 and TIM-2 are predominantly expressed on T helper type 2 (Th2) cells, whereas TIM-3 is preferentially expressed on Th1 and Th17 cells. We found that TIM-1 and TIM-3, but neither TIM-2 nor TIM-4, were constitutively expressed on mouse peritoneal mast cells and bone marrow-derived cultured mast cells (BMCMCs). After IgE + Ag stimulation, TIM-1 expression was down-regulated on BMCMCs, whereas TIM-3 expression was up-regulated. We also found that recombinant mouse TIM-4 (rmTIM-4), which is a ligand for TIM-1, as well as an anti-TIM-3 polyclonal Ab, can promote interleukin-4 (IL-4), IL-6, and IL-13 production without enhancing degranulation in BMCMCs stimulated with IgE + Ag. Moreover, the anti-TIM-3 Ab, but neither anti-TIM-1 Ab nor rmTIM-4, suppressed mast-cell apoptosis. These observations suggest that TIM-1 and TIM-3 may be able to influence T-cell-mediated immune responses in part through effects on mast cells.

Mast cell-derived TNF contributes to airway hyperreactivity, inflammation, and TH2 cytokine production in an asthma model in mice

BACKGROUND

Mast cells, IgE, and TNF, which have been implicated in human atopic asthma, contribute significantly to the allergic airway inflammation induced by ovalbumin (OVA) challenge in mice sensitized with OVA without alum. However, it is not clear to what extent mast cells represent a significant source of TNF in this mouse model.

OBJECTIVE

We investigated the importance of mast cell-derived TNF in a mast cell-dependent model of OVA-induced airway hyperreactivity (AHR) and allergic airway inflammation.

METHODS

Features of this model of airway inflammation were analyzed in C57BL/6J-wild-type mice, mast cell-deficient C57BL/6J-Kit(W-sh)(/W-sh) mice, and C57BL/6J Kit(W-sh/W-sh) mice that had been systemically engrafted with bone marrow-derived cultured mast cells from C57BL/6J-wild-type or C57BL/6J-TNF(-/-) mice.

RESULTS

Ovalbumin-induced AHR and airway inflammation were significantly reduced in mast cell-deficient Kit(W-sh/W-sh) mice versus wild-type mice. By contrast, Kit(W-sh/W-sh) mice that had been engrafted with wild-type but not with TNF(-/-) bone marrow-derived cultured mast cells exhibited responses very similar to those observed in wild-type mice. Mast cells and mast cell-derived TNF were not required for induction of OVA-specific memory T cells in the sensitization phase, but significantly enhanced lymphocyte recruitment and T(H)2 cytokine production in the challenge phase.

CONCLUSION

Mast cell-derived TNF contributes significantly to the pathogenesis of mast cell-dependent and IgE-dependent, OVA-induced allergic inflammation and AHR in mice, perhaps in part by enhancing lymphocyte recruitment and T(H)2 cytokine production.

CLINICAL IMPLICATIONS

Our findings in mice support the hypothesis that mast cell-derived TNF can promote allergic inflammation and AHR in asthma.

IgE- and FcepsilonRI-mediated enhancement of surface CD69 expression in basophils: role of low-level stimulation

Surface-expressed CD69 is a recently recognized activation marker for basophils and is reported to be strongly induced in vitro by IL-3. In this study, we investigated whether IgE- and high-affinity receptor for IgE (FcepsilonRI)-dependent stimuli can affect basophil CD69 expression. Highly purified basophils were cultured for 24 h in the presence of anti-FcepsilonRI alpha-chain mAb, CRA-1 and IL-3, and surface CD69 expression was analyzed by flow cytometry. CRA-1 mAb at 1 ng/ml or lower concentrations, levels too low to provoke direct histamine release, dose-dependently enhanced surface CD69 expression in the presence of IL-3, although low-dose CRA-1 mAb failed to induce CD69 expression in the absence of IL-3. Recombinant Der f 2 at 10 to 100 pg/ml enhanced CD69 levels in the presence of IL-3 in basophils from mite-sensitive subjects. These results suggest that allergens may influence basophil CD69 expression even when the levels of the antigens are too low to trigger direct degranulation. Upregulated CD69 expression on locally accumulated basophils in bronchial asthma may be attributed at least in part to a combination of local cytokines, especially IL-3, plus exposure to low levels of IgE-crosslinking allergens.

Trans-basement membrane migration of human basophils: role of matrix metalloproteinase-9

In allergic disorders, basophils migrate from the blood stream to inflamed tissue sites. Since trans-basement membrane migration is an important step for local basophil accumulation, we performed a human basophil transmigration assay using a model basement membrane, Matrigel. IL-3 in the upper chamber was critical for basophil trans-basement membrane migration over baseline levels, since none of the chemoattractants placed in the lower chambers induced migration. RANTES, IL-8, 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE) and platelet-activating factor (PAF) significantly up-regulated the transmigration of IL-3-treated basophils. Neutralizing experiments indicated the involvement of beta2 integrin and matrix metalloproteinase (MMP)-2/9 in basophil transmigration. Real-time quantitative PCR revealed that basophils constitutively expressed transcripts for MMP-9, and at lower levels, MMP-2, but cell-surface expression was only detected for MMP-9. MMP-9 was also detected in the cytoplasm and culture supernatant of the basophils. Treatment with IL-3 up-regulated the surface level of MMP-9 on the basophils. Our results suggest that basophils possess a unique regulatory mechanism for trans-basement membrane migration which is affected by cytokines, chemoattractants, beta2 integrin and MMPs, especially MMP-9. MMP-9 may be critically involved in the pathogenesis of local basophil influx in allergic diseases.

Mast Cells Enhance T Cell Activation: Importance of Mast Cell Costimulatory Molecules and Secreted TNF

We recently reported that mast cells stimulated via FcepsilonRI aggregation can enhance T cell activation by a TNF-dependent mechanism. However, the molecular mechanisms responsible for such IgE-, Ag- (Ag-), and mast cell-dependent enhancement of T cell activation remain unknown. In this study we showed that mouse bone marrow-derived cultured mast cells express various costimulatory molecules, including members of the B7 family (ICOS ligand (ICOSL), PD-L1, and PD-L2) and the TNF/TNFR families (OX40 ligand (OX40L), CD153, Fas, 4-1BB, and glucocorticoid-induced TNFR). ICOSL, PD-L1, PD-L2, and OX40L also are expressed on APCs such as dendritic cells and can modulate T cell function. We found that IgE- and Ag-dependent mast cell enhancement of T cell activation required secreted TNF; that TNF can increase the surface expression of OX40, ICOS, PD-1, and other costimulatory molecules on CD3(+) T cells; and that a neutralizing Ab to OX40L, but not neutralizing Abs to ICOSL or PD-L1, significantly reduced IgE/Ag-dependent mast cell-mediated enhancement of T cell activation. These results indicate that the secretion of soluble TNF and direct cell-cell interactions between mast cell OX40L and T cell OX40 contribute to the ability of IgE- and Ag-stimulated mouse mast cells to enhance T cell activation.

Monomeric IgE enhances human mast cell chemokine production: IL-4 augments and dexamethasone suppresses the response

BACKGROUND

Mouse monoclonal IgE antibodies can promote the survival of mouse bone marrow-derived cultured mast cells and induce the cells to secrete mediators in the absence of known specific antigen.

OBJECTIVE

To determine whether human IgE, in the absence of known specific antigen, had effects on the mediator secretion or survival of human mast cells.

METHODS

We tested whether human IgE induced human cord blood-derived mast cells to secrete mediators or enhanced their survival on withdrawal of stem cell factor.

RESULTS

Exposure to IgE, but not IgG, at concentrations as low as 2.5 microg/mL significantly enhanced the release of IL-8 and monocyte chemoattractant protein 1, but not histamine or cysteinyl leukotrienes. However, under the conditions tested, chemokine production in response to IgE alone was significantly less than that induced when aliquots of the same IgE-sensitized populations of human mast cells were stimulated with anti-IgE. The production of IL-8 and monocyte chemoattractant protein 1 in response to either IgE alone or IgE and anti-IgE was enhanced by preincubation of the cells in IL-4 and was inhibited by preincubation of the cells with dexamethasone. By contrast, we did not detect any ability of IgE to enhance mast cell survival on withdrawal of stem cell factor.

CONCLUSION

Exposure to human IgE in vitro in the absence of known specific antigen can enhance chemokine production by human mast cells, and this secretory response can be enhanced by preincubation of the mast cells with IL-4 and can be suppressed by dexamethasone.

5-Lipoxygenase products regulate basophil functions: 5-Oxo-ETE elicits migration, and leukotriene B4 induces degranulation

BACKGROUND

5-Lipoxygenase (5-LO) products have been strongly implicated in the pathogenesis of allergic diseases. In addition to their physiologic effects on residential cells, 5-LO products are capable of stimulating various eosinophil functions. However, little is known regarding the effects of 5-LO products on basophil functions.

OBJECTIVE

This study was designed to elucidate the effects of the main 5-LO products (ie, leukotriene [LT] B(4), LTD(4), and 5-oxo-6,8,11,14-eicosatetraenoic acid [5-oxo-ETE]), as well as their receptor expression on human basophils.

METHODS

We studied the effects of 5-LO products on Ca(2+) mobilization, migration, CD 11b expression, and degranulation of human basophils. Expression of the receptors for LTC(4)/D(4)/E(4) (cysteinyl leukotriene 1 [CysLT(1)] and CysLT(2)), LTB4 (BLT(1) and BLT(2)), and 5-oxo-ETE (oxoeicosanoid [OXE]) was assessed by means of real-time PCR and flow cytometry.

RESULTS

At the mRNA level, basophils strongly expressed OXE and predominantly expressed CysLT(1) and BLT(2). The expression level of OXE mRNA in basophils was approximately 20-fold higher than in neutrophils and similar to that in eosinophils. At the protein level, basophils expressed CysLT(1), CysLT(2), BLT(1), and OXE, but not BLT(2). All products elicited a transient increase of cytosolic calcium, with the order of magnitude being LTB(4)>5-oxo-ETE>LTD(4). 5-Oxo-ETE induced a strong basophil migratory response that was almost equivalent to that of prostaglandin D(2). LTB(4) elicited significant degranulation of IL-3-primed basophils. In contrast, no functional significance was observed for LTD(4).

CONCLUSION

Among 5-LO products, 5-oxo-ETE induces a potent basophil migratory response, and LTB(4) elicits degranulation under certain conditions. Our results strongly suggest that 5-oxo-ETE might afford opportunities for therapeutic targeting in allergic inflammation.

IgE- and FcepsilonRI-mediated migration of human basophils

Local accumulation of basophils at inflammatory sites is observed in experimental antigen challenge and in allergic diseases. It is not fully known what factor(s) regulates local basophil influx in tissues, and it has not been determined whether antigens belong in a panel of basophil chemoattractants. This study was designed to elucidate whether IgE- and high-affinity receptor for IgE (FcepsilonRI)-mediated stimulation can induce human basophil migration. The migration-inducing potency of an anti-FcepsilonRI alpha-chain mAb, CRA-1, was examined on human basophils. CRA-1 mAb elicited significant migration of basophils. The migration-inducing potency of this mAb was maximal at 100 ng ml-1, and CRA-1 mAb at 100 ng ml-1 attracted approximately 10% of total inoculated basophils above baseline levels after incubation for 2.5 h. Checkerboard analysis indicated that basophil migration induced by this mAb was mainly chemotactic and partially chemokinetic. An antigen, Der f 2, also induced migration of basophils from Der f-sensitive subjects. Basophils mixed with 1 ng ml-1 of CRA-1 mAb showed an exaggerated migration response to eotaxin, indicating that FcepsilonRI cross-linkage enhances basophil migration to other chemoattractants. Induction of basophil migration by IgE- and FcepsilonRI-cross-linking stimulation may, at least in part, explain the pathogenesis of local basophil accumulation clinically observed in allergic diseases such as asthma.

Transendothelial migration of human basophils

During allergic reactions, basophils migrate from the blood compartment to inflammatory sites, where they act as effector cells in concert with eosinophils. Because transendothelial migration (TEM) represents an essential step for extravasation of cells, for the first time we have studied basophil TEM using HUVEC. Treatment of HUVEC with IL-1beta significantly enhanced basophil TEM, which was further potentiated by the presence of a CCR3-specific ligand, eotaxin/CCL11. In addition to CCR3 ligands, MCP-1/CCL2 was also active on basophil TEM. Although stromal cell-derived factor-1/CXCL12, a CXCR4 ligand, failed to induce TEM in freshly isolated basophils, it caused strong TEM in 24-h cultured cells. IL-3 enhanced basophil TEM by increasing the chemokinetic response. Spontaneous TEM across activated HUVEC was inhibited by treatment of cells with anti-CD18 mAb, but not with anti-CD29 mAb, and also by treatment of HUVEC with anti-ICAM-1 mAb. Anti-VCAM-1 mAb alone failed to inhibit TEM, but showed an additive inhibitory effect in combination with anti-ICAM-1 mAb. In contrast, eotaxin- and IL-3-mediated TEM was significantly inhibited by anti-CD29 mAb as well as anti-CD18 mAb. These results indicate that beta2 integrins play the primary role in basophil TEM, but beta1 integrins are also involved, especially in TEM of cytokine/chemokine-stimulated basophils. In conclusion, the regulatory profile of basophil TEM is very similar to that reported for eosinophils. Our results thus support the previous argument for a close relationship between basophils and eosinophils and suggest that the in vivo kinetics of these two cell types are similar.

Differential modulation of human basophil functions through prostaglandin D2 receptors DP and chemoattractant receptor-homologous molecule expressed on Th2 cells/DP2

BACKGROUND

Both prostaglandin (PG) D receptor (DP) and CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells)/DP2 are high-affinity receptors for PGD2. Previous studies have demonstrated that PGD2 enhances releasability and induces CRTH2/DP2-mediated migration in human basophils, but the precise effects of PGD2 on basophils as well as receptor usage have not been fully clarified.

OBJECTIVE

We comprehensively explored the roles of DP and CRTH2/DP2 in basophil functions by using selective agonists and antagonists for each receptor.

METHODS

DP and CRTH2/DP2 transcripts were quantified by real-time PCR. We studied the effects of selective agonists (DP: BW245C; CRTH2/DP2: 13,14-dihydro-15-keto (DK)-PGD2) and/or antagonists (DP: BWA868C; CRTH2/DP2: ramatroban) on Ca2+ mobilization, migration, degranulation, CD11b expression and survival of human basophils.

RESULTS

Basophils expressed transcripts of both DP and CRTH2/DP2, but the levels of CRTH2/DP2 transcripts were ca. 100-fold higher compared with DP transcripts. Ca2+ influx was induced in basophils by either PGD2 or DK-PGD2/CRTH2 agonist but not by BW245C/DP agonist. Basophils treated with PGD2 were completely desensitized to subsequent stimulation with DK-PGD2, but not vice versa. DK-PGD2 as well as PGD2 up-regulated CD11b expression, induced migration and enhanced degranulation, and those effects were completely antagonized by ramatroban/CRTH2 antagonist. In contrast, BW245C/DP agonist exhibited an inhibitory effect on basophil migration and IgE-mediated degranulation, and the migration inhibitory effect was effectively antagonized by BWA868C/DP antagonist. On the other hand, while PGD2 significantly shortened the basophil life-span, neither DK-PGD2/CRTH2 agonist nor BW245C/DP agonist did.

CONCLUSION

CRTH2/DP2 is primarily responsible for the pro-inflammatory effects of PGD2 on human basophils, while DP introduces negative signals capable of antagonizing the effects of CRTH2/DP2 in these cells. The effects of PGD2 on longevity imply a mechanism(s) other than via DP or CRTH2/DP2. CRTH2/DP2 on basophils may afford opportunities for therapeutic targeting in allergic inflammation.

Identification of granulocyte subtype–selective receptors and ion channels by using a high-density oligonucleotide probe array

BACKGROUND

During inflammation, neutrophils, basophils, and eosinophils release cell type-specific mediators and proteases through signaling molecules, such as G protein-coupled receptors and ion channels. As such, ion channels and receptors, including G protein-coupled receptors, are common drug targets.

OBJECTIVE

We sought to identify, for the first time, ion channels and receptors preferentially expressed by each granulocyte subtype.

METHODS

Using GeneChip, we compared approximately 20,000 transcripts present in 7 leukocyte types, platelets, mast cells, and fibroblasts to identify granulocyte subtype-selective transcripts for receptors and ion channels. Granulocyte subtype-selective transcripts were chosen on the basis of several conditions, such as the transcript having a 5-fold or greater expression level compared with the maximum level of other leukocytes.

RESULTS

Fifty-one transcripts were chosen to be preferentially expressed by each granulocyte subtype. Seventeen of the 51 transcripts have not been previously reported as granulocyte subtype selective. Among the 17 receptors and ion channels, 6 were basophil selective, eosinophil selective, or both and were not highly expressed by other organs, indicating that they might be potential targets for antiallergy drugs.

CONCLUSION

Use of this database of potential cell type-selective drug targets should minimize the efforts required for pharmaceutical development.

[A case of eosinophilic lung disease presenting asthma-like symptoms and centrilobular shadows in both lung fields]

This case, in a 23-year-old man presenting with cough, sputum, dyspnea on effort and wheezing, had been diagnosed as bronchial asthma at another hospital. Because inhaled steroid and theophylline were far from effective, he was admitted to our hospital for further evaluation. A blood test revealed marked eosinophilia. Chest radiography showed diffuse, small nodular shadows in both lung fields, and a chest CT scan demonstrated diffuse centrilobular nodules and thickening of the bronchi and bronchioles. A spirometric test showed obstructive and restrictive ventilatory impairment, but the depressed forced vital capacity failed to show improvement in response to bronchodilator inhalation, discouraging a diagnosis of asthma. Eosinophilic lung disease with prominent eosinophilic bronchiolitis was diagnosed on the basis of BAL eosinophilia and thoracoscopic lung biopsy findings. The symptoms and blood eosinophilia were responsive to administration of oral prednisolone (30 mg daily); radiographic and CT findings also showed improvement. This case showed a marked similarity to the recently reported "eosinophilic bronchiolitis", and was probably not a type of bronchial asthma.

Induction of basophil desensitization in physiological medium: enhancement after IgE-dependent upregulation of surface IgE binding on basophils

BACKGROUND

Although the ability of basophils to release mediators, called releasability, may be an important aspect which influences the proinflammatory role of these cells, clinical approaches aiming at the depletion of the releasability have not been established. We examined whether the desensitization procedure in Ca(2+)-containing physiological conditions can make basophils completely unresponsive to IgE-mediated stimulation, and whether basophil desensitization is affected by the surface IgE levels.

METHODS

Human peripheral blood basophils were cultured with low concentrations of anti-IgE antibody or recombinant mite allergen. Following culture, cells were stimulated and their histamine release was measured.

RESULTS

Culturing with mite allergen or anti-IgE antibody below threshold concentrations induced potent desensitization in basophils. The desensitizing effect of anti-IgE was dose- and time-dependent; IgE-dependent releasability was completely suppressed when basophils were incubated with a near-threshold concentration of anti-IgE for > or= 4 h. In the continuous presence of subthreshold doses of anti-IgE, basophils remained desensitized even after 3 days. Basophils which had undergone an increase in surface IgE levels after 24-hour culture with IgE demonstrated enhanced desensitization.

CONCLUSIONS

Near-threshold stimulation in physiological medium can affect basophils, thereby inducing complete and sustained deprivation of releasability without triggering degranulation. Basophil desensitization is regulated by their surface IgE levels. Induction of full desensitization may represent a potentially important therapeutic strategy for IgE-mediated allergic diseases in which basophils play pathogenic roles.

[Acute exacerbation of interstitial pneumonia associated with active systemic lupus erythematosus in a patient with rheumatoid arthritis]

A 36-year-old woman with rheumatoid arthritis was admitted to our hospital for evaluation of newly developed active systemic lupus erythematosus (SLE). After hospitalization, she showed progressive respiratory failure. Chest CT revealed exacerbation of interstitial pneumonia, showing acute development of air-space consolidation and ground-glass opacity in addition to intensified reticular shadows. Administration of high-dose corticosteroids and cyclosporine A resulted in recovery from respiratory failure, accompanied by obvious improvement in the chest radiographs and CT, as demonstrated by the disappearance of air-space consolidation and ground-glass opacity. Clinically, the exacerbation of her interstitial pneumonia was compatible with acute lupus pneumonitis, a rare complication with active SLE.

Activation markers of human basophils: CD69 expression is strongly and preferentially induced by IL-3

BACKGROUND

The biological functions of basophils are precisely regulated by various cytokines in vitro, but little is known about surface markers that are upregulated during the cytokine-mediated activation process.

OBJECTIVE

It has been well established that CD69, CD44, and CD54 represent "activation markers" for cytokine-mediated eosinophil activation. The objective of this study was to elucidate the expression and regulation of these molecules in human basophils in vitro as well as in vivo.

METHODS

Basophils were purified from venous blood by means of density gradient centrifugation followed by negative selection. Surface expression was analyzed by means of flow cytometry. We also studied the expression of CD69, CD44, and CD54 on basophils in bronchoalveolar lavage fluid and blood specimens from patients with asthma.

RESULTS

CD44 and CD54 were constitutively expressed on basophils and moderately upregulated by IL-3. On the other hand, CD69 expression was only weakly observed in freshly isolated basophils, but IL-3 induced extremely high levels of expression. Surface CD69 appeared rather slowly in comparison with CD63 and CD11b, and the induction of expression was completed within 24 hours. Basophil CD69 had no functional relevance, but it did have biological relevance. Whole blood basophils from asthmatic individuals expressed significantly higher levels of CD69 than did those from normal individuals. Furthermore, bronchoalveolar lavage fluid basophils showed higher levels of CD69 expression than did blood basophils from the same donors.

CONCLUSION

CD69 expression on basophils was preferentially and strongly upregulated by IL-3. CD69 on basophils might be useful as an in vitro as well as in vivo marker of activation of these cells by IL-3.

Glucocorticoids induce basophil apoptosis

BACKGROUND

Induction of apoptosis represents an important mechanism by which glucocorticoids (GCCs) exert their anti-inflammatory properties. The effects of GCCs on apoptosis have been determined in various immune cells and found to vary among different cell types. On the other hand, the effects of GCCs on apoptosis of basophils, active participants in allergic inflammation, have remained obscure.

OBJECTIVE

The objective of this study was to investigate the effects of GCCs on basophil apoptosis.

METHODS

Basophils were highly purified (purity, >97%) by Percoll density gradient centrifugation followed by negative selection. Cell status was determined by their ability to bind annexin V and exclude propidium iodide. DNA fragmentation was determined by flow cytometry.

RESULTS

Dexamethasone (DEX) significantly accelerated the decrease in live cells and increased the number of apoptotic cells in a time-dependent fashion. Light microscopy as well as DNA fragmentation assay confirmed the induction of apoptosis by DEX. A half-maximal effect was observed in a DEX concentration range from 10(-9) to 10(-8) mol/L. Sex steroids did not induce basophil apoptosis at all. DEX also induced basophil apoptosis in the presence of low doses of IL-3.

CONCLUSION

GCCs exert potent apoptogenic effects on basophils. GCC-mediated apoptogenic effects on basophils might have implications with respect to the mechanism of action of this class of drugs in allergic disorders.

Chemokine receptors in human basophils: inducible expression of functional CXCR4

We examined the expression profile of chemokine receptors in human basophils and their regulation by cytokines. Basophils expressed transcripts of CC chemokine receptors (CCR)1, CCR2, CCR3, and CCR5 and CXC chemokine receptors (CXCR)1, CXCR2, and CXCR4. In contrast to the other receptors, surface-CXCR4 expression was not detected in fresh- and whole-blood basophils, but it became apparent gradually during incubation. Among 16 chemokines tested, eotaxin induced the most potent basophil migration. SDF-1 also induced a strong, migratory response comparable with that induced by eotaxin in 24-h, cultured basophils, but it failed to induce degranulation. IL-3 abrogated CXCR4 expression completely, and it only down-regulated CCR2 and CCR3 expression slightly. IL-5, GM-CSF, and IL-4 also down-regulated CXCR4 expression. Thus, expression of CXCR4 was the most strongly affected by cytokines, and this may represent an alternative mechanism for control of cell-specific, biological responses to SDF-1.

Regulation of surface FcepsilonRI expression on human eosinophils by IL-4 and IgE

BACKGROUND

Recent studies have demonstrated that eosinophils from allergic patients express low levels of FcepsilonRI on their surface, but the regulatory mechanisms of eosinophil surface FcepsilonRI expression are not fully understood. We investigated whether IL-4 and IgE, which are reported to regulate surface FcepsilonRI expression on human mast cells, are able to affect surface FcepsilonRI expression in normal human eosinophils.

METHODS

Eosinophils purified from peripheral blood were cultured with IL-5 and with or without IL-4 and/or IgE, and surface FcepsilonRI expression was analyzed by flow cytometry using an anti-FcepsilonRI mAb, CRA-1.

RESULTS

Apparent FcepsilonRI expression (approximately 1% of mast cell FcepsilonRI levels) was observed in eosinophils cultured with both IL-4 and IgE. A combination of IL-4 (>or=1 ng/ml) and IgE (>or= 0.5 microg/ml) was necessary for the maximal induction of surface FcepsilonRI expression. In the presence of IL-4 and IgE, eosinophils cultured for 2 days demonstrated low but statistically significant levels of surface FcepsilonRI, which reached a plateau after 7 days of culture. However, cross-linkage of surface FcepsilonRI molecules by CRA-1 or anti-IgE did not induce any eosinophil activation.

CONCLUSIONS

IL-4 and IgE can affect the levels of surface FcepsilonRI on normal human eosinophils. FcepsilonRI expression on eosinophils may be regulated by a mechanism similar to that in mast cells.

Secretory IgA-mediated basophil activation. II. Roles of GTP-binding regulatory proteins and phosphatidylinositol 3-kinase

Secretory IgA (sIgA) is the most abundant Ig isotype in mucous secretions in the upper and lower airways, where basophils exert effector functions during allergic inflammation. We recently demonstrated that immobilized sIgA on Sepharose beads is capable of inducing basophil degranulation ( approximately 15% of total histamine). To investigate the detailed mechanisms of this degranulation, we established in this study a new assay system for sIgA-mediated basophil activation. Immobilized sIgA on a plastic surface induced strong histamine release ( approximately 50% of total histamine) comparable to anti-IgE, and we analyzed the nature of basophil signal transduction by sIgA using various inhibitors. sIgA-induced basophil histamine release was inhibited completely by pertussis toxin, but anti-IgE-induced release was not affected. sIgA-mediated release was also inhibited by phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor, wortmannin. These results strongly suggest that sIgA activates basophils via an IgE-independent novel mechanism involving both Gi protein and PI 3-kinase.

Intracellular localization and release of eotaxin from normal eosinophils

Eotaxin is a potent and selective CC chemokine for eosinophils and basophils. We established several monoclonal antibodies (Mabs) allowing the neutralization and measurement of human eotaxin. Using the Mabs as probes, we demonstrated that normal eosinophils contained intracellular granule-associated eotaxin. Quantification of cell-associated eotaxin in different leukocyte subsets revealed that it was principally expressed in eosinophils. Finally, we showed that normal eosinophils released eotaxin upon stimulation with either of two secretagogues, C5a or ionomycin. These findings raise the possibility that eosinophil-derived eotaxin contributes to the local accumulation of eosinophils at the site of inflammation.

Secretory IgA induces degranulation of IL-3-primed basophils

We examined whether secretory IgA (sIgA), known to mediate eosinophil stimulation, has an effect on basophil functions. An immobilized preparation of sIgA, but not of monomeric IgA, induced histamine release (approximately 15% of total histamine contents) from human basophils in vitro. sIgA-induced basophil histamine release was totally dependent on pretreatment with IL-3. IL-5 and granulocyte-macrophage CSF also primed basophils for sIgA-mediated release. Exogenous divalent ions, i.e., Ca2+ and Mg2+, were essential for sIgA-mediated basophil degranulation, and the degranulation was completed within 45 min. A newly synthesized lipid mediator, leukotriene C4, was also liberated from IL-3-primed, sIgA-stimulated basophils. Enzyme digestion experiments revealed that the (Fc)2 x secretory component portion of sIgA is important for sIgA-mediated basophil activation, but the functional binding sites of sIgA on basophils were surmised to be different from FcalphaR. These observations reveal the novel finding that sIgA is able to stimulate basophils as well as eosinophils. Since sIgA is the most abundant Ig isotype in the secretions from mucosal tissues, and basophils are active participants in allergic late-phase reactions, sIgA-mediated basophil mediator release is potentially involved in exacerbation of the inflammation associated with allergic disorders.

Secretory IgA Induces Degranulation of IL-3-Primed Basophils

We examined whether secretory IgA (sIgA), known to mediate eosinophil stimulation, has an effect on basophil functions. An immobilized preparation of sIgA, but not of monomeric IgA, induced histamine release (approximately 15% of total histamine contents) from human basophils in vitro. sIgA-induced basophil histamine release was totally dependent on pretreatment with IL-3. IL-5 and granulocyte-macrophage CSF also primed basophils for sIgA-mediated release. Exogenous divalent ions, i.e., Ca2+ and Mg2+, were essential for sIgA-mediated basophil degranulation, and the degranulation was completed within 45 min. A newly synthesized lipid mediator, leukotriene C4, was also liberated from IL-3-primed, sIgA-stimulated basophils. Enzyme digestion experiments revealed that the (Fc)2·secretory component portion of sIgA is important for sIgA-mediated basophil activation, but the functional binding sites of sIgA on basophils were surmised to be different from FcαR. These observations reveal the novel finding that sIgA is able to stimulate basophils as well as eosinophils. Since sIgA is the most abundant Ig isotype in the secretions from mucosal tissues, and basophils are active participants in allergic late-phase reactions, sIgA-mediated basophil mediator release is potentially involved in exacerbation of the inflammation associated with allergic disorders.

Exogenous nitric oxide regulates the degranulation of human basophils and rat peritoneal mast cells

This study was designed to investigate whether anti-IgE-induced or ionophore A23187-induced histamine release from human basophils is regulated by exogenous nitric oxide (NO), and to assess some similarities between the effect of NO on basophils and that on rat peritoneal mast cells (RPMC). The NO donor, sodium nitroprusside (SNP), inhibited A23187-induced histamine release from crude human basophils and crude RPMC in a dose-dependent fashion. This downregulation was still observed when SNP was washed out just before the cell stimulation, indicating that the effect of SNP was irreversible. The downregulation disappeared in both purified cell populations after the removal of contaminating cells. However, when purified cells were preincubated with SNP in the presence of 5 mM N-acetylcysteine (NAC), increasing the bioavailability of NO, the downregulation was recovered. The presence of NAC significantly augmented the downregulation of SNP on A23187-induced histamine release from both crude cell populations. In contrast, SNP had no effect on anti-IgE-induced histamine release from either crude or purified basophil preparation in the absence of NAC, and SNP plus NAC inhibited anti-IgE-induced histamine release from both cell preparations. The same results were obtained with crude and purified RPMC preparations under the same conditions. These results show that SNP similarly downregulated exocytosis of basophils and RPMC, and acquired the potent effect in the presence of NAC, indicating that exogenous NO plays a part in the regulation of basophil and mast cell activation.

[Our experience of PEG and home care for twelve years]

Percutaneous endoscopic gastrostomy (PEG) was introduced in 1980 by Ponsky et al. This technique does not require general anesthesia and is performed safely and rapidly under local anesthesia without laparotomy. For the past twelve years, in order to maintain enteral alimentation for patients who suffered from dysphagia due to cerebral angiopathy, and to reduce patients' suffering from the long-term placement of a nasogastric tube, PEGs were performed in 150 patients (130 patients for enteral nutrition and 20 for drainage of gastrointestinal contents). We also provided home care service for 30 (27 for enteral nutrition and 3 for decompression) of these patients. We pointed out two problems connected with our retrospective studies for PEG. One is related to the indication of PEG, especially to the evaluation of preoperative status. We suggested a new method for measuring the preoperative status of patients for PEG (PEG-POS score). Retrospective studies showed the PEG-POS score was effective. Using this PEG-POS score, we have not had any early-stage deaths after PEG. Another is related to the home care service for patients with PEG. Consulting the questionnaire survey of families who experienced PEG home care, we examined various problems of home care.

Eotaxin is a potent chemotaxin for human basophils

We studied the effect of eotaxin, a novel eosinophil-active CC chemokine with high target cell specificity, on human basophils. Eotaxin induced higher levels of chemotactic response with a lower ED50 compared with RANTES in basophils; half-maximal migration occurred at a concentration of approximately 3 nM. On the other hand, it exerted only a marginal effect on either histamine release or leukotriene C4 generation. In addition, nested PCR amplification experiments revealed the expression of CC CKR3, a putative receptor for eotaxin, on basophils. Since accumulation of both basophils and eosinophils is an important aspect of allergic inflammation, eotaxin potentially plays a pathogenic role in allergic disorders by inducing migration of both of these cell types.

[Effects of low anterior resection on colonic motor activity and defecation. An experimental study]

The functional disorder of defecation after low anterior resection (LAR) was studied from the aspect of colonic motility in an experiment with dogs using a strain gage transducer, and the following results were obtained: 1) In early phase after LAR, the frequency of the colonic contractile waves increased at the proximal and distal sites of the anastomosis in both subgroups of dogs denervated and innervated of hypogastric and pelvic nerves. The increase was more remarkable at the distal site of the anastomosis. Also, the contractile waves were not propagated across the anastomosis. 2) After LAR, strong colonic contractions occurred during defecation only at the distal anastomosis. Various patterns of contraction time required for defecation were demonstrated as compared to a single pattern in control dogs. 3) The frequency of the occurrence of colonic contractile waves and the propagation of the contraction tended to be normalized with time after LAR both in denervated and innervated groups, though the recovery was faster in the latter subgroup. 4) The frequency of defecation increased after LAR both in denervated and innervated groups compared to be in the control dogs, though more remarkable in the denervated groups. Although tended to be gradually normalized with time after LAR, the colectomized dogs required a long time for normalization of the frequency of defecation. These results suggested the significant effect of reduction in reservoir space and disturbed continuity of intramural plexus caused by colectomy. Less severity, however, of functional disorder of defecation and earlier recovery from colonic motility disorder in the subgroup of the dogs innervated of autonomic nerves indicated usefulness of retaining autonomic nerves in colectomy.

[Effects of various histamine H2-receptor antagonists on gastrointestinal motility and gastric emptying]

Effects of various histamine H2-receptor antagonists (H2-RA) on gastrointestinal motility and gastric emptying were investigated. Ranitidine, nizatidine and cimetidine dose dependently induced contractions over the entire gastrointestinal tract, and the order of their effects was ranitidine > nizatidine > cimetidine. Roxatidine or famotidine had no effects on motility of the gastrointestinal tract. Ranitidine and nizatidine also induced contractions during the postprandial period and facilitated gastric emptying, while cimetidine, roxatidine or famotidine did not influence gastric emptying. Since acid reduction is thought to be the most important element of the treatment of peptic ulcer and reflux esophagitis, it was inferred that administration of a H2-RA selected with consideration of its property of facilitating gastrointestinal motility is effective in the treatment of patients with abnormal gastrointestinal motility.