Search

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis during infancy and is associated with subsequent wheezing and asthma, but the nature of this association is not fully understood. We investigated the role of RSV-specific IgE antibodies in the pathophysiology of virus-induced airway dysfunction in a mouse model. Lung infection with RSV resulted in significant increases in mRNA expression for IgE and both of its high- and low-affinity receptors. In serum, virus-specific IgE antibodies reached peak levels by Day 21 after infection. Data from in vitro experiments show that RSV can induce mast cell degranulation, but only if these cells are sensitized with specific IgE. When passively sensitized in vivo with virus-specific IgE, mice developed exaggerated airway responsiveness to methacholine on airway infection, an effect that required the high-affinity receptor of IgE. These data suggest that RSV-specific IgE may contribute to the pathophysiology of airway dysfunction in children who develop this class of specific antibody.

Allergic asthma is a complex syndrome characterized by airway obstruction, airway inflammation and airway hyper-responsiveness (AHR). Using a mouse model of allergen-induced AHR, we previously demonstrated that CD8-deficient mice develop significantly lower AHR, eosinophilic inflammation and interleukin (IL)-13 levels in bronchoalveolar lavage fluid compared with wild-type mice. These responses were restored by adoptive transfer of antigen-primed CD8(+) T cells. Previously, two distinct populations of antigen-experienced CD8(+) T cells, termed effector (T(EFF)) and central memory (T(CM)) cells, have been described. After adoptive transfer into CD8-deficient mice, T(EFF), but not T(CM), cells restored AHR, eosinophilic inflammation and IL-13 levels. T(EFF), but not T(CM), cells accumulated in the lungs, and intracellular cytokine staining showed that the transferred T(EFF) cells were a source of IL-13. These data suggest an important role for effector CD8(+) T cells in the development of AHR and airway inflammation, which may be associated with their Tc2-type cytokine production and their capacity to migrate into the lung.

The role of an interleukin (IL)-1 receptor antagonist (IL-1Ra) on the development of airway hyperresponsiveness (AHR) and airway inflammation following acute O(3) exposure in mice was investigated. Exposure of C57/BL6 mice to O(3) at a concentration of 2.0 ppm or filtered air for 3 h resulted in increases in airway responsiveness to inhaled methacholine (MCh) 8 and 16 h after the exposure, and an increase in neutrophils in the bronchoalveolar lavage (BAL) fluid. IL-1beta expression, assessed by gene microarray, was increased 2-fold 4 h after O(3) exposure, and returned to baseline levels by 24 h. Levels of IL-1beta in lung homogenates were also increased 8 h after O(3) exposure. Administration of (human) IL-1Ra before and after O(3) exposure prevented development of AHR and decreased BAL fluid neutrophilia. Increases in chemokine levels in lung homogenates, tumor necrosis factor-alpha, MIP-2, and keratinocyte chemoattractant following O(3) exposure were prevented by IL-1Ra. Inhalation of dexamethasone, an inhibitor of IL-1 production, blocked the development of AHR, BAL fluid neutrophilia, and decreased levels of IL-1 following O(3) exposure. In summary, acute exposure to O(3) induces AHR, neutrophilic inflammation, epithelial damage, and IL-1. An IL-1Ra effectively prevents the development of altered airway function, inflammation, and structural damage.

In certain models of allergic airway disease, mast cells facilitate the development of inflammation and airway hyper-responsiveness (AHR). To define the role of the high affinity IgE receptor (FcεRI) in the development of AHR, mice with a disruption of the α subunit of the high affinity IgE receptor (FcεRI−/−) were exposed on 10 consecutive days to nebulized OVA. Forty-eight hours after the last nebulization, airway responsiveness was monitored by the contractile response of tracheal smooth muscle to electrical field stimulation (EFS). After the 10-day OVA challenge protocol, wild-type mice demonstrated increased responsiveness to EFS, whereas similarly challenged FcεRI−/− mice showed a low response to EFS, similar to nonexposed animals. Further, allergen-challenged FcεRI−/− mice showed less airway inflammation, goblet cell hyperplasia, and lower levels of IL-13 in lung homogenates compared with the controls. IL-13-deficient mice failed to develop an increased response to EFS or goblet cell hyperplasia after the 10-day OVA challenge. We transferred bone marrow-derived mast cells from wild-type mice to FcεRI−/− mice 1 day before initiating the challenge protocol. After the 10-day OVA challenge, recipient FcεRI−/− mice demonstrated EFS-induced responses similar to those of challenged wild-type mice. Transferred mast cells could be detected in tracheal preparations. These results show that FcεRI is important for the development of AHR after an aerosolized allergen sensitization protocol and that this effect is mediated through FcεRI on mast cells and production of IL-13 in the lung.

The lung collectin surfactant protein D (SP-D) is an important component of the innate immune response but is also believed to play a role in other regulatory aspects of immune and inflammatory responses within the lung. The role of SP-D in the development of allergen-induced airway inflammation and hyperresponsiveness (AHR) is not well defined. SP-D levels progressively increased up to 48 hours after allergen challenge of sensitized mice and then subsequently decreased. The levels of SP-D paralleled the development of airway eosinophilia and AHR. To determine if this association was functionally relevant, mice were administered rat SP-D (rSP-D) intratracheally. When given to sensitized mice before challenge, AHR and eosinophilia were reduced by rSP-D in a dose-dependent manner but not by mutant rSP-D. rSP-D administration resulted in increased levels of interleukin (IL)-10, IL-12, and IFN-gamma in bronchoalveolar lavage fluid and reduced goblet cell hyperplasia. Culture of alveolar macrophages together with SP-D and allergen resulted in increased production of IL-10, IL-12, and IFN-gamma. These results indicate that SP-D can (negatively) regulate the development of AHR and airway inflammation after airway challenge of sensitized mice, at least in part, by modulating the function of alveolar macrophages.

Background: Pipecolic acid, a metabolite of lysine, is found in human physiological fluids and is thought to play an important role in the central inhibitory γ-aminobutyric acid system. However, it is unclear whether plasma D- and L-pipecolic acid originate from oral food intake or intestinal bacterial metabolites. Methods: We analyzed the contents of D- and L-pipecolic acid in several processed foods including dairy products (cow’s milk, cheese and yogurt), fermented beverages (beer and wine) and heated samples (beef, bovine liver, bread and tofu) to clarify the relationship between plasma D- and L-pipecolic acid and dietary foods. Results: Our study revealed that some of the samples contained high concentrations of total pipecolic acid, and a higher proportion of L- than D-isomers. The other samples also showed high proportions of L-pipecolic acid. It was also shown that there is no significant change in the ratio of the D-isomer before and after heat treatment. The heat treatments could not cause the racemization of pipecolic acid in this study. Conclusion: These findings suggest that plasma pipecolic acid, particularly the D-isomer, does not originate from direct food intake and that D- and L-pipecolic acid can possibly be derived from intestinal bacterial metabolites.

Summary Background Correcting Th1/Th2 imbalance with administration of IL-12 before and during antigen challenge holds therapeutic promise in asthma. However, the effects of IL-12 on the established asthmatic responses have not fully been examined. Objective We investigated whether IL-12 administered after antigen challenge could diminish airway hyper-reactivity (AHR) and eosinophilia in mice actively sensitized to ovalbumin. We also have investigated the ability of administered IL-12 to induce IL-18 receptor (IL-18R) expression that may lead possible synergic action of IL-12 with endogenous IL-18. Methods C57BL/6 mice immunized to ovalbumin (OVA) by intraperitoneal (i.p.) injection, were challenged three times with an aerosol of OVA every second day for 8 days. Recombinant IL-12 (500 ng) was intravenously administered on a single occasion 1 h after the final challenge of mice. Mice were analysed for effects of IL-12 on AHR, inflammatory cell infiltration and cytokine levels in lung tissue as well as serum immunoglobulin (Ig) E levels. Immunohistochemistry for IL-18R was performed using rat monoclonal antibody specific for murine IL-18Rα (IL-1 receptor related protein; IL-1Rrp). Results An intravenous IL-12 administration diminished AHR, pulmonary eosinophilia and T lymphocyte infiltration, serum IgE, IL-4 and IL-13 in lung tissue. Expression of IL-18R was induced in the mononuclear cells in the lung of mice exposed to OVA. IL-12 administration enhanced the IL-18R expression compared with the control. Conclusion These data indicate that IL-12 can attenuate established antigen-induced AHR and inflammation. In this mechanism it would be interpreted as follows: IL-12 administration in OVA-challenged mice decreased IL-4 production and IgE production thereafter through direct effect on inhibiting the activation of established Th2 cells response and also combined effect with up-regulation of IL-18R expression by inflammatory cells in the lung.

Background and objective Carbon monoxide (CO) is known to be present in measurable quantities in the exhalation of asthmatic patients. Corticosteroid treatment resulted in a decrease in exhaled CO levels in asthmatic patients, raising the possibility that an increase in exhaled CO concentration reflects inflammation of the asthmatic airway. Heme oxygenase-1 (HO-1) protein, also called HSP32, is the rate-limiting enzyme in the catabolism of heme to biliverdin, free iron and CO. However, it is unknown whether an expression of HO-1 within the lung tissue is related to allergic airway inflammation. We studied the expression of HO-1 in lung tissue and bronchoalveolar lavage cells in a mouse model of asthma. Methods Ovalbumin (OVA)-sensitized C57BL/6 mice were challenged with aerosolized OVA. HO-1 positive cells were identified by immunostaining in lung tissue and bronchoalveolar lavage fluid (BALF) after the challenge. Results HO-1 positive cell numbers increased in the subepithelium of the bronchi after OVA challenge. In cytospin preparations from BALF after OVA challenge, HO-1 was localized to alveolar macrophages. Inside the macrophages, HO-1 reactivity was expressed in the cytoplasm, and the perinuclear region in particular. Conclusion The expression of HO-1 is increased within the lung tissue in allergic airway inflammation. Measurement of HO-1 activity may be clinically useful in the management of asthma.

Background: T H2 cytokines are associated with airway inflammation and hyperreactivity in bronchial asthma, and restoration of the T H1 /T H2 imbalance is a potential avenue for novel therapies. IL-18 is a cytokine secreted by activated macrophages, and it shares some of its biologic activities with IL-12, a typical T H1 -type cytokine. Although IL-18 and IL-12 act on T cells synergistically to induce IFN-γ production, the contribution of IL-18 T H1 /T H2 imbalance and to subsequent asthmatic response has not been elucidated in vivo. Objective: We studied a model of allergic asthma in IL-18–deficient mice to investigate the modulatory role of IL-18 on induction and maintenance of T H2 mucosal immunity. We also have investigated the ability of intraperitoneal instilled IL-18 to reduce T H2 mucosal immunity in IL-18–deficient mice. Methods: IL-18–deficient mice immunized to ovalbumin by means of intraperitoneal injection were challenged 3 times with an aerosol of ovalbumin every second day for 8 days. Recombinant (r)IL-18 was intraperitoneally administered in mice before every first challenge. Mice were analyzed for effects on lung eosinophilia, cytokines, and serum IgE levels. Results: In IL-18–deficient mice, levels of eosinophilia and lung damage were significantly higher than in wild-type C57/BL6 litter mates. Intraperitoneal administration of rIL-18 in deficient mice reduced these antigen-induced changes to levels seen in wild-type mice in association with a decrease in IL-4 in bronchoalveolar lavage fluid and lung tissue. However, administration of rIL-18 did not affect the IFN-γ level and somewhat enhanced the production of IL-5. Notably, reconstitution with rIL-18 increased the numbers of cells staining for Fas ligand, as well as apoptotic cells stained by nick end-labeling in bronchial submucosa infiltrates. Conclusion: These findings indicate that in vivo IL-18 not only inhibited antigen-specific T H2 development but also affected apoptosis through Fas-Fas ligand interactions. These data support a role for IL-18 in the complex pathogenesis of allergic inflammation in which IL-18 limited the development of the local inflammatory response to antigen. (J Allergy Clin Immunol 2000;105:45-53.)

T1/ST2, an orphan receptor with homology with the interleukin (IL)-1 receptor family, is expressed constitutively and stably on the surface of T helper type 2 (Th2) cells, but not on Th1 cells. T1/ST2 is also expressed on mast cells, which are critical for Th2-mediated effector responses. To evaluate whether T1/ST2 is required for Th2 responses and mast cell function, we have generated T1/ST2-deficient (T1/ST2−/−) mice and examined the roles of T1/ST2. Naive CD4+ T cells isolated from T1/ST2−/− mice developed to Th2 cells in response to IL-4 in vitro. T1/ST2−/− mice showed normal Th2 responses after infection with the helminthic parasite Nippostrongylus brasiliensis as well as in the mouse model of allergen-induced airway inflammation. In addition, differentiation and function of bone marrow–derived cultured mast cells were unaffected. These findings demonstrate that T1/ST2 does not play an essential role in development and function of Th2 cells and mast cells.

Background The TH2-type cytokines have been reported to contribute to the asthmatic response. STAT6 has an essential role in IL-4 signalling and in production of TH2 cytokines from T cells and is involved in IgE and IgG 1 responses after nematode infections, indicating that STAT6 has an important role in allergic diseases. Objective In this study we investigated the effects of STAT6 deficiency on allergen-induced airways inflammation in mice. Methods Both ovalbumin (OVA)-sensitized STAT6 deficient (STAT6 -/-) mice and wild-type C57BL/6 mice were challenged with aerosolized OVA. Changes in inflammatory cell infiltration and cytokine levels in lung tissue as well as serum immunoglobulin levels were analysed in OVA-challenged STAT6 -/- and wild-type mice. Results The eosinophilia and lung damage normally resulting from aeroallergen challenge were not seen in STAT6 -/- mice. Expression of TH2 cytokines (IL-4 and IL-5) in the lung tissue as well as IgE and IgG1 responses after OVA challenge were profoundly reduced in STAT6 -/- mice, whereas expression of IFNγ was the same in STAT6 -/- mice and wild-type mice after OVA challenge. Immunocytochemical analysis of T cells showed the infiltration of CD4 + T cells but not CD8 + T cells increased into the lung of wild-type mice after OVA challenge. However, the OVA-exposed STAT6 -/- mice demonstrated the infiltration of both CD4 + T cells and CD8 + T cells with a significant increase in percentage and total number of CD8 + T cells compared with OVA-exposed wild-type mice. Conclusion These results indicate that factors which signal through STAT6 are important regulators of eosinophilia of allergic airway inflammation, regulating TH2-type cytokine production both in CD4 + T cells and CD8 + T cells.

Suppressing the abnormalities associated with asthma has been difficult to accomplish using immunotherapy or vaccination once the disease is established. The effector cells necessary for effective immunization/vaccination and immunotherapy of asthma are also not well understood. Therefore, we vaccinated allergen (OVA)-sensitized mice to determine whether therapeutic immunization could suppress airway hyperresponsiveness (AHR) and inflammation and to identify key immune effector cells and cytokines. Mice were immunized with a vaccine comprised of Ag and cationic liposome-DNA complexes (CLDC), a vaccine which has previously been shown to elicit strong CD4+ and CD8+ T cell responses and activation of Th1 immunity. We showed that immunization with the OVA-CLDC vaccine significantly suppressed AHR, eosinophilia, goblet cell metaplasia, and Th2 cytokine production. In contrast, immunization with CLDC alone suppressed eosinophilia and Th2 cytokine production, but failed to suppress AHR and goblet cell changes. Using adoptive transfer experiments, we found that suppression of AHR was mediated by Ag-specific CD8+ T cells and was dependent on IFN-γ production by the transferred T cells. Thus, we conclude that generation of strong, allergen-specific CD8+ T cell responses by immunization may be capable of suppressing AHR and allergic airway inflammation, even in previously sensitized and challenged mice.

The FcR common gamma-chain (FcRgamma) is an essential component of the receptors FcepsilonRI, FcgammaRI, and FcgammaRIII, which are expressed on many inflammatory cell types. The role of these receptors in the initiation or maintenance of allergic inflammation has not been well defined. FcRgamma-deficient (FcRgamma(-/-)) and control (wild-type (WT)) mice were sensitized and subsequently challenged with OVA. Following sensitization and challenge to OVA, FcRgamma-deficient (FcRgamma(-/-)) mice developed comparable levels of IgE and IgG1 as WT mice. However, numbers of eosinophils, levels of IL-5, IL-13, and eotaxin in bronchoalveolar lavage fluid, and mononuclear cell (MNC) proliferative responses to OVA were significantly reduced, as was airway hyperresponsiveness (AHR) to inhaled methacholine. Reconstitution of FcRgamma(-/-) mice with whole spleen MNC from WT mice before sensitization restored development of AHR and the numbers of eosinophils in bronchoalveolar lavage fluid; reconstitution after sensitization but before OVA challenge only partially restored these responses. These responses were also restored when FcRgamma(-/-) mice received T cell-depleted MNC, T and B cell-depleted MNC, or bone marrow-derived dendritic cells before sensitization from FcR(+/+) or FcgammaRIII-deficient but not FcRgamma(-/-) mice. The expression levels of FcgammaRIV on bone marrow-derived dendritic cells from FcR(+/+) mice were found to be low. These results demonstrate that expression of FcRgamma, most likely FcgammaRI, on APCs is important during the sensitization phase for the development of allergic airway inflammation and AHR.

IL-18 is known to induce IFN-gamma production, which is enhanced when combined with IL-2. In the present study, we investigated whether the combination of exogenous IL-2 and IL-18 alters airway hyperresponsiveness (AHR) and airway inflammation. Sensitized mice exposed to ovalbumin (OVA) challenge developed AHR, inflammatory cells in the bronchoalveolar lavage (BAL) fluid, and increases in levels of Th2 cytokines and goblet cell numbers. The combination of IL-2 and IL-18, but neither alone, prevented these changes while increasing levels of IL-12 and IFN-gamma. The combination of IL-2 and IL-18 was ineffective in IFN-gamma-deficient and signal transducer and activator of transcription (STAT)4-deficient mice. Flow cytometry analysis showed significant increases in numbers of IFN-gamma-positive natural killer (NK) cells in the lung after treatment with the combination therapy, and transfer of lung NK cells isolated from sensitized and challenged mice treated with the combination significantly suppressed AHR and BAL eosinophilia. These data demonstrate that the combination of IL-2 and IL-18 prevents AHR and airway inflammation, likely through IL-12-mediated induction of IFN-gamma production in NK cells.

RANTES (CC chemokine ligand 5) contributes to airway inflammation through accumulation of eosinophils, but the exact role of RANTES (CCL5) is not defined. C57BL/6 mice, sensitized by injection of ovalbumin (OVA) on Days 1 and 14, were challenged with OVA on Days 28, 29, and 30 (3 challenges, short-term–challenge model) or on Days 28, 29, 30, 36, 40, 44, and 48 (7 challenges, repeated–challenge model) and evaluated 48 h later. Anti-mouse RANTES was given intravenously, and recombinant mouse RANTES or PBS was given intratracheally. These reagents were given on Days 28, 29, and 30 in the short-term–challenge study and on Days 44 and 48 in the repeated-challenge study. After short-term challenge, there were no effects after administration of anti-RANTES or RANTES. In the repeated-challenge study, although control mice showed a decrease in airway hyperresponsiveness, administration of anti-RANTES sustained and enhanced airway hyperresponsiveness and increased goblet cell numbers. In contrast, administration of RANTES normalized airway function but reduced goblet cell numbers. IL-12 and IFN-γ levels in BAL decreased in the anti-RANTES group and increased in the RANTES group. IFN-γ–producing CD4 T cells in lung, and IFN-γ production from lung T cells in response to OVA in the anti-RANTES group, were significantly decreased but were increased in the RANTES group. Anti–IFN-γ, administered with RANTES, decreased the effects of RANTES on AHR after repeated challenge. These data indicate that RANTES plays a role in the regulation of airway function after repeated allergen challenge, in part through modulation of levels of IFN-γ and IL-12.

S -carboxymethylcysteine ( S -CMC) has been used as a mucoregulator in respiratory diseases. However, the mechanism of action of S -CMC on allergic airway inflammation has not yet been defined. In the present study, BALB/c mice were initially sensitised and challenged to ovalbumin (OVA) and, weeks later, re-challenged with OVA (secondary challenge). S -CMC (5–100 mg·kg −1 ) was administered from 2 days before the secondary challenge through to the day of assay. Mice developed airway hyperresponsiveness (AHR) 6 h after the secondary challenge and increased numbers of neutrophils were present in the bronchoalveolar lavage (BAL) fluid. At 72 h after secondary challenge, mice again developed AHR, but the BAL fluid contained large numbers of eosinophils. S -CMC treatment was found to reduce AHR and neutrophilia at 6 h, as well as eosinophilia and AHR at 72 h. These effects appeared to be dose dependent. Goblet cell hyperplasia, observed at 72 h, was reduced by S -CMC. In BAL fluid, increased levels of interferon-γ, interleukin (IL)-12 and IL-10 and decreased levels of IL-5 and IL-13 were detected. In conclusion, the data indicate that S -carboxymethylcysteine is effective in reducing airway hyperresponsiveness and airway inflammation at two distinct phases of the response to the secondary allergen challenge in sensitised mice.

There is conflicting information about the development and resolution of airway inflammation and airway hyperresponsiveness (AHR) after repeated airway exposure to allergen in sensitized mice.Sensitized BALB/c and C57BL/6 mice were exposed to repeated allergen challenge on 3, 7, or 11 occasions. Airway function in response to inhaled methacholine was monitored; bronchoalveolar lavage fluid inflammatory cells were counted; and goblet cell metaplasia, peribronchial fibrosis, and smooth muscle hypertrophy were quantitated on tissue sections. Bone marrow-derived dendritic cells were generated after differentiation of bone marrow cells in the presence of growth factors.Sensitization to ovalbumin (OVA) in alum, followed by three airway exposures to OVA, induced lung eosinophilia, goblet cell metaplasia, mild peribronchial fibrosis, and peribronchial smooth muscle hypertrophy; increased levels of interleukin (IL)-4, IL-5, IL-13, granulocyte-macrophage colony-stimulating factor, transforming growth factor-beta(1), eotaxin-1, RANTES (regulated on activation, normal T-cell expressed and secreted), and OVA-specific IgG1 and IgE; and resulted in AHR. After seven airway challenges, development of AHR was markedly decreased as was the production of IL-4, IL-5, and IL-13. Levels of IL-10 in both strains and the level of IL-12 in BALB/c mice increased. After 11 challenges, airway eosinophilia and peribronchial fibrosis further declined and the cytokine and chemokine profiles continued to change. At this time point, the number of myeloid dendritic cells and expression of CD80 and CD86 in lungs were decreased compared with three challenges. After 11 challenges, intratracheal instillation of bone marrow-derived dendritic cells restored AHR and airway eosinophilia.These data suggest that repeated allergen exposure leads to progressive decreases in AHR and allergic inflammation, through decreases in myeloid dendritic cell numbers.

The mechanisms by which respiratory syncytial virus (RSV) infection causes airway hyperresponsiveness (AHR) are not fully established. We hypothesized that RSV infection may alter the expression of airway sensory neuropeptides, thereby contributing to the development of altered airway function. BALB/c mice were infected with RSV followed by assessment of airway function, inflammation, and sensory neuropeptide expression. After RSV infection, mice developed significant airway inflammation associated with increased airway resistance to inhaled methacholine and increased tracheal smooth muscle responsiveness to electrical field stimulation. In these animals, substance P expression was markedly increased, whereas calcitonin gene-related peptide (CGRP) expression was decreased in airway tissue. Prophylactic treatment with Sendide, a highly selective antagonist of the neurokinin-1 receptor, or CGRP, but not the CGRP antagonist CGRP(8–37), inhibited the development of airway inflammation and AHR in RSV-infected animals. Therapeutic treatment with CGRP, but not CGRP(8–37) or Sendide, abolished AHR in RSV-infected animals despite increased substance P levels and previously established airway inflammation. These data suggest that RSV-induced airway dysfunction is, at least in part, due to an imbalance in sensory neuropeptide expression in the airways. Restoration of this balance may be beneficial for the treatment of RSV-mediated airway dysfunction.

The role of Th2/CD4 T cells, which secrete IL-4, IL-5, and IL-13, in allergic disease is well established; however, the role of CD8+ T cells (allergen-induced airway hyperresponsiveness (AHR) and inflammation) is less clear. This study was conducted to define the role of Ag-primed CD8+ T cells in the development of these allergen-induced responses. CD8-deficient (CD8−/−) mice and wild-type mice were sensitized to OVA by i.p. injection and then challenged with OVA via the airways. Compared with wild-type mice, CD8−/− mice developed significantly lower airway responsiveness to inhaled methacholine and lung eosinophilia, and exhibited decreased IL-13 production both in vivo, in the bronchoalveolar lavage (BAL) fluid, and in vitro, following Ag stimulation of peribronchial lymph node (PBLN) cells in culture. Reconstitution of sensitized and challenged CD8−/− mice with allergen-sensitized CD8+ T cells fully restored the development of AHR, BAL eosinophilia, and IL-13 levels in BAL and in culture supernatants from PBLN cells. In contrast, transfer of naive CD8+ T cells or allergen-sensitized CD8+ T cells from IL-13-deficient donor mice failed to do so. Intracellular cytokine staining of lung as well as PBLN T cells revealed that CD8+ T cells were a source of IL-13. These data suggest that Ag-primed CD8+ T cells are required for the full development of AHR and airway inflammation, which appears to be associated with IL-13 production from these primed T cells.

Ozone (O3) can induce airway hyperresponsiveness (AHR) and neutrophilic inflammation. We evaluated the role of complement in development of AHR and inflammation after acute O3 exposure in mice. Mice were exposed to O3 at 2 ppm for 3 hours, and airway responsiveness to methacholine was measured 8 hours after O3 exposure. Complement was depleted or inhibited by intraperitoneal injection of cobra venom factor (CVF) or complement receptor-related gene y (Crry)-Ig, a potent C3 convertase inhibitor; neutrophils were depleted using an antineutrophil monoclonal antibody. CVF attenuated the development of AHR by O3. Administration of Crry-Ig also prevented the development of AHR. Bronchoalveolar lavage (BAL) fluid neutrophilia after O3 exposure was significantly decreased by administration of either CVF or Crry-Ig. Increased BAL fluid total protein after O3 exposure was lowered by depletion or inhibition of complement. In contrast to the effects of complement inhibition or depletion, depletion of BAL neutrophil counts by more than 90% with the monoclonal antibody did not affect the development of AHR after O3 exposure. These data indicated that activation of the complement system follows acute O3 exposure and is important to the development of AHR and airway neutrophilia. However, this neutrophil response does not appear necessary for the development of AHR.

A 60-year-old man was admitted to our hospital complaining of progressive dyspnea. On admission, he had marked hypoxemia, and his chest radiography and computed tomography (CT) showed ground glass opacities and multiple emphysematous changes in both lung fields. On examining the patient's bronchoalveolar lavage fluid (BALF). Pneumocystis carinii pneumonia (PCP) was diagnosed. A serological test for human immunodeficiency virus (HIV)-1, 2 was positive, and acquired immunodeficiency syndrome (AIDS) was diagnosed. Since the chest CT performed a month before the patient's admission to our hospital revealed ground glass opacities in both lung fields we thought that he had already developed PCP at that time. In comparison with his previous CT, the chest CT on admission showed progressive ground glass opacities and emphysematous changes. Although PCP is known to display various findings on chest radiography and CT, emphysematous changes are rarely reported in Japan. In this case we were able to confirm these changes and observe its progression using chest CT.

On August 14, 2001, a 76-year-old woman with a history of rheumatoid arthritis was admitted to our hospital with fever, cough, dyspnea and diarrhea. On admission, her chest radiography showed pleural effusion on the right side, and thoracocentesis was used to diagnose empyema. The patient underwent pleural drainage and received antibiotics. Alpha-Streptococcus was detected in both aerobic and anaerobic cultures of the pleural effusion. After 2 weeks of therapy, her empyema had improved; but her diarrhea, which had started 1 week before admission, had worsened, and her hypoproteinemia had progressed. Examination of the fecal clearance of alpha-1-antitrypsin and biopsied rectal material revealed that the diarrhea was caused by protein-losing enteropathy due to gastrointestinal amyloidosis secondary to rheumatoid arthritis. The patient was treated with steroids, but developed an additional infectious disease and died on September 29, 2001. In this case, she suffered from various infectious diseases including empyema and fungus infections. It has been reported that protein-losing enteropathy accompanies abnormalities in the immune system, by the loss of immunoglobulins and lymphocytes from the gut. We therefore suspect that protein-losing enteropathy due to gastrointestinal amyloidosis caused this patient's empyema.

SUMMARY Allergic asthma, a chronic inflammatory disease of the airways, is characterized by the presence of T helper 2 cells and eosinophils in sputum, bronchoalveolar lavage, and mucosal biopsy specimens. Although the T helper 1-promoting cytokine, interleukin-12, is capable of inhibiting the T helper 2-driven asthma symptoms and bronchial responsiveness, the specific mechanisms underlying these interleukin-12 actions are unclear. The anti-allergic response to interleukin-12 is only partially dependent on interferon-γ, which induces apoptosis by enhancing expression of Fas antigen. We therefore investigated in vivo whether the anti-allergic action of interleukin-12 is mediated through induction of apoptosis. C57BL/6 mice immunized to ovalbumin by intraperitoneal injection were challenged three times with an ovalbumin aerosol every second day for 7 days. Recombinant interleukin-12 was administered intravenously after the final challenge. After the last ovalbumin challenge, mice were examined for effects of interleukin-12 on inflammatory cell infiltration and apoptosis in the lung as detected by terminal deoxynucleotidyl transferase-mediated deoxyribonucleoside triphosphate nick end-labelling. Administration of interleukin-12 reduced ovalbumin-induced pulmonary eosinophilia (P

On November 15, 2000, a 60-year-old man was admitted to our hospital with progressive dyspnea and right chest pain. He had a 40-year history of occupational asbestos exposure, which began when he was 20 years old. On admission, his chest radiographs showed pleural effusion on the right side, and asbestos bodies were detected in his sputum. Neither a cytological examination of the pleural effusion nor a histological examination of the pleura by percutaneous pleural biopsy revealed malignant cells. In addition, we could not find any other cause for the pleural effusion (such as tuberculosis, collagen disease, or heart failure). In May 2001, the patient also developed pleural thickening and pain in the right hypochondrium, and he was readmitted to our hospital on May 21, 2001. On readmission, an enhanced abdominal CT showed multiple liver tumors, and percutaneous pleural and liver biopsies were performed. The histological findings in the pleura and liver specimens revealed hypocellular collagen tissues without malignant cells. Thus, we could not determine the main cause either of the pleural effusion or of the patient's disease. However, his condition rapidly deteriorated, and he died on August 12, 2001. At the autopsy, bilateral pleural thickening, predominantly on the right side, and invasion of the lungs were observed. The histological findings in the pleural and hepatic tissues revealed hypocellular collagen fibers with a striate pattern and areas of neoplastic spindle cells. He was diagnosed as having malignant desmoplastic mesothelioma with liver metastasis. Cases of malignant desmoplastic mesothelioma have rarely been reported in Japan.

A 23-year-old man was admitted to our hospital for a complete medical evaluation of abnormal pulmonary shadows found on a chest radiograph during his annual check-up. Chest radiography and chest CT showed a diffuse spread of micronodules in both lung fields and mediastinal lymphadenopathy. A transbronchial lung biopsy demonstrated evidence of noncaseating epithelioid cell granuloma with multinucleated giant cells, and a diagnosis of sarcoidosis was made. The pulmonary shadows improved without therapy. Twenty months later, the patient was readmitted to the hospital because of chest pain and dyspnea. Pneumothorax appeared on the right in a chest radiograph, but subsided after drainage therapy, and two weeks later, a right side pleural effusion was seen. We determined that the pleura was involved in the sarcoidosis, and the patient was treated with oral prednisolone 20 mg daily. The pleural effusion gradually subsided. This is the first reported case in Japan of pulmonary sarcoidosis with pneumothorax and pleural effusion after improvement of pulmonary impairment.

A 70-year-old woman was admitted to our hospital for medical evaluation of a right side pleural effusion, which was pointed out at another hospital. Chest CT revealed a right pleural effusion with diffuse and irregular pleural thickening. Percutaneous pleural biopsy showed hypocellular collagenous tissue without malignant cells. Though she received antituberculosis therapy, the pleural thickening progressed and the serum CYFRA 21-1 level was elevated. Chest pain and dyspnea appeared, and she was readmitted. However, pneumonia was present as a complication, and she died. At autopsy, the right pleura was thickened and invasion of the lung and the chest wall was observed. Microscopic findings showed increased amounts of hyalinized collagen fibers forming a storiform pattern. At the tumor foci, atypical cells with distinct nucleoli were observed. Desmoplastic malignant mesothelioma, which is rarely reported in Japan, was diagnosed.

Pipecolic acid, a metabolite of lysine, is found in human physiological fluids and is thought to play an important role in the central inhibitory gamma-aminobutyric acid system. However, it is unclear whether plasma D- and L-pipecolic acid originate from oral food intake or intestinal bacterial metabolites.We analyzed the contents of D- and L-pipecolic acid in several processed foods including dairy products (cow's milk, cheese and yogurt), fermented beverages (beer and wine) and heated samples (beef, bovine liver, bread and tofu) to clarify the relationship between plasma D- and L-pipecolic acid and dietary foods.Our study revealed that some of the samples contained high concentrations of total pipecolic acid, and a higher proportion of L- than D-isomers. The other samples also showed high proportions of L-pipecolic acid. It was also shown that there is no significant change in the ratio of the D-isomer before and after heat treatment. The heat treatments could not cause the racemization of pipecolic acid in this study.These findings suggest that plasma pipecolic acid, particularly the D-isomer, does not originate from direct food intake and that D- and L-pipecolic acid can possibly be derived from intestinal bacterial metabolites.