Biological agents and tuberculosis: risk estimates and screening strategies

Advances in molecular mechanisms of interaction between Mycobacterium tuberculosis and lung cancer: a narrative review

Objective

We systematically review the molecular mechanism of the interaction between lung cancer (LC) and tuberculosis (TB), and put forward the existing problems in order to provide suggestions for early intervention and future research direction.

Background

TB and LC are two global public health problems affecting human health. LC is the main cause of cancer-related death worldwide and TB is one of the leading causes of death among infectious diseases, especially in resource-poor areas. Previous studies have suggested that a history of TB may be associated with an increased risk of LC. With the improvement of LC treatment, the occurrence of pulmonary tuberculosis in the course of LC treatment is also frequently reported recently.

Methods

The molecular immunological mechanisms of interaction between LC and TB, and related epidemiological literature are reviewed. The research progress and problems to be solved are summarized.

Conclusions

Chronic inflammation, immune abnormalities, scar formation, gene mutations and drug effects caused by TB may be associated with the occurrence of LC induced by abnormalities in various molecular pathways. LC and decreased immunity during treatment may also increase the risk of latent TB activation or new TB infection through immune pathways. Data on dual burden areas of TB and LC are still lacking, and more clinical studies are needed to elucidate the association.

Features of indeterminate results of QuantiFERON-TB Gold In-Tube test in patients with haematological malignancies

Background and aims

The application of QuantiFERON-TB Gold in-Tube (QFT-GIT) in patients with haematological malignancies (HMs) has not been well studied. Therefore, we aimed to investigate the features of patients with HMs whose QFT-GIT results were indeterminate.

Methods

This study enrolled patients with HMs for the analysis of QFT-GIT tests and additional 2-year follow-up. The characteristics and predictors of QFT-GIT indeterminate results were identified. Mycobacterium tuberculosis (TB) incidence rate (IR) and incidence rate ratio (IRR) were also investigated.

Results

Of 89 participants, 27 (30.3%) had QFT-GIT indeterminate results. The QFT-GIT indeterminate patients were characterized with the diagnosis of leukaemia (63.0% versus 32.3%, p = 0.044), abnormal white blood count (WBC) (88.9% versus 14.5%, p = 0.001), abnormal lymphocyte percentage (81.5% versus 14.5%, p = 0.001) and lower lymphocyte count (×10⁹/l) (0.5 versus 2.2, p = 0.000) when compared with those with determinate results. Meanwhile, abnormal WBC [odds ratios (OR): 15.18, p = 0.003] and lymphocyte percentage (OR: 6.90, p = 0.033) were predictors of indeterminate results. One patient with the QFT-GIT indeterminate status and high interferon-γ level of negative control result developed active TB with a TB IR of 18.5 per 1000 person-years and an IRR of 0.1 (95% confidence interval, 0.01-0.71) when compared with positive QFT-GIT patients without prophylaxis treatment.

Conclusion

Abnormal ranges of WBC and lymphocyte differential count percentage were independent predictors useful to determine the optimal timing of implementing QFT-GIT test in patients with HMs.

Tuberculosis following programmed cell death receptor-1 (PD-1) inhibitor in a patient with non-small cell lung cancer. Case report and literature review

Immune checkpoint inhibitors (ICIs)-anti-programmed death-1 (PD-1) and their ligands (PD-L1 and PD-L2) have become widely used in the treatment of several malignancies. Many immune-related adverse events (irAEs) have been linked to these agents. Nonetheless, tuberculosis (TB) reactivation during their use is increasingly recognized and reported. Herein, we present a 58-year-old lady with advanced non-small cell lung cancer (NSCLC) ALK-negative, EGFR wild, and PD-L1 immune histochemistry (IHC) strongly positive in 95% of tumor cells, on ongoing treatment with Pembrolizumab as a first-line monotherapy. Our patient presented with 1-week history of productive cough and high-grade fever. Further workup yielded the diagnosis of pulmonary tuberculosis after her Pembrolizumab sixth cycle with positive AFB smear and TB PCR from BAL (rifampin resistance not detected), with negative HIV status. Hence, immunotherapy was held, and patient was commenced on anti-TB regimen. History revealed contact with active TB patient over the past decade, without previous documentation of latent TB or previous TB infection. Her sputum AFB smear remained persistently positive 4 weeks through anti-TB regimen course. Later, the patient was discharged after her sputum was cleared from AFB (two negative sets). In light of pembrolizumab mechanism of action as an immune checkpoint inhibitor, we suspected its implication on reactivating latent TB which was observed in our patient demonstrating features of pulmonary tuberculosis. She was not re-challenged with Pembrolizumab following TB diagnosis.

Comparison of latent tuberculosis infection screening strategies before tumor necrosis factor inhibitor treatment in inflammatory arthritis: IGRA-alone versus combination of TST and IGRA

This study aims to compare the latent tuberculosis infection (LTBI) screening strategy of interferon-gamma release assay (IGRA)-alone and in combination with tuberculin skin tests (TSTs) before the initiation of tumor necrosis factor (TNF) inhibitor treatment in patients with inflammatory arthritis. Between January 2011 and June 2017, we enrolled 476 patients who were followed up for ≥1 year after the TNF inhibitor initiation in a tertiary referral center in South Korea. Inflammatory arthritis comprised rheumatoid arthritis in 266 (55.9%) and ankylosing spondylitis in 210 (44.1%) patients. The following strategies were used for LTBI screening during the study period: (i) from January 2011 to October 2014, the combination of TST and QuantiFERON-TB Gold In-Tube (QFT-GIT); (ii) between November 2014 and February 2015, QFT-GIT-alone and (iii) since March 2015, either the combination of TST and QFT-GIT or QFT-GIT-alone depending on the attending physician's choice. We compared the screening strategies of QFT-GIT alone and in combination with TST. Overall, 338 (71.0%) patients received LTBI screening tests using the combination of TST and QFT-GIT, and 138 (29.0%) received QFT-GIT-alone. In addition, the LTBI tests were positive in 159 (47.0%) of 338 patients using the combination tests, and 43.8% (148/338) required LTBI treatment. Meanwhile, the LTBI tests were positive in 32.6% (45/138) of QFT-GIT-alone patients, and 30.4% (42/138) required LTBI treatment. Among 338 patients who received combination tests, 2 patients developed active tuberculosis within 1 year after the TNF inhibitor initiation. Of patients who received QFT-GIT-alone, no patient developed tuberculosis. In conclusion, among patients who received QFT-GIT-alone, the number of patients who required LTBI treatment declined compared to the TST and QFT-GIT combination, and none developed active tuberculosis within 1 year, suggesting that QFT-GIT-alone could be a potential screening strategy for diagnosing LTBI in patients with inflammatory arthritis in South Korea.