Antigen And Molecular Biology Research On Early Diagnosis Of Invasive Aspergillosis In Patient With Hematologic Malignancies

Objective: To evaluation the value of Aspergillus antigen galactomannan (GM), 1,3-β-D glucan antigen (BG) and Real-Time PCR method for early diagnosis of invasive aspergillosis in patient with hematologic malignancies as well as the diagnostic value of these methods in monitoring the effect of anti-fungal treatment .Methods:Double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) method, colorimetric assay, as well as Real-Time PCR were performed to screen for circulating galactomannan (GM), 1,3-β-D glucan antigen (BG), and the concentration of Aspergillus DNA copy number which is defined as positive GM test for detection of two different points A value> 0.5 or a single> 0.8, BG-positive test defined as> 80pg/ml, Real-Time PCR in two specimens the mean Ct hole is defined as≤30 positive. And in accordance with the development of China's blood disease / malignant tumors in patients with invasive fungal infections (IFI) of the diagnostic criteria and treatment of the principles of standards, research subjects will be divided into: proven, probable, possible and no IFI in four categories. namely, sensitivity,specificity and predictive values were calculated respectively and compared,and assess follow-up value of GM,BG, DNA copy number serially determination in invasive aspergillosis(IA).Results: we collected a total of 613 serum samples from 197 cases of leukemia and hematopoietic stem cell transplantation ,1 patients were grouped to proven IA,52 probable IA cases,52 possible IFI cases,76 excluded IFI cases.(1)Defined in accordance with the test cutoff, GM to the test ,sensitivity was 81.1% and specificity was 88.2%, positive predictive value of 90.2%, negative predictive value of 86.5%. The sensitivity of BG was 89.9%, specificity was 85.5%, positive predictive value of 84.9%, negative predictive value was 90.2%, the false-positive rate of the two tests were 12.8%, 14.5%, there was no significant difference (P> 0.05), the distribution of false-positive patients have a statistically significant difference (P <0.05). Combined the two tests can improve specificity (98%) and positive predictive value (98%), and the specificity of the test and the negative predictive value of no effect.(2) Real-Time PCR were two holes in the mean Ct was defined as≤30 positive , the sensitivity was 90.6% and specificity of 80.3%, positive predictive value was 76.2%, negative predictive value 92.4%.(3) Three diagnostic detection methods joint evaluation and diagnosis of patients withproven and probable diagnosis of IA for the true positive group, no IFI for the negative group .It shows that the three combined ,the sensitivity was100% and specificity was 78.5%, positive predictive value of 75.1%, negative predictive value was 100%, three joint, improved diagnostic sensitivity and specificity only slightly decreased.(4) In this study, found that the three detection methods resulted in a positive sputum culture than those in clinical and imaging features of typical earlier (Table 3.6), Real-time PCR results suggest that positive than GM, BG antigen test in advance, but t test( P = 0.824, P = 0.641), no statistically significant difference.(5) Completed for 38 cases of aspergillus infection in patients treated with the first treatment ,according to efficacy,it was divided into an effective group and invalid group respectively, prior to the use of intravenous antifungal agents at -3,0,3,7,11,15 d, 6 time points to detection GM, BG, Ct mean, results are as follows: a.Treatment effective group showed a downward trend of GM value and fell to normal.The invalid group but increased its value. Invalid group and effective group of de facto GM detection in different locations to carry out the overall value of Wilcoxon rank sum test. Effective group and ineffective group of GM values in the distribution of pre-treatment is no difference (P = 0.864), after the treatment of 7 d ,the detection of the value of the distribution of their difference was significant (P <0.05). b. BG antigen in the treatment of changes are similar with GM in the course of treatment. c.Real-time PCR: before Clinical and microbiological diagnosis based on , Ct values are on a downward trend of the average. after the first anti-Aspergillus treatment, therapy effective group's Ct value is of its rapid rise, the ineffective group is also starting its Ct value an upward trend, then the Ct valueis on the downward trend,.Before treatment, the difference between effective group and invalid group was not statistically significant in the treatment group prior to the effective Ct value with invalid group there was no significant difference (P> 0.05), after treatment in the detection of the Ct value of the reference time-point there is no statistically significant difference (P> 0.05). Therefore, the detection of the dynamic GM, BG antigen of the evaluation of efficacy against fungi is a certain significance, and monitoring of Ct values were evaluated no significant.Conclusions: Serum BG, GM antigen test and real-time fluorescence quantitative PCR for the early diagnosis of IA can provide strong evidence .Joint BG, GM antigen detection methods in two judgments is in favor of false-positive test results, dynamic detection of GM, BG antigen levels, is conducive to judge the efficacy and prognosis; Real-Time PCR, in order to sample the two-hole average Ct was defined as≤30 to obtain a higher sensitivity and specificity, and dynamic monitoring of Ct values were evaluated no significant.