Primary and secondary nonresponse to infliximab: mechanisms and countermeasures

Introduction: Primary and secondary non-response to infliximab are common in patients with inflammatory bowel disease and remain a management challenge in clinical practice.

Areas covered: This article describes the epidemiology, mechanisms and risk factors for primary and secondary nonresponse to infliximab in patients with inflammatory bowel disease. Data on proactive and reactive therapeutic drug monitoring are examined in this review. An algorithm for evaluation and management of non-response to infliximab is provided. Preventative measures are also discussed. Relevant articles were identified after a literature search using PubMed. Search terms included ‘infliximab’, ‘loss of response’, ‘immunogenicity’, and ‘drug monitoring’. References of identified articles were also reviewed to identify additional references.

Expert opinion: A common cause for primary and secondary non-response include inadequate dosing of infliximab; inadequate dosing can be identified through assessment of drug and anti-drug antibody levels. Therapeutic drug monitoring should be done in patients losing response to infliximab. Use of drug monitoring proactively is still under debate.     

生物技术药物免疫原性评价的技术发展概述

药物的免疫原性是指药物刺激机体形成特异抗体或致敏淋巴细胞的性质。评价非期望的免疫原性是生物技术药物临床前和临床评价的重要内容。免疫原性评价内容包括方法的开发、验证、药物诱导的抗体反应水平检测（滴度）、抗体的特性研究、抗体的中和活性测定、分析抗体产生对疗效、毒性和药动学的影响,并预测对人体潜在的免疫原性强弱。如何提高动物模型的预测性、优化检测技术、实现评价方法的规范化和标准化,是未来免疫原性评价亟需解决的问题。     

单克隆抗体非临床免疫毒性研究的考虑要点

大多数单克隆抗体可诱导免疫反应,免疫毒性是免疫调节类单克隆抗体主要担心的毒性反应。本文总结了单克隆抗体的免疫毒性特征、免疫毒性的相关因素,非临床免疫毒性研究与评价的考虑要点。建议在临床前研究阶段应根据单克隆抗体的作用特征,对药物的免疫毒性进行逐步分层研究,当需要追加试验时,应追加研究;还应体内外研究相结合,动物种属和人体离体细胞相结合,多途径进行研究。     

Vaccinomics: A scoping review

BackgroundThis scoping review summarizes a key aspect of vaccinomics by collating known associations between heterogeneity in human genetics and vaccine immunogenicity and safety.MethodsWe searched PubMed for articles in English using terms covering vaccines routinely recommended to the general US population, their effects, and genetics/genomics. Included studies were controlled and demonstrated statistically significant associations with vaccine immunogenicity or safety. Studies of Pandemrix®, an influenza vaccine previously used in Europe, were also included, due to its widely publicized genetically mediated association with narcolepsy.FindingsOf the 2,300 articles manually screened, 214 were included for data extraction. Six included articles examined genetic influences on vaccine safety; the rest examined vaccine immunogenicity. Hepatitis B vaccine immunogenicity was reported in 92 articles and associated with 277 genetic determinants across 117 genes. Thirty-three articles identified 291 genetic determinants across 118 genes associated with measles vaccine immunogenicity, 22 articles identified 311 genetic determinants across 110 genes associated with rubella vaccine immunogenicity, and 25 articles identified 48 genetic determinants across 34 genes associated with influenza vaccine immunogenicity. Other vaccines had fewer than 10 studies each identifying genetic determinants of their immunogenicity. Genetic associations were reported with 4 adverse events following influenza vaccination (narcolepsy, GBS, GCA/PMR, high temperature) and 2 adverse events following measles vaccination (fever, febrile seizure).ConclusionThis scoping review identified numerous genetic associations with vaccine immunogenicity and several genetic associations with vaccine safety. Most associations were only reported in one study. This illustrates both the potential of and need for investment in vaccinomics. Current research in this field is focused on systems and genetic-based studies designed to identify risk signatures for serious vaccine reactions or diminished vaccine immunogenicity. Such research could bolster our ability to develop safer and more effective vaccines.     

The Pregnancy,Arsenic, and Immune Response (PAIR) Study in rural northern Bangladesh

Background

Arsenic exposure and micronutrient deficiencies may alter immune reactivity to influenza vaccination in pregnant women, transplacental transfer of maternal antibodies to the foetus, and maternal and infant acute morbidity.

Objectives

The Pregnancy, Arsenic, and Immune Response (PAIR) Study was designed to assess whether arsenic exposure and micronutrient deficiencies alter maternal and newborn immunity and acute morbidity following maternal seasonal influenza vaccination during pregnancy.

Population

The PAIR Study recruited pregnant women across a large rural study area in Gaibandha District, northern Bangladesh, 2018–2019.

Design

Prospective, longitudinal pregnancy and birth cohort.

Methods

We conducted home visits to enrol pregnant women in the late first or early second trimester (11–17 weeks of gestational age). Women received a quadrivalent seasonal inactivated influenza vaccine at enrolment. Follow-up included up to 13 visits between enrolment and 3 months postpartum. Arsenic was measured in drinking water and maternal urine. Micronutrient deficiencies were assessed using plasma biomarkers. Vaccine-specific antibody titres were measured in maternal and infant serum. Weekly telephone surveillance ascertained acute morbidity symptoms in women and infants.

Preliminary Results

We enrolled 784 pregnant women between October 2018 and March 2019. Of 784 women who enrolled, 736 (93.9%) delivered live births and 551 (70.3%) completed follow-up visits to 3 months postpartum. Arsenic was detected (≥0.02 μg/L) in 99.7% of water specimens collected from participants at enrolment. The medians (interquartile ranges) of water and urinary arsenic at enrolment were 5.1 (0.5, 25.1) μg/L and 33.1 (19.6, 56.5) μg/L, respectively. Water and urinary arsenic were strongly correlated (Spearman's ⍴ = 0.72) among women with water arsenic ≥ median but weakly correlated (⍴ = 0.17) among women with water arsenic < median.

Conclusions

The PAIR Study is well positioned to examine the effects of low-moderate arsenic exposure and micronutrient deficiencies on immune outcomes in women and infants. Registration : NCT03930017.     

葡激酶研究进展

葡激酶是由金黄色葡萄球菌分泌的新一代天然的纤溶酶原激活剂,具有高效的溶栓活性和纤维蛋白特异性.进入机体后引起的免疫反应是限制其临床使用的主要原因,近年来生物工程技术的发展为解决这些问题提供了新的重要途径.现将从结构特点、溶栓机制、免疫原性及分子结构改造等方面重点介绍葡激酶的研究进展.     

Phase I clinical trial of O-acetylated pectin conjugate,a plant polysaccharide based typhoid vaccine

Background

Typhoid fever remains an important cause of morbidity and mortality in the developing countries. Vi capsular polysaccharide conjugate vaccine demonstrated safety and efficacy in young children in high endemic regions. A novel typhoid conjugate vaccine based on plant polysaccharide pectin was studied in a phase I trial.

Methods

Fruit pectin, having the same carbohydrate backbone structure as Vi, was purified from citrus peel and used as the polysaccharide source to prepare a semi-synthetic typhoid conjugate vaccine. Pectin was chemically O-acetylated (OAcPec) to antigenically resemble Vi and conjugated to carrier protein rEPA, a recombinant exoprotein A from Pseudomonas aeruginosa. 25 healthy volunteers, 18–45 years old, were injected once with OAcPec-rEPA. Safety and IgG antibodies reactive with Vi and pectin were analyzed.

Results

No vaccine associated serious adverse reaction was reported. Six weeks after the injection of OAcPec-rEPA, 64% of the volunteers elicited >4-fold rise of anti-Vi IgG. At 26 weeks the level declined, but the difference between the levels at 6 and 26 weeks are not statistically significant. There is a direct correlation between the level of anti-Vi IgG before and after the injection (R² = 0.96). The anti-Vi IgG can be absorbed by Vi, but not by pectin. There was no corresponding increase of anti-pectin after the injection, indicating the antibody response to OAcPec-rEPA was specific to Vi. There is no Vi-rEPA data in US adults for comparison of immune responses. The OAcPec-rEPA elicited significantly less IgG anti-Vi in US adults than those by Vi-rEPA in Vietnamese adults.

Conclusion

The O-acetylated pectin conjugate, a plant based typhoid vaccine, is safe and immunogenic in adult volunteers.ClinicalTrial.gov identifier: NCT00277147, NIH Protocol ID number: OH06-CH-0070, FDA BB Investigation New Drug (IND) number 6989.     

The immunogenicity of cells derived from induced pluripotent stem cells

With their ability to undergo unlimited self-renewal in culture and to differentiate into all cell types in the body, human embryonic stem ceils （hESCs） hold great potential for the treatment of currently incurable diseases. Two hESC-based cell therapies for spinal cord injury and macular degeneration have been advanced into human clinical trials. Despite this rapid progress, one key challenge of hESC-based cell therapy is the allogeneic immune rejection of hESC-derived cells by recipients. This problem could be mitigated by a recent breakthrough in the technology of induced pluripotent stem cells （iPSCs） by nuclear reprogramming of patient-specific somatic cells with defined factors, which could become a renewable source of autologous ceils for cell therapy. However, recent studies revealing the abnormal epigenetics, genomic stability and immunogenicity of iPSCs have raised safety concerns over iPSC-based therapy. Recent findings related to the immunogenicity of iPSC derivatives will be summarized in this review.     

High expression and frequently humoral immune response of melanoma-associated antigen D4 in glioma

MAGE-D4 is a novel member of MAGE super-family. It has preliminarily been demonstrated that MAGE-D4 mRNA is not expressed in majority of normal tissues except for brain and ovary in which only trace amount of MAGE-D4 mRNA can be detected, but predominantly expressed in glioma. MAGE-D4 protein expression and its immunogenicity in glioma have not been elucidated well. This study was designed to analyze MAGE-D4 expression both at mRNA and protein level, characteristic of humoral immune response, and their relationships with glioma patients’ clinicopathological parameters. Recombinant MAGE-D4 protein and antiserum were generated. Quantitative RT-PCR analysis revealed that MAGE-D4 mRNA expression was overall up-regulated in 41 glioma specimens compared with that in 14 normal brain tissues. Immunohistochemistry analysis showed that 78% (21/27) glioma tissues expressed MAGE-D4 protein, which was predominantly located in the cytoplasm of tumor cells, but absent in any neuroglia cell of normal brain tissues. ELISA analysis demonstrated that humoral response against MAGE-D4 was detected in 17% (7/41) of glioma patients’ sera but not in 77 healthy donors. No apparent correlation was observed between the expression and immunogenicity of MAGE-D4 with clinicopathological parameters of glioma. In summary, these results indicate that MAGE-D4 is highly expressed in glioma and can develop specifically humoral response in glioma patients, which supports that it may be a promising biomarker for glioma diagnosis and immunotherapy.     

Cancer testis antigens – their importance in immunotherapy and in the early detection of cancer

The development of successful immunotherapeutic strategies requires the identification and characterisation of immunogenic cancer antigens that will be recognised by the host immune system, leading to tumour rejection. The concept of immunotherapy is based on the assumption that antigenic structures expressed in tumours can be used for therapeutic approaches employing the autologous immune system or by the application of immunotherapeutic reagents. Based on this concept, there is a great need to gain profound knowledge of the actual protein/antigen expression and its distribution pattern within normal tissues and cancerous tissues. Cancer testis (CT) antigens represent a unique class of tumour antigens, which are expressed in a variety of cancerous tissues and are silent in normal tissues, except for the testis. Owing to their restricted gene expression in the testis and various malignancies, CT antigens represent potential defined targets for antigen-based vaccination and antigen-directed immunotherapy to control cancer growth. Moreover, the analysis of humoral and cellular immune responses to CT antigens has proved useful for identifying novel cancer serum biomarkers with potential implications in early diagnosis of cancer.