[18FDG-PET applications in thoracic oncology]

PositIon emission tomography using 18-fluorodeoxyglucose (FDG-PET) is an imaging technique based on metabolic criteria rather than morphological criteria. We discuss the contribution of this technique in the field of pulmonary oncology and we summarize our work which has demonstrated the performance capacity of PET: to discriminate the malignant nature of a solitary pulmonary nodule; to improve sensitivity over CT for mediastinal assessment in non-small cell lung cancer; to seRach for distant metastasis in patients with non-small cell lung cancer; to complement CT imaging to better dissociate tumor residue or recurrence from post-therapeutic sequelae in non-small cell lung cancer. Finally, we present different expected progress for the future.

[How I investigate ... a broncho-pulmonary cancer by metabolic imaging (PET-18-FDG)]

Continuing advances in PET imaging have resulted in an improved ability to evaluate thoracic malignancies. Published reports demonstrate that PET provides accurate noninvasive detection of malignancy that is useful in the characterization of a pulmonary solitary nodule and in the mediastinal or extrathoracic staging of known lung cancer. Preliminary studies suggest that PET may also be able to assess the therapeutic response after surgery or radiation therapy.

Value of FDG-PET in detecting residual or recurrent nonsmall cell lung cancer

In order to evaluate the usefulness of 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in the assessment of therapeutic effects, a study was performed before and after therapy in 126 patients with non-small cell lung cancer (NSCLC) codified stage I to stage IIIB. Treatment with an early curative result was given in 58 patients, whereas in 68 cases it was limited to palliation. During the treatment follow-up period (8-40 months), each patient was evaluated every 3 months by clinical examination and < or =6 months by imaging techniques (PET and computed tomography (CT)). A diagnosis of persistent or recurrent tumour was established by means of pathological analysis in 31 patients and by clinical evolution and subsequent imaging progression in 29 other patients. PET showed increased FDG uptake in all cases (n = 60) of persistent or recurrent tumour, whereas CT was nonspecific in 17 cases. Conversely, there were five false positive cases via PET imaging and three via CT. In detecting residual or recurrent NSCLC, PET had a sensitivity of 100% and specificity of 92%, whereas CT had a sensitivity and specificity of 71% and 95% respectively. In conclusion, 18-fluorodeoxyglucose positron emission tomography correctly identified response to therapy in 96% (121 of 126) of patients. Positron emission tomography appears to be more accurate (p = 0.05) than conventional imaging in distinguishing persistent or recurrent tumour from fibrotic scar in patients undergoing treatment for non-small cell lung cancer.

[Breast abscess and pregnancy toxemia revealing multidrug resistant tuberculosis]

We report here the case of a 33-year-old woman admitted in hospital for eclampsia. An infectious course led to the diagnosis of tuberculosis breast abscess with laryngitis and tuberculous bilateral excavated bronchopneumonia. The isolated strain demonstrated resistance to the principals antituberculous agents. However outcome was favorable after cesarean and treatment adapted to sensitivity studies.

Bronchial responsiveness in active steelworkers

Coke-oven workers are exposed to dust and irritant gases. Therefore they are at risk of developing lung diseases including chronic bronchitis. Nonspecific bronchial hyperresponsiveness (BHR) has been advocated as a potential risk factor predisposing to the development of chronic bronchitis. In a previous study, we showed that prevalence of BHR was higher in retired coke-oven workers than in retired blast furnace workers. The present study was carried out to determine the prevalence of BHR in active steelworkers. Thus, 137 coke-oven workers and 150 blast furnace workers underwent clinical examination, a standardized questionnaire for the study of respiratory symptoms, pulmonary function testing and methacholine aerosol challenge. The study demonstrates a higher prevalence and degree of BHR [provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (PC20) < or = 8 mg x mL(-1)] in coke-oven workers than in blast furnace workers (31.4 versus 6.7%; p<0.001). Moreover, the frequency of respiratory symptoms and basal bronchial obstruction were greater among coke-oven workers with BHR in nonresponders. The basal maximum expiratory flow from 25-75% of forced vital capacity and the respiratory symptoms were correlated with bronchial responsiveness. The lack of correlation observed between BHR and the intensity of smoking or years spent in coke-oven environment may be explained by the high proportion of smokers, the worker turnover in the steel plant, and the "healthy worker effect". In conclusion, the higher prevalence and degree of bronchial hyperresponsiveness in coke-oven workers suggests that coke-oven pollutants are more intense irritants than those that escape from blast furnaces.

Whole-body 18FDG positron emission tomography in the staging of non-small cell lung cancer

Despite advances in morphological imaging, some patients with lung cancer are found to have nonresectable disease at surgery or die of recurrence within yr of surgery. We performed a prospective study in 109 patients to compare the accuracy of whole-body positron emission tomography (PET) using fluorine-18 deoxyglucose (18FDG) and conventional imaging (CI) methods for the staging of non-small cell lung cancer (NSCLC). When CI or PET study suggested metastatic disease, confirmation was obtained by biopsy or follow-up information. As compared to CI, 18FDG-PET correctly changed the N stage in 22 patients (33%) and the M stage in 15 patients (14%). For the detection of distant metastases, PET study showed five false-positive sites and no false-negative cases. Currently, the accuracy of PET in the detection of M stage is 96%. Our study shows that visual interpretation of whole-body fluorine-18 deoxyglucose-positron emission tomography images can improve the diagnostic accuracy in the staging of non-small cell lung cancer. Further experience is needed to establish if metabolic imaging would be a cost-effective tool in the future management of lung cancer.

[Bronchial reactivity in diabetic patients]

The data of the literature concerning bronchial reactivity in diabetic patients are controversial. Therefore, we studied the influence of the presence of a diabetic cardiac autonomic neuropathy (CAN) on the ventilatory parameters measured during a methacholine-induced bronchoconstriction test. Ten insulin-dependent diabetic patients without CAN, ten insulin-dependent diabetic patients with CAN and ten healthy volunteers, all non-smokers and free of respiratory symptoms, have undergone a functional respiratory check-up before the methacholine test. The presence of CAN was classically studied by the decrease in heart rate changes during three standardized tests (deep breathing at 6 cycles/min, Valsalva manoeuver, orthostatism) which all mainly explore the parasympathetic function. The bronchial response to methacholine was similar in the healthy subjects and in the diabetic patients without CAN. However, the fall in forced expiratory volume in 1 second induced by the highest dose of methacholine was significantly less marked in the diabetic subjects with CAN than in the two other groups. These results suggest that the diabetic autonomic neuropathy also involves the vagal innervation of the respiratory tract.

Correlation between bronchoalveolar lavage (BAL) fluid cell lysate histamine content and BAL fluid eosinophil count in atopic and nonatopic asthmatics

We have compared the bronchoalveolar lavage fluid (BAL) cellular composition and the BAL cell lysate histamine content (fluorometric assay) in 28 stable mild to moderate asthmatics (atopic n = 18 and intrinsic n = 10) and 11 control subjects. When compared to control subjects, the whole group of asthmatics had a higher proportion of BAL eosinophils (p < 0.01) and metachromatic cells (p < 0.05). The BAL cell lysate histamine was increased in atopic (p < 0.05) and intrinsic asthmatics (p < 0.05) in comparison with control subjects. In the whole group of asthmatics, the BAL cell lysate histamine content correlated with the percentage of BAL eosinophils (r = 0.58, p < 0.01). This relationship was significant in both atopic (r = 0.48, p < 0.05) and intrinsic (r = 0.70, p < 0.05) asthmatics. For the whole group of asthmatics, both the BAL cell lysate histamine and the percentage of BAL eosinophils inversely correlated with the percent predicted FEV1 (r = -0.42, p < 0.05; r = -0.51, p < 0.05). We conclude that an increased BAL cell lysate histamine content correlates with airway eosinophilic infiltration and lung function impairment in mild to moderate atopic and intrinsic asthmatics. This suggests that BAL mast cells play a key role in recruiting eosinophils in the airways of asthmatics irrespective of the presence of an atopic status.

Evaluation of pleural diseases with FDG-PET imaging: preliminary report

BACKGROUND

Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) is an accurate method for differentiating benign from malignant disease. The use of FDG-PET for the aetiological diagnosis of pleural disease was investigated in 25 patients.

METHODS

PET was performed on each subject before invasive procedures were used to determine the aetiological diagnosis. The PET data were analysed by visual interpretation of coronal, sagittal, and transverse slices.

RESULTS

Sixteen patients were found to have malignant pleural disease and nine had benign disease. All patients with histologically confirmed malignant disease showed FDG uptake within the pleural thickening which was intense in 14 cases and moderate in two. PET imaging showed the absence of FDG uptake and correctly categorised seven non-malignant lesions. Two patients with infectious pleural diseases showed a localised and moderate FDG uptake.

CONCLUSION

Our preliminary results suggest that FDG-PET could be an effective tool for differentiating between benign and malignant pleural diseases.

Usefulness of induced sputum analysis in pulmonary diseases

In this study, we analysed the cellular component of induced sputum in healthy control subjects (n = 30), asthmatics (n = 44), patients suffering from COPD (n = 15), pulmonary tuberculosis (PTB) (n = 14) and healthy steel workers (HSW) (n = 14). Sputum was induced by inhalation of hypertonic saline (NaCl 5%) for 20 min. When compared to the healthy control group, all the disease groups as well as the one of healthy steelworkers exhibited significantly higher total sputum cell counts. Analysis of the differential cell counts showed that there was a significant increase in % eosinophils in asthmatics, in % neutrophils in COPD, asthmatics, tuberculosis and healthy steelworkers and in % lymphocytes in pulmonary tuberculosis. Our study illustrates the feasibility and the possible clinical application of induced sputum analysis in several pulmonary diseases and shows how this technique could be useful in assessing airway inflammatory processes in subjects exposed to industrial pollutants.

Gastrin levels in serum and bronchoalveolar lavage fluid of patients with lung cancer: comparison with patients with chronic obstructive pulmonary disease

BACKGROUND

The gastrin gene is known to be expressed in all classes of bronchogenic carcinomas. Furthermore, high levels of gastrin have been reported in both the bronchoalveolar lavage (BAL) fluid and serum of patients with lung cancer. Based on these preliminary data a study was conducted to evaluate the usefulness of gastrin measurements in the diagnosis and staging of lung cancer.

METHODS

Thirty-five patients with lung cancer (26 non-small cell (NSCLC) and nine small cell (SCLC)) and 25 patients with chronic obstructive pulmonary disease underwent fibreoptic bronchoscopy and BAL. Gastrin levels were determined in both BAL fluid and the serum and compared with each other and with staging.

RESULTS

No difference was found between the gastrin levels in the BAL fluid or serum of the study groups. There was no correlation with the stage in NSCLC and no correlation was found between the gastrin levels in the serum and the BAL fluid. A significant difference was seen in gastrin levels in BAL fluid between extensive and limited SCLC (p < 0.05).

CONCLUSION

There is no evidence of clinical usefulness for gastrin measurements in lung cancer.

Staging of the mediastinum: value of positron emission tomography imaging in non-small cell lung cancer

Recent studies have shown limitations of morphological imaging in staging mediastinal lymph node involvement in lung cancer. In contrast to computed tomography (CT), which depends primarily on anatomical imaging features, positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) depends mainly on the metabolic characteristics of a tissue for the diagnosis of disease. We have performed a prospective study comparing FDG-PET and CT of the thorax in the presurgical assessment of the mediastinum in 50 patients with newly diagnosed non-small cell lung cancer (NSCLC). CT and PET scans were interpreted separately, and results were compared to pathological staging obtained during thoracotomy. Hilar or mediastinal lymph node involvement was present in 58%. In staging for lymph node involvement, CT had a sensitivity of 72% and specificity of 81%, whereas PET had a sensitivity and specificity of 90% and 86%, respectively. When the PET study was compared to histological results, there were four cases showing more advanced mediastinal involvement with PET and four cases showing less involvement with PET. From our preliminary results, we conclude that positron emission tomography with 18-fluorodeoxyglucose is significantly more accurate than computed tomography in the mediastinal staging of non-small cell lung cancer.

[Positron emission tomography in the evaluation of intrathoracic lymphatic extension of non-small cell bronchial cancer. A preliminary study of 30 patients]

Current methods for evaluating the mediastinum include chest radiography, computed tomography (CT) or magnetic resonance (MR) imaging and mediastinoscopy. Despite advances in morphologic imaging, some lung cancer patients are found to have unresectable disease at surgery. In contrast to CT scan or MR imaging, which depend primarily on anatomic and morphological criteria, positron emission tomography (PET) with 18fluorodeoxyglucose (FDG) depends mainly of the metabolic characteristics of a tissue for the diagnosis of disease. We perform a prospective study to compare FDG-PET and CT of the thorax in the presurgical assessment of the mediastinum in patients with newly diagnosed non-small cell lung cancer. Thirty patients have been included. CT and PET-scans were interpreted separately and results were compared to surgical staging during thoracotomy. In assessing mediastinal involvement, CT scan had a sensitivity of 56% and a specificity of 64%. For diagnosis mediastinal nodal disease, FDG-PET was 87% sensitive and 78% specific. Its positive predictive value was 82%, and the negative value was 83%. In conclusion, our preliminary results show that FDG-PET appears more accurate than CT in staging of mediastinal non-small cell lung cancer.

High neuron specific enolase levels in bronchoalveolar lavage fluid of patients with lung carcinoma: diagnostic value, relation to serum neuron specific enolase, and staging

BACKGROUND

High levels of neuron specific enolase (NSE) have recently been described in the bronchoalveolar lavage (BAL) fluid of patients with lung carcinoma. Although its value in serum has been extensively studied, its diagnostic value in BAL fluid in terms of sensitivity, specificity, and predictive value have not been evaluated. In addition, its value in staging and relation to serum NSE are yet unknown.

METHODS

NSE levels were determined on the same day in the BAL fluid and the sera of two groups of patients: those with newly diagnosed lung carcinoma and those with smoking related chronic obstructive pulmonary disease (COPD). Clinical TNM staging was also performed. Levels of NSE in BAL fluid were expressed as nanograms per 100 international units of lactate dehydrogenase. BAL fluid NSE levels of the two groups were compared with staging and serum NSE.

RESULTS

A highly significant difference exists in BAL NSE in the two groups. For diagnostic purposes, the simultaneous measurements of serum NSE increases its sensitivity, but specificity remains unchanged. No correlation exists between BAL NSE and serum NSE, tumor size, nodal status, or the presence of metastases. BAL NSE is a better predictor of malignancy than serum NSE.

CONCLUSION

BAL fluid measurements of NSE may have diagnostic value, specially if it is simultaneously measured in the serum. However, our study does not show any value for this technique in staging of lung carcinoma. Also it has no correlation with serum NSE. Studies will have to be performed to determine if BAL NSE can predict chemotherapeutic sensitivity.

Evaluation of the solitary pulmonary nodule by positron emission tomography imaging

Current noninvasive imaging methods are not sufficiently reliable for accurate detection of malignancy in most solitary pulmonary nodules (SPNs). Positron emission tomography (PET) using 18-fluorodeoxyglucose (FDG), showing increased FDG uptake and retention in malignant cells, has proved useful to differentiate malignant from benign tissue and could, therefore, contribute to the evaluation of the SPN. We performed a prospective study of 50 patients referred to the Pneumology Department with unclear diagnoses of SPN after conventional radiological screening. PET study was performed on each subject before an invasive procedure was proposed. Thirty three patients had a malignant nodule and 17 had a benign nodule. The mean size of malignant nodule was 3 cm (range 1.5-4.5 cm). All showed a marked increase in 18-FDG uptake. The mean size of benign nodule was 1.8 cm (range 0.5-3.5 cm). PET imaging showed the absence of 18-FDG uptake and correctly identified 15 of 17 benign nodules. There was two false-positive cases with a moderate increase in 18-FDG uptake (1 postprimary tuberculosis; and 1 anthracosilicotic nodule with nonspecific inflammation). At present, the sensitivity and specificity of the method are 100 and 88%, respectively. The positive and negative predictive values of PET imaging for SPNs are 94 and 100%, respectively. Our preliminary results demonstrate that PET-FDG imaging is a noninvasive technique, which appears highly accurate in differentiating malignant SPN from benign SPN.

Nonfibrous mineralogical analysis of bronchoalveolar lavage fluid from blast-furnace workers

Steelworkers are exposed to many pollutants, and they are at risk for developing lung cancer. We demonstrated previously that steelworkers may be subject to an occult exposure to amphiboles in the plant environment. In the current study, we further analyzed bronchoalveolar lavage fluid of steelworkers by measuring intramacrophagic trace-metal content and nonfibrous mineral particles, using the particle-induced x-ray emission method and electron microscopy, respectively. Forty-seven blast-furnace workers and 45 healthy white-collar workers volunteered for this study. Significantly increased levels of iron, titanium, zinc, and bromine were found in the steelworkers, and levels of lead, chromium, arsenic, and strontium tended to increase in the macrophages and bronchoalveolar lavage fluid of the steelworkers. Nonfibrous particles, including illite, kaolinite, talc, chlorite, amorphous silica, quartz, iron (compounds), and titanium hydroxide, were found in both groups, but the particle number per ml bronchoalveolar lavage fluid (particularly iron hydroxides and silicates) was more pronounced in blast-furnace workers. These elements and particles may act synergistically with other occupational carcinogens and cigarette smoke, the result of which may be an increased incidence of lung cancer in the ironsteel industry.

Changes in bronchial responsiveness, circulating leucocytes and ex vivo cytokine production by blood monocytes after PAF inhalation in allergic asthmatics

We investigated the effects of inhaled platelet-activating factor (PAF) on methacholine bronchial responsiveness, circulating leucocyte counts, and ex vivo tumour necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) production from blood monocytes in eight allergic asthmatics. Bronchial responsiveness was defined as the provocative concentration of methacholine causing a 20% decrease in forced expiratory volume in one second (PC20). Circulating leucocytes were counted by means of an automatic haemocytometer, and cytokines were measured with specific immunoassays. The different variables were measured before and 4, 24, 48, 72 and 168 h after a PAF (225 micrograms), a lyso-PAF (225 micrograms) and a saline bronchial challenge. When compared with lyso-PAF and saline, inhalation of PAF resulted in a significant decrease in PC20 over a period of one week. Two falls in bronchial responsiveness were identified, the first by 4 h and the second beginning 48 h and reaching a maximum by 168 h. The increases in spontaneous TNF alpha and IL-1 production which occurred during the week after both PAF, lyso-PAF and saline, did not differ significantly. Likewise, the changes in circulating neutrophil counts, characterized by a transient rise by 4 h after PAF and lyso-PAF but not saline, followed by a fall by 24 h and a persistent decrease until 168 h, were not significantly different after PAF, lyso-PAF and saline. On the other hand, in comparison with lyso-PAF and saline, inhaled PAF caused a significant protracted augmentation in circulating eosinophil counts, which was maximal by 48 h but did not correlate with the delayed decline in PC20.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in bronchial responsiveness, circulating leucocytes and ex vivo cytokine production by blood monocytes after PAF inhalation in allergic asthmatics

We investigated the effects of inhaled platelet-activating factor (PAF) on methacholine bronchial responsiveness, circulating leucocyte counts, and ex vivo tumour necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) production from blood monocytes in eight allergic asthmatics. Bronchial responsiveness was defined as the provocative concentration of methacholine causing a 20% decrease in forced expiratory volume in one second (PC20). Circulating leucocytes were counted by means of an automatic haemocytometer, and cytokines were measured with specific immunoassays. The different variables were measured before and 4, 24, 48, 72 and 168 h after a PAF (225 micrograms), a lyso-PAF (225 micrograms) and a saline bronchial challenge. When compared with lyso-PAF and saline, inhalation of PAF resulted in a significant decrease in PC20 over a period of one week. Two falls in bronchial responsiveness were identified, the first by 4 h and the second beginning 48 h and reaching a maximum by 168 h. The increases in spontaneous TNF alpha and IL-1 production which occurred during the week after both PAF, lyso-PAF and saline, did not differ significantly. Likewise, the changes in circulating neutrophil counts, characterized by a transient rise by 4 h after PAF and lyso-PAF but not saline, followed by a fall by 24 h and a persistent decrease until 168 h, were not significantly different after PAF, lyso-PAF and saline. On the other hand, in comparison with lyso-PAF and saline, inhaled PAF caused a significant protracted augmentation in circulating eosinophil counts, which was maximal by 48 h but did not correlate with the delayed decline in PC20.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of histamine release from human bronchoalveolar lavage mast cells by stem cell factor in several respiratory diseases

We investigated the effects of stem cell factor (SCF) on histamine release (HR) from human bronchoalveolar lavage (BAL) mast cells. BAL cells were recovered from lavage performed in patients undergoing clinical bronchoscopy. SCF (0.02-20 ng/ml), which is by itself a poor secretagogue (mean +/- SEM HR: 3.7 +/- 0.9%; n = 27), strongly enhanced HR induced by anti-IgE in a concentration-related manner. Significant potentiation began at 0.2 ng/ml (30 +/- 10%; p < 0.05; n = 12) and reached a plateau at 2 ng/ml (40 +/- 10%; P < 0.01 at 2 ng/ml and 45 +/- 10%; P < 0.01 at 20 ng/ml; n = 12). In contrast, SCF failed to enhance HR induced by calcium ionophore A23187. Among the BAL cell samples initially unresponsive to anti-IgE (55% of samples), 36% (10/28) were converted to responders if the cells were shortly preincubated with SCF. In 25% of samples (7/27), SCF (20 ng/ml) caused direct HR of 10 +/- 2.1%. The mast cells which released histamine when challenged with SCF also secreted higher levels of histamine in response to anti-IgE and calcium ionophore than those nonresponsive to SCF. While interleukin (IL)-3 and IL-5 (20 ng/ml) were unable to modulate immunologic HR, GM-CSF (20 ng/ml) produced significant potentiation (P < 0.05), which was, however, smaller than that observed with SCF.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute bronchial and hematologic effects following inhalation of a single dose of PAF. Comparison between asthmatics and normal subjects

This study compared the acute bronchial and hematologic effects of inhaled platelet activating factor (PAF) (30 micrograms as a single dose) in 19 patients with mild asthma and 19 normal subjects. Each subject underwent a methacholine bronchial challenge 1 week before PAF challenge to determine the concentration of methacholine causing a 20 percent fall in FEV1 (PC20M). On the day of PAF challenge, specific conductance (SGaw), FEV1, FEF25-75, and platelet and leukocyte counts were measured before, and 5, 10, 15, and 20 min after PAF inhalation. Changes in pulmonary and hematologic parameters were expressed as percent of control (saline solution/ethanol solution). Unlike normal subjects, subjects with asthma had bronchial hyperresponsiveness to methacholine: geometric mean (range): 0.59 mg/ml (0.07 to 9.8) vs > 32 mg/ml. Acute bronchial obstruction over the first 20 min after PAF inhalation was more pronounced in asthmatics than in normal subjects whatever the functional index considered (p < 0.01). In asthmatics (n = 19), mean (SEM) maximal fall in SGaw, FEV1, and FEF25-75 reached 50 percent (6), 11 percent (4), and 19 percent (5), respectively, while in normal subjects (n = 19) the maximal decreases were 24 percent (6), 4 percent (1), and 6 percent (1), respectively. In asthmatics, no correlation was found between log PC20M and log fall in FEV1 after PAF (r = 0.04 p > 0.05). In asthmatics and normal subjects, inhaled PAF caused a transient fall in neutrophils and monocytes by 5 min followed by a full recovery at 15 min and 20 min. These hematologic changes were not significantly different between the two groups. While not correlated with their airway responsiveness to methacholine, asthmatics, compared with normal subjects, develop an exaggerated acute airway obstruction in response to PAF. In contrast, hematologic changes induced by PAF do not differ between asthmatics and normal subjects.

Cytokine modulation of basophil histamine release in wasp-venom allergy

We report the effect of interleukin-3 (IL-3) and of other cytokines on antigen-induced basophil histamine release in wasp-venom-allergic subjects. Leukocytes from 12 patients with documented anaphylactic sensitivity to wasp venom were preincubated in the presence or absence of IL-3, granulocyte/macrophage-colony stimulating factor (GM-CSF), IL-5, IL-8, or stem cell factor (SCF). Washed cells were then exposed to venom and to other secretagogues, and histamine release in the supernatant was measured fluorometrically. Preincubation of leukocytes with IL-3, GM-CSF, or IL-5 (0.02-2 ng/ml), but not with IL-8 and SCF, caused a dose-dependent enhancement of antigen-induced basophilic histamine release in all subjects tested. Mean maximum increase was about 100% for IL-3, IL-5, and GM-CSF. The priming effect of IL-3 was rapid, persisted up to 12 h, and was not accompanied by a change in cellular histamine. IL-3 had a comparable enhancing effect when basophils were triggered with anti-IgE or N-formylmethionylphenylalanine (FMP). By contrast, IL-3 had no effect on substance-P-induced histamine release. The significant enhancement of basophil releasability to antigen in wasp-venom allergy by very low concentrations of IL-3, GM-CSF, and IL-5 suggests that cytokines in the basophil (mast-cell?) microenvironment could be critical factors in determining the variability of sting reactions in Hymenoptera-venom-allergic subjects.

Decrease of T-lymphocyte proliferation in exercise-induced asthma

The present study was designed to examine the effect of physical exercise on T-lymphocyte proliferation in patients with exercise-induced asthma (EIA). Indeed, a decrease in different immune functions is described in normal man after exercise. Thirty subjects (10 normal and 20 asthmatic subjects with or without EIA) underwent a submaximal exercise test on an electrically driven treadmill. Before and after this test, ventilatory variables were measured, and venous blood was taken to study plasma histamine (RIA) and spontaneous and phytohemagglutinin (PHA)-pulsed T-lymphocyte proliferation (mononuclear cells isolated on Ficoll-Hypaque; tritiated thymidine incorporation). Ten minutes after the end of the exercise, there was a significant FEV1 decrease only in asthmatic subjects with EIA (mean: 24 +/- 5%). In the same group, the mean plasma histamine level was 0.31 ng/ml-1 (+/- 0.06) before the challenge. It rose to 0.62 ng/ml-1 (+/- 0.14) 10 min after the end of the exercise (P < 0.05), and returned to normal limits 20 min after the test. In this group, there was also a significant decrease (by about 35%) of spontaneous and PHA-pulsed T-lymphocyte proliferation 2 and 4 h after the exercise. By contrast, exercise challenge had no effect on either plasma histamine level or T-lymphocyte proliferation in the normal group. Our results show a rapid and transient increase in plasma histamine in EIA. This was followed 2 and 4 h later by a significant decrease of T-lymphocyte proliferation. A possible relationship between these two phenomena is discussed.