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Objective To explore the application of the TST-IGRA two-step method in the screening of close contacts of active tuberculosis patients among three high schools in Jinshan District in 2020-2021，and to provide evidence for improving the prevention and control of tuberculosis in schools. Methods Three school tuberculosis outbreaks in Jingshan District from 2020 to 2021 were included in the present study. After excluding active tuberculosis, tuberculin skin test and γ-interferon release assay (IGRA) were conducted to screen latent infection of Mycobacterium tuberculosis in close contacts, and the necessity of the two-step method was analyzed. Results A total of 362 close contacts were screened in the three outbreaks, and 350 people were tested by TST. Comparing the results of TST and IGRA among different types of close contacts, it was found that the positive rate of TST in teachers was higher than that in students（54.84% vs 20.38%，P<0.05）. The positive rate of TST among students from high-burden areas of pulmonary tuberculosis in Shanghai was higher than that of local students（24.71% vs 18.80%，P<0.05). IGRA detection was performed on those with moderate and strong positive TST results, and the results showed that the positive rate of IGRA in those with strong positive TST results was only 17.7%, with Kappa value of 0.3. Conclusion The prevention and control of tuberculosis in school should strengthen the annual health examination of teachers and staff, promote timely medical treatment for suspected tuberculosis symptoms, reasonably increase the screening frequency of students in high-burden areas of tuberculosis in Shanghai, and collect students’ previous history of tuberculosis exposure. When screening close contacts, after excluding active tuberculosis, it is recommended that TST and IGRA should be combined to determine latent Mycobacterium tuberculosis infection and achieve accurate intervention.
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Objective:To study the correlation between type 2 innate lymphocyte (ILC2) and Treg/Th17 ratio in the peripheral blood of patients at different stages of Mycobacterium tuberculosis ( Mtb) infection. Methods:This study recruited 30 individuals with active tuberculosis (ATB group), 26 with treated tuberculosis (RTB group), 22 with latent tuberculosis infection (LTBI group) and 17 negative for tuberculin skin test (TST-negative group). Flow cytometry was used to detect the proportion of ILC2 in CD45 + cells, and that of Th17 and Treg cells in CD4 + T lymphocytes in the peripheral blood of patients in each group. Expression of Foxp3 and RORγt at mRNA level was detected by real-time fluorescence quantitative PCR. Pearson method was used to analyze the correlation between Th17 and Treg, and that between ILC2 and Treg/Th17 ratio in the peripheral blood of patients with ATB and RTB. Results:The proportions of ILC2 in RTB and ATB groups were significantly higher than those of LTBI and TST-negative groups, and the proportion of ILC2 in RTB group was significantly higher than that of ATB group ( P<0.05). The proportion of Th17 in RTB group was lower than that of ATB group ( P<0.05), and the proportions of Th17 in ATB and RTB groups were lower than those of LTBI and TST-negative groups. The proportion of Treg in RTB group was lower than that of ATB group ( P<0.05), and close to that of LTBI group and TST-negative group, but the Treg/Th17 ratios in ATB and RTB groups were higher than those of LTBI and TST-negative groups. There was no significant difference in Treg/Th17 ratio between ATB and RTB groups ( P>0.05). The expression of Foxp3 and RORγt at mRNA level and Foxp3/RORγt ratio changed accordingly. Meanwhile, there was no correlation between Th17 and Treg in ATB or RTB group ( r=0.023, P=0.444; r=0.428, P=0.150). There was a positive correlation between ILC2 and Treg/Th17 ratio in ATB group ( r=0.794, P=0.000), while no correlation was found between ILC2 and Treg/Th17 ratio in RTB group ( r=0.197, P=0.297). Conclusions:In this study, the proportion of ILC2 was increased in the peripheral blood of TB patients, and the proportion of ILC2 in RTB group was higher than that of ATB group. In RTB group, Th17 accounted for a low proportion in the peripheral blood and was involved in inflammatory reactions, while Tregs were not involved in inflammatory reactions, but might have a certain inhibitory effect in patients with ATB. Further studies found that Th17-involved inflammatory reactions were not regulated by Tregs. ILC2 was involved in Treg/Th17 imbalance in ATB patients, but not in RTB patients.
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