Granulocyte macrophage colony-stimulating factor augments ICAM-1 and VCAM-1 activation of eosinophil function

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are members of the immunoglobulin superfamily adhesion molecules on vascular endothelium and important in the development of eosinophil (EOS) accumulation in allergic inflammation. To define the role of these adhesion proteins in EOS inflammation, peripheral blood EOS from allergic donors were incubated in either buffer (control)-, recombinant human (rh)-VCAM-1-, or rh-ICAM-1-coated plates, and the effects of these adhesion proteins on EOS effector functions were determined. VCAM-1 induced spontaneous EOS adhesion whereas EOS adhesion to ICAM-1 required a second signal, such as granulocyte macrophage colony-stimulating factor (GM-CSF). Although only VCAM-1 stimulated EOS superoxide anion (O2-) generation, the addition of GM-CSF (100 pM) to the reactions resulted in a greater and equivalent production of O2- with VCAM-1 and ICAM-1. In the presence of GM-CSF, ICAM-1 and VCAM-1 caused significant release of EOS-derived neurotoxin (EDN). Moreover, only ICAM-1 (no GM-CSF) promoted calcium ionophore A23187 (0.2 microM)-induced EOS leukotriene C4 (LTC4). Enhanced O2- generation, EDN release, and LTC4 generation observed with ICAM-1 and VCAM-1 were significantly inhibited by anti-beta2-integrin antibody. These results suggest that ICAM-1 and VCAM-1 are important in determining the eventual function of airway EOS.

Sulfonylureas inhibit cytokine-induced eosinophil survival and activation

Eosinophils play a key role in the pathogenesis of asthma and other allergic inflammatory diseases. We have previously shown that treatment of eosinophils with lidocaine preferentially inhibits IL-5-induced survival. This inhibition cannot be overcome by increasing concentrations of IL-5 and is not due to the blocking of Na+ channels by lidocaine. Here we report that one class of K+ channel blockers, the sulfonylureas, inhibits eosinophil survival in a manner similar to lidocaine. The sulfonylurea glyburide inhibits eosinophil survival even at high concentrations of IL-5. In contrast, increasing concentrations of IL-3 or granulocyte-macrophage CSF overcome glyburide inhibition. Glyburide also blocks cytokine-induced eosinophil superoxide production. Similar results were seen with the sulfonylureas tolbutamide and glipizide. Interestingly, the effects of glyburide are not antagonized by the ATP-sensitive K+ channel openers cromakalim, pinacidil, or diazoxide. Although Scatchard analysis of [3H]glyburide binding to eosinophil membranes indicated that the high affinity sulfonylurea receptor (SUR1) is not present on eosinophils, human eosinophils do express mRNA homologous to the sulfonylurea receptor family, in keeping with the presence of a sulfonylurea receptor. Finally, coculture of eosinophils with combinations of glyburide, lidocaine, and dexamethasone resulted in synergistic inhibition of cytokine-mediated eosinophil survival and superoxide production. These results have intriguing clinical implications for the treatment of eosinophil-associated diseases.

Localization of eosinophil-derived neurotoxin and eosinophil cationic protein in neutrophilic leukocytes

Eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) are generally regarded as eosinophil-specific proteins. We tested whether EDN and ECP are present in mature neutrophils. By indirect immunofluorescence, both eosinophils and neutrophils stained with antibodies to EDN and ECP. Lysates of purified (<0.1% eosinophil contamination) neutrophils contained EDN, 112+/-4 ng/10(6) cells, and ECP, 163+/-2 ng/10(6) cells, whereas eosinophil major basic protein (MBP) was not detectable. Electron microscopic examination of immunogold-labeled buffy coat cells stained with EDN antibody showed that EDN is localized to neutrophil granules. Finally, EDN mRNA was detected in lysates of highly purified neutrophils (0.001% eosinophil contamination) by the reverse transcription-polymerase chain reaction. We conclude that proteins that are either identical to or immunologically cross-reactive with EDN and ECP are present in neutrophils and that EDN is synthesized and localized to neutrophil granules. Thus, caution must be exercised in interpreting the presence of EDN and ECP as specific markers of eosinophil-associated inflammation in human disease.

Eosinophilia and gastrointestinal symptoms after ingestion of shiitake mushrooms

BACKGROUND

Shiitake mushrooms are a dietary staple in Asia and are increasingly popular worldwide. A cholesterol-lowering study with shiitake showed that 17 of 49 participants withdrew because of rash or abdominal discomfort, and two had marked eosinophilia. One of these latter participants was subsequently challenged for 14 days with shiitake powder and again had eosinophilia.

OBJECTIVE

We investigated whether ingestion of shiitake mushroom powder induces eosinophilia or symptoms.

METHODS

We studied 10 normal persons. Each participant ingested 4 gm shiitake powder (open label) daily for 10 weeks (trial 1), and the protocol was repeated in these same subjects after 3 to 6 months (trial 2). Blood counts and serum samples were obtained biweekly (trial 1) or weekly along with stool specimens (trial 2). Eosinophil major basic protein and IL-5, IgE, and IgG antishiitake antibodies were measured in sera. Eosinophil-derived neurotoxin was measured in stool extracts. We defined responders as subjects having peak eosinophil counts four or more times their average baseline counts.

RESULTS

Each trial had four responders, and trial 2 had one new and three repeat responders. Eosinophilia ranged from 400 to 3900/mm3. Responders had increased blood eosinophils, serum major basic protein, stool eosinophil-derived neurotoxin, and factors that enhanced eosinophil viability. Antishiitake IgE was not detected, and antishiitake IgG increased in two responders. Gastrointestinal symptoms coincided with eosinophilia in two subjects. Symptoms and eosinophilia resolved after discontinuing shiitake ingestion.

CONCLUSIONS

Daily ingestion of shiitake mushroom powder in five of 10 healthy persons provoked blood eosinophilia, increased eosinophil granule proteins in serum and stool, and increased gastrointestinal symptoms. Shiitake ingestion suggests a model to study the eosinophil's role in the blood and gastrointestinal tract. Finally, our report raises concerns of possible adverse systemic reactions to this increasingly popular food.

Ligation of the beta2 integrin triggers activation and degranulation of human eosinophils

Evidence suggests that cellular adhesion is critical for eosinophil effector functions. Here, we tested the hypothesis that an adhesion molecule, specifically beta2 integrin, participates in intracellular signaling events of eosinophils. Eosinophils stimulated with interleukin (IL)-5 and adherent to protein-coated tissue culture plates via beta2 integrin (CD18) showed tyrosine phosphorylation of a number of proteins. Among these proteins, tyrosine phosphorylation of the 105 kD and 115 kD proteins and the product of the c-cbl protooncogene, Cbl, was specifically inhibited using soluble anti-CD18 monoclonal antibody (mAb) to block eosinophil cell adhesion. Furthermore, phosphoinositide turnover of IL-5-stimulated adherent eosinophils was also inhibited by anti-CD18 mAb, suggesting that cellular adhesion plays important roles in eosinophil signal transduction. alphaM beta2 (Mac-1, CD11b/18) was one of the beta2 integrins involved in eosinophil adhesion to protein-coated plates. We found that direct ligation of eosinophil alphaM beta2 with anti-CD11b mAb coupled to polystyrene microbeads induced tyrosine phosphorylation of a 115 kD protein and Cbl. Furthermore, anti-CD11b mAb microbeads induced increases in both phosphoinositide hydrolysis and the eosinophil degranulation response. Control antibodies, such as mouse myeloma IgG1 and anti-HLA class I antigen mAb, did not induce these cellular responses. These results suggest that engagement of beta2 integrin either by cell adhesion or by anti-CD11b mAb triggers activation of an intracellular signaling cascade, including protein tyrosine phosphorylation and phosphoinositide turnover, and subsequent cellular degranulation in human eosinophils. Tyrosine phosphorylation of a 115 kD protein and Cbl may play important roles in adhesion-dependent cellular functions of eosinophils.

Effectiveness of polyclonal and monoclonal antibodies prepared for an immunoassay of the etofenprox insecticide

Two polyclonal antibodies and three monoclonal antibodies specific to the etofenprox insecticide were prepared from rabbits and mice, respectively. The monoclonal antibodies were more reactive with etofenprox than the polyclonal antibodies by C-ELISA. Monoclonal antibody cl 205-65 was found to be the most tolerant to methanol, most highly reactive and most specific to etofenprox among the antibodies tested.

Lidocaine and its analogues inhibit IL-5-mediated survival and activation of human eosinophils

Eosinophils and cytokines active on eosinophils, especially IL-5, are believed to be critically involved in chronic allergic diseases. IL-5 activates eosinophils and enhances their survival in vitro by delaying apoptosis. In this study, we found that lidocaine and six analogues blunt responses of eosinophils to IL-5. Lidocaine and its derivatives inhibit IL-5-mediated eosinophil survival in a concentration-dependent manner (IC50 = 110 microM for 30 pg/ml IL-5). At suboptimal lidocaine concentrations, the eosinophil survival response to IL-5 shifts and more IL-5 is required to maintain survival. The inhibitory effect requires at least 24-h exposure of eosinophils to lidocaine, and the protein kinase C activator, PMA, completely reverses the inhibition. A multiparameter flow-cytometric analysis shows that lidocaine hastens the apoptosis of eosinophils normally delayed by IL-5. Lidocaine does not affect IL-5R expression or IL-5-induced protein tyrosine phosphorylation. Lidocaine also inhibits eosinophil survival mediated by IL-3 or granulocyte-macrophage CSF, although less potently than that mediated by IL-5. Furthermore, lidocaine inhibits eosinophil superoxide production stimulated by IL-5, granulocyte-macrophage CSF, or IL-3, but not that stimulated by platelet-activating factor, immobilized IgG, or PMA. Lidocaine and its derivatives show novel immunomodulatory properties and are able to blunt eosinophil responses to cytokines in addition to their local anesthetic or antiarrhythmic properties. Thus, lidocaine and its derivatives may represent a new class of therapeutic agents to treat patients with allergic diseases.

Effect of Radiotherapy on the Levels of Secretory Immunoglobulin A Against Indigenous and Virulent Streptococci

If is well known that the frequency of upper respiratory infection is clinically increased after radiotherapy of the head and neck region. This study found higher antibacterial secretory immunoglobulin A (S-IgA) activity against three indigenous streptococci ( Streptococcus mitis, S. salivarius, and S. sanguis I) and S. pneumoniae in patients who had undergone radiation therapy of the head and neck region than in control subjects. This showed no relation to the extent of the radiation field. Compared with before radiotherapy, the S-IgA titer against S. pneumoniae and its ratio to the activities against the indigenous streptococci were significantly higher in patients with fully irradiated major salivary glands. These results indicated that the radiotherapy promoted the antigen-specific S-IgA production of virulent streptococci in most patients with head and neck cancer, even more than 6 months after radiotherapy. The resulting altered balance in the S-IgA system of normal indigenous streptococci may also impair the ability to maintain the stable bacterial interference between normal indigenous and virulent streptococci in the oropharyngeal cavity.

Effect of radiotherapy on the levels of secretory immunoglobulin A against indigenous and virulent streptococci

It is well known that the frequency of upper respiratory infection is clinically increased after radiotherapy of the head and neck region. This study found higher antibacterial secretory immunoglobulin A (S-IgA) activity against three indigenous streptococci (Streptococcus mitis, S. salivarius, and S. sanguis I) and S. pneumoniae in patients who had undergone radiation therapy of the head and neck region than in control subjects. This showed no relation to the extent of the radiation field. Compared with before radiotherapy, the S-IgA titer against S. pneumoniae and its ratio to the activities against the indigenous streptococci were significantly higher in patients with fully irradiated major salivary glands. These results indicated that the radiotherapy promoted the antigen-specific S-IgA production of virulent streptococci in most patients with head and neck cancer, even more than 6 months after radiotherapy. The resulting altered balance in the S-IgA system of normal indigenous streptococci may also impair the ability to maintain the stable bacterial interference between normal indigenous and virulent streptococci in the oropharyngeal cavity.

Production of IL-8 and release of eosinophil-derived neurotoxin by normal peripheral blood eosinophils

To study the regulation of IL-8 production and release of eosinophil-derived neurotoxin (EDN) by normal blood eosinophils, we isolated eosinophils from healthy individuals and stimulated them with immobilized secretory IgA with or without exogenous IL-5 for 3, 12, and 24 h, and with different concentrations of ionomycin for 24 h. Eosinophils cultured with secretory IgA for 3 and 12 h showed strong expression of mRNA for IL-8 by reverse transcription polymerase chain reaction. Exogenous IL-5 enhanced mRNA for IL-8 expression by eosinophils after 24 h of incubation. IL-8 secretion increased in a time-dependent manner throughout the 24 h of observation; in contrast, EDN release reached a plateau value after 12 h. Furthermore, at least 2 microM ionomycin was necessary for induction of IL-8 secretion, whereas 0.5 microM induced detectable EDN release by eosinophils. These results suggest that the mechanism of eosinophil degranulation may be different from those of cytokine secretion.

Migration of eosinophils through basement membrane components in vitro: role of matrix metalloproteinase-9

In general, inflammatory cells cross basement membranes by producing proteinases. To investigate the role of proteinases in eosinophil basement membrane migration, we studied peripheral blood eosinophils in Matrigel-coated chemotaxis chambers. Electron microscopy showed degradation of the Matrigel layer when eosinophils, added to the upper chamber, transmigrated the membrane in the presence of both platelet-activating factor (PAF) in the lower chamber and interleukin (IL)-5 in both chambers. In the absence of either or both PAF and IL-5, no changes occurred in the Matrigel layer. Matrigel transmigration of eosinophils induced by PAF and IL-5 was inhibited by 1,10-phenanthroline, batimastat, 3,4-dichloroisocoumarin, chymostatin, and a neutralizing antibody for the matrix metalloproteinase (MMP)-9, indicating that serine proteinase(s) and MMP, specifically MMP-9, were involved in the transmigration of eosinophils through Matrigel. In contrast, eosinophil migration through a bare membrane was not affected by batimastat. Using gelatin zymography and immunoblotting, MMP-9 was detected in the migration upper chamber supernatant of the eosinophil transmigration assay and in the conditioned medium of eosinophils. Release of MMP-9 by eosinophils was increased by IL-5, PAF, or both, but the substrate-degrading activity of MMP-9 was increased only in the presence of both IL-5 and PAF, indicating that the releasing and activating mechanisms of MMP-9 are involved in eosinophil basement membrane migration. This study implicates MMP-9 in basement membrane migration of eosinophils and suggests its involvement in inflammatory diseases where tissue eosinophilia plays a role.

Role of tyrosine kinases in human eosinophil degranulation

Degranulation of eosinophils and subsequent release of toxic granule proteins play a key role in allergic diseases such as bronchial asthma. However, little is known about the intracellular signaling mechanism of eosinophil degranulation. In this report, we investigated the role of protein tyrosine kinases (PTK) in the degranulation of human peripheral blood eosinophils. Stimulation of eosinophils with Sepharose beads coated with secretory IgA (sIgA) or IgG triggered the phosphorylation of tyrosine residues in several proteins, including 50-65, 73, 78, 100, 105 and 113 kD. In addition, IgG-coated beads induced a rapid increase in the tyrosine kinase activity of src-like PTK, Fgr. The tyrosine kinase inhibitors, genistein and herbimycin A, inhibited both the tyrosine phosphorylation and degranulation responses of eosinophils induced by sIgA- or IgG-coated beads. In contrast, eosinophil degranulation induced by phorbol myristate acetate was not affected by genistein. These findings suggest that a PTK-dependent signaling pathway plays an important role in triggering the eosinophil degranulation induced by immobilized immunoglobulin.

Ventilatory support during exercise in patients with pulmonary tuberculosis sequelae

STUDY OBJECTIVE

The aim of this study was to determine whether intermittent positive pressure ventilation through a nasal mask (NIPPV) applied during exercise in patients with pulmonary tuberculosis sequelae (PTS) could improve arterial blood gas measurements, ameliorate breathlessness, and increase exercise endurance.

PATIENTS

Seven PTS patients with a severe restrictive ventilatory defect (mean [SD] vital capacity, 1.02 [0.25] I) enrolled in this study had experienced NIPPV previously, and were familiar with the procedure.

DESIGN

The patients underwent four constant-load cycle ergometer tests in the supine position to tolerance. The tests were performed with and without NIPPV, while breathing normoxic air (Air) or supplemental oxygen (O2; 35%). NIPPV was delivered during exercise in a controlled, volume-cycled mechanical ventilation mode, and the ventilator settings were modulated manually to meet patients' respiratory demands as estimated from the airway pressure waveform and the patient's breathlessness.

RESULTS

All patients matched their breathing to the ventilator cycle during most of the exercise while receiving NIPPV. NIPPV significantly prolonged their exercise endurance time, from a mean (SD) of 180 (58) s to 310 (96) s in Air, and from 227 (64) s to 465 (201) s in O2. During exercise, NIPPV effectively decreased their breathlessness and significantly improved arterial blood gas measurements.

CONCLUSIONS

NIPPV applied during exercise can effectively support ventilation, significantly ameliorate breathlessness, and consequently improve exercise endurance in patients with PTS.

Roles of CD9 molecules in survival and activation of human eosinophils

CD9 is a cell surface glycoprotein belonging to the transmembrane 4 superfamily. In this report, we demonstrate that cross-linking CD9 with different forms of mAb activates distinct functions of human eosinophils. Anti-CD9 mAb (clone ALB6) immobilized onto tissue culture plates induced eosinophil degranulation. This effect of anti-CD9 mAb (clone ALB6) was unique because other immobilized clones of anti-CD9 mAb (clones FMC56 and ML13) or anti-HLA Class I mAb failed to induce degranulation. In addition, neutrophil degranulation was not provoked by the immobilized clone ALB6, consistent with a lack of expression of CD9 on neutrophils. Eosinophil degranulation induced by anti-CD9 mAb (clone ALB6) was abolished by pretreatment of eosinophils with anti-CD18 mAb, suggesting that beta2 integrins are involved in the reaction. In contrast to the results with immobilized clones, all clones of anti-CD9 mAb in soluble form enhanced eosinophil survival. This enhanced survival was inhibited by anti-granulocyte-macrophage-CSF (GM-CSF) mAb, suggesting that autocrine production of GM-CSF by eosinophils mediated the enhanced survival. In fact, by ELISA and RT-PCR, GM-CSF protein and mRNA were detected in supernatants and cell lysates of eosinophils stimulated by soluble anti-CD9 mAb, but not by immobilized mAb. These results indicate that CD9 serves as a molecule that delivers stimulation signals on eosinophils. The eosinophil's cellular responses may differ and be dependent on the manner of receptor ligation.

Roles of CD9 molecules in survival and activation of human eosinophils

CD9 is a cell surface glycoprotein belonging to the transmembrane 4 superfamily. In this report, we demonstrate that cross-linking CD9 with different forms of mAb activates distinct functions of human eosinophils. Anti-CD9 mAb (clone ALB6) immobilized onto tissue culture plates induced eosinophil degranulation. This effect of anti-CD9 mAb (clone ALB6) was unique because other immobilized clones of anti-CD9 mAb (clones FMC56 and ML13) or anti-HLA Class I mAb failed to induce degranulation. In addition, neutrophil degranulation was not provoked by the immobilized clone ALB6, consistent with a lack of expression of CD9 on neutrophils. Eosinophil degranulation induced by anti-CD9 mAb (clone ALB6) was abolished by pretreatment of eosinophils with anti-CD18 mAb, suggesting that beta2 integrins are involved in the reaction. In contrast to the results with immobilized clones, all clones of anti-CD9 mAb in soluble form enhanced eosinophil survival. This enhanced survival was inhibited by anti-granulocyte-macrophage-CSF (GM-CSF) mAb, suggesting that autocrine production of GM-CSF by eosinophils mediated the enhanced survival. In fact, by ELISA and RT-PCR, GM-CSF protein and mRNA were detected in supernatants and cell lysates of eosinophils stimulated by soluble anti-CD9 mAb, but not by immobilized mAb. These results indicate that CD9 serves as a molecule that delivers stimulation signals on eosinophils. The eosinophil's cellular responses may differ and be dependent on the manner of receptor ligation.

Hypoxic ventilatory response and breathlessness following hypocapnic and isocapnic hyperventilation

STUDY OBJECTIVES

To investigate the etiology of posthyperventilation (post-HV) hypoxemia following voluntary hyperventilation (VHV), we examined the effects of hypocapnic (hypo-CO2) and isocapnic (iso-CO2) VHV on the hypoxic ventilatory response (O2-response) and on the sensation of breathlessness during the O2-response.

METHODS

O2-responses and visual analog scale (VAS) scores for estimating breathlessness in 10 normal subjects during the O2-response under iso-CO2 conditions and under hypo-CO2 conditions immediately following voluntary maximal HV of 3 min duration were examined.

RESULTS

Although there was no significant difference in the post-HV ventilation levels following hypo-CO2 vs iso-CO2 VHV, the VAS scores at the start of the O2-response following hypo-CO2 VHV (30.2+/-24.2 mm) were significantly higher (p<0.05) than the VAS scores at the start of the O2-response following iso-CO2 VHV (13.7+/-8.4 mm). However, VHV did not have a significant effect on the O2-response at 2 min after the VHV when the arterial O2 saturation (SaO2) was below 90%. The nonsteady-state hypo-CO2 induced by VHV greatly attenuated the O2-response below 90% SaO2 and VAS scores at 70% SaO2.

CONCLUSIONS

Elevated VAS scores immediately following the hypo-CO2 VHV, which might be independent of actual breathing levels, and the attenuation of the O2-response following the hypo-CO2 VHV were not due to input from lung and chest wall mechanoreceptors induced by the hyperpnea itself, but rather to the hypo-CO2 induced by hyperpnea.

Impaired induction of cytotoxic T lymphocytes by antagonism of a weak agonist borne by a variant hepatitis C virus epitope

An epitope that acted as a weak agonist in the cytotoxicity assay was identified as part of the capsid protein of a hepatitis C virus (HCV) variant. In a low concentration, the variant epitope also had a weak antagonistic effect. When a minute amount of this variant epitope was added to the culture for induction, it selectively attenuated the expansion of major cytotoxic T cell populations and drastically reduced the cytotoxic responses against the wild-type epitope. Thus, antagonism to induction suppressed immune responses against both the wild type and the variant, thereby helping the persistence of not only variant itself but also the wild-type HCV. Because this variant was a weak agonist, most cytotoxic T cells induced with the wild-type epitope were cross-reactive with the variant and susceptible to the antagonism to induction. Only the T cells which were not cross-reactive with the variant and not susceptible to the antagonism survived the antagonism in induction. This implied that the specificity of the remaining immune response, if any, was directed exclusively to the wild-type epitope after the emergence of the variant. For viruses like HCV, being heterogeneous itself may contribute significantly toward persistent infection through antagonism to induction.

Hypoxaemia in patients with hyperventilation syndrome

We assessed 12 patients with hyperventilation syndrome (HVS) who had experienced hypoxaemia (PaO2 < 60 Torr or SaO2 < 90%) despite the lack of any other organic disease and variability in their blood gas data. Hypoxic and hypercapnic ventilatory responses were measured in nine. Eight of the 12 patients had been referred from other hospitals to our institution for hypoxaemia of unknown origin. Mean PaO2 (n = 12) at rest (non-attack stage) was 87.3 +/- 7.5 Torr (mean +/- SD). Their (n = 9) hypoxic (-0.53 +/- 0.32 l/min/%; range 0.12-0.99) and hypercapnic (2.01 +/- 0.76 l/min/Torr; range 0.69-3.17) ventilatory responses were both within the normal range in our laboratory. The patients with HVS had variable blood gas data, and some of them also exhibited hypercapnia (PaCO2 > 45 Torr). Clinicians who treat patients with HVS should be aware of the possibility of hypoxaemia, even when ventilatory responses are normal. Physicians should also consider HVS as a diagnosis when treating patients with hypoxaemia of unknown origin.

Heat shock protein 72 level decreases during sleep in patients with obstructive sleep apnea syndrome

Patients with obstructive sleep apnea syndrome (OSAS) suffer from stresses related to repetitive apneas during sleep. To examine whether the level of 72 kDa heat shock protein (HSP72) increases during sleep, 11 OSAS patients (apnea-hypopnea index: 63.5 +/- 36.1, mean +/- SD) underwent polysomnography and their peripheral blood mononuclear cells (PBMC) were isolated before, during, and after sleep. HSP72 level was determined by Western blotting and hsp72 mRNA level was quantified by Northern blotting. Nine normal subjects without OSAS were examined as normal controls. HSP72 level decreased progressively during sleep and its level at 8:00 A.M. was 78.0 +/- 17.5% of that at 8:00 P.M. (p < 0.01). No such decrease was seen in normal subjects. When OSAS patients received nasal continuous positive airway pressure (NCPAP) therapy, HSP72 level did not decrease significantly. In untreated OSAS patients, hsp72 mRNA level decreased during sleep (p < 0.01). When OSAS patients were treated with NCPAP therapy, the decrease in hsp72 mRNA level was not observed. HSP72 level before sleep in OSAS patients was higher than that in normal subjects (p < 0.01). We concluded that repetitive apneas caused high HSP72 level before sleep in OSAS patients and that NCPAP therapy had significant effect on HSP72 levels during sleep.

Assessment of cardiac sympathetic function with iodine-123-MIBG imaging in obstructive sleep apnea syndrome

Iodine-123-MIBG imaging has been used to evaluate myocardial sympathetic function in various cardiac diseases. In patients with obstructive sleep apnea syndrome (OSAS), increased sympathetic activity has been widely recognized, as assessed by measuring the plasma concentration and urinary excretion of catecholamines and by measuring muscle sympathetic nerve activity. However, these measurements are not specific indices of cardiac sympathetic function. Therefore, this study was undertaken to assess cardiac sympathetic function in patients with OSAS using MIBG cardiac scintigraphy.

METHODS

This study consisted of 11 patients (10 men, 1 woman; mean age 43 +/- 16 yr) with a diagnosis of OSAS established by polysomnography, and 8 age-matched normal control subjects (7 men, 1 woman; mean age 45 +/- 18 yr). Early (15 min) and delayed (3 hr) planar images were taken after the injection of 111 MBq of [123I]MIBG. The mean counts of the whole heart and the mediastinum were obtained to calculate heart-to-mediastinum count ratios from the early images (H/Me) and from the delayed images (H/Md) and the myocardial washout rate (WR). Eight patients were restudied after 1 mo of nasal continuous positive airway pressure treatment.

RESULTS

The H/Me and H/Md ratios were significantly lower in the patients than in the control subjects (H/Me, 2.49 +/- 0.32 versus 2.84 +/- 0.34, p = 0.0207; and H/Md, 2.33 +/- 0.30 versus 3.02 +/- 0.36, p = 0.0013). The WR was higher in the patients than in the control subjects (36.2 +/- 9.0% versus 23.6 +/- 4.9%, p = 0.0022). The H/Me and H/Md ratios in the patients were significantly correlated with the apnea-hypopnea index and the degree of hypoxemia during sleep. After treatment, H/Me and H/Md remained unchanged, but WR significantly recovered (from 34.9 +/- 10.4% to 26.3 +/- 7.7%, p = 0.0357).

CONCLUSION

Cardiac sympathetic function and integrity are impaired in subjects with OSAS when compared with age-matched control subjects. MIBG cardiac imaging can be helpful in evaluating cardiac involvement and efficacy of therapy in OSAS.

Transmigration of eosinophils through basement membrane components in vitro: synergistic effects of platelet-activating factor and eosinophil-active cytokines

Migration of eosinophils through the basement membrane barrier is an important step for their infiltration into tissues. To investigate the mechanism of transmigration, we used a chamber fitted with a Matrigel membrane as a model of the basement membrane. In this model, eosinophils treated with cytokines or chemotactic factors alone did not transmigrate from the upper to the lower chamber. However, platelet-activating factor (PAF) strongly induced transmigration of eosinophils stimulated by interleukin (IL)-5, indicating that both a cytokine and a chemotactic factor are required for eosinophil migration through Matrigel. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-3 also stimulated eosinophil transmigration in the presence of PAF. Of seven eosinophil chemotactic factors tested, leukotriene B4, C5a, RANTES, macrophage inflammatory protein-1alpha, and IL-8 did not induce significant eosinophil transmigration. Only PAF and eotaxin induced transmigration of eosinophils through Matrigel in the presence of IL-5; PAF was more potent than eotaxin at the optimal concentration. In contrast, PAF, eotaxin, and RANTES all potently induced migration of eosinophils through bare membrane in the absence of IL-5. Finally, eosinophil migration through Matrigel was markedly reduced by a combination of anti-CD18 and anti-CD29 monoclonal antibodies, suggesting that it is mediated by beta1- and beta2-integrin adhesion molecules. Our findings demonstrate that eosinophil transmigration through a basement membrane model requires both a specific chemoattractant, such as PAF, and an eosinophil-activating cytokine, such as IL-5. This synergistic effect is likely important in the tissue accumulation of activated eosinophils in allergic and other eosinophil-associated diseases.

Cytotoxic T lymphocyte response and viral load in hepatitis C virus infection

A cytotoxic T lymphocyte (CTL) response to the hepatitis C virus (HCV) nucleoprotein residues 88-96 that are the minimal and optimal epitope for human leukocyte antigen (HLA) B44-restricted CTLs was assessed in 27 HLA B44-positive patients with chronic HCV infection. Serum HCV RNA concentration and the amino acid sequence of the residues 81-100 were also determined. Three patients were infected with HCV with uncommon amino acid substitutions within the epitope. One was infected with HCV with an amino acid substitution in the flanking residues of the epitope. To stimulate CTLs in the peripheral blood, 9-mer peptides that corresponded to the residues 88-96 of the individual patients were synthesized and used. Seven of the 27 patients demonstrated a CTL response to the residues 88-96 with specific cytotoxic activities higher than 20%. The CTL activities were significantly higher in patients with a low titer of serum HCV RNA than in those with a high titer of serum HCV RNA (P = .0006). Some of the patients that demonstrated a CTL response to the residues 88-96 also demonstrated a CTL response to a newly identified HLA B44-restricted CTL epitope or a known HLA A11-restricted CTL epitope or both. No apparent association was observed between the CTL response and the stage of disease, or between the CTL response and the grade of necroinflammatory activity. The results suggest that the HLA B44-restricted CTLs together with other HCV-specific CTLs may inhibit the outgrowth of HCV and that high-titer infection with HCV may suppress the CTL responses.