[A pathological report of three COVID-19 cases by minimal invasive autopsies]

Objective: To investigate the pathological characteristics and the clinical significance of novel coronavirus (2019-nCoV)-infected pneumonia (termed by WHO as coronavirus disease 2019, COVID-19). Methods: Minimally invasive autopsies from lung, heart, kidney, spleen, bone marrow, liver, pancreas, stomach, intestine, thyroid and skin were performed on three patients died of novel coronavirus pneumonia in Chongqing, China. Hematoxylin and eosin staining (HE), transmission electron microcopy, and histochemical staining were performed to investigate the pathological changes of indicated organs or tissues. Immunohistochemical staining was conducted to evaluate the infiltration of immune cells as well as the expression of 2019-nCoV proteins. Real time PCR was carried out to detect the RNA of 2019-nCoV. Results: Various damages were observed in the alveolar structure, with minor serous exudation and fibrin exudation. Hyaline membrane formation was observed in some alveoli. The infiltrated immune cells in alveoli were majorly macrophages and monocytes. Moderate multinucleated giant cells, minimal lymphocytes, eosinophils and neutrophils were also observed. Most of infiltrated lymphocytes were CD4-positive T cells. Significant proliferation of type Ⅱ alveolar epithelia and focal desquamation of alveolar epithelia were also indicated. The blood vessels of alveolar septum were congested, edematous and widened, with modest infiltration of monocytes and lymphocytes. Hyaline thrombi were found in a minority of microvessels. Focal hemorrhage in lung tissue, organization of exudates in some alveolar cavities, and pulmonary interstitial fibrosis were observed. Part of the bronchial epithelia were exfoliated. Coronavirus particles in bronchial mucosal epithelia and type Ⅱ alveolar epithelia were observed under electron microscope. Immunohistochemical staining showed that part of the alveolar epithelia and macrophages were positive for 2019-nCoV antigen. Real time PCR analyses identified positive signals for 2019-nCoV nucleic acid. Decreased numbers of lymphocyte, cell degeneration and necrosis were observed in spleen. Furthermore, degeneration and necrosis of parenchymal cells, formation of hyaline thrombus in small vessels, and pathological changes of chronic diseases were observed in other organs and tissues, while no evidence of coronavirus infection was observed in these organs. Conclusions: The lungs from novel coronavirus pneumonia patients manifest significant pathological lesions, including the alveolar exudative inflammation and interstitial inflammation, alveolar epithelium proliferation and hyaline membrane formation. While the 2019-nCoV is mainly distributed in lung, the infection also involves in the damages of heart, vessels, liver, kidney and other organs. Further studies are warranted to investigate the mechanism underlying pathological changes of this disease.

First co-infection case of melioidosis and Japanese encephalitis in China

BACKGROUND

Melioidosis is endemic in Southeast Asia and northern Australia. Infection usually follows percutaneous inoculation or inhalation or ingestion of the causative bacterium, Burkholderia pseudomallei, which is present in soil and surface water in endemic regions. Japanese encephalitis (JE) is a vector-borne viral zoonosis caused by Japanese encephalitis virus (JEV), leading to epidemic encephalitis in Southeast Asia. Both B. pseudomallei and JEV have spread dominantly in the Hainan and Guangdong provinces in China. Here we reported the first case of co-infection of B. pseudomallei and JEV, which was discovered in Huizhou in the Guangdong province in June 2016.

CASE PRESENTATION

A 52-year-old man was admitted to the hospital with acute febrile illness and headache, diagnosed as respiratory infection, central nervous system (CNS) infection, septicemia, and hepatic dysfunction. Based on B. pseudomallei-positive blood and cerebrospinal fluid (CSF) cultures, the patient was diagnosed with melioidosis and treated aggressively with antibiotics. However, the patient failed to make a full recovery. Further laboratory tests focused on CNS infection were conducted. The co-infection of B. pseudomallei and JEV was confirmed after the positive IgM antibodies of JEV were detected in both CSF and blood. After diagnosis of co-infection with B. pseudomallei and JEV, the patient was provided supportive care in hospital and recovered after approximately 3 weeks.

CONCLUSION

Given the possibility of co-infection of B. pseudomallei and JEV, as well as variable case presentations, it is critical to enhance the awareness, detection, and treatment of co-infection in regard to melioidosis.

Establishment of a Quantitative Polymerase Chain Reaction Assay for Monitoring Chimeric Antigen Receptor T Cells in Peripheral Blood

BACKGROUND

The chimeric antigen receptor (CAR) consists of an antigen recognition moiety from a monoclonal antibody fused to an intracellular signalling domain capable of activating T cells. The specific structure of the CAR molecule has been used in various basic research and clinical settings to detect CAR expression, but it is necessary to develop more specific and simpler monitoring methods to observe real-time changes.

MATERIALS AND METHODS

To develop a quantitative assay for the universal detection of DNA from anti-CD19 CAR-T cells, a TaqMan real-time quantitative polymerase chain reaction (qPCR) assay was developed using primers based on FMC63-28Z gene sequences. We identified the numbers of copies of CAR gene on T cells transduced with the CAR gene that were obtained from peripheral blood.

RESULTS

The assay had a minimum detection limit of 10 copies/μL and a strong linear standard curve (y = -3.3682x + 38.594; R² = 0.999) within the range of the input CAR gene (10-10⁷ copies/μL). The reproducibility test showed a coefficient of variation ranging from 0.63%-1.65%. Real-time qPCR is a highly sensitive, specific, reproducible, and universal method that can be used to detect anti-CD19 CAR-T cells in peripheral blood.

[The understanding of Epstein-Barr virus associated lymphoproliferative disorder]

In recent years, there are increasing articles concerning Epstein-Barr virus associated lymphoproliferative disorder (EBV+ LPD), and the name of EBV+ LPD is used widely. However, the meaning of EBV+ LPD used is not the same, which triggered confusion of the understanding and obstacles of the communication. In order to solve this problem. Literature was reviewed with combination of our cases to clarify the concept of EBV+ LPD and to expound our understanding about it. In general, it is currently accepted that EBV+ LPD refers to a spectrum of lymphoid tissue diseases with EBV infection, including hyperplasia, borderline lesions, and neoplastic diseases. According to this concept, EBV+ LPD should not include infectious mononucleosis (IM) and severe acute EBV infection (EBV+ hemophagocytic lymphohistiocytosis, fatal IM, fulminant IM, fulminant T-cell LPD), and should not include the explicitly named EBV+ lymphomas (such as extranodal NK/T cell lymphoma, aggressive NK cell leukemia, Burkitt lymphoma, and Hodgkin lymphoma, etc.) either. EBV+ LPD should currently include: (1) EBV+ B cell-LPD: lymphomatoid granulomatosis, EBV + immunodeficiency related LPD, chronic active EBV infection-B cell type, senile EBV+ LPD, etc. (2) EBV+ T/NK cell-LPD: CAEBV-T/NK cell type, hydroa vacciniforme, hypersensitivity of mosquito bite, etc. In addition, EBV+ LPD is classified, based on the disease process, pathological and molecular data, as 3 grades: grade1, hyperplasia (polymorphic lesions with polyclonal cells); grade 2, borderline (polymorphic lesions with clonality); grade 3, neoplasm (monomorphic lesions with clonality). There are overlaps between EBV+ LPD and typical hyperplasia, as well as EBV+ LPD and typical lymphomas. However, the most important tasks are clinical vigilance, early identification of potential severe complications, and treating the patients in a timely manner to avoid serious complications, as well as the active treatment to save lives when the complications happened.

Association of glutathione S-transferase (GST) genetic polymorphisms with treatment outcome of cisplatin-based chemotherapy for advanced non-small cell lung cancer in a Chinese population

The aim of this study was to evaluate the association of GSTM1 null/present, GSTT1 null/present, and GSTP1 IIe105Val polymorphisms with the chemotherapy response and overall survival of advanced NSCLC. Two hundred and sixty-two patients with histologically confirmed advanced NSCLC (inoperable TNM stages IIIA, IIIB, and IV) were enrolled to this hospital-based study between May 2009 and May 2012. The GSTM1 null/present, GSTT1 null/present, and GSTP1 IIe105Val polymorphisms were genotyped by polymerase chain reaction coupled with restriction fragment length polymorphism. A logistic regression analysis revealed a correlation between the null genotype of GSTM1 and improved response to chemotherapy [odds ratio = 1.82; 95% confidence interval (CI) = 1.06-3.14]. Analyses with the Cox proportional hazards model also indicated that the null genotype of GSTM1 was associated with lower risk of death (hazard ratio = 0.40; 95%CI = 0.23-0.69). In conclusion, the null genotype of GSTM1 was found to be correlated with improved response to chemotherapy and lower risk of death in advanced NSCLC patients.

Comparison of the Effect of Vessel Size Imaging and Cerebral Blood Volume Derived from Perfusion MR Imaging on Glioma Grading

BACKGROUND AND PURPOSE

Vascular proliferation is a major criterion for grading gliomas on the basis of histology. Relative cerebral blood volume can provide pathophysiologic information about glioma grading. Vessel size imaging, in some animals, can be used to estimate the microvascular caliber of a glioma, but its clinical use remains unclear. Herein, we aimed to compare the predictive power of relative cerebral blood volume and vessel size imaging in glioma grading, with grading based on histology.

MATERIALS AND METHODS

Seventy patients with glioma participated in the study; 30 patients underwent MR perfusion imaging with a spin-echo sequence and vessel size imaging with a gradient-echo and spin-echo sequence successively at 24-hour intervals before surgery. We analyzed the vessel size imaging values and relative cerebral blood volume of differently graded gliomas. The microvessel parameters were histologically evaluated and compared with those on MR imaging. The cutoff values of vessel size imaging and relative cerebral blood volume obtained from receiver operating characteristic curve analyses were used to predict glioma grading in another 40 patients.

RESULTS

Vessel size imaging values and relative cerebral blood volume were both increased in high-grade gliomas compared with low-grade gliomas (P < .01). Moreover, vessel size imaging values had higher specificity and sensitivity in differentiating high-grade from low-grade gliomas compared with relative cerebral blood volume. In addition, a significant correlation was observed between vessel size imaging values and microvessel diameters (r > 0.8, P < .05) and between relative cerebral blood volume and microvessel area (r = 0.6579, P < .05). Most important, the use of vessel size imaging cutoff values to predict glioma grading was more accurate (100%) than use of relative cerebral blood volume (85%) values.

CONCLUSIONS

Vessel size imaging can provide more accurate information on glioma grading and may serve as an effective biomarker for the prognosis of patients with gliomas.

Lysine-specific demethylase 1 promotes the stemness and chemoresistance of Lgr5(+) liver cancer initiating cells by suppressing negative regulators of β-catenin signaling

Cancer initiating cells (CICs) are responsible for the unrestrained cell growth and chemoresistance of malignant tumors. Histone demethylation has been shown to be crucial for self-renewal/differentiation of stem cells, but it remains elusive whether lysine-specific demethylase 1 (LSD1) regulates the stemness properties of CICs. Here we report that the abundant expression of leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) is associated with the progression of hepatocellular carcinoma (HCC). Lgr5(+) HCC cells behave similarly to CICs and are highly tumorigenic and resistant to chemotherapeutic agents. Importantly, Lgr5(+) cells express higher levels of LSD1, which in turn regulates Lgr5 expression and promotes the self-renewal and drug resistance of Lgr5(+) CICs. Mechanistically, LSD1 promotes β-catenin activation by inhibiting the expression of several suppressors of β-catenin signaling, especially Prickle1 and APC in Lgr5(+) CICs, by directly regulating the levels of mono- and di-methylation of histone H3 lysine-4 at the promoters of these genes. Furthermore, LSD1-associated activation of the β-catenin signaling is essential for maintaining the activity of Lgr5(+) CICs. Together, our findings unravel the LSD1/Prickle1/APC/β-catenin signaling axis as a novel molecular circuit regulating the stemness and chemoresistance of hepatic Lgr5(+) CICs and provide potential targets to improve chemotherapeutic efficacies against HCC.