A polo-like kinase inhibitor identified by computational repositioning attenuates pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease with few effective therapeutic options. Recently, drug repositioning, which involves identifying novel therapeutic potentials for existing drugs, has been popularized as a new approach for the development of novel therapeutic reagents. However, this approach has not yet been fully utilized in the field of pulmonary fibrosis. METHODS: The present study identified novel therapeutic options for pulmonary fibrosis using a systematic computational approach for drug repositioning based on integration of public gene expression signatures of drug and diseases (in silico screening approach). RESULTS: Among the top compounds predicted to be therapeutic for IPF by the in silico approach, we selected BI2536, a polo-like kinase (PLK) 1/2 inhibitor, as a candidate for treating pulmonary fibrosis using an in silico analysis. However, BI2536 accelerated mortality and weight loss rate in an experimental mouse model of pulmonary fibrosis. Because immunofluorescence staining revealed that PLK1 expression was dominant in myofibroblasts while PLK2 expression was dominant in lung epithelial cells, we next focused on the anti-fibrotic effect of the selective PLK1 inhibitor GSK461364. Consequently, GSK461364 attenuated pulmonary fibrosis with acceptable mortality and weight loss in mice. CONCLUSIONS: These findings suggest that targeting PLK1 may be a novel therapeutic approach for pulmonary fibrosis by inhibiting lung fibroblast proliferation without affecting lung epithelial cells. In addition, while in silico screening is useful, it is essential to fully determine the biological activities of candidates by wet-lab validation studies.

Type A thymoma: a rare cause of neoplastic cardiac tamponade with long-term survival.

BACKGROUND: The prognosis of thymoma with cardiac tamponade is generally poor. Most of the reported thymomas with cardiac tamponade were type B or type AB (mixed thymoma), and cardiac tamponade due to type A thymoma, which has a better prognosis compared to type B thymoma, is extremely rare. CASE PRESENTATION: We encountered a case of cardiac tamponade in a 71-year-old male. He visited our emergency department due to exacerbation of fatigue and dyspnea on exertion that lasted for two weeks. Chest imaging revealed a large amount of pericardial fluid and a contrast-enhanced tumor with calcification in the anterior mediastinum. The patient underwent thoracoscopic tumor biopsy and pathological examinations revealed type A thymoma. In this case, long-term disease-free survival (7.5 years) was achieved by multidisciplinary treatment (preoperative chemotherapy, surgical excision, and postoperative radiation therapy), in accordance with the histological type. CONCLUSIONS: This case indicates that neoplastic cardiac tamponade, even in elderly patients, should not necessarily be regarded as a terminal cancer and requires a systematic investigation for underlying causes.

Blockade of Pan-Fibroblast Growth Factor Receptors Mediates Bidirectional Effects in Lung Fibrosis.

FGFs (fibroblast growth factors) are major factors associated with the pathogenesis of pulmonary fibrosis. On the one hand, nintedanib, a tyrosine kinase inhibitor targeting several growth factor receptors, including the FGF receptor (FGFR), has been approved for the treatment of idiopathic pulmonary fibrosis. On the other hand, recent reports suggest that FGFs are required for epithelial recovery. In this study, we focused on FGF signaling to both fibroblasts and alveolar epithelial cells (AECs), and we examined the effect of a pan-FGFR blocker on experimental pulmonary fibrosis in mice. The effects of BGJ398, a pan-FGFR inhibitor, on the migration and proliferation of fibroblasts and AECs were assessed using Transwell migration or [3H]thymidine incorporation assays. The expression of FGFR was analyzed using IB or flow cytometry. We also investigated the effect of BGJ398 on pulmonary fibrosis induced by bleomycin in mice. Both lung fibroblasts and AECs expressed FGFRs. BGJ398 significantly inhibited the proliferation and migration of lung fibroblasts stimulated with FGF2. BGJ398 also reduced the proliferation of AECs in response to FGF2. Although the administration of BGJ398 ameliorated pulmonary fibrosis in bleomycin-treated mice, it increased mortality resulting from alveolar injury and inhibition of AEC regeneration. These data suggest that the total inhibition of FGFR signaling can suppress lung fibrosis by inhibiting fibroblast activities, although alveolar injury is simultaneously caused.

The Tyrosine Kinase Inhibitor TAS-115 Attenuates Bleomycin-induced Lung Fibrosis in Mice.

The signaling pathways of growth factors, including platelet-derived growth factor, can be considered specific targets for overcoming the poor prognosis of idiopathic pulmonary fibrosis. Nintedanib, the recently approved multiple kinase inhibitor, has shown promising antifibrotic effects in patients with idiopathic pulmonary fibrosis; however, its efficacy is still limited, and in some cases, treatment discontinuation is necessary owing to toxicities such as gastrointestinal disorders. Therefore, more effective agents with less toxicity are still needed. TAS-115 is a novel multiple tyrosine kinase inhibitor that preferably targets platelet-derived growth factor receptor (PDGFR), vascular endothelial growth factor receptor, and c-FMS in addition to other molecules. In this study, we evaluated the antifibrotic effect of TAS-115 on pulmonary fibrosis in vitro and in vivo. TAS-115 inhibited the phosphorylation of PDGFR on human lung fibroblast cell line MRC-5 cells and suppressed their platelet-derived growth factor-induced proliferation and migration. Furthermore, TAS-115 inhibited the phosphorylation of c-FMS, a receptor of macrophage colony-stimulating factor, in murine bone marrow-derived macrophages and decreased the production of CCL2, another key molecule for inducing pulmonary fibrosis, under the stimulation of macrophage colony-stimulating factor. Importantly, the inhibitory effects of TAS-115 on both PDGFR and c-FMS were 3- to 10-fold higher than those of nintedanib. In a mouse model of bleomycin-induced pulmonary fibrosis, TAS-115 significantly inhibited the development of pulmonary fibrosis and the collagen deposition in bleomycin-treated lungs. These data suggest that strong inhibition of PDGFR and c-FMS by TAS-115 may be a promising strategy for overcoming the intractable pathogenesis of pulmonary fibrosis.

The novel inhibitor PRI-724 for Wnt/ß-catenin/CBP signaling ameliorates bleomycin-induced pulmonary fibrosis in mice.

Purpose/Aim of the Study: Wnt/ß-catenin signaling was reported to be activated in pulmonary fibrosis, and was focused on as a target for antifibrotic therapy. However, the mechanism how the inhibition of Wnt/ß-catenin signaling ameliorate pulmonary fibrosis has not been fully elucidated. The purpose of this study is to explore the target cells of Wnt/ß-catenin inhibition in pulmonary fibrosis and to examine the antifibrotic effect of the novel inhibitor PRI-724 specifically disrupting the interaction of ß-catenin and CBP. Materials and Methods: The effect of C-82, an active metabolite of PRI-724, on the expression of TGF-ß1 and α-smooth muscle actin (SMA) was examined on fibroblasts and macrophages. We also examined the effects of PRI-724 in mouse model of bleomycin-induced pulmonary fibrosis. Results: The activation and increased accumulation of ß-catenin in the canonical pathway were detected in lung fibroblasts as well as macrophages stimulated by Wnt3a using Western blotting. Treatment with C-82 reduced CBP protein and increased p300 protein binding to ß-catenin in the nucleus of lung fibroblasts. In addition, C-82 inhibited the expression of SMA in lung fibroblasts treated with TGF-ß, indicating the inhibition of myofibroblast differentiation. In the fibrotic lungs induced by bleomycin, ß-catenin was stained strongly in macrophages, but the staining of ß-catenin in alveolar epithelial cells and fibroblasts was weak. The administration of PRI-724 ameliorated pulmonary fibrosis induced by bleomycin in mice when administered with a late, but not an early, treatment schedule. Analysis of bronchoalveolar fluid (BALF) showed a decreased number of alveolar macrophages. In addition, the level of TGF-ß1 in BALF was decreased in mice treated with PRI-724. C-82 also inhibited the production of TGF-ß1 by alveolar macrophages. Conclusions: These results suggest that the ß-catenin/CBP inhibitor PRI-724 is a potent antifibrotic agent that acts by modulating the activity of macrophages in the lungs.

Disseminated tuberculosis after pregnancy progressed to paradoxical response to the treatment: report of two cases.

BACKGROUND: Early postpartum women are more likely to develop tuberculosis than nonpregnant women mainly due to immune reconstitution after delivery. Paradoxical response (PR) during antituberculosis treatment also arises via recovery from immunosuppression. However, no study focused on PR during antituberculosis treatment in a postpartum patient has been reported. CASE PRESENTATION: We present two sequential cases (Patient 1: 26-year-old; Patient 2: 29-year-old) of postpartum tuberculosis with pulmonary and extrapulmonary lesions (Patient 1: peritonitis; Patient 2: psoas abscess secondary to spondylitis). Both cases progressed to PR (worsening of pre-existing lung infiltrations (Patients 1, 2) and new contralateral effusion (Patient 2)) in a relatively short time after initiation of treatment (Patient 1: 1 week; Patient 2: 3 weeks), suggesting that immune modulations during pregnancy and delivery may contribute to the pathogenesis of both disseminated tuberculosis and its PR. The pulmonary lesions and effusion of both cases gradually improved without change of chemotherapy regimen. CONCLUSION: Physicians should recognize PR in tuberculosis patients with postpartum and then evaluate treatment efficacy.

A novel BRD4 degrader, ARV-825, attenuates lung fibrosis through senolysis and antifibrotic effect.

BACKGROUND: Recent studies suggest that cellular senescence is related to the pathogenesis of idiopathic pulmonary fibrosis. However, cellular senescence has yet to be targeted therapeutically in clinical practice. ARV825, a recently developed BRD4 degrader, has been reported as a novel senolytic drug. Conversely, it has also been reported that BRD4 regulates the pro-fibrotic gene expression of fibroblasts. Therefore, this study focuses on the senolytic and anti-fibrotic effects of ARV825 and evaluated these effects on lung fibrosis. METHODS: Lung fibroblasts were induced to senescence through serial passage. The expression of senescence markers and pro-fibrotic markers were determined through quantitative PCR or immunoblot analysis. Lung fibrosis was induced in mice through intratracheal administration of bleomycin. Mice treated with ARV825 underwent histological analysis of lung fibrosis using the Ashcroft score. Total lung collagen was quantified through a hydroxyproline assay. Respiratory mechanics analysis was performed using the flexiVent system. RESULTS: For senescent cells, ARV825 induced the expression of an apoptosis marker while reducing the expression of BRD4 and senescence markers. On the other hand, for early passage pre-senescent cells, ARV825 reduced the expression of collagen type 1 and α-smooth muscle actin. In an experimental mouse model of lung fibrosis, ARV825 attenuated lung fibrosis and improved lung function. Immunohistochemical staining revealed a significant decrease in the number of senescent alveolar type 2 cells in lung tissue due to ARV825 treatment. CONCLUSIONS: These results suggest that ARV825 may impact the progressive and irreversible course of fibrotic lung diseases.

Immune checkpoint inhibitor-related pneumonitis with atypical radiologic features in a patient with anti-aminoacyl-tRNA synthetase antibody.

A man with non-small-cell lung cancer who was negative for anti-nuclear antibodies was admitted for dyspnea after immune checkpoint inhibitor (ICI) administration. Computed tomography (CT) showed complexed radiologic features, including subpleural and basal predominant reticular shadow with cystic structures and peribronchovascular consolidation. Although we treated him with high-dose steroid under a diagnosis of ICI-related pneumonitis, he developed acute exacerbation of pneumonitis with progressive fibrosis and volume loss. A re-evaluation identified anti-aminoacyl-tRNA synthetase antibody in the serum collected before ICI administration. This case highlights the importance of re-evaluating pre-existing autoimmune disorders in patients who develop ICI-related pneumonitis with atypical radiologic features.

The lymphocyte-specific protein tyrosine kinase-specific inhibitor A-770041 attenuates lung fibrosis via the suppression of TGF-ß production in regulatory T-cells.

BACKGROUND: Lymphocyte-specific protein tyrosine kinase (Lck) is a member of the Src family of tyrosine kinases. The significance of Lck inhibition in lung fibrosis has not yet been fully elucidated, even though lung fibrosis is commonly preceded by inflammation caused by infiltration of T-cells expressing Lck. In this study, we examined the effect of Lck inhibition in an experimental mouse model of lung fibrosis. We also evaluated the effect of Lck inhibition on the expression of TGF-ß1, an inhibitory cytokine regulating the immune function, in regulatory T-cells (Tregs). METHODS: Lung fibrosis was induced in mice by intratracheal administration of bleomycin. A-770041, a Lck-specific inhibitor, was administrated daily by gavage. Tregs were isolated from the lung using a CD4+CD25+ Regulatory T-cell Isolation Kit. The expression of Tgfb on Tregs was examined by flow cytometry and quantitative polymerase chain reaction. The concentration of TGF-ß in bronchoalveolar lavage fluid (BALF) and cell culture supernatant from Tregs was quantified by an enzyme-linked immunosorbent assay. RESULTS: A-770041 inhibited the phosphorylation of Lck in murine lymphocytes to the same degree as nintedanib. A-770041 attenuated lung fibrosis in bleomycin-treated mice and reduced the concentration of TGF-ß in BALF. A flow-cytometry analysis showed that A-770041 reduced the number of Tregs producing TGF-ß1 in the lung. In isolated Tregs, Lck inhibition by A-770041 decreased the Tgfb mRNA level as well as the concentration of TGF-ß in the supernatant. CONCLUSIONS: These results suggest that Lck inhibition attenuated lung fibrosis by suppressing TGF-ß production in Tregs and support the role of Tregs in the pathogenesis of lung fibrosis.

Lysophosphatidic acid, ceramide 1-phosphate and sphingosine 1-phosphate in peripheral blood of patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial pneumonias. Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are signaling lipids that evoke growth factor-like responses to many cells. Recent studies revealed the involvement of LPA and S1P in the pathology of IPF. In this study, we determined LPA, S1P and ceramide 1-phosphate (C1P) in peripheral blood plasma of IPF patients, and examined correlation to the vital capacity of lung (VC), an indicator of development of fibrosis. Blood plasma samples were taken from eleven patients with IPF and seven healthy volunteers. The lipids of the sample were extracted and subjected to liquid chromatography-tandem mass spectrometry for analysis. Results showed that there is a significant negative correlation between VC and plasma LPA levels, indicating that IPF patients with advanced fibrosis had higher concentration of LPA in their plasma. Average of S1P levels were significantly higher in IPF patients than those in healthy subjects. Although it is not statistically significant, a similar correlation trend that observed in LPA levels also found between VC and S1P levels. These results indicated that plasma LPA and S1P may be associated with deterioration of pulmonary function of IPF patients. J. Med. Invest. 69 : 196-203, August, 2022.

Retroperitoneal hemorrhage in a patient with coronavirus disease 2019 (COVID-19):A case report.

INTRODUCTION: Early prophylactic administration of anticoagulants is recommended in patients with coronavirus disease 2019 (COVID-19). A case of retroperitoneal hemorrhage during inpatient treatment for COVID-19 is reported. CASE PRESENTATION: A 69-year-old man was diagnosed with COVID-19 6 days after symptom onset. After admission for difficulty of breathing, he was treated with steroid pulse therapy, remdesivir, and heparin sodium. On day 16 after admission, his hemoglobin and blood pressure dropped. Computed tomography showed a left retroperitoneal hematoma and multiple areas of extravasation in bilateral iliopsoas muscles. Anticoagulation therapy was stopped, and blood transfusion therapy was chosen by considering poor general condition caused by severe pneumonia. On day 19, the hemoglobin and blood pressure improved, and blood transfusion was stopped. However, he died on day 25 due to pneumonia. CONCLUSION: When retroperitoneal hemorrhage occurs as a complication of COVID-19, appropriate treatment decision, transcatheter arterial embolization or conservative treatment, should be chosen based on patient's condition. J. Med. Invest. 69 : 148-151, February, 2022.

Lenvatinib-induced Interstitial Pneumonia in a Patient with Hepatocellular Carcinoma.

Lenvatinib is a multi-targeted tyrosine kinase inhibitor available for the treatment of unresectable hepatocellular carcinoma (HCC). We herein report an 84-year-old-man with interstitial pneumonia caused by lenvatinib. Four months after the start of lenvatinib administration for HCC, chest computed tomography revealed bilateral ground-glass opacity. However, he continued to take lenvatinib for four more months until he complained of dyspnea on exertion. This is a case of lenvatinib-induced interstitial pneumonia that progressed relatively slowly with a long asymptomatic period despite the appearance of pneumonia on image findings.

Radiation-associated Angiosarcoma Presenting as Massive Pleural Effusion.

A 67-year-old man was admitted to our hospital for massive pleural effusion. He had a history of mandibular gingival carcinoma treated with radiation therapy (RT). Based on the cytology findings of pleural effusion and a thoracoscopic pleural biopsy, we finally diagnosed him with radiation-associated angiosarcoma. Retrospective cell-block immunocytochemistry with pleural effusion also showed potential utility for the diagnosis. This case highlights the importance of considering the possibility of radiation-associated secondary cancer in patients with pleural effusion who have a history of RT.

Development of improved method to identify and analyze lung fibrocytes with flow cytometry in a reporter mouse strain.

INTRODUCTION: Fibrocytes are emerging myeloid-derived circulating cells that can migrate into damaged tissues and usually contribute to their repair. Key features of fibrocytes include the expression myeloid markers, production of extracellular matrix proteins, and secretion of various humoral factors that activate resident fibroblasts; they also have the potential to differentiate into fibroblasts. However, no specific surface markers have been identified to identify fibrocytes in vivo. One reason could be that the method used to detect fibrocytes requires intracellular collagen staining. METHODS: In the present study, to establish an improved method for the detection of lung fibrocytes and to analyze viable fibrocytes, we used collagen I(α)2-green fluorescent protein (Col-GFP) reporter mice, which had undergone the intratracheal instillation of bleomycin (BLM). RESULTS: Using flow cytometry to gate out cells with autofluorescence, we clearly found that CD45+ GFP+  cells resided in the lungs of Col-GFP mice at a steady state and these cells increased after BLM injury, peaking at Day 14. These cells expressed not only known cell surface markers of fibrocytes, but also some novel markers, in addition to a low level of collagen I in comparison to CD45- GFP+  cells. CONCLUSION: Our findings suggest that the improved method can be a useful for the detection of pure lung fibrocytes and allows us to further analyze the characteristics of viable fibrocytes.

Functional analysis of human fibrocytes derived from monocytes reveals their profibrotic phenotype through paracrine effects.

Fibrocytes, which are bone marrow-derived collagen-producing cells, were reported to play a role in the pathogenesis of pulmonary fibrosis. However, their function in pulmonary fibrosis is unclear. We analyzed their function compared with that of monocytes and localization in fibrotic tissues in patients with idiopathic pulmonary fibrosis (IPF). We compared the gene expression profile of monocyte-derived fibrocytes with that of monocytes by microarray analysis. Proliferation and differentiation into myofibroblasts were examined by 3H-thymidine incorporation assay and Western blotting. We measured the level of growth factors in the culture supernatant of fibrocytes by ELISA. The localization of fibrocytes in lung tissues of patients with IPF was determined by immunofluorescence staining. Compared with monocytes, fibrocytes had higher expression of extracellular matrix- and growth factor-encoding genes, including PDGF-B, FGF-2 and VEGF-B. Although fibrocytes did not proliferate in response to PDGF, co-culture of fibrocytes stimulated the growth of lung fibroblasts through the production of PDGF-BB. In the lung of IPF patients, CD45+Collagen-I+FSP-1+ cells, which have a similar phenotype to fibrocytes, were detected and co-stained with anti-PDGF antibody. This study suggested that fibrocytes function in pulmonary fibrosis partly by producing PDGF in the lungs of IPF patients. J. Med. Invest. 67 : 102-112, February, 2020.

Distinct improvement of pulmonary function, ground-glass opacity, hypoxia and physical findings in an idiopathic pulmonary fibrosis patient after pirfenidone treatment : a case report with a review of the literature.

Background : Pirfenidone (PFD), an anti-fibrosis drug for idiopathic pulmonary fibrosis (IPF), suppresses disease progression and delays decline of forced vital capacity. However, this drug rarely makes marked improvement of pulmonary function, chest high-resolution computed tomography (HRCT) findings and hypoxia. Case presentation : A 59 year-old-man, who was a former smoker and had a history of alcoholic liver cirrhosis, developed exertional dyspnea and was referred to our hospital. HRCT showed honeycomb changes with surrounding ground-glass opacity (GGO) in a predominantly basal and subpleural distribution. He was diagnosed with IPF and the treatment with PFD was started. At 16 months after the start of treatment, the predicted forced vital capacity value markedly improved from 82.9% to 98.6%. His resting-state partial pressure of arterial oxygen while breathing room air increased from a minimum of 54.7 mmHg (at 2 months treatment) to 72.5 mmHg. The GGO observed at diagnosis disappeared in HRCT. But after 32 months of treatment, his general condition got worse gradually, and he died from chronic progression of IPF after 48 months of treatment. Conclusion : Our case suggests that a complication of chronic liver disease and the existence of GGO may be characteristics of super-responder to PFD treatment for IPF patients. J. Med. Invest. 67 : 358-361, August, 2020.

Clinical features of interstitial pneumonia associated with systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) commonly affects the lungs. However, the incidence of interstitial pneumonia (IP) related to SLE was reported to be about 10%, less than in the case of other connective tissue diseases, and the mechanism via which IP is related to SLE remains to be elucidated. METHODS: We retrospectively reviewed the medical records and high-resolution computed tomography (HRCT) images of 69 SLE patients who were admitted to our hospital between January 2011 and December 2015. RESULTS: Fifty-five of the patients were female (80%), and the mean age at the onset of SLE was 42.4 years. IP developed in 20 patients (29%), 14 of whom were female (70%), and the mean age at SLE onset was 53.4 years, significantly older than those without IP (38.0 years) (p = 0.003). Half of the patients were found to have IP during the initial diagnosis of SLE. The IP pattern on the HRCT images was consistent with that of usual interstitial pneumonia (UIP) in 25% of the patients and of nonspecific interstitial pneumonia (NSIP) in 55%. One patient exhibited acute exacerbation but survived. The radiological findings revealed that the disease progressed slowly in most of the patients; however, pulmonary function was retained. No significant differences were observed in the survival rates between patients with and without IP. CONCLUSION: In SLE cases, IP primarily occurred in male and elderly patients. In addition to the NSIP pattern, the UIP pattern was evident on HRCT scans of IP-related SLE. The survival of SLE patients was unrelated to IP.

Development, validation, and comparison of gene analysis methods for detecting EGFR mutation from non-small cell lung cancer patients-derived circulating free DNA.

The feasibility and required sensitivity of circulating free DNA (cfDNA)-based detection methods in second-line epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment are not well elucidated. We examined T790M and other activating mutations of EGFR by cfDNA to assess the clinical usability. In 45 non-small cell lung cancer (NSCLC) patients harboring activating EGFR mutations, cfDNAs were prepared from the plasma samples. EGFR mutations in cfDNA were detected using highly sensitive methods and originally developed assays and these results were compared to tissue-based definitive diagnoses. The specificity of each cfDNA-based method ranged 96-100% whereas the sensitivity ranged 56-67%, indicating its low pseudo-positive rate. In EGFR-TKI failure cohort, 41-46% samples were positive for T790M by each cfDNA-based method, which was comparable to re-biopsy tissue-based T790M positive rates in literature. The concordance of the results for each EGFR mutation ranged from 83-95%. In eight patients, the results of the cfDNA-based assays and re-biopsy-derived tissue-based test were compared. The observed overall agreement ranged in 50-63% in T790M, and in 63-100% in activating EGFR mutations. In this study, we have newly developed three types of assay which have enough sensitivity to detect cfDNA. We also detected T790M in 44% of patients who failed prior EGFR-TKI treatment, indicating that cfDNA-based assay has clinical relevance for detecting acquired mutations of EGFR.

Primary Gingival Tuberculosis Diagnosed Based on Genetic Identification.

A case of primary gingival tuberculosis in a 71-year-old Japanese woman is herein presented. A serous saliva culture was positive for tuberculosis, and we recognized that the origin of the tuberculosis infection was the gingiva based on the genetic identification in gingival biopsy tissue. The definitive diagnosis was facilitated by the genetic identification, a useful modern tool for diagnosing infectious diseases. The location and clinical presentation of this lesion were unusual, which underlines the importance of considering tuberculosis in the differential diagnosis of oral lesions that affect the gingiva.