Distinct immunopathological mechanisms of EBV-positive and EBV-negative posttransplant lymphoproliferative disorders

EBV-positive and EBV-negative posttransplant lymphoproliferative disorders (PTLDs) arise in different immunovirological contexts and might have distinct pathophysiologies. To examine this hypothesis, we conducted a multicentric prospective study with 56 EBV-positive and 39 EBV-negative PTLD patients of the K-VIROGREF cohort, recruited at PTLD diagnosis and before treatment (2013–2019), and compared them to PTLD-free Transplant Controls (TC, n = 21). We measured absolute lymphocyte counts (n = 108), analyzed NK- and T cell phenotypes (n = 49 and 94), and performed EBV-specific functional assays (n = 16 and 42) by multiparameter flow cytometry and ELISpot-IFNγ assays (n = 50). EBV-negative PTLD patients, NK cells overexpressed Tim-3; the 2-year progression-free survival (PFS) was poorer in patients with a CD4 lymphopenia (CD4⁺<300 cells/mm³, p <  .001). EBV-positive PTLD patients presented a profound NK-cell lymphopenia (median = 60 cells/mm³) and a high proportion of NK cells expressing PD-1 (vs. TC, p = .029) and apoptosis markers (vs. TC, p < .001). EBV-specific T cells of EBV-positive PTLD patients circulated in low proportions, showed immune exhaustion (p = .013 vs. TC) and poorly recognized the N-terminal portion of EBNA-3A viral protein. Altogether, this broad comparison of EBV-positive and EBV-negative PTLDs highlight distinct patterns of immunopathological mechanisms between these two diseases and provide new clues for immunotherapeutic strategies and PTLD prognosis.     

COVID-19 in solid organ transplant recipients: A national cohort study from Sweden

Solid organ transplant (SOT) recipients run a high risk for adverse outcomes from COVID-19, with reported mortality around 19%. We retrospectively reviewed all known Swedish SOT recipients with RT-PCR confirmed COVID-19 between March 1 and November 20, 2020 and analyzed patient characteristics, management, and outcome. We identified 230 patients with a median age of 54.0 years (13.2), who were predominantly male (64%). Most patients were hospitalized (64%), but 36% remained outpatients. Age >50 and male sex were among predictors of transition from outpatient to inpatient status. National early warning Score 2 (NEWS2) at presentation was higher in non-survivors. Thirty-day all-cause mortality was 9.6% (15.0% for inpatients), increased with age and BMI, and was higher in men. Renal function decreased during COVID-19 but recovered in most patients. SARS-CoV-2 antibodies were identified in 78% of patients at 1–2 months post-infection. Nucleocapsid-specific antibodies decreased to 38% after 6–7 months, while spike-specific antibody responses were more durable. Seroprevalence in 559 asymptomatic patients was 1.4%. Many patients can be managed on an outpatient basis aided by risk stratification with age, sex, and NEWS2 score. Factors associated with adverse outcomes include older age, male sex, greater BMI, and a higher NEWS2 score.     

COVID-19 in pediatric kidney transplantation: The Improving Renal Outcomes Collaborative

There are limited data on the impact of COVID-19 in children with a kidney transplant (KT). We conducted a prospective cohort study through the Improving Renal Outcomes Collaborative (IROC) to collect clinical outcome data about COVID-19 in pediatric KT patients. Twenty-two IROC centers that care for 2732 patients submitted testing and outcomes data for 281 patients tested for SARS-CoV-2 by PCR. Testing indications included symptoms and/or potential exposures to COVID-19 (N = 134, 47.7%) and/or testing per hospital policy (N = 154, 54.8%). Overall, 24 (8.5%) patients tested positive, of which 15 (63%) were symptomatic. Of the COVID-19-positive patients, 16 were managed as outpatients, six received non-ICU inpatient care and two were admitted to the ICU. There were no episodes of respiratory failure, allograft loss, or death associated with COVID-19. To estimate incidence, subanalysis was performed for 13 centers that care for 1686 patients that submitted all negative and positive COVID-19 results. Of the 229 tested patients at these 13 centers, 10 (5 asymptomatic) patients tested positive, yielding an overall incidence of 0.6% and an incidence among tested patients of 4.4%. Pediatric KT patients in the United States had a low estimated incidence of COVID-19 disease and excellent short-term outcomes.     

Letermovir in lung transplant recipients with cytomegalovirus infection: A retrospective observational study

Letermovir is a new antiviral drug approved for the prophylaxis of CMV infection in allogeneic stem cell transplants. The aim of the study was to assess the therapeutic efficacy of letermovir in difficult to treat CMV infections in lung transplant recipients. All lung transplant recipients between March 2018 and August 2020, who have been treated with letermovir for ganciclovir-resistant or refractory CMV infection were included in the study and analysed retrospectively. In total, 28 patients were identified. CMV disease was present in 15 patients (53.6%). In 23 patients (82.1%), rapid response was noticed, and CMV-viral load could be significantly decreased (>1 log₁₀) after a median of 17 [14–27] days and cleared subsequently in all of these patients. Five patients (17.9%) were classified as non-responder. Thereof, development of a mutation of the CMV UL56 terminase (UL-56-Gen: C325Y) conferring letermovir resistance could be observed in three patients (60%). Common side effects were mild and mostly of gastrointestinal nature. Mild adjustments of the immunosuppressive drugs were mandatory upon treatment initiation with letermovir. In addition to other interventions, letermovir was effective in difficult to treat CMV infections in lung transplant recipients. However, in patients with treatment failure mutation conferring letermovir, resistance should be taken into account.     

基质金属蛋白酶类水平与抗结核药物性导致肝损伤的相关性分析CSCD

目的:分析抗结核药物导致的肝损伤(anti-tuberculosis drug-induced liver injury,ATB-DILI)患者基质金属蛋白酶类(matrix metalloproteinases,MMP)水平及其相关性。方法:采用回顾性研究方法,收集2019年6月至2020年6月昆明市第三人民医院收治的肺结核患者中发生ATB-DILI的98例患者作为病例组;选取同期门诊健康体检者30名作为对照组。采集研究对象晨起空腹静脉血6 ml,采用双抗体夹心法检测其MMP-1、MMP-2、MMP-7、MMP-9、MMP-13、MMP-14浓度。病例组研究对象根据ATB-DILI临床分型分为肝细胞损伤型(A组)、胆汁淤积型(B组)、肝血管损伤型(C组)、混合型(D组);根据ATB-DILI严重程度分为0级(无肝损伤)、1级(轻度肝损伤)、2级(中度肝损伤)、3级(重度肝损伤)、4级(急性肝功能衰竭)、5级(致命)。比较不同临床分型组及对照组研究对象MMP水平;分析MMP水平与ATB-DILI严重程度分级相关性。结果:按照ATB-DILI临床分型,病例组中A组有51例,B组有12例,C组有15例,D组有20例;根据ATB-DILI严重程度分级,病例组中1级有33例,2级有27例,3级有22例,4级有14例,5级有2例。A、B、C、D组及对照组MMP-1浓度分别为:(89.1±11.2)ng/ml、(32.3±6.3)ng/ml、(47.5±9.1)ng/ml、(55.2±11.1)ng/ml、(27.5±8.2)ng/ml;MMP-2浓度分别为:(8.2±2.1)ng/ml、(6.2±2.3)ng/ml、(15.5±1.8)ng/ml、(7.2±1.6)ng/ml、(3.2±1.3)ng/ml;MMP-9浓度分别为:36.1(25.9,47.3)ng/ml、11.3(5.1,20.6)ng/ml、14.1(6.1,21.3)ng/ml、15.3(3.8,28.1)ng/ml、6.4(2.8,8.6)ng/ml;MMP-14浓度分别为:5.2(2.8,7.5)ng/ml、6.0(3.6,8.9)ng/ml、11.2(5.2,17.4)ng/ml、4.0(1.8,6.2)ng/ml、2.8(1.4,4.3)ng/ml。A组MMP-1和MMP-9浓度明显升高,C组MMP-2和MMP-14浓度明显升高,差异均有统计学意义(F=7.983,P=0.031;H=9.979,P=0.041;F=9.381,P=0.010;H=10.555,P=0.032)。ATB-DILI严重程度1、2、3、4、5级患者MMP-9浓度分别为:16.2(13.2,19.3)ng/ml、21.5(18.4,23.6)ng/ml、24.3(20.6,27.1)ng/ml、30.3(25.1,35.3)ng/ml、38.5(33.9,43.1)ng/ml,与严重程度分级呈正相关(r=0.882,P=0.000)。结论:不同临床分型ATB-DILI患者MMP-1、MMP-2、MMP-9、MMP-14浓度有不同程度升高;MMP-9浓度与ATB-DILI严重程度呈正相关;MMP水平可能为ATB-DILI发生的影响因素。     

A Theoretical Model for the Margination of Particles within Blood Vessels

The margination of a particle circulating in the blood stream has been analyzed. The contribution of buoyancy, hemodynamic forces, van der Waals, electrostatic and steric interactions between the circulating particle and the endothelium lining the vasculature has been considered. For practical applications, the contribution of buoyancy, hemodynamic forces and van der Waals interactions should be only taken into account, whilst the effect of electrostatic and steric repulsion becomes important only at very short distances from the endothelium (1–10 nm). The margination speed and the time for margination t_s have been estimated as a function of the density of the particle relative to blood , the Hamaker constant A and radius R of the particle. A critical radius R_c exists for which the margination time t_s has a maximum, which is influenced by both and A: the critical radius decreases as the relative density increases and the Hamaker constant decreases. Therefore, particles used for drug delivery should have a radius smaller than the critical value (in the range of 100 nm) to facilitate margination and interaction with the endothelium. While particles used as nanoharvesting agents in proteomics or genomics analysis should have a radius close to the critical value to minimize margination and increase their circulation time.     

7-取代-1-取代-6,8-二氟-1,4-二氢-4-氧-3-喹啉羧酸化合物的合成及其抗菌活性

目的：研究7－取代－2－取代－6,8二氟－1,4－二氢－4－氧－3－喹啉羧酸的合成,体外抗菌活性及其构效关系。方法：通过缩合,Gould-Jacobs环合,亲核取代得到关键中间体,然后通过反应制得目标化合物,选用临床常见致病菌的标准菌株进行体外抗菌活性测定。结果：设计合成26个化合物,其中20个化合物为首次报道,抗菌活性实验以氟罗沙星为对照Ⅲi,Ⅲj和苯环上无取代的化合物Ⅲb1,Ⅲb2的活性比氟罗沙星稍好,特别是化合物Ⅲb2的活性优于氟罗沙星。结论：合成的26个化合物中有一些化合物显示了较好的抗菌活性。其中化合物Ⅲb2的活性优于氟罗沙星,该类化合物值刘进一步研究。     

新型三唑苄胺类化合物体外抗真菌活性及构效关系

目的：研究23个1－[2－（N－甲基－N－取代苄基）氨基－2（2,4－二氟苯基）乙基]－1H－1,2,4－三唑类化合物的体外抗真菌活性,并初步探讨其构效关系。方法：选择8种临床致病真菌为试验菌,观察本类化合物对它们的体外抑菌作用,并与布替萘芬和益康唑作比较。结果和结论：所有目标化合物对8种试验真菌均有不同程度的抑制作用,大部分化合物对白念珠菌和近平滑念珠菌的活性明显高于布替萘芬;化合物2、13对新型隐球菌的活性是益康唑的64－128倍,化合物2、3、13、16对多数真菌显示较强活性。构效关系研究表明,苄胺类和氮唑类化合物的特征结构组合在一起,对某些真菌的抑菌活性起到了取长补短的作用;但苄基为萘苄时,对多数深部真菌活性较差。