CD4+ T cells in classical Hodgkin lymphoma express exhaustion associated transcription factors TOX and TOX2: Characterizing CD4+ T cells in Hodgkin lymphoma.

In classical Hodgkin lymphoma (cHL), the highly abundant CD4+ T cells in the vicinity of tumor cells are considered essential for tumor cell survival, but are ill-defined. Although they are activated, they consistently lack expression of activation marker CD26. In this study, we compared sorted CD4+CD26- and CD4+CD26+ T cells from cHL lymph node cell suspensions by RNA sequencing and T cell receptor variable gene segment usage analysis. This revealed that although CD4+CD26- T cells are antigen experienced, they have not clonally expanded. This may well be explained by the expression of exhaustion associated transcription factors TOX and TOX2, immune checkpoints PDCD1 and CD200, and chemokine CXCL13, which were amongst the 100 significantly enriched genes in comparison with the CD4+CD26+ T cells. Findings were validated in single-cell RNA sequencing data from an independent cohort. Interestingly, immunohistochemistry revealed predominant and high frequency of staining for TOX and TOX2 in the T cells attached to the tumor cells. In conclusion, the dominant CD4+CD26- T cell population in cHL is antigen experienced, polyclonal, and exhausted. This population is likely a main contributor to the very high response rates to immune checkpoint inhibitors in cHL.

Accuracy of whole genome sequencing versus phenotypic (MGIT) and commercial molecular tests for detection of drug-resistant Mycobacterium tuberculosis isolated from patients in Brazil and Mozambique.

BACKGROUND: The fast and accurate diagnosis of drug-resistant tuberculosis (DR-TB) is critical to reducing the spread of disease. Although commercial genotypic drug-susceptibility tests (DST) are close to the goal, they are still not able to detect all relevant DR-TB related mutations. Whole genome sequencing (WGS) allows better comprehension of DR-TB with a great discriminatory power. We aimed to evaluate WGS in M. tuberculosis isolates compared with phenotypic and genotypic DST. METHODS: This cross-sectional study evaluated 30 isolates from patients with detected DR-TB in Brazil and Mozambique. They were evaluated with phenotypic (MGIT-SIRE™) and genotypic (Xpert-MTB/RIF™, Genotype-MTBDRplus™, and MTBDRsl™) DST. Isolates with resistance to at least one first- or second-line drug were submitted to WGS and analyzed with TB profiler database. RESULTS: WGS had the best performance among the genotypic DST, compared to the phenotypic test. There was a very good concordance with phenotypic DST for rifampicin and streptomycin (89.6%), isoniazid (96.5%) and ethambutol (82.7%). WGS sensitivity and specificity for detection resistance were respectively 87.5 and 92.3% for rifampicin; 95.6 and 100% for isoniazid; 85.7 and 93.3% for streptomycin while 100 and 77.2% for ethambutol. Two isolates from Mozambique showed a Val170Phe rpoB mutation which was neither detected by Xpert-MTB/RIF nor Genotype-MTBDRplus. CONCLUSION: WGS was able to provide all the relevant information about M. tuberculosis drug susceptibility in a single test and also detected a mutation in rpoB which is not covered by commercial genotypic DST.

Evaluation of resistance acquisition during tuberculosis treatment using whole genome sequencing.

Tuberculosis (TB) is still considered a major global public health problem in the world and there is a concern about the worldwide increase of drug-resistance (DR). This paper describes the analysis of three Mycobacterium tuberculosis isolates from a single patient collected over a long treatment period of time. DR was initially investigated through phenotypic testing, followed by line probe assays (LPAs) and whole genome sequencing (WGS). It presents an intriguing situation where a multidrug-resistant (MDR-) TB case was diagnosed and treated based only on late phenotypic drug susceptibility testing of isolate 1. During the treatment, another two isolates were cultivated: isolate 2, nine months after starting MDR-TB treatment; and isolate 3, cultivated five months later, during regular use of anti-TB drugs. These two isolates were evaluated using molecular LPA and WGS, retrospectively. All mutations detected by LPA were also detected in the WGS, including conversion from fluoroquinolones susceptibility to resistance from isolate 2 to isolate 3. WGS showed additional mutations, including some which may confer resistance to other drugs not tested (terizidone/cycloserine) and mutations with no correspondent resistance in drug susceptibility testing (streptomycin and second-line injectable drugs).