Diffusing Capacity For CO Research Articles

Amiodarone-lnduced Pulmonary Toxicity: Immunoallergologic Tests and Bronchoalveolar Lavage Phospholipid Content

Amiodarone (A) is a widely-used antiarrhythmic drug. Pulmonary toxicity is the most serious adverse effect with an estimated mortality of 1 to 33 percent. In order to determine an element helpful for diagnosis, we examined four patients with amiodarone-induced pulmonary toxicity, three patients treated with A, without evidence of pulmonary toxicity but with a main underlying pulmonary disease, and four healthy volunteers. Daily and cumulative doses or duration of treatment were similar in the first two groups. Pulmonary function tests (spirometry, CO-diffusing capacity, arterial blood gases), roentgenographic examinations, pulmonary biopsies or immunoallergologic tests (skin reaction, lymphoblastic transformation test and human basophile degranulation test) did not provide any discriminatory element. In APT+, we observed an increased cellularity of the bronchoalveolar lavage. Neither the differential cell count nor the presence of foamy macrophages were distinguishable between APT+ and APT-. The phospholipid composition of BAL fluid showed a decreased total phospholipid and phospholipid/protein ratio in all patients compared to normal subjects. These changes reflect more the severity of pulmonary disease than the specificity of the causative agent. However, we observed that the unique PL which decreases in APT- and remains normal in APT+ is phosphatidyl-serine + phosphatidylinositol (PS + PI). This has to be confirmed and should be evaluated at different stages of the disease to determine an eventual specific element. We conclude that there are no data currently available to establish the diagnosis of APT except perhaps for the analysis of BAL PL content.

Effects of Nifedipine on Diffusing Capacity and Pulmonary Capillary Blood Volume in Chronic Obstructive Pulmonary Disease

The acute dose-dependent effects of nifedipine on the pulmonary diffusing capacity for CO and other lung function indices were investigated in patients with chronic obstructive pulmonary disease (COPD) in a randomized double-blind, cross-over, placebo-controlled trial. Seventeen successive, clinically stable, moderate COPD patients with pulmonary hypertension and 15 control subjects were included in the study. The diffusing capacity of the lungs for carbon monoxide (DLCO) was measured with the single-breath method. Nifedipine (10 and 20 mg) and placebo were administered sublingually at room air. Nifedipine (10 and 20 mg) increased DLCO and DLCO/alveolar volume; however, a larger effect was observed with 10 mg. In addition, nifedipine increased the pulmonary capillary blood volume dose-dependently while arterial oxygenation was improved only with 10 mg nifedipine. Venous shunt was significantly increased with 20 mg nifedipine whereas spirometric parameters were unaffected. The percent DLCO change with 10 or 20 mg nifedipine was inversely correlated with baseline DLCO, but not with the severity of obstruction. Nifedipine did not have any effect in the control group, except for mild hypotension and a reflex increase in the heart rate. It is concluded that 10 mg nifedipine probably has an effect on the pulmonary circulation in moderate COPD patients with pulmonary hypertension.

Determinants of restrictive lung function in asbestos-induced pleural fibrosis

We evaluated whether restrictive lung function among asbestos-exposed individuals with pleural fibrosis was caused by radiographically inapparent parenchymal inflammation and/or parenchymal fibrosis. All 24 study participants were sheet metal workers who were nonsmokers with normal parenchyma on posteroanterior chest radiograph. These subjects had either normal pleura (n = 7), circumscribed plaques (n = 9), or diffuse pleural thickening (n = 8). After controlling for age, years in the trade, and pack-years of smoking, we found that sheet metal workers with diffuse pleural thickening had a lower forced vital capacity (P less than 0.001), total lung capacity (P less than 0.01), and CO-diffusing capacity of the lung (P less than 0.05) than those with normal pleura. Similarly, sheet metal workers with circumscribed plaques were found to have a reduced forced vital capacity; however, because of the small number of study subjects, this difference (regression coefficient = -11.0) was only marginally significant (P = 0.06). Although circumscribed plaque and diffuse pleural thickening were both associated with a lymphocytic alveolitis and a higher prevalence of parenchymal fibrosis on high-resolution computerized tomography (HRCT) scan, neither a lymphocytic alveolitis nor the finding of parenchymal fibrosis on HRCT scan influenced the relationship between pleural fibrosis and restrictive lung function. We conclude that pleural fibrosis is associated with restrictive lung function and abnormally low diffusion that appears to be independent of our measures of parenchymal injury (chest X-ray, bronchoalveolar lavage, and HRCT scan).(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Monoxide Diffusing Capacity, Other Indices of Lung Function, and Respiratory Symptoms in a General Population Sample

To assess the relationships among single-breath diffusing capacity for CO (DLCOsb) (13), respiratory symptoms, and cigarette smoking in a general population sample, the data of 718 men and 894 women 20 yr of age or older were analyzed, and comparisons were performed with flow-volume curve (MEFV) variables and the slope of the alveolar plateau (DN2%/L) as well. Percent predicted DLCOsb and its correction for alveolar volume (DL/VA) were significantly lower in smokers than in nonsmokers. The relationship of presence/absence of respiratory symptoms and cigarette smoking with DLCOsb and DL/VA was significant. DLCO indices were almost always selected as discriminant variables in multivariate analysis between asymptomatic and symptomatic subjects. Poor concordance among lung function tests was evident: in men, 30% with abnormal (i.e., lower than 97.5% percentile) and 21% with normal DLCO indices also had abnormal MEFV parameters and/or DN2%/L. In women, the corresponding figures were 24 and 10%, respectively. In men, when considering only DLCO indices, the percentage of symptomatic subjects with abnormal lung function tests ranged from 33% in those with at least one symptom to 45% in those complaining of dyspnea. When the proportion of symptomatic subjects with DN2%/L and MEFV abnormalities were added, it increased to 56 and 66%, respectively. However, in women the proportion of symptomatic subjects with abnormal lung function indices was very small. These results indicate the usefulness of including CO diffusing capacity in epidemiologic surveys in the detection of abnormalities.

Characteristics of pulmonary diffusing capacity for CO at rest and during exercise.

Characteristic patterns of changes in pulmonary diffusing capacity (DL) at rest and during exercise were investigated and characteristics of normal DL values concerned on sex, age, and ethnic groups were examined by viewing our studies and other reports. The relation of DL and pulmonary capillary blood volume (Vc) was represented as a logarithmic regression at rest and as a linear regression during exercise. The curve relation at rest is considered to show that the increase in Vc mainly reflects the process of transport from pulmonary capillary recruitment to pulmonary capillary dilation. The increasing rate of DL was not decreased during exercise, which seemed to be due to an increase in pulmonary blood flow accompanying exercise. The linear regression was also found between DL and oxygen intake during exercise and the slope was always constant among individuals and among subject groups. The general results concerned with sex difference in Japanese or ethnic difference between Japanese and Caucasians in both sexes could show that DL per stature was greater in males or Caucasians than in females or Japanese in young adults, however, the sex or ethnic difference disappeared in middle or old aged group. DL per alveolar volume which showed no sex or ethnic difference in young adults, was greater in middle or old aged group of females or Japanese than in that of males or Caucasians.

Functional, biochemical, and histopathological evidence of airway obstruction in rats following a four-hour acute inhalation exposure to n-butyl isocyanate

Pulmonary function, arterial blood gases, acid-base status, and bronchoalveolar lavage fluid (BALF) composition were assessed in male Wistar rats after a single 4-h exposure to 0, 7.6, 23.5 or 55.2 mg n-butyl isocyanate (n-BIC)/m3 air. No significant changes other than transient clinical signs were observed in the rats exposed to 7.6 mg/m3 air. Four weeks after exposure the animals of the 55.2 mg/m3 group showed significant effects: those were pronounced histopathological changes of airways and parenchyma, and elevated relative lung weight. The neutrophils, LDH, and protein in BALF were elevated. Quasi-static lung compliance, peak expiratory flow rate, mean mid expiratory flow rate were decreased whereas lung resistance, residual volume, and single breath CO-diffusing capacity were increased. Blood gas measurements revealed an elevation in hemoglobin, pH, arterio-alveolar oxygen difference, and venous admixture. Arterial pO2 and pCO2 were decreased. In animals exposed to 23.5 mg/m3 only marginal effects were detectable.

Oxygen transfer kinetics of red blood cells of the turtle Pseudemys scripta elegans

The kinetics of O 2 uptake into, and release from, the red blood cells (RBC) of the turtle Pseudemys scripta elegans were determined with a stopped-flow technique at varied temperature (10–30°C) and pH (7.5–7.9). The results were compared to those obtained for RBC of other vertebrates and related to morphometric and physiological data on gas/blood diffusion in turtle lungs. The O 2 transfer conductance of RBC, G, for O 2 release into high concentrations of dithionite, considered to represent the best estimate of true RBC transfer conductance for O 2 uptake and release, averaged 0.17 ± 0.01 at 30°C, 0.13 ± 0.01 at 20°C, 0.09 ± 0.01 at 10°C (mean ± SSD, in mmol·min −1·Torr −1·(mlRBC) −1). These values are about one half the corresponding value for human RBC, and this difference may be due to the larger size of turtle RBC (volume, 327 μm 3) compared to human RBC (90μm 3). The temperature dependence of G, Q 10 = 1.3 indicates that, as in human RBC, diffusion through aqueous media is the main limiting factor for O 2 exchange. Morphometric data on the lungs of Pseudemys scripta suggest that the resistance to O 2 transfer by RBC is lower than that offered by the gas-blood barrier. The total apparent transfer resistance to CO, obtained from previous measurements of pulmonary diffusing capacity for CO in the same species, is much higher than that predicted from the combination of RBC O 2 kinetics and morphometric data on gas-blood barrier.

The effect of thoracic irradiation for cancer of the breast on ventilation, perfusion and pulmonary permeability. A one-year follow-up.

Regional and overall lung function was studied in 14 women during a one-year follow-up after postmastectomy irradiation for cancer of the breast. The dose was 40 Gy in the chest wall and 20-40 Gy in the apex of the lung. Immediately after irradiation there was a slight increase in pulmonary clearance of 99TCm-DTPA compared to baseline values. This increase, however, was not restricted to the field of irradiation. Three months after irradiation there were regional defects in the ventilation and perfusion scintigrams in 11 of the patients. At the same time there was a greater decrease in total lung capacity, vital capacity and diffusion capacity for CO than in ventilation and perfusion. One year after irradiation the lung function impairment had only insignificantly regressed. It is concluded that local lung irradiation may cause persistent regional and generalized lung function impairment. The early increase in pulmonary clearance of 99Tcm-DTPA could not be used as a predictor of subsequent lung function impairment.

Evaluation of lung diffusing capacity by physiological and morphometric techniques.

Determinations of pulmonary diffusing capacity for CO (DLCO) by physiological and morphometric techniques have resulted in substantially different values for both DLCO and its major components. To evaluate the differences in these methods of measurement of DLCO, measurements were made under controlled conditions on isolated perfused dog lungs. Multiple gas-rebreathing techniques were used to measure DLCO, the membrane component of the diffusing capacity for CO (DmCO), and pulmonary capillary blood volume (Vc) in both anesthetized dogs and after isolation and perfusion of their lungs. The isolated perfused lungs were than perfusion fixed for morphometric analysis of the components of DLCO. The values obtained morphometrically for Vc were similar to those measured by physiological techniques. Perfusion fixation did not substantially alter the morphometric estimate of DmCO when compared with previous values obtained on inflation fixed lungs. However, the morphometric estimate of DmCO was over 10 times higher than that estimated physiologically. Analysis of the potential errors in the techniques suggests that the correct value for DmCO is substantially higher than that commonly estimated by use of physiological techniques and that the explanation for the difference is due to a number of factors that can influence the binding of CO to hemoglobin under in vivo conditions. The net effect of these factors can be represented by an unknown in each component of the Roughton-Forster relationship so that 1/DL = 1/(U1.Dm) + 1/(U2.theta Vc), where theta is the binding rate for CO to hemoglobin. Because the magnitudes of the unknown terms (U1 and U2) in the Roughton-Forster relationship are likely to be large, this relationship cannot be reliably used to determine Dm and Vc.

IMPAIRMENT OF VENTILATORY FUNCTION AND PULMONARY GAS EXCHANGE IN NON-SMOKING COALMINERS

Indices of ventilatory function and pulmonary gas exchange in 32 non-smoking coalminers (mean age 38·1) were compared with those of 34 non-smoking steelworkers of similar age. The coalminers had significantly lower forced expiratory volume in 1 s (FEV 1) and maximum expiratory flow rates and significantly higher residual volume, but similar vital capacity and indices derived from the single-breath test. Pulmonary diffusing capacity for CO and indices of CO 2 exchange were similar in both groups. Arterial partial pressure of O 2 (PaO 2) was significantly lower and alveolar-arterial O 2 difference was significantly higher in coalminers than in controls, both at rest and during exercise. There was no relation between lung function and radiological signs of simple pneumoconiosis (10 coalminers had pneumoconiosis). The differences in FEV 1 (0·42 1) and in PaO 2 (10 mm Hg) between the two groups are the same or larger than those usually found between smokers and non-smokers. Exposure to coaldust may result in biologically significant alterations of lung function even in the absence of pneumoconiosis.

Gas Exchange in the Loggerhead Sea Turtle Caretta Caretta

ABSTRACT Pulmonary CO diffusion capacity (DLCO), lung volume (VL), oxygen uptake and pulmonary blood flow (Q̇L) were measured simultaneously in the loggerhead sea turtle Caretta caretta (Linnaeus) (8-11 kg) using a gas rebreathing technique (syringe pump ventilation). Calculated DLCO and values in the loggerhead turtle are approximately twice those of non-varanid reptiles and about 25 % of values for resting mammals. Evidence based on an estimated lung-capillary O2 gradient, , shows that only a small driving gradient is required for O2 conductance across the loggerhead turtle lung. Pulmonary blood flow values are high compared to those for other reptiles; on the basis of the Fick principle, this implies a substantial blood convection requirement. Differences in oxygen transport mechanisms between the loggerhead sea turtle and other highly aerobic but terrestrial reptiles may result from divergent lung structures and breathing patterns. In sea turtles, the coupling of respiration with locomotory behaviour is one factor that may limit aerobic performance. Since sea turtles have only intermittent access to air, they are required to load both arterial and venous blood with O2 before submerging.

One-sampling rebreathing method to measure diffusing capacity for CO.

To simplify the rebreathing method to obtain the pulmonary diffusing capacity for CO (DLCO), a one-sampling method was developed, combined with a simulation technique. The change in CO fraction in rebreathing air depends on the rebreathing volume (VRB), the dead space volume (VD), the gas volume in the lung-bag-system (VS) as well as the DLCO: Using the measured VRB, VD, and VS, the changes in CO fraction in bag and alveolar air were simulated by varying the DLCO, where the expired and inspired gas volumes were represented by a sinusoidal function of time. The DLCO was determined by checking the similarity between the simulated and measured CO fractions at the 7th expiratory period. To confirm the validity of the simulation method, two-sampling rebreathing and single breath methods were additionally carried out in 6 normal subjects in the sitting position. The DLCO measured by the simulation agreed well with that measured simultaneously by the two-sampling method. The DLCO measured by this method was also compatible with that obtained from the single breath method, when the dead space was excluded from the measured lung gas volume.

A method for estimating contact time of red cells in lung capillaries from O2 and CO2 concentrations in rebreathing air in man.

In a previous paper (Mochizuki et al., 1986) we described the relation between alveolar- and venous-Pco2 and the contact time (tc). However, at that time, Pco2-dependency of the arterio-venous difference in O2 content ((a-v)Co2), the contact-time-dependency of the Haldane effect, and linearity of the relation between the experimental gas exchange ratio and Pco2 (R-Pco2 line) in rebreathing air were not taken into account. Recently, we have precisely analysed the above correlations from the numerical solutions of the simultaneous O2 and CO2 diffusions in the red blood cell (RBC). Based upon the results we have derived a corrected contact time equation. When the time constant of the reaction rate of the extracellular dehydration reaction was less than 0.2 sec, good agreement was observed between the contact time obtained from the pulmonary diffusing capacity for CO (Uchida, Shibuya and Mochizuki, 1986) and that from the present method.

Simultaneous measurement of cardiac output and pulmonary diffusing capacity for CO by a rebreathing method.

A rebreathing method was developed to obtain the pulmonary diffusing capacity for CO, DL(CO) and the cardiac output, Q, simultaneously at rest and during exercise. From DL(CO) and Q, contact time of the red blood cell (RBC) through the lung capillary, tc, was estimated by referring to a reaction rate factor of CO with RBC, Fc(CO). The DL(CO) and Q were calculated from the changes in CO, O2, and CO2 concentrations in rebreathing air. The Fc(CO) was evaluated so as to attain a proportional relation between the DL(CO) and Fc(CO) by varying a transfer coefficient for CO across the RBC boundary including the capillary wall. The PO2 dependence of Q was also taken into account in the above analyses. The tc was determined by dividing the DL(CO) by Fc(CO), Q, and fractional hematocrit. The DL(CO) and Q measured in five normal subjects in a sitting position were 26.6 +/- 2.9 ml X min-1 X Torr-1 and 5.9 +/- 0.6 l X min-1 (mean +/- S.D.), respectively, which increased during moderate exercise up to 34.6 +/- 3.9 ml X min-1 X Torr-1 and 13.0 +/- 1.2 l X min-1. The tc was 0.70 +/- 0.06 s at rest and 0.40 +/- 0.05 s during exercise. The rebreathing method for measuring DL(CO) was more advantageous than the single breath method, because the tc could be obtained as well as the Q and the influence of the dead space and ventilation-perfusion uneveness on DL(CO) was reduced.

Characteristics of pulmonary diffusing capacity in Japanese. On the sexual and ethnic differences.

Pulmonary diffusing capacity for CO (DL), the diffusing capacity of the pulmonary capillary membrane, and pulmonary capillary blood volume were measured for 63 male and female subjects aged 17 to 33 years in both sitting and supine postures. From the relationship of these values to morphological factors, the existence and cause of sexual and ethnic differences in DL were investigated. The average DL values for males in both positions were about 35% larger than those for females; even when corrected by body size, such as body surface area or stature, significant sexual difference was found. This difference disappeared when DL was corrected by difference in alveolar volume. That is, differences between men and women in body size and ratio of lung volume to body size are thought to account for sexual difference in DL. From comparison with other reports, an ethnic difference in DL was recognized between Caucasians and Japanese, and its cause is suggested to be the same as cause which accounts for the difference by sex among Japanese.

Change in O2 uptake during rebreathing in hyperoxia in man.

In pertaining to PO2 dependency of the pulmonary CO diffusing capacity during rebreathing, the O2 uptake (VO2) and cardiac output (Q) were measured at three different PO2 levels between 100 and 500 Torr. Since the VO2 measured by an O2 injection method is strongly influenced in hyperoxia by a gas exchange ratio (R), a simulation method using a R-PCO2 relation during rebreathing was developed. Gas volume in the lung-bag-system needed in the computation was measured from the difference in O2 concentration between before and after injecting a known amount of O2 into the rebreathing circuit. The accuracy of the volume was checked by comparing it with the volume measured successively with a body box. The VO2 was determined by comparing the simulated O2 and CO2 concentrations in rebreathing gas with the measured ones. The VO2 significantly increased by rebreathing in hyperoxia. To analyze the VO2 increase, the Q was computed by dividing the VO2 by the arteriovenous O2 content difference, which in turn was obtained by dividing the slope of the CO2 dissociation curve by that of the R-PCO2 line. The Q was almost linearly related to the VO2. Since there was no difference in VO2 in steady state breathing between normoxia and hyperoxia, the increase in VO2 and Q seemed to occur transiently. This finding is very important in evaluating the PO2 dependency of the pulmonary diffusing capacity for CO.

Pulmonary diffusing capacity for carbon monoxide by rebreathing in awake dogs.

In order to reduce the effects of functional inhomogeneities on the determination of pulmonary diffusing capacity (transfer factor) for CO (DLCO), DLCO was measured by a rebreathing method in 5 awake chronically tracheostomized dogs (mean body weight 28 kg) during high ventilation (15-25 times above normal) induced by hypoxia, hypercapnia, exercise, or their combinations. The animals rebreathed for 15 s a mixture containing 1% He, 0.1% C18O, with CO2 and O2 concentrations adjusted to maintain end-tidal PCO2 and PO2 close to their prerebreathing values. Gas partial pressures in the trachea were continuously monitored by mass spectrometry. DLCO was calculated from C18O equilibration kinetics, effective ventilation (obtained from He mixing kinetics) and lung volume (obtained from He dilution). Each of the factors, hypoxia, hypercapnia and exercise, contributed to increasing DLCO. During exercise in combined hypoxia and hypercapnia, DLCO (mean +/- SE) was 71.7 +/- 1.8 ml/(min X Torr). The mechanisms for increases in DLCO might have involved improvement of diffusion conditions, decrease of functional inhomogeneities and reduction of the effects of functional inhomogeneities. The highest DLCO values were close to values derived from morphometry.

Structure-function correlation of early stages of lung injury induced by intratracheal bleomycin in the rabbit.

After measurement of lung volume, pressure-volume relationship of the lungs, flow-volume relationship, and single-breath diffusing capacity, the effect of endotracheal injection of bleomycin (10 micrograms/kg) on structural and functional changes was assessed in 21 rabbits and compared with 8 rabbits who received endotracheal injection of saline. Lung function was reassessed in the control rabbits at 1, 3, and 5 wk, and they were then killed. The bleomycin-treated rabbits were divided into 3 groups and retested at 1 (n = 7), 3 (n = 6), and 5 (n = 8) wk. Each group of animals was killed after the functional assessment, and after fixation the lungs were examined morphometrically. The degree of fibrosis in the bleomycin-treated animals was small even at 5 wk. Volume densities of pulmonary structures, alveolar wall thickness, airway diameters, airway inflammation scores, and fibrosis scores were determined and their correlation with the functional measurements was assessed. Lung volume subdivisions, pressure-volume characteristics, and diffusing capacity for carbon monoxide were significantly reduced, and the resistance of the upstream segment of airways was significantly increased after the bleomycin injection. Changes in lung volume correlated significantly with the volume densities of free alveolar cells, nonparenchymal tissue, and alveolar wall thickness. The exponent K, derived by fitting an exponential function to the pressure-volume data, which is indicative of lung elastic behavior, did not correlate with any morphometric index of interstitial disease. The diffusing capacity for CO was significantly correlated with the volume densities of alveolar wall, nonparenchymal tissue, and alveolar wall thickness, but these correlations became nonsignificant when the diffusing capacity was corrected for alveolar volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrogen washout and mortality.

We studied the association between different tests of pulmonary function and subsequent mortality. Subjects were drawn from an epidemiology study of chronic obstructive pulmonary disease. Between 1971 and 1976, 2,539 nonpatient adults had tests of forced expiration, diffusing capacity, and single-breath nitrogen washout. By 1981, 115 of those subjects had died, including 3 from known lung disease. In assessing the relationship between lung function and mortality, the following tests of pulmonary function were examined: forced expiratory volume in one second as a percentage of forced vital capacity, forced expiratory volume divided by height cubed, slope of phase III from the single-breath nitrogen test, closing capacity, diffusing capacity for CO, and the ratio of maximal flow at 75% to that at 25% vital capacity. When adjustments for age and smoking were made, slope of phase III was strongly associated with mortality, even more so than tests of forced expiration. There are two possible explanations for this striking relationship between these observed abnormalities of lung function and subsequent overall mortality (which is largely from nonpulmonary disease): the lungs may serve to protect other systems of the body and therefore poor pulmonary function may contribute to a number of diseases leading to death, or lung function may merely reflect existing disorders in other systems of the body, and the observed association between mortality and pulmonary function is a byproduct of nonpulmonary diseases.

Prognostic value of chest radiograph, serum-angiotensin-converting enzyme and T helper cell count in blood and in bronchoalveolar lavage of patients with pulmonary sarcoidosis.

We studied the prognostic value of the initial radiologic stage, the serum-angiotensin-converting enzyme (SACE) and T helper cells in blood (OKT-4-Bl) and in bronchoalveolar lavage (OKT-4-BAL) for patients with biopsy-proven pulmonary sarcoidosis. Thirty-seven patients without prior treatment were followed up for a period of 2 years. A BAL was performed in 22 of them as part of the diagnostic workup. Clinical examination, chest radiographs, vital capacity, diffusion capacity for CO, airway resistance and PaO2 at rest and during exercise were determined initially and after 6, 12 and 24 months. According to these results, patients were classified as having progressive or nonprogressive disease. The radiologic stage and the initial SACE (38.3 +/- 10.2 vs. 43.7 +/- 13.0 nmol/ml/min) could not discriminate between the two groups. Patients with progressive disease had significantly fewer OKT-4-Bl cells (403.3/microliter +/- 146.7/microliter vs. 842.0/microliter +/- 430.1/microliter) and more OKT-4-BAL cells (24.5 +/- 15.4% vs. 7.0 +/- 2.6%) than patients with stable disease (p less than 0.01). A negative correlation between OKT-4-Bl and OKT-4-BAL cells was shown (Rs = -0.79; p less than 0.001). We conclude that the number of OKT-4-Bl and OKT-4-BAL cells can be used as prognostic parameter for patients with sarcoidosis.