The utility of ultrasound superb microvascular imaging for evaluation of breast tumour vascularity: comparison with colour and power Doppler imaging regarding diagnostic performance.

AIM: To investigate the utility of superb microvascular imaging (SMI) for evaluating the vascularity of breast masses in comparison with colour or power Doppler ultrasound (US) and the effect on diagnostic performance. MATERIALS AND METHODS: A total of 191 biopsy-proven masses (99 benign and 92 malignant) in 166 women with greyscale, colour Doppler, power Doppler, and SMI images were enrolled in this retrospective study. Three radiologists analysed the vascular images using a three-factor scoring system to evaluate the number, morphology, and distribution of tumour vessels. They assessed the Breast Imaging-Reporting and Data System categories for greyscale US alone and combinations of greyscale US and each type of vascular US. The Kruskal-Wallis test was performed and the area under the receiver-operating characteristic curve (AUC) measured. On SMI, vascular scores were compared between benign and malignant masses and the optimal cut-off value for the overall score was determined. RESULTS: SMI showed higher vascular scores than colour or power Doppler US and malignant masses had higher scores than benign masses (p<0.001). The diagnostic performance of the combination of greyscale US and SMI was higher than those of greyscale US alone and greyscale and colour or power Doppler US (AUC, 0.815 versus 0.774, 0.789, 0.791; p<0.001). The optimal cut-off value of the overall vascular score was 5 with a sensitivity of 82.3% and a specificity of 65.3% (AUC, 0.808). CONCLUSION: SMI is superior to colour or power Doppler US for characterising the vascularity in breast masses and improving diagnostic performance.

Tenofovir versus tenofovir plus entecavir for chronic hepatitis B with lamivudine resistance and entecavir resistance.

We compared the viral suppressive efficacy of tenofovir disoproxil fumarate (TDF) mono-rescue therapy (TDF group) and TDF plus entecavir (ETV) combination-rescue therapy (TDF + ETV group) in chronic hepatitis B (CHB) patients with lamivudine resistance and entecavir resistance. One hundred and thirty-three CHB patients with lamivudine and entecavir resistance were investigated. Ninety-six patients were treated with TDF and 37 with TDF + ETV for at least 6 months. We compared the virologic response rate (HBV DNA level <20 IU/mL) between the two groups and identified the predictive factors of treatment outcome. There were no significant differences between the two groups in demographic characteristics. Up to 24 months [median: 18 (range 6-24) months], 85.4% and 89.2% of the TDF group and TDF + ETV group, respectively, achieved a virologic response (P=.068). Only the HBV DNA level at baseline was significantly associated with a virologic response in the multivariate analysis. In a subanalysis of patients with HBV DNA levels ≥4 log (IU/mL) at baseline, a higher proportion of patients in the TDF + ETV group than the TDF group achieved a virologic response (92.9% vs 68.3%; P<.001), while 90% of patients with HBV DNA (IU/mL) levels <4 log in all both TDF and TDF + ETV groups achieved a virologic response. TDF mono-rescue therapy is a reasonable option in patients with lamivudine resistance and entecavir resistance. However, the combination strategy should be considered in patients with high baseline HBV DNA levels.

Impact of COVID-19 on TB epidemiology in South Korea.

SETTING: Five referral hospitals, South Korea.OBJECTIVE: To assess epidemiological changes in TB before and during the COVID-19 pandemic.DESIGN: This was a multicentre cohort study of 3,969 patients diagnosed with TB.RESULTS: We analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years, P < 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019; P = 0.005).CONCLUSIONS: The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.

An ion optics study for KSTAR neutral beam injector development.

Ion optics of three accelerator geometries was studied in terms of an analytic linear optics analysis, a numerical simulation using the IGUN program, an optical multichannel measurement of Doppler-shifted H(alpha) lines, and a water-flow calorimetry on the beam absorbing target. In general, there was a reasonable agreement observed between the four analysis methods and thus the theoretical analyses can be utilized with confidence for design iteration.

Predictors of failure to detect early hepatocellular carcinoma in patients with chronic hepatitis B who received regular surveillance.

BACKGROUND: A proportion of chronic hepatitis B (CHB) patients are diagnosed with advanced hepatocellular carcinoma (HCC) despite regular surveillance. AIMS: To determine predictors for HCC detection failure in CHB patients who underwent regular surveillance. METHODS: CHB patients with well-preserved liver function, who underwent ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, were enrolled. Cox regression analysis was used to identify predictors for detection failure, defined as HCC initially diagnosed at Barcelona Clinic Liver Cancer (BCLC) stage B or C. RESULTS: Of the 4590 CHB patients (mean age, 52.1 years; men, 61.6%), 169 patients were diagnosed with HCC (3.68%) and 35 (20.7%) HCC patients were initially diagnosed with HCC BCLC stage B or C. The cumulative incidence of HCC detection failure was 0.2% at year 1 and 1.3% at year 5. Multivariate analyses indicated that cirrhosis (hazard ratio [HR], 3.078; 95% CI, 1.389-6.821; P = 0.006), AFP levels ≥9 ng/mL (HR, 5.235; 95% CI, 2.307-11.957; P = 0.010), and diabetes mellitus (HR, 3.336; 95% CI, 1.341-8.296; P = 0.010) were independent predictors of HCC detection failure. Another model that incorporated liver stiffness (LS) values identified LS values ≥11.7 kPa (HR, 11.045; 95% CI, 2.066-59.037; P = 0.005) and AFP levels ≥9 ng/mL (HR, 4.802; 95% CI, 1.613-14.297; P = 0.005) as predictors of detection failure. CONCLUSIONS: In CHB patients undergoing regular surveillance with ultrasonography and alpha-foetoprotein (AFP) analysis every 6 months, the HCC detection failure rate was not high (0.8% per person; 0.1% per test). However, careful attention should be paid in patients with advanced liver fibrosis (clinical cirrhosis or LS value >11.7 kPa), high AFP levels, or diabetes mellitus, who are prone to surveillance failure.

Day 3 versus Day 1 disseminated intravascular coagulation score among sepsis patients: a prospective observational study.

The role of disseminated intravascular coagulation (DIC) has not been extensively studied in patients with sepsis. A prospective study was performed in a single university hospital. The incidences of DIC at day 1 (<24 hours post-sepsis diagnosis) and day 3 (48 to 72 hours) were investigated among patients with sepsis. The International Society of Thrombosis and Haemostasis criteria for DIC were used. Among 381 patients initially screened, 219 were enrolled in this study and the incidences of overt DIC were 27.9% and 30.1% on day 1 and day 3, respectively. Patients with pneumonia had a lower incidence of DIC on day 1, but a higher hospital mortality rate compared to those with non-pneumonia sepsis. In multivariate models, although day 1 and day 3 DIC scores were not associated with hospital mortality after adjusting for existing severity scores, the change in DIC scores (odds ratio 1.862; 95% confidence interval 1.061 to 3.266) exhibited a significant association. Day 3 DIC scores were more accurate in predicting hospital mortality than day 1 DIC scores (P <0.001), especially in patients with non-pneumonia sepsis. However, DIC scores did not give additional discriminative power to the existing prognostic scores in predicting mortality of patients with sepsis. In conclusion, the change in DIC score was significantly associated with hospital mortality. Patients with pneumonia sepsis had a lower incidence of DIC on day 1, despite their higher disease severity and mortality rate, compared to those with other sources of sepsis.

Prognostic relevance of pretransplant Deauville score on PET-CT and presence of EBV DNA in patients who underwent autologous stem cell transplantation for ENKTL.

High-dose chemotherapy and autologous stem cell transplantation (ASCT) for extranodal natural killer/T-cell lymphoma (ENKTL) is a reasonable option for a subset of patients. The impact of response status, according to positron emission tomography/computed tomography (PET/CT) results and/or presence of circulating EBV DNA prior to ASCT, has not yet been established. We analyzed 27 ENKTL patients with pre-ASCT circulating EBV DNA who had undergone pre-ASCT PET/CT between 2009 and 2014. We classified patients into two groups based on the result of pretransplantation assessment: a favorable risk group (pretransplant five-point Deauville score (DS) of 1-2 based on PET/CT and no detectable EBV DNA) and an unfavorable risk group (DS 1-2 with detectable EBV DNA, DS 3-5 with or without detectable EBV DNA). After a median follow-up of 37 months, overall survival and PFS were significantly different between the two groups (median OS: not reached for favorable risk group vs 7.0 months for unfavorable risk group, P=0.017; median PFS: 16.0 vs 5.0 months, P=0.019). Multivariate analysis revealed that pre-ASCT DS and EBV DNA was the only independent prognostic factor considering stage, IPI and NKPI. Precise assessment of the status of disease before transplantation may provide more benefit from ASCT to ENKTL patients.

Binding mode of 4',6-diamidino-2-phenylindole and ethidium to poly(dG).poly(dC).poly(dC)(+) triplex and poly(dG).poly(dC) duplex.

Optical spectroscopic properties of 4',6-diamidino-2-phenylindole (DAPI) and ethidium bromide complexed with poly(dG).poly(dC).poly(dC)(+) triplex and poly(dG).poly(dC) duplex were compared in this study. When complexed with both duplex and triplex, ethidium is characterized by hypochromism and a red shift in the absorption spectrum, a complicate induced circular dichroism (CD) band in the polynucleotide absorption region, and a negative reduced linear dichroism signal in both polynucleotide and drug absorption regions. The spectral properties for both duplex- and triplex-bound ethidium are identical and both can be understood by the intercalation binding mode. In contrast, the absorption and CD spectra of DAPI complexed with triplex differ from those of the DAPI-duplex complex, although both complexes can be understood by the intercalation binding mode. Considering that the third strand runs along the major groove of the template duplex, we conclude that the DAPI molecule partially intercalates near the major groove of the duplex, where the third strand can affect its spectroscopic properties.

Arytenoid appearance and vertical level difference between the paralyzed and innervated vocal cords.

OBJECTIVES/HYPOTHESIS: In unilateral vocal fold paralysis, it has been generally accepted that the paralyzed vocal fold presents at a higher level than a normally innervated vocal fold. In this study, we correlate the appearances of the paralyzed arytenoid and the differences in level between the paralyzed and innervated vocal folds. STUDY DESIGN: Retrospective review using video-recorded images of larynx. METHODS: A total of 38 patients were selected for this study who reported symptoms of voice change attributable to a paralyzed vocal fold unilaterally. Video recordings were obtained using the laryngeal telescope. The heights were assessed according to the paralyzed positions, status (inspiration or phonation), and appearances of the paralyzed arytenoid. The appearances of paralyzed arytenoid were further clarified as the portions of the medial surface of the arytenoid that were visualized. RESULTS: In medial paralysis, the paralyzed vocal fold appeared mainly as being at an equal vertical level or as having no distinct difference from normal vocal fold during phonation. However, a few cases of medial paralysis showed a lower than normal or higher than normal vocal fold during phonation, depending on the appearance of the paralyzed arytenoid. In lateral paralysis, most of the paralyzed vocal folds were not higher than the innervated vocal folds during phonation. CONCLUSIONS: The heights of paralyzed vocal folds were variable depending on the paralyzed positions, the status of the larynx, and appearances of the paralyzed arytenoid. The fact that the paralyzed vocal fold is at a higher level than the normal vocal fold should be reconsidered.

The N-terminal region of the dopamine D2 receptor, a rhodopsin-like GPCR, regulates correct integration into the plasma membrane and endocytic routes.

BACKGROUND AND PURPOSE: Functional roles of the N-terminal region of rhodopsin-like GPCR family remain unclear. Using dopamine D(2) and D(3) receptors as a model system, we probed the roles of the N-terminal region in the signalling, intracellular trafficking of receptor proteins, and explored the critical factors that determine the functionality of the N-terminal region. EXPERIMENTAL APPROACH: The N-terminal region of the D(2) receptor was gradually shortened or switched with that of the D(3) receptor or a non-specific sequence (FLAG), or potential N-terminal glycosylation sites were mutated. Effects of these manipulations on surface expression, internalization, post-endocytic behaviours and signalling were determined. KEY RESULTS: Shortening the N-terminal region of the D(2) receptor enhanced receptor internalization and impaired surface expression and signalling; ligand binding, desensitization and down-regulation were not affected but their association with a particular microdomain, caveolae, was disrupted. Replacement of critical residues within the N-terminal region with the FLAG epitope failed to restore surface expression but partially restored the altered internalization and signalling. When the N-terminal regions were switched between D(2) and D(3) receptors, cell surface expression pattern of each receptor was switched. Mutations of potential N-terminal glycosylation sites inhibited surface expression but enhanced internalization of D(2) receptors. CONCLUSIONS AND IMPLICATIONS: Shortening of N-terminus or mutation of glycosylation sites located within the N-terminus enhanced receptor internalization but impaired the surface expression of D(2) receptors. The N-terminal region of the D(2) receptor, in a sequence-specific manner, controls the receptor's conformation and integration into the plasma membrane, which determine its subcellular localization, intracellular trafficking and signalling properties.

Acute respiratory distress syndrome caused by miliary tuberculosis: a multicentre survey in South Korea.

BACKGROUND: Miliary tuberculosis (TB) is an unusual cause of acute respiratory distress syndrome (ARDS). OBJECTIVE: To evaluate the clinical characteristics and outcomes of patients with ARDS caused by miliary TB admitted to the intensive care unit (ICU). DESIGN: A total of 67 patients were enrolled during the period 1999-2008. RESULTS: The median age of the patients was 56 years (range 17-81), 19 (28.4%) were aged >71 years, and 38 (56.7%) were male. All-cause mortality in the ICU and hospital were respectively 58.2% and 61.2%. Of the total number of enrolled patients, 49 (73.1%) were prescribed anti-tuberculosis medication within 3 days of hospital admission. On the day of ARDS diagnosis (10.0 ± 3.7 vs. 7.4 ± 3.5, P = 0.005), non-survivors had a significantly higher Sequential Organ Failure Assessment (SOFA) score than survivors. Multivariate analysis showed that SOFA score on the day of ARDS diagnosis was a significant predictor of survival (OR 0.809, 95%CI 0.691-0.946, P = 0.008). It was difficult to determine the efficacy of systemic corticosteroids on patient survival. CONCLUSION: ARDS caused by miliary TB was associated with a high in-hospital mortality rate, with SOFA score on the day of ARDS diagnosis being a valuable prognostic indicator.

A national survey on the practice and outcomes of mechanical ventilation in Korean intensive care units.

A study was undertaken to describe the practice and outcomes of mechanical ventilation throughout Korea. This prospective cohort study was conducted over a three-month period enrolling patients (n = 519) who received mechanical ventilation for more than 72 hours in 21 university hospital intensive care units throughout Korea. The most common indication for mechanical ventilation was acute respiratory failure. The most common cause of acute-on-chronic respiratory failure was tuberculous lung disease. The most common initial mode for ventilation was volume-controlled ventilation. The mean tidal volume of acute respiratory distress syndrome patients was 7.6 ml/kg of the predicted body weight and the mean positive end-expiratory pressure was 9.4 cmH20. The weaning success rate at 28 days was 50.3%. Pressure support and the T-piece were most commonly used as initial and final weaning modes respectively. Preventive measures against deep vein thrombosis during mechanical ventilation were performed more frequently in intensive care units with full-time critical care physicians than those without such physicians. Multivariate analysis showed that the APACHE II score, indication for mechanical ventilation, respiratory rate at 72 hours, enteral feeding and prophylaxis of deep vein thrombosis were prognostic factors for survival. In Korean intensive care units, tuberculous lung disease remains an important cause for mechanical ventilation. The practice of mechanical ventilation in Korean intensive care units in general appeared to comply with the current international recommendations with regard to lung protection and weaning. However, intensive care units lacking critical care physicians seemed to be adopting fewer ancillary measures, such as deep vein thrombosis prophylaxis.

Enhanced neutrophil chemotactic activity after bronchial challenge in subjects with grain dust-induced asthma.

BACKGROUND: There have been few reports suggesting involvement of neutrophils in induction of bronchoconstriction after inhalation of grain dust. OBJECTIVES: To understand the role of neutrophils in pathogenesis of grain dust-induced asthma. MATERIALS AND METHODS: We observed serum neutrophil chemotactic activity during grain dust-bronchoprovocation tests in six asthmatic subjects with positive bronchial challenges (group I). They were compared with those of six symptomatic subjects from the same workplace with negative bronchial challenges (group II). RESULTS: After grain dust inhalation, serum neutrophil chemotactic activity significantly increased at 30 minutes (P = .028), and then decreased to baseline level at 240 minutes (P = .028) in five subjects of group I having isolated early asthmatic responses. Enhanced neutrophil chemotactic activity was persistent for up to 240 minutes in one asthmatic subject having both early and late asthmatic responses. There was, however, no significant change in serum neutrophil chemotactic activity during bronchial challenges in subjects of group II. Pre-incubation of sera with anti-interleukin-8 (IL-8) antibody did not affect the neutrophil chemotactic activity results of group I subjects. CONCLUSION: These results suggest that enhanced neutrophil chemotactic activity distinct from IL-8 may contribute to significant bronchoconstriction induced by grain dust.

Evidence for neutrophil activation in occupational asthma.

In order to evaluate the role of neutrophils in the pathogenesis of occupational asthma (OA), 15 toluene diisocyanate (TDI)-asthma and six grain dust-asthma patients were recruited. Controls were the same number of subjects showing negative bronchoprovocation test (BPT) and six house dust mite-sensitive asthma. Bronchoscopic biopsy specimens were stained with monoclonal antibodies to mast cell (AA1), eosinophil (EG2), pan T cell (CD3) and neutrophil (NE). Serum neutrophil chemotactic activity (NCA) was measured before and 10-420 min after BPT. Sputum interleukin-8 (IL-8) and myeloperoxidase (MPO) were also measured. There was a significant increase of NE+ cells as well as AA1+ and EG2+ cells in grain dust- and TDI-asthma compared with house dust-sensitive asthma (P < 0.05). Neutrophil+ cells and AA1+ cells showed a significant correlation in TDI-asthma (r = 0.73, P = 0.02). Serum NCA was significantly increased at 10 min after BPT and decreased at 60 min in subjects with TDI-asthma. In grain dust-asthma, serum NCA increased at 30 min and decreased at 240 min after BPT (P < 0.05). Sputum IL-8 and MPO were significantly increased after BPT in both TDI- and grain dust-asthma (P < 0.05). These findings suggested that neutrophils in the lungs might contribute to bronchoconstriction induced by either TDI or grain dust. The possible involvement of IL-8 in activation of neutrophils was also suggested.

Occupational asthma caused by chromium.

We report four cases of occupational asthma caused by chromium salts, three of whom showed dual and one isolated early asthmatic responses on specific chromium bronchoprovocation test (BPT). All of them were ex-smokers. Two showed positive skin-prick tests to 10 mg/ml of Cr2(SO4)3, but negative results on patch testing. The remaining two showed positive results on patch testing with Cr2(SO4)3. Three had airway hyperresponsiveness to methacholine on initial examination. Although initial methacholine airway challenge testing showed a negative result in the remaining patient, airway hyperresponsiveness developed transiently 24 h after an isolated immediate asthmatic reaction induced by chromium. Three patients were reassessed after complete avoidance of chromium. Two subjects showed marked improvement of their symptoms with significant increases of PC20 methacholine. We conclude that chromium induces occupational asthma in exposed workers. Further investigations are needed to clarify the pathogenetic mechanism.

Secondary rhinoplasty via transcolumellar incision.

The transcolumellar rhinoplasty was used in 90 patients with severe nasal sequelae caused by one or more previous surgical interventions. In each case the deformity was located mainly on the nasal tip making it extremely difficult to correct with conventional surgical procedures. We chose the transcolumellar rhinoplasty procedure to avoid another failure for these patients who sought complete resolution of their problem. At the same time, the technique provides a more secure surgical field to make a definitive diagnosis and to treat the sequelae properly.

Characterization of pncA mutations of pyrazinamide-resistant Mycobacterium tuberculosis in Korea.

Pyrazinamide (PZA) is one of the most important drugs for the treatment of Mycobacterium tuberculosis infection. However, the increasing frequency of PZA-resistant strains limits its effectiveness. In Korea, most PZA-resistant strains also exhibit both isoniazid and rifampin resistance making it essential to identify these resistant strains accurately and rapidly for effective treatment of mycobacterial infection. In this study, the characteristics and frequency of mutations of the pncA gene encoding pyrazinamidase were investigated in PZA-resistant clinical isolates from Korea. Automated DNA sequencing was used to evaluate the usefulness of DNA-based detection of PZA resistance. Among 95 PZA-resistant clinical isolates, 92 (97%) exhibited mutations potentially affecting either the production or the activity of the enzyme. Mutations were found throughout the pncA gene including the upstream region. Single nucleotide replacement appeared to be the major mutational event (69/92), although multiple substitutions as well as insertion and deletion of nucleotides were also identified. The high frequency of pncA mutations observed in this study supports the usefulness of DNA-based detection of PZA-resistant M. tuberculosis. Having verified the scattered and diverse mutational characteristics of the pncA gene, automated DNA sequencing seems to be the best strategy for rapid detection of PZA-resistant M. tuberculosis.

Hypersensitivity pneumonitis induced by Penicillium expansum in a home environment.

An episode of fever, cough, shortness of breath and leucocytosis developed in a 31-year-old atopic housewife from mould exposure in her home environment is evaluated. A chest radiograph revealed diffuse tiny nodular infiltrations in both whole lung fields. Spirometry revealed a severe restrictive type of ventilation impairment. Bronchoalveolar lavage (BAL) showed an increased lymphocyte count with reversed CD4+/CD8+ ratio and transbronchial lung biopsy showed markedly increased lymphocytic infiltration in alveolar septa. Fungal cultures in the air of her home were positive for Penicillium expansum and other fungi. Double immunodiffusion test with the patient's serum showed two precipitin bands to P. expansum antigens. Her symptoms, abnormal findings of radiograph, and spirometric abnormalities disappeared after 2 months' avoidance. The serum precipitin disappeared after 1 month's avoidance. This study indicates that the patient had hypersensitivity pneumonitis (HP) on exposure to P. expansum in her home environment.

Are there any links between Hop Japanese pollen and other weed pollens or food allergens on skin prick tests?

Recent investigations suggest that the importance of Hop Japanese pollen, which has been known as one of the major causative weed pollens, is increasing in this country. There have been few data dealing with the allergenic relationship between Hop J pollen and other food or inhalant allergens. Among 2909 patients who visited the Allergy Clinic of Ajou University Hospital, Suwon, Korea, 471 patients sensitized to Hop J, mugwort, or ragweed pollens on skin-prick test were enrolled. Positive rates to common inhalant or food allergens and their allergenic relationships with other pollens or food allergens were analyzed based upon skin-prick test results. The positive rates to sunflower, fat hen, nettle, grass (Bermuda, Orchard) and tree (alder, birch, and poplar) pollen were significantly higher in those sensitized to Hop J pollen than in those of negative responders (p < 0.05, respectively). No significant associations were noted with ragweed or mugwort pollen (p > 0.05, respectively). In regard to food-related allergens, an association was noted between Hop (Humulus lupulus) or celery allergens in those sensitized to Hop J pollen (p < 0.05, respectively). Hop J pollen may have possible links with celery, Hop, and sunflower pollens on skin-prick test. Further in vitro investigations will be needed to evaluate the possibility of cross-reacting components between them.

Allergen-induced release of GM-CSF and IL-8 in vitro by nasal polyp tissue from atopic subjects prolongs eosinophil survival.

Eosinophilia is a feature of nasal polyposis. The aim of this study was to determine the role of cytokines and allergen in maintaining the eosinophilic infiltrate in this condition. Polyp fragments from house dust mite (HDM)-sensitive atopic individuals and nonatopic individuals were cultured in the presence of HDM, or phytohaemagglutinin (PHA) or culture medium alone. Culture supernatants were assayed for interleukins (IL) 3, 5, and 8 and granulocyte macrophage colony stimulating factor (GM-CSF), and eosinophil survival enhancing activity (ESEA) in vitro. Significant ESEA was produced spontaneously. When polyp tissue from atopics, but not from nonatopics, was stimulated with allergen for 2 days there was a further increase in ESEA associated with a median 12 and fourfold increase in IL-8 and GM-CSF, respectively. This increased ESEA was markedly reduced with anti-GM-CSF and, to a lesser extent, anti-IL-8 blocking antibodies. When stimulated with PHA, polyp tissue from atopic subjects also produced increased ESEA, implicating possible T-cell involvement. This was associated with a small (twofold), but significant, increase in IL-8 and a less consistent increase in GM-CSF. However, anti-IL-8 or anti-GM-CSF blocking antibodies failed to reduce the ESEA in these supernatants, suggesting involvement of other mechanisms. This study suggests that in sensitized individuals, allergen may contribute to polyp eosinophilia by stimulating the production of granulocyte/macrophage colony stimulating factor and interleukin 8.