Urinary Leukotriene E4 after Lysine-Aspirin Inhalation in Asthmatic Subjects1 , 2
PANDORA E. CHRISTIE, PHILIP TAGARI, ANTHONY W. FORD-HUTCHINSON, CHERYL BLACK, ANDRE MARKENDORF, MICHAEL SCHMITZ-SCHUMANN, and TAK H. LEE
Introduction
Arachidonic acid released from membrane phospholipids by the action of phospholipase A 2 may be metabolized by the cycloxygenase pathway to generate prostaglandins and thromboxane A 2 or via the 5-lipoxygenase pathway to generate the sulfidopeptide leukotrienes leukotriene C 4 (LTC4 ) , leukotriene D4 (LTD4 ) and leukotriene E 4 (LTE4 ) (1). In humans, LTC4 is converted enzymatically in the blood to LTD4 and then to LTE4 , which is excreted in the urine. Measurement of urinary LTE4 may act as a marker of systemic release of sulfidopeptide leukotrienes (2-6). After ingestion of aspirin, a proportion of asthmatic individuals develop bronchospasm that may be accompanied by naso-ocular symptoms and urticaria. Aspirin-sensitive asthma tends to occur after the third decade of life and is often associated with persistent asthma, nasal polyps, and rhinitis (7-9). Aspirin-sensitive asthmatic patients have elevated baseline urinary LTE4 concentrations (6) and an increased airway sensitivity to LTE4 , which decreases after desensitization with aspirin (10). Urinary LTE4 concentrations increase after asthmatic reactions provoked by oral aspirin challenge (6). Christie and colleagues demonstrated that prior inhalation of the sulfidopeptide leukotriene receptor antagonist SK&F 104353 attenuated aspirin-induced asthma, supporting the viewthat the sulfidopeptide leukotrienes are critical mediators in aspirin sensitivity (11). Inhalation of lysine-aspirin solution elicits airflow obstruction in aspirinsensitive, but not aspirin-insensitive, asthmatic patients. It may be a safer method for diagnosis of aspirin-induced asthma than oral aspirin challenge because it is accompanied by fewer systemic complications (12-14). Oral administration of aspirin in sensitive patients often results in flushing and urticaria. In order to clarify the pulmonary component, we have assessed whether lysine-
SUMMARY The FEV, and urinary leukotrlene E. (LTE.)concentrations were determined in six aspirinsensitive and six non-aspirin-sensltive asthmatic subjects before and after inhalation challenge with lysine-aspirin or placebo solution. Lysine-aspirin produced a mean fall in FEV, of 26.7 ± 4.9% (mean ± SEM) In subjects with aspirin sensitivity and of 8.5 ± 6.5% (mean ± SEM) In non-asplrlnsensitive asthmatic subjects. The mean baseline urinary LTE. concentration of 83 pg/mg creatinine (geometric mean [GM). range 15 to 326 pg/mg creatinine) In aspirin-sensitive subjects was significantly higher than the 33.8 pg/mg creatinine (GM, range 10 to 111 pg/mg creatinine) In non-asplrinsensitive subjects (p = 0.02). In aspirin-sensitive SUbjects, Inhalation challenge with lysine-aspirin produced a significant increase In urinary LTE. concentration to 240 pg/mg creatinine (GM, range 60 to 1,113pg/mg creatinine). which was not observed after placebo challenge. There was no significant change In urinary LTE. concentration after inhalation challenge with either lysine-aspirin or placebo solution In non-asplrln-sensltlve asthmatic subjects. Thus, sulfldopeptide leukotrlenes are released after inhalation of lysine-aspirin in aspirin-sensitive asthmatic patients. AM REV RESPIR DIS 1992; 146:1531-1534
aspirin inhalation results in the release of the sulfidopeptide leukotrienes. Methods Subjects Six aspirin-sensitive and six non-aspmnsensitivesubjects werestudied (table 1).There was no significant difference in resting FEY. in the aspirin-sensitive or non-aspirin-sensitive asthmatic subjects. The patients with aspirin sensitivity were selected on the basis of a positive past history of aspirin sensitivity and a previous challenge with oral aspirin that produced a > 150/0 fall in FEY •. Atopy was defined as the presence of at least two positive reactions (weal 3 mm greater than saline control) to skin prick tests with the following allergens: cat fur, dog hair, grass pollen, and Dermatophagoides pteronyssinus. All subjects gave informed consent, and the study was approved by the Hochgebirgsklinic, Davos-Wolfgang, ethical committee. Study Protocol Each subject attended the laboratory on two occasions, at which times inhalation challenge with lysine-aspirin or placebo was performed in a single-blind, randomized fashion at the same time of day. Study days were separated by a period of at least 1 wk. Urine collections for urinary LTE4 were made just before and at 3 and 6 h after the inhalation challenge. Subjects withheld medication for 12h before the challenge and had not experienced an upper respiratory tract infection for at least 4 wk before the study day.
Lysine-Aspirin Inhalation Challenge Lysine-aspirin inhalation challenge was performed by the method of Schmitz-Schumann and coworkers (13). Lysine-aspirin (Synthelabopharma, Lausanne, Switzerland) as a powder containing 900 mg lysine acetylsalicylate with 100 mg glycine was used. The powder was diluted in 5 ml of water to produce a solution of 180 mg/ml (0.55 mol/L) lysine acetylsalicylate, which is equivalent to 100mg/rnl acetylsalicylic acid. This solution was diluted with sodium chloride to produce a range of increasing doubling concentrations from 1.25mg/ml to 25 mg/ml (0.076mmol/L to 3.8 mol/L). The placebo solution consisted of 1,200 mg of lysine with 300 mg of glycine and was reconstituted with 5 ml water. One milliliter of lysine-aspirin or placebo solution was placed in a Heyer nebulizer (Bad Instruments, Germany) that was driven by compressed air (output 8 L/min) and generated an aerosol with a mass median particle (Received in original form May 6, 1992 and in revised form August 3, 1992) , From the Swiss Institute for Asthma and Allergy Research, Davos, Switzerland, The Department of Pharmacology, Merck-Frosst, Quebec, Canada, the Hochgebirgsklinik, Daves-Wolfgang, Switzerland, and the Department of Allergy and Allied Respiratory Disorders, U.M.D.S., Guy's Hospital, London, United Kingdom. 2 Correspondence and requests for reprints should be addressed to Professor Tak H. Lee, M.D., ER.C.P., Department of Allergy and Allied Respiratory Disorders, 4th Floor, Hunt's House, Guy's Hospital, London SEI 9RT, UK.
1531
1532
CHRISTIE, TAGARI, FORD-HUTCHINSON, BLACK, MARKENDORF, SCHMITZ·SCHUMANN, AND LEE
TABLE 1 CHARACTERISTICS OF SUBJECTS STUDIED
Subject
Age (yr)
Aspirin-sensitive asthmatic subjects 1 2 3 4 5 6
40 43 52 41 53 36
Mean SEM
44 2.8
Non-aspirin-sensitive asthmatic subjects 1 2 3 4 5 6
23 28 36 46 52 28
Mean SEM
36 4.0
Sex
Atopy
F F F F M F
+ + + + + +
Baseline FEV, (% predicted)
80 83 94 76 65 72
Treatment
AB AB AB AB ABC
+ + +
+
82 89 99 77 82 84
2.5 2.5 25 5.0 1.25 1.25 6.25 3.7
78 4.2 F F F M M F
Dose Lysine-Aspirin (mg)
A AB AB AB A A
25 25 25 25 25 25
85.5 3.1
Definition of abbreviations: A = inhaled albuterol; B = inhaled corticosteroid; C = theophylline (serum theophylline concentration before challenge was 9.2 mg/L and 10.2 mg/L on the lysine-aspirin and placebo study days, respectively).
diameter of 5 urn throughout. Subjects inhaled the aerosol solution via a mouthpiece during normal tidal breathing. Measurements of airway response were made using a spirometer (Micromedical Ltd., Rochester, Kent), and the subjects were studied if baseline FEV, was greater than 65010 of predicted. If the decrease in FEV, was less than 10010 after inhalation of normal saline, challenge with placebo or lysine-aspirin solution was performed. Three measurements of FEV, were made at 15and 30 min after each dose of lysine-aspirin or placebo solution, and the maximal reading was recorded. If the fall in FEV, was < 10%, a doubling dose of lysine-aspirin was inhaled and the protocol repeated until there was a > 15% fall in FEV,. Measurements of airway response were continued for up to 4 h after a positive reaction.
Measurement of Urinary LTE. Concentration Urine was collected before and at 3 and 6 h after the inhalation challenge with lysineaspirin or placebo. The free radical scavenger 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy (4-hydroxy TEMPO; Aldrich Chemical Co., Milwaukee, WI) was added at a final concentration of 1 mM, and the samples were adjusted to pH 9.0 with sodium hydroxide to stabilize endogenous leukotriene metabolites. The samples were coded and stored at - 700 C until sent in dry ice to Canada for measurement of the LTE4 as previously described (2). Briefly, 1.14 nCi [1l,12-H]LTC 4 (38.4kCi/mol; New England Nuclear, Lachine, Canada) was added to 10 ml thawed urine samples. The pH of the samples was adjusted to pH 5.4 with acetic acid. The [3H]LTC4 and endogenous LTE4 were then extracted from the urine using an "in line" reversed-phase precolumn (C,. Adsorbosphere, 5-~m diameter packing
material; Alltech, Mandel Scientific, Lachine, Canada). Leukotrienes were retrogradely eluted, via twin switching valves, onto a reversedphase 8-~m diameter, lO-cmlong radial compression analytical column (C,. NovaPak, 4-~m diameter packing material; Waters Co, St. Laurent, Canada) with a mobile phase consisting of MEOH:ammonium acetate buffer (0.1% containing 1 mM disodium EDTA, pH 5.4) in the proportions 60:40(vol:vol)at a flow rate of 2 ml/min. The column was calibrated for the retention times of synthetic LTC4 , (5.33 ± 0.05 min, n == 18) and LTE 4 (14.01 ± 0.15 min, n == 18). The radioactivity of the fractions eluting with retention time of synthetic LTC4 was assessed by liquid scintillation spectrometry to determine leukotriene recovery. Fractions eluting with retention time of synthetic LTE4 were evaporated to dryness under nitrogen gas, and the LTE4 concentration was measured by specific radioimmunoassay as previously described (2). The sensitivity of the assay is 8 pg/mI. The intra- and interassay coefficients of variation were 12% and 16%, respectively.
Data Analysis Repeated measures analysis of variance was carried out separately for each of the two groups, treatment (two levels)and time (three levels)being analyzed as "within subjects" factors. The dependent variable was the log transformation of LTE 4 • Results
There was no significant difference in baseline FEV 1 between the two study days. The baseline FEV 1 in the aspirinsensitive subjects before aspirin and placebo challenge was 2.6 ± 0.3 L (mean ± SEM) and 2.5 ± 0.3 L (mean ± SEM),
respectively. The FEV 1 in non-aspirinsensitive subjects before aspirin and placebo challenge was 2.7 ± 0.1 L (mean ± SEM) and 2.6 ± 0.2 L (mean ± SEM), respectively. The dose of lysine-aspirin that produced bronchoconstriction in the aspirin-sensitive asthmatic subjects was 6.2 ± 3.8 mg/ml (mean ± SEM, n = 6). Subjects who were non-aspirin-sensitive inhaled 25 mg/ml of lysine-aspirin. The changes in FEV 1 in aspirin-sensitive and non-aspirin-sensitive subjects after aspirin or placebo challenge are shown in figure 1. In aspirin-sensitive subjects there was a 26.7 ± 4.9070 (mean ± SEM) decrease in FEV 1 from baseline value at 45 min after lysine-aspirin challenge and a 9 ± 5.9% (mean ± SEM) fall in FEV 1 at 90 min after placebo challenge. In subjects without aspirin sensitivity the maximum fall in FEV 1 was 8.5 ± 6.5% (mean ± SEM) at 90 min and 4.1 ± 1.9% (mean ± SEM) at 120 min on the lysine-aspirin and placebo study days, respectively. The baseline LTE4 concentration in aspirin-sensitive asthmatic subjects was 83 pg/mg creatinine (OM, range 15 to 326 pg/mg creatinine) (n = 6) as determined by assay of LTE4 concentrations in urinary samples collected from each individual on two separate occasions. This was significantly higher than that of nonaspirin-sensitive subjects in whom the baseline LTE4 concentration was 34 pg/ mg creatinine (OM, range 10to 111 pg/mg creatinine) (n = 6) (p = 0.02). LTE4 release in individual subjects af-
1533
URINARY LTE, AFTER LYSINE-ASPIRIN INHALATION
p = > 0.5). In asthmatic subjects without aspirin intolerance there was no increase in urinary LTE4 concentration for 6 h after ingestion of aspirin or placebo.
o ~ -10
:> UJ
Discussion
u. .~
-20
Q)
Ol C
PANDORA E. CHRISTIE, PHILIP TAGARI, ANTHONY W. FORD-HUTCHINSON, CHERYL BLACK, ANDRE MARKENDORF, MICHAEL SCHMITZ-SCHUMANN, and TAK H. LEE
Introduction
Arachidonic acid released from membrane phospholipids by the action of phospholipase A 2 may be metabolized by the cycloxygenase pathway to generate prostaglandins and thromboxane A 2 or via the 5-lipoxygenase pathway to generate the sulfidopeptide leukotrienes leukotriene C 4 (LTC4 ) , leukotriene D4 (LTD4 ) and leukotriene E 4 (LTE4 ) (1). In humans, LTC4 is converted enzymatically in the blood to LTD4 and then to LTE4 , which is excreted in the urine. Measurement of urinary LTE4 may act as a marker of systemic release of sulfidopeptide leukotrienes (2-6). After ingestion of aspirin, a proportion of asthmatic individuals develop bronchospasm that may be accompanied by naso-ocular symptoms and urticaria. Aspirin-sensitive asthma tends to occur after the third decade of life and is often associated with persistent asthma, nasal polyps, and rhinitis (7-9). Aspirin-sensitive asthmatic patients have elevated baseline urinary LTE4 concentrations (6) and an increased airway sensitivity to LTE4 , which decreases after desensitization with aspirin (10). Urinary LTE4 concentrations increase after asthmatic reactions provoked by oral aspirin challenge (6). Christie and colleagues demonstrated that prior inhalation of the sulfidopeptide leukotriene receptor antagonist SK&F 104353 attenuated aspirin-induced asthma, supporting the viewthat the sulfidopeptide leukotrienes are critical mediators in aspirin sensitivity (11). Inhalation of lysine-aspirin solution elicits airflow obstruction in aspirinsensitive, but not aspirin-insensitive, asthmatic patients. It may be a safer method for diagnosis of aspirin-induced asthma than oral aspirin challenge because it is accompanied by fewer systemic complications (12-14). Oral administration of aspirin in sensitive patients often results in flushing and urticaria. In order to clarify the pulmonary component, we have assessed whether lysine-
SUMMARY The FEV, and urinary leukotrlene E. (LTE.)concentrations were determined in six aspirinsensitive and six non-aspirin-sensltive asthmatic subjects before and after inhalation challenge with lysine-aspirin or placebo solution. Lysine-aspirin produced a mean fall in FEV, of 26.7 ± 4.9% (mean ± SEM) In subjects with aspirin sensitivity and of 8.5 ± 6.5% (mean ± SEM) In non-asplrlnsensitive asthmatic subjects. The mean baseline urinary LTE. concentration of 83 pg/mg creatinine (geometric mean [GM). range 15 to 326 pg/mg creatinine) In aspirin-sensitive subjects was significantly higher than the 33.8 pg/mg creatinine (GM, range 10 to 111 pg/mg creatinine) In non-asplrinsensitive subjects (p = 0.02). In aspirin-sensitive SUbjects, Inhalation challenge with lysine-aspirin produced a significant increase In urinary LTE. concentration to 240 pg/mg creatinine (GM, range 60 to 1,113pg/mg creatinine). which was not observed after placebo challenge. There was no significant change In urinary LTE. concentration after inhalation challenge with either lysine-aspirin or placebo solution In non-asplrln-sensltlve asthmatic subjects. Thus, sulfldopeptide leukotrlenes are released after inhalation of lysine-aspirin in aspirin-sensitive asthmatic patients. AM REV RESPIR DIS 1992; 146:1531-1534
aspirin inhalation results in the release of the sulfidopeptide leukotrienes. Methods Subjects Six aspirin-sensitive and six non-aspmnsensitivesubjects werestudied (table 1).There was no significant difference in resting FEY. in the aspirin-sensitive or non-aspirin-sensitive asthmatic subjects. The patients with aspirin sensitivity were selected on the basis of a positive past history of aspirin sensitivity and a previous challenge with oral aspirin that produced a > 150/0 fall in FEY •. Atopy was defined as the presence of at least two positive reactions (weal 3 mm greater than saline control) to skin prick tests with the following allergens: cat fur, dog hair, grass pollen, and Dermatophagoides pteronyssinus. All subjects gave informed consent, and the study was approved by the Hochgebirgsklinic, Davos-Wolfgang, ethical committee. Study Protocol Each subject attended the laboratory on two occasions, at which times inhalation challenge with lysine-aspirin or placebo was performed in a single-blind, randomized fashion at the same time of day. Study days were separated by a period of at least 1 wk. Urine collections for urinary LTE4 were made just before and at 3 and 6 h after the inhalation challenge. Subjects withheld medication for 12h before the challenge and had not experienced an upper respiratory tract infection for at least 4 wk before the study day.
Lysine-Aspirin Inhalation Challenge Lysine-aspirin inhalation challenge was performed by the method of Schmitz-Schumann and coworkers (13). Lysine-aspirin (Synthelabopharma, Lausanne, Switzerland) as a powder containing 900 mg lysine acetylsalicylate with 100 mg glycine was used. The powder was diluted in 5 ml of water to produce a solution of 180 mg/ml (0.55 mol/L) lysine acetylsalicylate, which is equivalent to 100mg/rnl acetylsalicylic acid. This solution was diluted with sodium chloride to produce a range of increasing doubling concentrations from 1.25mg/ml to 25 mg/ml (0.076mmol/L to 3.8 mol/L). The placebo solution consisted of 1,200 mg of lysine with 300 mg of glycine and was reconstituted with 5 ml water. One milliliter of lysine-aspirin or placebo solution was placed in a Heyer nebulizer (Bad Instruments, Germany) that was driven by compressed air (output 8 L/min) and generated an aerosol with a mass median particle (Received in original form May 6, 1992 and in revised form August 3, 1992) , From the Swiss Institute for Asthma and Allergy Research, Davos, Switzerland, The Department of Pharmacology, Merck-Frosst, Quebec, Canada, the Hochgebirgsklinik, Daves-Wolfgang, Switzerland, and the Department of Allergy and Allied Respiratory Disorders, U.M.D.S., Guy's Hospital, London, United Kingdom. 2 Correspondence and requests for reprints should be addressed to Professor Tak H. Lee, M.D., ER.C.P., Department of Allergy and Allied Respiratory Disorders, 4th Floor, Hunt's House, Guy's Hospital, London SEI 9RT, UK.
1531
1532
CHRISTIE, TAGARI, FORD-HUTCHINSON, BLACK, MARKENDORF, SCHMITZ·SCHUMANN, AND LEE
TABLE 1 CHARACTERISTICS OF SUBJECTS STUDIED
Subject
Age (yr)
Aspirin-sensitive asthmatic subjects 1 2 3 4 5 6
40 43 52 41 53 36
Mean SEM
44 2.8
Non-aspirin-sensitive asthmatic subjects 1 2 3 4 5 6
23 28 36 46 52 28
Mean SEM
36 4.0
Sex
Atopy
F F F F M F
+ + + + + +
Baseline FEV, (% predicted)
80 83 94 76 65 72
Treatment
AB AB AB AB ABC
+ + +
+
82 89 99 77 82 84
2.5 2.5 25 5.0 1.25 1.25 6.25 3.7
78 4.2 F F F M M F
Dose Lysine-Aspirin (mg)
A AB AB AB A A
25 25 25 25 25 25
85.5 3.1
Definition of abbreviations: A = inhaled albuterol; B = inhaled corticosteroid; C = theophylline (serum theophylline concentration before challenge was 9.2 mg/L and 10.2 mg/L on the lysine-aspirin and placebo study days, respectively).
diameter of 5 urn throughout. Subjects inhaled the aerosol solution via a mouthpiece during normal tidal breathing. Measurements of airway response were made using a spirometer (Micromedical Ltd., Rochester, Kent), and the subjects were studied if baseline FEV, was greater than 65010 of predicted. If the decrease in FEV, was less than 10010 after inhalation of normal saline, challenge with placebo or lysine-aspirin solution was performed. Three measurements of FEV, were made at 15and 30 min after each dose of lysine-aspirin or placebo solution, and the maximal reading was recorded. If the fall in FEV, was < 10%, a doubling dose of lysine-aspirin was inhaled and the protocol repeated until there was a > 15% fall in FEV,. Measurements of airway response were continued for up to 4 h after a positive reaction.
Measurement of Urinary LTE. Concentration Urine was collected before and at 3 and 6 h after the inhalation challenge with lysineaspirin or placebo. The free radical scavenger 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy (4-hydroxy TEMPO; Aldrich Chemical Co., Milwaukee, WI) was added at a final concentration of 1 mM, and the samples were adjusted to pH 9.0 with sodium hydroxide to stabilize endogenous leukotriene metabolites. The samples were coded and stored at - 700 C until sent in dry ice to Canada for measurement of the LTE4 as previously described (2). Briefly, 1.14 nCi [1l,12-H]LTC 4 (38.4kCi/mol; New England Nuclear, Lachine, Canada) was added to 10 ml thawed urine samples. The pH of the samples was adjusted to pH 5.4 with acetic acid. The [3H]LTC4 and endogenous LTE4 were then extracted from the urine using an "in line" reversed-phase precolumn (C,. Adsorbosphere, 5-~m diameter packing
material; Alltech, Mandel Scientific, Lachine, Canada). Leukotrienes were retrogradely eluted, via twin switching valves, onto a reversedphase 8-~m diameter, lO-cmlong radial compression analytical column (C,. NovaPak, 4-~m diameter packing material; Waters Co, St. Laurent, Canada) with a mobile phase consisting of MEOH:ammonium acetate buffer (0.1% containing 1 mM disodium EDTA, pH 5.4) in the proportions 60:40(vol:vol)at a flow rate of 2 ml/min. The column was calibrated for the retention times of synthetic LTC4 , (5.33 ± 0.05 min, n == 18) and LTE 4 (14.01 ± 0.15 min, n == 18). The radioactivity of the fractions eluting with retention time of synthetic LTC4 was assessed by liquid scintillation spectrometry to determine leukotriene recovery. Fractions eluting with retention time of synthetic LTE4 were evaporated to dryness under nitrogen gas, and the LTE4 concentration was measured by specific radioimmunoassay as previously described (2). The sensitivity of the assay is 8 pg/mI. The intra- and interassay coefficients of variation were 12% and 16%, respectively.
Data Analysis Repeated measures analysis of variance was carried out separately for each of the two groups, treatment (two levels)and time (three levels)being analyzed as "within subjects" factors. The dependent variable was the log transformation of LTE 4 • Results
There was no significant difference in baseline FEV 1 between the two study days. The baseline FEV 1 in the aspirinsensitive subjects before aspirin and placebo challenge was 2.6 ± 0.3 L (mean ± SEM) and 2.5 ± 0.3 L (mean ± SEM),
respectively. The FEV 1 in non-aspirinsensitive subjects before aspirin and placebo challenge was 2.7 ± 0.1 L (mean ± SEM) and 2.6 ± 0.2 L (mean ± SEM), respectively. The dose of lysine-aspirin that produced bronchoconstriction in the aspirin-sensitive asthmatic subjects was 6.2 ± 3.8 mg/ml (mean ± SEM, n = 6). Subjects who were non-aspirin-sensitive inhaled 25 mg/ml of lysine-aspirin. The changes in FEV 1 in aspirin-sensitive and non-aspirin-sensitive subjects after aspirin or placebo challenge are shown in figure 1. In aspirin-sensitive subjects there was a 26.7 ± 4.9070 (mean ± SEM) decrease in FEV 1 from baseline value at 45 min after lysine-aspirin challenge and a 9 ± 5.9% (mean ± SEM) fall in FEV 1 at 90 min after placebo challenge. In subjects without aspirin sensitivity the maximum fall in FEV 1 was 8.5 ± 6.5% (mean ± SEM) at 90 min and 4.1 ± 1.9% (mean ± SEM) at 120 min on the lysine-aspirin and placebo study days, respectively. The baseline LTE4 concentration in aspirin-sensitive asthmatic subjects was 83 pg/mg creatinine (OM, range 15 to 326 pg/mg creatinine) (n = 6) as determined by assay of LTE4 concentrations in urinary samples collected from each individual on two separate occasions. This was significantly higher than that of nonaspirin-sensitive subjects in whom the baseline LTE4 concentration was 34 pg/ mg creatinine (OM, range 10to 111 pg/mg creatinine) (n = 6) (p = 0.02). LTE4 release in individual subjects af-
1533
URINARY LTE, AFTER LYSINE-ASPIRIN INHALATION
p = > 0.5). In asthmatic subjects without aspirin intolerance there was no increase in urinary LTE4 concentration for 6 h after ingestion of aspirin or placebo.
o ~ -10
:> UJ
Discussion
u. .~
-20
Q)
Ol C
