Development Of A Method For AMP Provocation Test And Its Clinical Significance

Background and ObjectiveAsthma is a bronchial inflammatory disease which accompanys airway hyperresponsiveness and reversible bronchoconstriction. Bronchial response can be measured by bronchial provocation test which is for diagnosing athma, differential diagnosis and judging the efficiency of therapy. At present, direct bronchial provocation test which uses histamine and methacholine as stimuli has been uses to examine the airway responsiveness since 1950s. It was extensive used in clinic and aboratory in recent twenty years. The method of histamine and methacholine bronchial provocation test was standardize, simplify and low effect. However, the application of them is still limited. They have the feature of high sensitive, but low specificity, not enough relation with bronchial inflammatory, fail to judging the serious of bronchial inflammatory, not enough accuracy to assese the effect of corticosteroid therapy. Accordingly, people pay more attention for another methods which assess AHR well, especilly the indirect bronchial provocation test which induce bronchoconstriction through activate cells to release bronchial inflammatory media and cytokine.Overseas, AMP has been conducted of research for more than 10 years. In 1995, Polosa R discovered that the response to endobronchial stimulation with AMP was characterized by a prompt reduction in airway caliber paralleled by a significant rise in PGD2, histamine, and tryptase levels in the lavage fluid compared with the saline-challenged segment. In recent years, AMP bronchial provocation test has been used in clinic and research. The literate covered that it has high sensitive, specificity and safety, low adverse reaction.At present, the clinic research of AMP bronchial provocation test in our country is empty.Moreover,the oversea research has only compared AMP with Mch, never with histamin and never compared in athma patient who are in different degree of controlled. Accordingly, this research must find the method of AMP bronchial provocation test at first. On one hand, the healty nonsmoker volunteers were enrolled in order to explore whether the bronchial function of the controll group is not changed obviously after absord AMP solution and the safety application of AMP-BPT in healty peaple. On the other hand, the intention of the representative athma patient enrolled is to research the validity of AMP-BPT in diagnosing bronchial athma. It need to research the clinic application value of AMP-BPT after the establishment of the method. Accordingly, athma patients of different controlled degree were enrolled in partⅡin order to explore the clinic application value of AMP-BPT in athma treatment project. Moreover, we think that there is AHR in acute upper respiratory tract infection patients too. It can realize the specificity of AMP-BPT if the acute upper respiratory tract infection patients were enrolled. At last, we can discover if the clinic application of AMP is better than histamin which were used to be provocation stimulation in our country through comparing the two provocation tests.PartⅠThe establishment of adenosine monophosphate (AMP) bronchial provocation test.Methods24 healthy nonsmoker volunteers (Control group) and 41 patients of asthma (Asthma group) were enrolled. AMP was nebulization inhaled from low to high concentration to achieve cumulative doubling dosage. Pulmonary function test was performed before and after each provocation dose. PD20FEV1-AMP<40mg was set as a cut-off value to determine the positive response. Positive rate, PD20FEV1-AMP, sensitivity, specificity accuracy and adverse reactions of AMP provocation test were accessed. Resuls No positive response to AMP were found in control group, ,however, 38 patients with asthma group (92.7%) responded to AMP with PD20FEV1-AMP as 1.25mg(6.98mg). There were negative correlations between PD20FEV1-AMP and the percentage change in FEV1 (r = -0.607, P<0.01), FVC(r = -0.447, P=0.003) and PEF(r = -0.352, P=0.024). The sensitivity, specificity and accuracy was 93%,100% and 95%, respectively. Percentage of asthmatics who experienced wheezing, dyspnea, cough and chest tightness were 78%, 29%, 29% and 10%, respectively, but no severe adverse reaction were found.ConclusionsThe High sensitivity, specificity and accuracy of AMP-BPT provide a useful, effective and safety test for the assessment of bronchial asthma. It is well tolerated. AMP-BPT was successfully established.PartⅡThe Clinical meaning of adenosine monophosphate (AMP) bronchial provocation test to asthmaticsMethods24 healthy volunteers (control group), 60 asthmatics, including 19 uncontrolled (uncontrolled group), 22 partially controlled (partially controlled group),19 controlled (controlled group), and 20 patients with upper respiratory tract infection (URI group) were enrolled and performed with AMP bronchoprovocation test (AMP-BPT). PD20FEV1-AMP < 40 mg was set as a cut-off value of positive response to AMP. Positive rate, sensitivity, specificity, accuracy and adverse reactions of AMP-BPT were accessed. 23 asthmatics (11 in uncontrolled group and 12 in partially controlled group) were followed 3 months and 6 months after inhaled corticosteroids (ICS) treatment with AMP-BPT. Asthma symptom scores were recorded a week early before each challenge. The relation between PD20FEV1- AMP and asthma symptom score were analyzed.ResultsNo positive responses to AMP were found in both control group and URI group. However, positive responses to AMP were found in all uncontrolled group with PD20FEV1-AMP as 0.6 mg (0.4 mg). 19 asthmatics (86.4%) in partially controlled group responded to AMP with PD20FEV1-AMP as 5.38 mg (32.67 mg), and 5 asthmatics (26.3%) in controlled group responded to AMP with PD20FEV1-AMP as 40 mg (29.3 mg). There were negative correlations between the logarithms of PD20FEV1- AMP and logarithms of asthma symptom scores (r=-0.598, P<0.01). The sensitivity, specificity and accuracy was 72%, 100% and 84%, respectively. Percentage of subjects who experienced wheezing, cough, dyspnea, swallows stimulation, chest tightness, expectoration and cyanosis during AMP-BPT were 37.5%, 21.2%, 15.4%, 7.7%, 7.7%, 4.8% and 1.0%, respectively. No severe adverse reaction was found.ConclusionsAMP-BPT was helpful to the diagnosis and differential diagnosis bronchial asthma. It also can be used to estimate the severity degree, level of control and to monitor the therapeutic effects of asthma in clinical practice. AMP-BPT is well tolerated.PartⅢComparison of adenosine monophosphate (AMP) and histamine bronchial provocation testMethods24 healthy volunteers (control group), 60 asthmatics, including 19 uncontrolled (uncontrolled group), 22 partially controlled (partially controlled group),19 controlled (controlled group), and 20 patients with upper respiratory tract infection (URI group) were enrolled and performed with histamin bronchoprovocation test and AMP bronchoprovocation test (AMP-BPT) respectively. PD20FEV1-AMP < 40 mg was set as a cut-off value of positive response to AMP and PD20FEV1-histamin < 2.2 mg was to histamin. Positive rate, sensitivity, specificity, accuracy and adverse reactions of the two challenge were accessed. 23 asthmatics (11 in uncontrolled group and 12 in partially controlled group) were followed 3 months and 6 months after inhaled corticosteroids (ICS) treatment with the two test. Asthma symptom scores were recorded a week early before each challenge. The relation between PD20FEV1 of the two challenge and asthma symptom score were analyzed. ResultsNo positive responses to both histamin and AMP were found in control group. Positive responses to both histamin and AMP were found in all uncontrolled group with PD20FEV1-histamin as 0.07mg(0.06mg)and PD20FEV1-AMP as 0.6 mg (0.4 mg). 19 asthmatics (86.4%) in partially controlled group responded to both histamin and AMP with PD20FEV1-histamin as 0.49mg(1.12mg) and PD20FEV1-AMP as 5.38 mg (32.67 mg). However, 7 asthmatics (36.8%) responded to histamin and 5 asthmatics (26.3%) responded to AMP in controlled group with PD20FEV1-histamin as 2.20mg(1.27mg) and PD20FEV1-AMP as 40 mg (29.3 mg). 3 patients with URI (15%) responses to histamin with PD20FEV1-histamin as 2.2mg(0). But no positive responses to AMP were found in URI group. There were positive correlations between the logarithms of PD20FEV1- histamin and logarithms of PD20FEV1- AMP(r=0.747,P<0.01). The sensitivity, specificity and accuracy was 74%, 93% and 81% in histamin-BPT and 71%, 100% and 82% in AMP-BPT. There were negative correlations between the logarithms of the PD20FEV1-histamin(r=-0.379,P<0.01), PD20FEV1- AMP( r=-0.598, P<0.01) and logarithms of asthma symptom scores. Percentage of subjects who experienced cough, wheezing, dyspnea, chest tightness, swallows stimulation, expectoration, hoarse, and cyanosis were 38.5%, 37.5%, 24.0%, 21.1%, 6.7%, 5.8%, 4.8% and 2.9% in histamin-BPT, respectively. Percentage of subjects who experienced wheezing, cough ,dyspnea, swallows stimulation, chest tightness, expectoration and cyanosis were 37.5%, 21.2%, 15.4%, 7.7%, 7.7%, 4.8% and 1.0% in AMP-BPT, respectively, but no hoarse reaction was found. No severe adverse reaction was found in the two BPT. The swallows stimulation (P=0.003), hoarse (P=0.03) and cough (P=0.006) of histamin-BPT were obviously higher than that of AMP-BPT. The histamin-BPT costs $0.09 and 26±6 mins per time, however, the AMP-BPT costs$1.60 and 35±10 mins.ConclusionsIt has the trendency that the sensitivity of histamin-BPT is higher than AMP-BPT, the specificity of AMP-BPT is higher than histamin-BPT. AMP-BPT can judge the treatment effectiveness better than histamin-BPT. Moreover, its adverse reactions were lower than histamin-BPT. But the spend cost and time of the AMP-BPT were higher than that of the histamin-BPT. The clinic application value of AMP-BPT is worth discussing.