Objectives The value of QuantiFERON-TB Gold In-Tube (QFT-GIT) in the diagnosis of TB varies by population, comorbidities, and other factors. In this study, we aimed to investigate factors that influence false-negative results of QFT-GIT test in the diagnosis of TB as well as the impact of different cutoffs on the diagnostic value. Methods A total of 3562 patients who underwent QFT-GIT tests at Shanghai Pulmonary Hospital were enrolled retrospectively between May 2016 and May 2017. False-negative and false-positive results were analyzed using different clinical stratifications. The optimal cutoff values were established under different clinical conditions. Results Positive QFT-GIT results greatly shortened the time taken to diagnose smear-negative TB. The factors of age, smear and culture results, site of TB, comorbidity with tumors, white blood cell count, neutrophil count, and CD4/CD8 ratio were significantly correlated with false-negative QFT-GIT results (p < 0.05). Personalized cutoff values were established according to different influencing factors. The results showed high consistency between the smear-negative and total populations. Conclusion QFT-GIT can facilitate the early diagnosis of smear-negative TB. The diagnostic performance of the QFT-GIT test in the diagnosis of active TB was shown to be affected by many clinical factors. Personalized cutoff values may have superior value in the identification of active tuberculosis under different conditions.

Bedaquiline (BDQ) has gradually become a core drug in drug-resistant tuberculosis (DR-TB) treatment, and the additional benefits of prolonging BDQ use remain unclear. Patients with DR-TB who received a BDQ-containing regimen from three Chinese clinical centers between 1 March 2018 and 31 December 2021 were retrospectively analyzed. Treatment outcomes and adverse drug reactions were compared between 6-month and prolonged BDQ treatment group before and after adjustment by propensity score matching (PSM). A total of 160 patients were enrolled, 72 patients were treated with BDQ for 6 months, and 88 patients were over 6 months, of which the median duration was 9 months (IQR: 8–11 months). After PSM adjustment, there were no significant differences in treatment outcome between the prolonged groups (7–9, 10−12, >12 months) and the 6-month group (all P > 0.05). A total of 35 patients met the criteria for BDQ prolongation but did not receive it, resulting in a success rate of 60%, significantly lower than the prolonged group (78.4%, P = 0.038); however, after adjustment by PSM, there was no statistically significance ( P > 0.05). The median treatment duration (23 months, IQR: 18.50–25.00 months) was significantly longer than the prolonged group (18 months, IQR: 15.00–20.25 months, P < 0.001). Additionally, two deaths occurred in the prolonged group, and none in the 6-month group. The cause of death in one patient was adjudicated as anti-TB treatment-related, while the other one was considered not. There were no significant differences in the effectiveness and safety between 6-month and prolonged group, it’s still recommended to prolong BDQ use under close monitoring when anti-TB drugs are insufficient to form an effective treatment regimen. Prolonged use of BDQ achieved similar treatment outcomes while potentially shortening the overall anti-TB duration. IMPORTANCE: This real-world retrospective cohort study provides critical evidence on the extended application of Bedaquiline (BDQ) in managing drug-resistant tuberculosis (DR-TB). To date, the effectiveness and safety data regarding prolonged BDQ treatment are still lacking, and the additional benefits of prolonged BDQ use remain unclear. Our findings notably demonstrate that prolonged use of BDQ can achieve similar treatment success rates while potentially shortening the overall anti-TB treatment duration. We conclude that when the anti-TB drugs are insufficient to form an effective treatment regimen, prolonged BDQ use with rigorous safety monitoring is recommended. Our study significantly advances the evidence base for prolonged use of BDQ in clinical practice.

This study aimed to analyze the differences in lymphocyte subsets and immune function between tuberculosis (TB) and nontuberculous mycobacterial pulmonary disease (NTM-PD), thereby deepening the understanding of the pathogenesis of these diseases and providing important insights for clinical diagnosis, treatment, and prognosis evaluation. Patients with pulmonary imaging abnormalities admitted to the Tuberculosis Department of Shanghai Pulmonary Hospital from January 2023 to December 2023 were included. Based on diagnostic assessments, they were categorized into active tuberculosis (ATB), NTM-PD, and other pulmonary diseases (including inflammatory and neoplastic lung diseases). Flow cytometry was used to detect lymphocyte subset counts. (1) There were no significant differences in lymphocyte subset counts between the ATB and NTM groups; however, both groups showed marked differences when compared with the group of patients with other respiratory diseases. Specifically, the percentages and absolute counts of CD3⁺ T cells, CD4⁺ T cells, CD8⁺ T cells, and CD19⁺ B cells were significantly lower in the ATB and NTM groups, whereas the levels of CD16⁺56⁺ natural killer (NK) cells were higher compared to those with other respiratory diseases.(2) Patients in the non-severe ATB (nSATB) group exhibited higher levels of CD3⁺ T cells and CD19⁺ B cells compared to those in the severe ATB (SATB) group.(3) Among patients with ATB, those with concomitant diabetes had lower CD8⁺ T cell counts and percentages, as well as a higher CD4/CD8 ratio, compared to those without diabetes.(4) In patients with NTM-PD, those with severe disease had lower percentages of CD16⁺56⁺ NK cells than those with non-severe NTM-PD.(5) No significant differences in lymphocyte subset parameters were observed between drug-resistant and drug-sensitive ATB patients, or between patients with rapidly growing and slowly growing NTM species. This study revealed the lymphocyte subset characteristics of patients with TB and NTM infections and identified potential associations between disease severity, diabetes comorbidities, and immune cell subsets with disease status. These findings provide a basis for further research on the immune mechanisms of infectious pulmonary diseases and contribute to the development of precision medicine strategies.