Suppression of IgE production by IPD-1151T (suplatast tosilate), a new dimethylsulfonium agent: (2). Regulation of human IgE response

Formononetin isolated from Sophorae flavescentis inhibits B cell-IgE production by regulating ER-stress transcription factor XBP-1

Rationale

IgE plays an important pathologic role in most, if not all, allergic conditions. We previously showed that ASHMI (anti-asthma herbal medicine intervention) suppressed IgE production in murine models of asthma and in asthma subjects. However, the active compounds in ASHMI responsible for the IgE suppression are still unknown.

Objective

We sought to identify the compound(s) in ASHMI that are responsible for IgE inhibition as well as investigate the mechanisms by which the identified compound(s) decreases IgE production.

Methods

The compounds in Sophorae Flavescentis were separated using Column chromatography and preparative-HPLC. The separated compounds were identified using LC-MS and ¹H-NMR. U266 cells, an IgE-producing plasma cell line, were cultured with various concentrations of identified compounds. The levels of IgE production by the U266 cell were measured by ELISA. Trypan blue exclusion was used to determine the cell viability. The gene expression of XBP-1 and IgE-heavy chain was determined by RT-PCR.

Results

A single compound identified as formononetin was isolated from Sophorae Flavescentis. Formononetin significantly and dose dependently decreased the IgE production in U266 cells across a concentration range of 2-20 µg/ml (p < 0.05-0.001 vs. untreated cells) with an IC50 value of 3.43 μg/ml. There was no cytotoxicity at any tested concentration. Formononetin significantly decreased XBP-1, and IgE-heavy chain gene expression compared with untreated cells (p < 0.001).

Conclusion

Formononetin decreased IgE production in human B cell line U266 cells in a dose-dependent fashion through the regulation of XBP-1 ER transcription. Formononetin may be a potential therapy for allergic asthma and other IgE-mediated diseases.

Suplatast tosilate reduces radiation-induced lung injury in mice through suppression of oxidative stress

PURPOSE

Although radiotherapy is important in the treatment of malignant thoracic tumors, it has harmful effects on healthy tissues. We previously showed that suplatast tosilate, an anti-allergic agent, scavenged reactive oxygen species (ROS), including hydroxyl radicals. Because ROS-mediated oxidative stress is involved in radiation-induced lung injury, we hypothesized that suplatast tosilate could reduce radiation-induced lung injury via suppression of oxidative stress.

METHODS AND MATERIALS

Murine alveolar epithelial cells were irradiated with or without a medium containing suplatast tosilate in vitro to determine whether the agent had cytoprotective effects against radiation-induced injury. On the other hand, the thoracic region of C57BL/6 mice was exposed to a single irradiation dose of 15 Gy and the effects of suplatast tosilate were determined by a histological evaluation and assessment of the following parameters: cell number and inflammatory cytokine levels in bronchoalveolar lavage fluid, and oxidative stress markers and hydroxyproline content in pulmonary tissues.

RESULTS

Suplatast tosilate protected murine alveolar epithelial cells in vitro from irradiation-induced inhibition of cell proliferation, which was accompanied by the suppression of intracellular ROS and DNA double-strand breaks induced by irradiation. Oxidative stress markers and the levels of inflammatory and fibrogenic cytokines were upregulated in irradiated murine lungs in vivo. Suplatast tosilate suppressed both oxidative stress markers and the levels of cytokines, which resulted in reduced pulmonary fibrosis and clearly improved the survival rate after irradiation.

CONCLUSIONS

These findings demonstrate that suplatast tosilate could be a useful lung-protective agent that acts via suppression of oxidative stress associated with thoracic radiotherapy.

The effects of suplatast tosilate on acutely dissociated sensory and paratracheal ganglia neurons

In this study, we investigated the effects of suplatast on acutely dissociated single neurons of sensory and paratracheal ganglia using a patch-clamp technique. Suplatast had little effect on various responses caused by capsaicin, acid, bradykinin, serotonin and adenosine 5'-triphosphate in rat sensory neurons. Suplatast, even at 10-3 M, also did not induce any current at various membrane potentials in rat and guinea pig paratracheal ganglia neurons. Further, acetylcholine- and bradykinin-induced depolarizations were not affected by suplatast. On the other hand, in rat paratracheal ganglia neurons, 10-5 M nicotine-induced current were inhibited by suplatast in a concentration-dependent manner with a 50% inhibitory concentration of 9.86x10-5 M. The effect was noncompetitive and voltage-dependent. Furthermore, the effect was use-independent and not affected by the pretreatment time of suplatast. The results suggested that suplatast may inhibit neurotransmission at the paratracheal ganglia via the inhibition of nicotinic current. Thus, suplatast may attenuate cough production through the improvement of pathological conditions of the lower airway via suppressed acetylcholine release from the postganglionic nerve terminal.

Novel antitussive effect of suplatast tosilate in guinea pigs

We studied the antitussive effects of suplatast, a Th2 cytokine inhibitor, and compared them with the effects of codeine using an experimental cough model in guinea pigs. Suplatast and codeine dose-dependently inhibited cough caused by mechanical stimulation of the larynx, but they did not inhibit cough caused by mechanical stimulation of the bifurcation of the trachea. In guinea pigs with bronchitis, suplatast had an antitussive effect on cough caused by stimulation of the larynx, whereas codeine did not inhibit such cough. In SO2-exposed guinea pigs, suplatast tended to inhibit cough caused by mechanical stimulation of the tracheal bifurcation. Further, suplatast inhibited citric acid-induced cough augmented by pretreatment with an angiotensin-converting enzyme inhibitor, whereas codeine did not inhibit such cough. Suplatast also inhibited bradykinin-induced discharges of airway vagal afferent nerves and significantly inhibited 4-aminopyridine-induced discharges of airway vagal afferent nerves. These findings indicate that the antitussive effects of suplatast are mediated by a novel mechanism involving the peripheral nervous system.

Accumulation of Mast Cells in the Lesions and Effects of Antiallergic Drugs on the Patients with Inflammatory Bowel Disease

The pathomechanism of inflammatory bowel disease (IBD) has not yet been fully demonstrated. However, it is well known that mast cells are present in the gastrointestinal tract, suggesting that mast cells may take part in it. So, we investigated the number of mast cells in IBD, such as ulcerative colitis (UC) and eosinophilic colitis, and showed that the number of mast cells was increased in the inflammatory lesions. We also presented a case of UC which was treated successfully with an antiallergic drug, tranilast. Furthermore, possible new approaches to treating the disease with immunomodulators including suplatast are introduced. However, our investigations were performed with a limited number of patients with IBD, and additional further studies are required to confirm the findings.

Case of eosinophilic cystitis treated with suplatast tosilate as maintenance therapy

Eosinophilic cystitis is a rare inflammatory lesion of the bladder, characterized by massive eosinophilic infiltration of the bladder wall. Its cause is not known definitely. A 49-year-old man consulted our department with a miction pain, gross hematuria, and frequent micturition. Urinalysis showed combined hematuria and pyuria, but urine culture was sterile. Abnormal findings of laboratory examination included an elevated white blood cell (WBC) count (15,700/μL) and the proportion of eosinophils in the peripheral blood was 12% of the WBCs (normal 0–5%). Cystoscopy revealed a solid mass with severe edematous mucosa. Magnetic resonance imaging (MRI) also indicated marked bladder wall thickening, which was suspected for invasive bladder cancer. Transurethral biopsy of the bladder mass was performed with pathological examination revealing features of eosinophilic cystitis. After administration of a combination of prednisolone and suplatast tosilate, followed by monotherapy with suplatast tosilate, regression of the bladder mass, and normalization of the count of peripheral eosinophils were achieved. Fourteen months after steroid therapy, under treatment with suplatast tosilate, there was no relapse of urinary symptoms and the bladder mass.

Recent research and developmental strategy of anti-asthma drugs

Extensive research over the past decade has provided information about the pharmacotherapy of bronchial asthma (BA). Anti-asthma drugs are classified into two categories: relievers (for the relief of asthma attack symptoms) and controllers (for the prevention of asthma symptoms). This paper aims to review the recent advancements of anti-asthma drugs that are controller medicines. The controllers mainly act on immune and inflammatory responses in BA development. 1) Immunomodulators. Drugs that act on the immune response are classified into two categories: immunosuppressors and immunomodulators, including immunopotentiators. The immunomodulation of the Th1 and Th2 imbalance is the first strategy of the controller because allergic BA is thought to be caused by Th2-polarized immunity. Suplatast is a novel immunomodulator that can adjust the imbalance in the Th1/Th2 immune response and shows clear clinical efficacy against BA. The immunomodulator approach has shifted from a more theoretical and conceptual model to one supported by evidence of clinical efficacy.2) Anti-inflammatory agents. Corticosteroids,mast cell stabilizers and autacoid inhibitors are anti-inflammatory agents for BA. The clinical superiority of the combined therapy of inhaled corticosteroids and long-acting beta2 agonists is evident. This combined therapy shows a potent synergic anti-inflammatory effect compared to the effect by corticosteroids alone. Currently, the anti-inflammatory agents for BA under development are drugs affecting lipid mediators. The prostaglandin (PG) D2 antagonist, PGE2, EP3 agonist and PGI2 agonist are being considered in addition to well-established leukotriene and thromboxane A2 inhibitors. New development strategies and therapeutics for controllers are described in this review.

Increase effect of transforming growth factor on eotaxin production by normal cultured dermal fibroblasts stimulated with interleukin-4: inhibitory effect of suplatast tosilate on eotaxin production

Eotaxin plays a central role in the development of allergic disease, including atopic dermatitis, asthma, and nasal allergy. Interleukin (IL)-4 induces eotaxin production in normal human dermal fibroblasts. On the other hands, Transforming growth factor-beta (TGF-beta), a multifunctional regulatory cytokine, affects many biological functions, including fibroblast growth and differentiation and Th2 cytokine regulation. In this study, we investigated the effect of TGF-beta on IL-4-induced eotaxin production by normal human fibroblasts, as well as the effect of suplatast tosilate, an antiallergic drug that selectively inhibits Th2 cytokine production. Dermal fibroblast treatment with IL-4 and TGF-beta for 24 h increased eotaxin production and expression of eotaxin mRNA, as measured by enzyme-linked immunosorbent assay (ELISA) and reverse-transcriptase polymerase chain reaction (RT-PCR), respectively. TGF-beta synergistically up-regulated eotaxin production and eotaxin mRNA expression when stimulated with IL-4. Suplatast tosilate dose-dependently inhibited eotaxin production induced by IL-4 or IL-4 plus TGF-beta. These results suggest that TGF-beta may regulate skin allergic inflammation by up-regulating eotaxin production in dermal fibroblasts. Suplatast tosilate might suppress this inflammation by inhibiting eotaxin production.

Usefulness of suplatast tosilate for chronic cough following lung cancer surgery

OBJECTIVE

Chronic dry cough is reported to occur in about 25% of patients following lung cancer surgery. Experimental data suggest that it may be caused mainly by stimulation of C-fibers, which are widely distributed to the lower trachea and bronchi. We assessed the clinical usefulness of suplatast tosilate (IPD) for chronic dry cough after lung cancer surgery.

METHODS

The subjects were patients with stage I lung cancer who had undergone lobectomy combined with mediastinal lymph node dissection. IPD was administered orally at 400 mg daily, and its efficacy was evaluated by patient interview 1, 2, and 3 months after the start of treatment. The subjects were 19 patients, and the duration of cough before entering the study was 393.2 days.

RESULTS

The response rate was 84.2% (16/19) 1 month after the start of treatment. It seems that IPD inhibits cough resulting from stimulation of the bifurcated trachea with a high content of C-fibers.

CONCLUSION

The present study suggested the efficacy of IPD for controlling chronic dry cough after lung cancer surgery.

Early intervention with suplatast tosilate for prophylaxis of pediatric atopic asthma: a pilot study

The onset of asthma may be related to Th2 cytokine dominance at the time when food allergies occur several months after birth. This study investigated the effectiveness of early intervention with a Th2 cytokine inhibitor (suplatast tosilate) for prevention of asthma in infants with food allergies and atopic dermatitis. Suplatast tosilate dry syrup (6 mg/kg daily) or a histamine H(1)-blocker (ketotifen fumarate dry syrup: 0.06 mg/kg daily) was administered randomly to 53 infants with atopic dermatitis caused by food allergies. The primary endpoints were the incidence of asthma and the time to the onset of wheezing. The peripheral blood Th1/Th2 ratio, total IgE level, and eosinophil count were measured before and after treatment. After 24 months of treatment, the prevalence of asthma was significantly lower in the suplatast group (20.8%) than in the ketotifen group (65.6%, p < 0.01). Additionally, the time from the start of treatment to the initial episode of wheezing for infants who developed asthma was significantly longer in the suplatast group than the ketotifen group (p < 0.01). Furthermore, the eosinophil count was significantly decreased by suplatast treatment (p < 0.05), and there was a significant difference between the suplatast and ketotifen groups with respect to both the eosinophil count (p < 0.01) and the Th1/Th2 ratio (p < 0.05). The results of the present pilot study suggest that suplatast tosilate is useful for the primary prevention of wheezing and asthma in children.

Th2 cytokine inhibitor suplatast tosilate inhibits antigen-induced mucus hypersecretion in the nasal epithelium of sensitized rats

OBJECTIVES

Th2 cytokines such as interleukin (IL) 4 and IL-13 are potential mediators for mucus hypersecretion in allergic inflammation. To elucidate the functions of Th2 cytokines in allergic rhinitis, we examined the in vivo effects of the Th2 cytokine inhibitor suplatast tosilate on mucus hypersecretion and eosinophil infiltration in rat nasal epithelium.

METHODS

We induced hypertrophic and metaplastic changes in goblet cells in the nasal epithelium of ovalbumin-sensitized rats by intranasal challenge with ovalbumin. The effects of orally administered suplatast tosilate on mucus production and eosinophil infiltration were examined.

RESULTS

Suplatast tosilate (30 and 100 mg/kg) dose-dependently inhibited ovalbumin-induced mucus production and eosinophil infiltration. These suppressions of mucus production and eosinophil infiltration were only effective when suplatast tosilate was given in the effector phase; administration in the induction phase resulted in no effect.

CONCLUSIONS

These results indicate that Th2 cytokines are important mediators of mucus hypersecretion and eosinophil infiltration in allergic rhinitis. Suplatast tosilate may be useful for the treatment of allergic rhinitis by attenuating the inflammation of the effector phase.

Substituted 2-phenyl-benzimidazole derivatives: novel compounds that suppress key markers of allergy

The pharmacotherapy of allergy and asthma has traditionally focused on the effecter molecules of the allergic cascade, while neglecting targets that play an early role in their development. Reasoning that IgE is central to the expansion of atopic diseases, we identified and extended a novel family of 2-(substituted phenyl)-benzimidazole inhibitors of IgE response. Pharmacological activity depends on an intact phenylbenzimidazole-bis-amide backbone, and is optimized by the presence of lipophilic terminal groups composed of either bis cycloalkyl or combinations of aliphatic and halogen-substituted aromatic groups. These compounds also inhibit IL-4 and IL-5 responses in T cells and CD23 expression on B cells, with potencies that parallel their inhibition of IgE. The broad profile of these compounds thus underscores their potential for treating the multifarious pathology of asthma.

Topical suplatast tosilate (IPD) ameliorates Th2 cytokine-mediated dermatitis in caspase-1 transgenic mice by downregulating interleukin-4 and interleukin-5

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by elevated serum levels of IgE. AD is associated with Th2 cytokines including interleukin (IL)-4, IL-5, IL-13 and IL-10. Systemic administration of suplatast tosilate (IPD) is currently used to treat Th2 cytokine-mediated AD.

OBJECTIVES

To evaluate the effect of topical IPD on skin lesions of AD using a genetically engineered AD mouse model (K14/caspase-1 transgenic mouse: KCASP1Tg).

METHODS

IPD ointment (3%) and white petrolatum (WP) were applied to KCASP1Tg mice every other day from 6 to 14 weeks after birth. Histopathological analysis of skin lesions and measurement of mRNA expression of cytokines in skin lesions and spleen cells were carried out. We also compared changes in serum parameters between IPD-treated and WP-treated KCASP1Tg mice.

RESULTS

WP-treated mice developed dermatitis at 8 weeks after birth. However, skin lesions in IPD-treated mice were limited. Histopathologically, skin lesions in WP-treated KCASP1Tg mice showed marked inflammatory changes with increased mast cell infiltration. However, mice treated with IPD showed minimum skin lesions with scarce mast cell infiltration. WP-treated KCASP1Tg mice had significant elevation in the serum levels of histamine, IgE and IL-18 as compared with IPD-treated KCASP1Tg mice. mRNA expression of IL-4 and IL-5 in the skin lesions from WP-treated KCASP1Tg mice was significantly higher than in those from IPD-treated mice. In the spleen, the expression of IL-4, IL-5 and interferon-gamma was significantly increased in WP-treated KCASP1Tg mice as compared with their IPD-treated counterparts.

CONCLUSIONS

This study shows that topical therapy with IPD inhibits the expression of IL-4 and IL-5 and ameliorates skin manifestations in an AD mouse model, suggesting the potential usefulness of topical IPD for the treatment of AD.

A novel low molecular weight inhibitor of dendritic cells and B cells blocks allergic inflammation

RATIONALE AND OBJECTIVE

During allergic lung inflammation dendritic cells (DCs) direct the generation and function of effector T-helper type 2 cells. T-helper type 2 cells not only orchestrate the inflammatory processes in the tissue by inducing the accumulation and activation of proinflammatory cells but also induce IgE production by B cells. Thus, inhibitors of DC function should have therapeutic benefits in patients with allergies.

METHODS AND MEASUREMENTS

VAF347, a novel low molecular weight immunomodulator, is described and acts as an antiinflammatory compound by a dual mode of action.

RESULTS

VAF347 inhibited the function of human monocyte-derived DCs to induce T-cell proliferation and cytokine production. Mechanistically, this effect may be due to reduced expression of CD86, HLA-DR, and interleukin 6 by DCs. In addition, the compound inhibited IgE synthesis in an isotype-specific fashion by human B lymphocytes. In a mouse model of antigen-induced eosinophilic inflammation, VAF347 blocked lung eosinophilia, mucus hyperplasia, and serum IgE levels, representing the hallmarks of allergic lung inflammation. The biological effects in vivo are most likely mediated by the immunoregulatory role of VAF347 on DCs because allergic lung inflammation was also inhibited in B-cell-deficient mice.

CONCLUSION

VAF347 represents a novel type of immunomodulator by affecting two major pathways in allergic airway pathogenesis: dendritic cell-mediated T-helper-cell activation and induction of IgE production by human B lymphocytes.

Effect of suplatast tosilate on goblet cell metaplasia in patients with asthma

BACKGROUND

Goblet cell metaplasia is a pathologic characteristic of asthma, associated with excess mucus secretion. Interleukin (IL)-4 and IL-13 plays an important role in mucus hypersecretion. Suplatast tosilate (suplatast), an antiallergic agent, is a Th2 cytokine inhibitor that suppresses the synthesis of IL-4, IL-5, IL-13, and eosinophilic airway inflammation.

OBJECTIVE

We examined the effects of suplatast on mucus production in bronchial biopsy specimens taken from asthmatic subjects.

METHODS

Oral suplatast 300 mg daily, or placebo was administered for 3 months in a double-blind, parallel-group study in 25 patients with asthma. Biopsy specimens were evaluated at before and after treatment for alcian blue/period acid-Schiff (AB/PAS), MUC5AC staining in bronchial epithelium and IL-4+, IL-13+ cells as well as inflammatory cells in lamina propria.

RESULTS

There were significant decreases in the percentage of AB/PAS (P < 0.01) and MUC5AC (P < 0.01) stained area in the suplatast group. These changes were accompanied by significant decreases in IL-4+ and IL-13+ cells in suplatast-treated subjects. Additionally, we have observed that the number of infiltrating eosinophils and CD4+ T cells significantly decreased.

CONCLUSIONS

These findings suggest that suplatast prevents goblet cell metaplasia through modulation of Th2 cytokine production and the recruitment of eosinophils and CD4+ T cells in the asthmatic airways.

A preliminary study of PEFR monitoring in patients with chronic cough

It is important to make a differential diagnosis of cough variant asthma in patients with chronic cough. To examine whether or not peak expiratory flow rate (PEFR) is useful for the differential diagnosis of cough variant asthma in such patients, diurnal variation rates of PEFR were calculated in 23 patients who presented with dry cough lasting four or more weeks and who showed no abnormalities on chest radiographs. None of the patients had wheezes, and pulmonary function testing at the time of visit to the hospital revealed no abnormalities. During the control period, the mean diurnal variation rate of PEFR in 23 patients was 16.3 +/- 7.9%. Six, nine and eight patients had PEFR diurnal variations rates of <10% (Group 1), 10-19% (Group 2), and > or = 20% (Group 3), respectively. At week 3 of treatment with bronchodilators, only Group 3 showed a significant decrease in PEFR diurnal variation rate from 25.7% to 10.1%. The cough score decreased significantly in Group 3 only. These patients had enhanced bronchial hyperresponsiveness and showed eosinophils in induced sputum, leading to the diagnosis of cough variant asthma (CVA). After making the diagnosis of CVA, an inhaled corticosteroid or a Th2 cytokine production inhibitor suplatast tosilate was administered to patients; consequently, they showed no recurrence of cough. PEFR monitoring allowed the detection of morning dip and was suggested to be potentially useful for the differential diagnosis of cough variant asthma in patients with chronic cough.

CD28 and secretory immunoglobulin A-dependent activation of eosinophils: inhibition of mediator release by the anti-allergic drug, suplatast tosilate

BACKGROUND

Eosinophils are major effector cells in allergic diseases. After their recruitment to sites of inflammation, they contribute to the pathophysiology of the disease by releasing granule proteins and cytokines. Suplatast tosilate (IPD-1151T), a new anti-allergic agent, has shown beneficial effect in the treatment of asthma, associated with reduced bronchoalveolar lavage eosinophil infiltration and eosinophilic cationic protein (ECP) release in serum and sputum.

OBJECTIVE

We investigated whether suplatast tosilate could exert direct effects on human eosinophil activation.

METHODS

Eosinophils from hypereosinophilic patients or normal donors were purified by Percoll gradient and the magnetic cell separation system. Chemotaxis was studied using the Boyden chamber technique using three chemoattractants, formyl-methionine-leucine-phenylalanine (fMLP), IL-5 and eotaxin. Oxidative metabolism was determined by a luminol-dependent chemiluminescence assay after activation with eotaxin or secretory IgA (sIgA). The release of ECP and eosinophil derived neurotoxin (EDN) was measured by radioimmunoassay and cytokine production was determined by ELISA following activation with sIgA or anti-CD28.

RESULTS

The chemotactic response to fMLP, IL-5 and eotaxin was significantly inhibited by IPD-1151T. Suplatast tosilate was partially inhibiting the release of reactive oxygen species (ROS) induced by eotaxin and sIgA. Activation by sIgA and CD28 ligation resulted in the release of ECP and EDN, which was inhibited by IPD-1151T. Upon activation by anti-CD28, only IL-13 production was inhibited by IPD-1151T, whereas release of IL-2 and IFN-gamma was not affected. IL-10 release induced by sIgA was also inhibited by IPD-1151T. Additionally, the pro-inflammatory cytokine IL-6, which was secreted following anti-CD28 and sIgA stimulation, was strongly inhibited by IPD-1151T.

CONCLUSION

Through inhibition of chemotaxis, IPD-1151T might limit the number of eosinophils at the inflammation site. Furthermore, it could reduce the pathological potential of eosinophils by inhibiting the release of ROS and cationic proteins, main inflammatory mediators produced by eosinophils. Moreover, the inhibition of immunoregulatory cytokines released by eosinophils could locally modify the immune response.

Rationale for new treatments aimed at IgE immunomodulation

OBJECTIVE

To review potential or current therapies that decrease IgE synthesis or effects.

DATA SOURCES

Relevant literature in peer-reviewed journals and abstracts from national meetings.

STUDY SELECTION

Key articles were selected by the authors.

RESULTS

Modulation of IgE-mediated diseases can occur at several levels. Transcription factors may be altered to differentiate lymphocytes into a TH1 phenotype, thus decreasing TH2-driven IgE production. This may be accomplished by inhibiting GATA-3 with peroxisome proliferator-activated receptor agonists or promoting T-bet expression with CpG motifs. Inhibiting IgE-promoting cytokines may be accomplished by blocking the effects or synthesis of interleukin 4 (IL-4) or IL-13 by suplatast tosilate. Cytokine therapy with anti-IL-4 or anti-IL-13 has the potential to directly influence IgE-mediated diseases, but strategies aimed at IL-4 alone have been disappointing. Clinical trials with interferon-gamma or IL-12, 2 cytokines important in promoting TH1 and inhibiting TH2 responses, have been fraught with adverse effects that make their use limited. The use of plasmids encoding interferon-gamma or IL-12 has shown promise in animal models. Inhibition of IgE synthesis has been demonstrated with anti-CD23 antibodies. Early human studies have been very encouraging, and larger studies are under way. The only IgE immunomodulator currently available for use is omalizumab. Omalizumab is effective for allergic asthma in children and adults.

CONCLUSIONS

Newer therapies hold great promise for the future treatment of allergic respiratory diseases, but clinical trials are necessary to accurately evaluate risk-benefit ratios of IgE immunomodulators.

Add-on effects of suplatast tosilate in bronchial asthma patients treated with inhaled corticosteroids

Th2 cytokines play an important role in the pathogenesis of asthma. In the present study, we investigated the effect of suplatast tosilate, a selective Th2 cytokine inhibitor, on asthma control, in terms of subjective symptoms and pulmonary function in patients treated with inhaled corticosteroids. Thirty-eight patients with bronchial asthma being treated with inhaled corticosteroids were given suplatast tosilate (100 mg three times daily) for 12 weeks, in a multicenter setting. During the study period, other medications were continued. Morning and evening peak expiratory flow, asthma symptoms, blood eosinophil count and serum IgE levels were monitored. Suplatast tosilate treatment was associated with a significant improvement in mean morning peak expiratory flow (from 295 L/min to 348 L/min, P < 0.01) and evening peak expiratory flow (from 313 L/min to 357 L/min, P < 0.01). The mean daily variation in peak expiratory flow was significantly reduced (from 11.6% to 7.3%, P < 0.01) by suplatast tosilate treatment. The greatest improvement in peak expiratory flow was observed in patients whose blood eosinophil counts were decreased by suplatast tosilate treatment. Treatment with suplatast tosilate improved pulmonary function in patients with bronchial asthma. Our results suggest the therapeutic effects observed may occur through suppression of eosinophilic inflammation.

Breath malodor in an asthmatic patient caused by side-effects of medication: a case report and review of the literature

OBJECTIVE

The purpose of this report is to document the presence of dimethyl sulfide in mouth air as the predominant volatile sulfur compound (VSC) in an asthmatic patient who was regularly taking suplatast tosilate.

STUDY DESIGN

The patient was a 33-year-old woman who complained of bad breath. She had been diagnosed as having asthma and was receiving periodical medical examinations once a month. VSC in her mouth air were measured with a gas chromatograph. Oral physiotherapy was also carried out to remove any oral malodor of which the source was intraoral.

RESULTS

With the improvement in oral hygiene and periodontal conditions, the level of VSC was reduced but dimethyl sulfide still remained as the predominant VSC.

CONCLUSIONS

Dimethyl sulfide metabolized from suplatast tosilate may be a potential cause of halitosis.

Prolongation of heart allograft survival of rats treated by a Th2 inhibitor

In terms of Th1/Th2 balance in response to signals given during donor antigen presentation, induction of tolerance is more often correlated with Th2-type than with Th1-type reactions. However, in our study, heart allograft survival was prolonged by treatment of rats with a Th2 inhibitor. Suplatast tosilate (IPD; Taiho; Tokyo, Japan) is a novel immunoregulator that suppresses IgE production and eosinophil infiltration through selective inhibition of interleukin (IL)-4 and IL-5 synthesis by Th2-like cells but not IFN-gamma production in Th1 cells. Five LEW rats of DA heart grafts were treated with IPD (100 microg/day, p.o.) for 10 days. Heart allograft survival of all IPD-treated cases was prolonged more than 14 days while the beating of heart grafts in control groups was stopped within 9 days. In an in vitro study, the cell proliferation both in Con A blast and in mixed lymphocyte reaction assay was suppressed by IPD in dose-dependent manner. We could at least in part conclude that Th2 inhibition might temporarily suppress heart allograft rejection.

Effects of suplatast tosilate on allergic eosinophilic airway inflammation in patients with mild asthma

BACKGROUND

Bronchial asthma is a chronic inflammatory disease characterized mainly by infiltration of the airway mucosa by various inflammatory cells, notably eosinophils. T(H)2-type cytokines are suggested to be deeply involved in the pathogenesis of asthma.

OBJECTIVE

We sought to determine the suppressive effects of suplatast tosilate, an inhibitor of T(H)2-type cytokines, on eosinophilic inflammation of the bronchial mucosa in patients with mild asthma.

METHODS

Airway hyperresponsiveness tests, pulmonary function tests, eosinophil measurements in induced sputum, and bronchial mucosa biopsies were performed before and after treatment with suplatast tosilate for 6 weeks in 15 patients with mild asthma and in 13 control patients with mild asthma not receiving suplatast tosilate. This study was performed as a case-controlled open study.

RESULTS

In the treatment group a significant improvement in the provocation concentration of histamine was observed (P <.05). Improvements in peak expiratory flow (P <.01) and in symptom score (P <.05) were also noted in the suplatast tosilate-treated group. Moreover, the average number of infiltrating eosinophils and EG2(+) cells significantly decreased (both P <.05), as did the ratios of eosinophils and EG2(+) cells in sputum (both P <.01). The average number of CD4(+) and CD25(+) T lymphocytes also decreased (both P <.05).

CONCLUSION

Suplatast tosilate appears to inhibit allergic airway inflammation mediated by T(H)2-type cytokine and to improve clinical symptoms in patients with mild asthma.

Effects of suplatast tosilate on cytokine profile of bronchoalveolar cells in allergic inflammation of the lung

OBJECTIVE

Suplatast tosilate is an anti-allergic agent that inhibits IgE antibody production. It appears to have an inhibitory effect on the production of Th2 cytokines (interleukin (IL)-4, IL-5) in vitro. In the present study, we investigated the effects of suplatast on eosinophil infiltration and cytokine mRNA expression in bronchoalveolar lavage (BAL) fluid in a Brown Norway (BN) rat model of bronchial asthma.

METHODOLOGY

Suplatast (50 mg/kg per day) was administered intraperitoneally for 15 consecutive days to 8-week-old male BN rats that had been actively sensitized to ovalbumin (OA) and alum and rats were challenged with OA aerosol to induce allergic bronchial inflammation. The control group was examined 48 h after antigen inhalation to measure the cell count and cell fraction in BAL fluid. Reverse transcription-polymerase chain reaction using primers for IL-4, IL-5, interferon (IFN)-gamma and beta-actin was used to semiquantitatively measure mRNA expression in BAL cells 24 h after antigen inhalation.

RESULTS

Suplatast was found to decrease the total cell count and the eosinophil count. The mean total cell count in BAL in the suplatast-treated group was 18.8 x 10(5) and the mean eosinophil count was 7.8 x 10(5) compared with 73.0 x 10(5) and 48.9 x 10(5), respectively, in the control group. Suplatast also suppressed expression of IL-4 and IL-5 mRNA in BAL cells. However, there were no significant changes in IFN-gamma expression.

CONCLUSIONS

Suplatast was found to have an inhibitory effect on eosinophil infiltration in a rat model of bronchial asthma. It also appeared to inhibit allergic inflammation by altering the cytokine profile.

Effect of suplatast tosilate on airway hyperresponsiveness and inflammation in asthma patients

Because eosinophilic airway inflammation is a characteristic of bronchial asthma, the treatment of such inflammation is important in the management of this disease. Suplatast tosilate is a novel anti-asthma drug that suppresses eosinophil proliferation and infiltration through selective inhibition of Th2 cytokine synthesis. We investigated the effect of oral suplatast tosilate therapy in patients with mild and moderate asthma. Twenty-eight asthma patients were randomized into two groups with or without suplatast tosilate treatment (100 mg t.i.d. for 28 days). We examined the blood eosinophil counts, eosinophilic cationic protein level, sputum eosinophil count, exhaled nitric oxide level, and airway responsiveness before and after treatment. In patients treated with suplatast tosilate, the eosinophil count in the blood and sputum was significantly decreased after treatment, while there was no such change in the patients without suplatast treatment. The exhaled nitric oxide level and airway responsiveness (measured using an Astograph) were also decreased after treatment with suplatast tosilate, while there were no significant changes in patients without suplatast tosilate. These results strongly suggest that oral administration of suplatast tosilate suppresses airway hyperresponsiveness in asthma patients by reducing eosinophilic inflammation in the airways.

Effects of suplatast tosilate, a new type of anti-allergic agent, on airway cough hypersensitivity induced by airway allergy in guinea-pigs

BACKGROUND

Cough receptor hypersensitivity is a fundamental feature of some conditions presenting with chronic non-productive cough. Suplatast tosilate, an anti-allergic agent, is a T helper (Th)2 cytokine inhibitor that inhibits the synthesis of interleukin (IL)-4, IL-5, immunoglobulin (Ig)E production, and local eosinophil accumulation.

OBJECTIVE

The purpose of this study was to investigate the effect of suplatast on antigen-induced airway cough hypersensitivity and eosinophil infiltration into the airway.

METHODS

Number of coughs elicited by inhalation of increasing concentrations of capsaicin (10-8, 10-6 and 10-4 M) was counted 24 h after an antigen challenge in conscious guinea-pigs and then bronchoalveolar lavage was performed. We investigated the effect of single (before antigen challenge or capsaicin provocation) or repetitive treatment with intraperitoneal suplatast at a dose of 10 or 30 mg/kg on antigen-induced cough hypersensitivity.

RESULTS

Twenty-four hours after antigen challenge, guinea-pigs developed an increase in cough receptor sensitivity to inhaled capsaicin and eosinophil infiltration in the airways. After a 2-week treatment with suplatast, but not after only a single treatment before antigen challenge or capsaicin provocation, the antigen-induced early phase bronchoconstriction, cough hypersensitivity, and airway eosinophilia were inhibited in a dose-dependent manner.

CONCLUSION

These results indicate that suplatast inhibits airway cough hypersensitivity underlying allergic eosinophilic inflammation.

Wistar strain rats as the model for IgE antibody experiments

The amount of plasma IgE antibody formed and its change over time were investigated by enzyme-linked immunosorbent assay (ELISA) in male and female Sprague-Dawley (SD), Donryu, and Wistar strain rats. IgE antibody formation was initiated by injecting a mixture of 2,4-dinitrophenylated ascaris extract (DNP-As) as antigen and killed Bordetella pertussis as adjuvant into the paws of the animals. The amount of IgE antibody formed was low on day 10 in both male and female SD (40-80 ng/ml) and Donryu (20-40 ng/ml) strain rats, and an increase in the amount was observed on day 20. The peak value of IgE antibody was observed day 10 in Wistar strain rats and was 130 and 200 ng/ml in the male and female rats, respectively. These results suggest that Wistar strain rats produce the most IgE antibody when DNP-As is used as antigen and they can serve as a model for allergic diseases.

Drugs for the treatment of allergic diseases

Many kinds of drugs are used for the treatment of allergic diseases. Glucocorticoids are the most efficacious drugs and widely used for the treatment of allergic diseases. Recently, effectiveness of inhaled glucocorticoids for the treatment of bronchial asthma has been established. Beclomethasone dipropionate and fluticasone propionate, which are degraded easily after absorption, are applied by inhalation. Histamine is one of the most important mediators in allergic reactions and antihistamines have widely been applied for the treatment of allergic skin diseases. In Japan, over 20 antiallergic drugs, such as mediator release inhibitors, mediator antagonists and mediator synthesis inhibitors, have been developed. Recently developed compounds such as pranlukast and suplatast are very effective. To relieve the asthmatic attack, bronchodilators such as beta2-adrenoceptor agonists, theophylline and anti-cholinergic drugs are used. Clinical application of tacrolimus ointment has just started for the treatment of atopic dermatitis. Recently the number of allergic patients has increased. The onset and development of allergic diseases are considered to be dependent on both the genetic factors and the environmental factors. For the successful treatment of patients with allergic diseases, it is also important to consider the control of environmental factors.

Effects of suplatast tosilate on airway inflammation and airway hyperresponsiveness

Suplatast tosilate (IPD) is a Th2 cytokine inhibitor that lowers the titer of the IgE antibody through specific inhibition of the production of IL (interleukin)-4 and IL-5 by T cells and inhibits tissue infiltration by eosinophils. In this clinical trial, suplatast tosilate (300 mg/day) was administered orally for 4 weeks to 25 patients (13 patients with atopic asthma, 12 patients with nonatopic asthma) whose bronchial asthma was staged in step 1 or step 2 according to the Guidelines for Prevention and Management of Bronchial Asthma, 1998. Before and after administration, the parameters of airway inflammation, that is, peripheral blood eosinophils count, serum level of eosinophil cationic protein (ECP), ECP level in induced sputum, airway hyperresponsiveness (Dmin), and morning peak expiratory flow (PEF), were measured. The peripheral blood eosinophil count, serum level of ECP, and ECP level in induced sputum decreased significantly. Of these parameters, the ECP level in induced sputum was the most sensitive. Furthermore, suplatast tosilate significantly inhibited Dmin. These results were especially significant in patients with atopic asthma. Suplatast tosilate was considered to have inhibited airway eosinophilic inflammation through decreases in peripheral blood eosinophils counts and in ECP levels in induced sputum, which resulted in inhibition of airway hyperresponsiveness.

Effects of suplatast tosilate (IPD Capsules) on the production of active oxygen by neutrophils and of IL-8 by mononuclear cells

In bronchial asthma, eosinophils and neutrophils are activated, so that the production of active oxygen species increases, causing airway epithelial injury. Suplatast tosilate (IPD Capsules) is a novel immunomodulating antiallergic drug that acts against bronchial asthma through a new mechanism. To evaluate the effects of suplatast tosilate on mononuclear cell-mediated IL-8 production, and neutrophil-mediated active oxygen species production at sites of inflammation, we collected peripheral blood from healthy subjects and separated the neutrophils as well as mononuclear cells. Suplatast tosilate was added at a concentration of 1 x 10(-6), 1 x 10(-7) or 1 x 10(-8) M, and cells were incubated for 10 min at 37 degrees C. Then, the neutrophils were stimulated with fMLP, and luminol-dependent chemiluminescence (LDCL) was measured, while IL-8 production was determined with an ELISA kit. Suplatast tosilate (1 x 10(-6) M) inhibited neutrophil-mediated active oxygen species production by 12.4% in terms of the peak, and by 16% in terms of the integral value. Moreover, it significantly inhibited mononuclear cell-mediated IL-8 production at concentrations of 1 x 10(-6), 1 x 10(-7) and 1 x 10(-8) M, in a concentration-dependent manner. This study indicated that suplatast tosilate may inhibit neutrophil infiltration by suppressing monocyte-mediated IL-8 production, and it may also inhibit the activation of neutrophils at sites of inflammation. These results suggest the possibility that suplatast tosilate may not only be of benefit for asthma, but may also prevent or control pulmonary fibrosis or emphysema, for which no effective treatment is presently available.

What are the most promising strategies for the therapeutic immunomodulation of allergic diseases?

Specific immunotherapy and other immunomodulatory strategies have long been a stronghold in the management of allergic diseases. In particular, "immunodeviation-therapy" or "vaccination for allergies", i.e. the redirection of Th2-type immune responses towards a Th1-response pattern, has become an ever more popular concept. The present feature of CONTROVERSIES complements our previous discussion of atopy (Röcken et al., Exp Dermatol 7: 97--104, 1998), and is dedicated to a critical analysis of the general problems and limitations one faces with the main immunomodulatory strategies traditionally considered in this context. We also explore alternative approaches that appear promising in order to achieve both a more effective and/or a more specific immunotherapy of allergic diseases. Given that the mast cell remains a key protagonist in the pathogenesis of allergic diseases finally, this feature examines how innovative, more selectively mast cell-targeted strategies may be developed for the management of allergic diseases.

Effect of suplatast tosilate, a Th2 cytokine inhibitor, on steroid-dependent asthma: a double-blind randomised study. Tokyo Joshi-Idai Asthma Research Group

BACKGROUND

Th2 cytokines play an important part in the pathogenesis of asthma. Our aim was to study the effect of suplatast tosilate, a selective Th2 cytokine inhibitor, on asthma control and asthma exacerbations during reduction of inhaled corticosteroid dose in patients with steroid-dependent asthma.

METHODS

85 patients with moderate to severe asthma taking high doses (> or = 1500 microg per day) of inhaled beclometasone dipropionate, were assigned suplatast tosilate (100 mg three times daily) or placebo for 8 weeks in a double-blind, randomised, parallel-group, multicentre trial. During the first 4 weeks, other medications remained unchanged (add-on phase); during the next 4 weeks, the doses of beclometasone were halved (steroid-reduction phase). Main outcome measures were pulmonary function, asthma symptoms, and use of beta2-agonists.

FINDINGS

Data were available from 77 patients. During the add-on phase, suplatast tosilate treatment, compared with placebo, was associated with higher forced expiratory volume in 1 s (mean difference between groups for changes from baseline at week 4, 0.20 L [95% CI 0.16-0.24], p=0.043), morning peak expiratory flow (18.6 L/min [14.1-23.1], p=0.037), and less diurnal variation in peak expiratory flow rate, asthma symptom scores (7.1 [6.6-7.6], p=0.029), and serum concentrations of eosinophil cationic protein and IgE. In the steroid-reduction phase, pulmonary function, asthma symptoms, and use of beta2-agonist deteriorated significantly more in the placebo group than in the suplatast group.

INTERPRETATION

Treatment with a Th2 cytokine inhibitor in steroid-dependent asthma improves pulmonary function and symptom control, and allows a decrease in dose of inhaled corticosteroid without significant side-effects. Some improvements in pharmacokinetics are, however, needed.

Suplatast tosilate inhibits goblet-cell metaplasia of airway epithelium in sensitized mice

BACKGROUND

IL-4 and IL-13 play a putative role in mucus hypersecretion in asthma. Suplatast tosilate prevents the synthesis of T(H2) cytokines.

OBJECTIVE

Because suplatast tosilate inhibits T(H2) cytokines but does not inhibits IFN-gamma production, we examined the effect of suplatast on IL-4- or IL-13- and ovalbumin (OVA)-induced mucin synthesis in NCI-H292 cells in vitro and in bronchi of pathogen-free BALB/c mice in vivo.

METHODS

In vitro, NCI-H292 cells were preincubated with suplatast tosilate (0.1-100 microgram/mL) 1 hour before adding human recombinant IL-4 (10 ng/mL). In vivo, mouse recombinant IL-4 or IL-13 (250 ng per/mouse) was instilled intranasally in mice pretreated with suplatast tosilate (50 mg.kg(-1).d(-1)). Mucous glycoconjugates were stained with Alcian blue (AB)/periodic acid-Schiff (PAS) stain. To evaluate effects of suplatast tosilate on goblet-cell metaplasia in OVA-sensitized mice, animals were pretreated with suplatast tosilate (1-50 mg.kg(-1).d(-1)) intragastrically. IL-4 and IL-13 were measured, and allergic inflammatory cells were analyzed in bronchoalveolar lavage fluid of OVA-sensitized mice.

RESULTS

Pretreatment with suplastast did not prevent IL-4- or IL-13-induced increase in mucous glycoconjugate production in NCI-H292 cells or in mice. OVA sensitization increased AB/PAS-stained area of the epithelium (48.1% +/- 2.4%, P <.01 compared with control mice). Suplatast tosilate inhibited OVA-induced goblet-cell metaplasia in airway epithelium in a dose-dependent fashion; 50 mg.kg(-1).d(-1) decreased the AB/PAS area to 22.7% +/- 2.7% (P <.05 compared with OVA sensitization alone). Pretreatment with suplatast tosilate also prevented OVA-induced increase in IL-4 and IL-13 levels and decreased the number of lymphocytes and eosinophils in bronchoalveolar lavage fluid (P <.05 compared with values of mice given OVA alone).

CONCLUSION

These results indicate that suplatast tosilate prevents allergen-induced goblet-cell metaplasia and the recruitment of eosinophils and lymphocytes into the airways. These results suggest that this effect is due to the prevention of the production of T(H2) cytokines in airways.

Effect of suplatast tosilate (IPD-1151T) on cytokine production by allergen-specific human Th1 and Th2 cell lines

Suplatast tosilate (IPD-1151T) is an antiallergic agent that suppresses airway eosinophil infiltration in asthma. We investigated the effects of IPD-1151T on proliferative response and cytokine production by human antigen-specific T cell lines. Purified protein derivatives (PPD)-specific T helper 1 (Th1) cell lines and Dermatophagoides farinae (Der f)-specific T helper 2 (Th2) cell lines were established from patients with asthma sensitized with house dust mite. Stimulation of PPD-specific and Der f-specific T cell lines with relevant antigens resulted in production of mostly interferon (IFN)-gamma and of interleukin (IL)-4 and IL-5, respectively. IPD-1151T did not inhibit the proliferative responses of either the Th1 or Th2 cell line to antigens. Although IPD-1151T did not inhibit IFN-gamma production by PPD-specific Th1 cell lines, it did inhibit IL-4 and IL-5 production by antigen-stimulated Der f-specific Th2 cell lines in a dose-dependent manner. IPD-1151T directly inhibited cytokine production by Der f-specific Th2 cell lines stimulated with immobilized anti-CD3 antibodies. Although IPD-1151T did not inhibit the clonal expansion of memory T cells among PBMCs into PPD-specific Th1 and Th2 cell lines, it did inhibit IL-4 and IL-5 production by Der f-specific Th2 cell lines but not IFN-gamma production by PPD-specific Th1 cell lines. These results suggest that IPD-1151T selectively inhibits Th2-type cytokine production.

Suplatast tosilate inhibits late response and airway inflammation in sensitized guinea pigs

The effect of suplatast tosilate, which has been proven to inhibit T-cell synthesis of IL-4 and IL-5, on the response to antigen inhalation challenge was investigated in sensitized guinea pigs. The animals were given an oral dose of 30 or 100 mg/kg of suplatast or vehicle (distilled water) daily for 1 wk before antigen challenge. Measurement of pulmonary resistance for 6 h was followed by bronchoalveolar lavage and lung fixation. After antigen challenge, all guinea pigs in the vehicle group displayed dual-phase airway obstruction and accumulation of eosinophils and lymphocytes in the airways. After 1 wk of treatment with the high dose of suplatast, the late asthmatic response and the recruitment of eosinophils and lymphocytes into the airways were significantly inhibited, but the early asthmatic response was not affected. In situ hybridization revealed that challenge-induced increases in IL-5 mRNA-positive cells in lung tissue were significantly inhibited after treatment. Thus, suplatast inhibited airway obstruction in the late phase by specifically inhibiting the inflammatory process after mast cell degranulation.

IPD-1151T (suplatast tosilate) inhibits interleukin (IL)-13 release but not IL-4 release from basophils

The effect of suplatast tosilate (IPD-1151T), which is known to suppress interleukin (IL)-4 release from T cells, on the release of IL-4 and IL-13 from human peripheral basophils was investigated. Basophils were obtained from 16 mite-sensitive atopic asthmatic patients. IPD-1151T clearly inhibited the antigen-induced release of IL-13 but not IL-4. These results suggest that IPD-1151T possesses different activity for the regulation of cytokine release in basophils and T cells.

Selective enhancement of production of IgE, IgG4, and Th2-cell cytokine during the rebound phenomenon in atopic dermatitis and prevention by suplatast tosilate

BACKGROUND

Atopic dermatitis is a chronic inflammatory skin disease, which is commonly treated with topical steroids. It is, however, associated with rebound after therapy has been discontinued.

OBJECTIVE

This study was designed to elucidate the mechanisms of the rebound phenomenon, and to test the effect of an oral anti-allergic medication, suplatast tosilate, on atopic dermatitis.

METHODS

This is a randomized, placebo controlled study. Patients with atopic dermatitis who had been treated with strong steroid ointment (dexamethasone valerate) for several years were divided into two groups. One group (the control group, n = 15) was treated with a non-steroid anti-inflammatory ointment (bufexamac ointment), while the other group (the suplatast tosilate group, n = 17) was treated with the anti-allergic medications, suplatast tosilate and bufexamac ointment. In each group, in vitro production of immunoglobulins and cytokines before and after 2 weeks of treatment was measured.

RESULTS

In the control group, 15 of the 15 patients experienced rebound and mean production of IgE, IgG4, IL-4, IL-5, IL-10, and IL-13 was enhanced after 2 weeks. In contrast, only 2 of the 17 patients in the suplatast tosilate group experienced rebound. There was no enhancement of production of immunoglobulins and cytokines after 2 weeks of treatment.

CONCLUSION

Enhanced production of the Th2-cell cytokines, which selectively induces IgE and IgG4 production, may be involved in the pathogenesis of the rebound phenomenon, and that suplatast tosilate may prevent the rebound phenomenon by down-regulating the production of these cytokines.

Suplatast tosilate (IPD), a new immunoregulator, is effective in vitiligo treatment

The major type of vitiligo is considered to be an autoimmune disorder. Anti-melanocyte antibodies are frequently detected in sera of patients with this disease. Interleukin (IL)-4 released from Th2 cells is an important factor in stimulating autoantibody production by B-cells. In this study, seven patients with vitiligo treated with suplatast tosilate (IPD), three showed repigmentation and improvement of their lesions after administration of the drug. IPD halted the continuous spread of the lesions in three of the other patients, and, in two of them, also reduced microsome test and thyroid test titers. The efficacy of IPD in treating vitiligo was thought to be due to the suppressive effect of this drug on IL-4 production. No side effect was observed. Thus IPD may represent a new alternative in vitiligo treatment due to its inhibition of autoimmunity by the suppression of IL-4.

Suplatast tosilate, a new type of antiallergic agent, prevents the expression of airway hyperresponsiveness in guinea pigs

Suplatast tosilate (suplatast) is an antiallergic agent capable of down-regulating the functions of CD4+ T cells. We now investigated the effects of suplatast on the antigen-induced airway hyperresponsiveness and the underlying allergic inflammatory response in sensitized guinea pigs. Animals that had been immunized twice by ovalbumin inhalation on day 0 and day 7 developed an increased airway responsiveness against inhaled acetylcholine 24 h after the ovalbumin challenge on day 14. Suplatast (10 and 100 mg/kg per day) and ketotifen (10 mg/kg per day) given orally from day 0 to day 14 effectively inhibited the expression of airway hyperresponsiveness. They also inhibited the infiltration of eosinophils and macrophages into broncho-bronchiolar walls and lumen. Interestingly, suplatast, but not ketotifen, inhibited the infiltration of lymphocytes including CD4+ T cells. Collectively, these results strongly suggest that suplatast prevents the expression of airway hyperresponsiveness due to the ability to suppress the infiltration of inflammatory cells into lung tissues.