Efficacy of macozinone in mice with genetically diverse susceptibility to Mycobacterium tuberculosis infection.

Host heterogeneity in pulmonary tuberculosis leads to varied responses to infection and drug treatment. The present portfolio of anti-TB drugs needs to be boosted with new drugs and drug regimens. Macozinone, a clinical-stage molecule targeting the essential enzyme, DprE1, represents an attractive option. Mice (I/St, B6, (AKRxI/St)F1, B6.I-100 and B6.I-139) genetically diverse susceptibility to Mycobacterium tuberculosis (Mtb) H37Rv infection were subjected to aerosol- or intravenous infection to determine the efficacy of macozinone (MCZ). They were treated with macozinone or reference drugs (isoniazid, rifampicin). Lung and spleen bacterial burdens were measured at four and eight weeks post-infection. Lung histology was evaluated at four weeks of treatment. Treatment with macozinone resulted in a statistically significant reduction in the bacterial load in the lungs and spleen as early as four weeks after treatment initiation in mice susceptible or resistant to Mtb infection. In the TB hypoxic granuloma model, macozinone was more potent than rifampicin in reducing the CFU counts. However, histopathological analysis revealed significant lung changes in I/St mice after eight weeks of treatment initiation. Macozinone demonstrated efficacy to varying degrees across all mouse models of Mtb infection used. These results should facilitate its further development and potential introduction into clinical practice.

High-Definition Videobronchoscopy for the Diagnosis of Airway Involvement in Sarcoidosis: The Enhance Sarcoidosis Multicenter Study.

BACKGROUND: The ability of high-definition (HD) videobronchoscopy to detect airway involvement in sarcoidosis has not been evaluated previously. RESEARCH QUESTION: What is the role of HD videobronchoscopy in the identification of sarcoidosis-associated airway abnormalities (AAs)? What are the patterns of AAs more commonly observed and more frequently associated with the detection of granulomas in endobronchial biopsy (EBB)? STUDY DESIGN AND METHODS: In this prospective international multicenter cohort study, consecutive patients with suspected sarcoidosis underwent airway inspection with an HD videobronchoscope and EBB using a standardized workflow. AAs were classified according to six patterns defined a priori: nodularity, cobblestoning, thickening, plaque, increased vascularity, and miscellaneous. We assessed diagnostic yield of EBB, prevalence of AAs, and interobserver agreement for different patterns of AAs. RESULTS: AAs were identified in 64 of 134 patients with sarcoidosis (47.8%), with nodularity (n = 23 [17.2%]), plaque (n = 19 [14.2%]), and increased vascularity (n = 19 [14.2%]) being the most prevalent. The diagnostic yield of EBB was 36.6%. AAs were significantly more prevalent in patients with than in those without nonnecrotizing granulomas on EBB (67.4% vs 36.5%; P = .001). Likewise, parenchymal disease on CT scan imaging was significantly more common in patients with than in those without nonnecrotizing granulomas on EBB (79.6% vs 54.1%; P = .003). On a per-lesion analysis, nonnecrotizing granulomas were seen especially in EBB samples obtained from areas of cobblestoning (9/10 [90%]) and nodularity (17/29 [58.6%]). The overall diagnostic yield of random EBB was low (31/134 [23.1%]). The interobserver agreement for the different patterns of AA was fair (Fleiss κ = 0.34). INTERPRETATION: In a population with a large prevalence of White Europeans, HD videobronchoscopy detected AAs in approximately one-half of patients with sarcoidosis. The diagnostic yield of EBB was higher in patients with parenchymal involvement on CT scan imaging and in those with AAs, especially if manifesting as cobblestoning and nodularity. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT4743596; URL: www. CLINICALTRIALS: gov.

Morphologically, immunohistochemically and PCR proven lymphocytic viral peri-, endo-, myocarditis in patients with fatal COVID-19.

BACKGROUND: Despite a reported cardiac injury in patients with new coronavirus infection, the possibility and specifics of genuine viral myocarditis in COVID-19 remains not fully clear. PURPOSE: To study the presence of SARS-CoV-2 in the myocardium and the morphological properties of myocarditis in patients with severe coronavirus infection (COVID-19). METHODS: Autopsy data of eight elderly patients (75.6 ± 7.4 years), four male and four female, with severe new coronavirus infection were studied. The lifetime diagnosis of COVID-19 is based on a positive result of the PCR study. The inclusion criterion was the presence of morphological signs of myocarditis according to the Dallas criteria. A standard histological examination included staining by hematoxylin and eosin, toluidin blue and Van Gieson. An immunohistochemical study was performed using antibodies to CD3, CD 68, CD20, perforin, toll-like receptor (TLR) types 4 and 9. PCR in real-time was performed to determine the viral RNA in the myocardium. RESULTS: All patients had severe bilateral viral pneumonia. In all cases, myocarditis was not clinically diagnosed. Morphological examination of the heart found signs of active lymphocytic myocarditis. PCR identified the SARS-Cov2 RNA in all cases. There were also signs of destructive coronaritis in all cases, thrombovasculitis, lymphocytic pericarditis (in 3 cases) and endocarditis (in 2 cases). The absence of neutrophils confirms the aseptic nature of inflammation. An immunohistochemical study showed the CD3-positive T lymphocytes in the infiltrates. Increased expression of TLR type 4 and less 9 was also detected. CONCLUSION: Morphological and immunohistochemical evidence of myocarditis in COVID-19 was presented. Lymphocytic infiltrations and positive PCR confirm the viral nature of inflammation. Myocarditis in COVID-19 is also characterized by coronaritis with microvascular thrombosis and associated with lymphocytic endo- and pericarditis.