COVID-19 and BCG vaccine: is there a link?

The spread of the novel coronavirus infection (COVID-19) makes the search for new approaches to prevent the infection of great importance. As one of the relevant approaches, the vaccination of risk groups with BCG vaccine has recently been suggested. BCG (Mycobacterium bovis, Bacillus Calmette–Guérin) is a live vaccine for tuberculosis, which is used in many countries with a high tuberculosis prevalence and helps preventing childhood tuberculosis, primarily, military disease and tuberculosis meningitis. Whether BCG may be used to increase the protection against COVID-19 is currently a question of debates. The review considers scientific background underlying possible impact of BCG in increased protection against COVID-19. BCG is able of inducing the heterologous and trained immunity, and its capacity to stimulate antiviral immune response has been demonstrated in experimental animals and humans. Our comparison of the dynamics of COVID-19 morbidity and mortality in countries with different BCG vaccination policies has demonstrated a milder course of COVID-19 (i.e., a slower increase in disease cases and mortality) in countries where BCG vaccination is mandatory for all children. However, an association between BCG vaccination and a milder COVID-19 course is not obligatory direct. Other factors that may affect the association, such as the level of virus testing, the rigidity and the speed of quarantine implementation and others are discussed. An important argument against a role of BCG in the protection against COVID-19 is that BCG is given in childhood and may hardly induce long-lasting immunity. Because mandatory BCG vaccination is implemented in countries with high TB burden and because in these countries latent tuberculosis infection is widely spread, we suggest a hypothesis that latent tuberculosis infection may contribute to the maintenance of heterologous/trained antiviral immunity in countries with mandatory BCG vaccination. Four countries have recently initiated clinical trials to investigate whether BCG vaccination can increase the level of protection against COVID-19 in risk groups. The results of these studies, as well as COVID-19 epidemiological modeling will help understanding the impact of BCG in the level of the protection against COVID-19. Performing analogous clinical trials in Russia seems appropriate and scientifically sound

Dynamic balance of pro‐ and anti‐inflammatory signals controls disease and limits pathology

Immune responses to pathogens are complex and not well understood in many diseases, and this is especially true for infections by persistent pathogens. One mechanism that allows for long‐term control of infection while also preventing an over‐zealous inflammatory response from causing extensive tissue damage is for the immune system to balance pro‐ and anti‐inflammatory cells and signals. This balance is dynamic and the immune system responds to cues from both host and pathogen, maintaining a steady state across multiple scales through continuous feedback. Identifying the signals, cells, cytokines, and other immune response factors that mediate this balance over time has been difficult using traditional research strategies. Computational modeling studies based on data from traditional systems can identify how this balance contributes to immunity. Here we provide evidence from both experimental and mathematical/computational studies to support the concept of a dynamic balance operating during persistent and other infection scenarios. We focus mainly on tuberculosis, currently the leading cause of death due to infectious disease in the world, and also provide evidence for other infections. A better understanding of the dynamically balanced immune response can help shape treatment strategies that utilize both drugs and host‐directed therapies.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146448/1/imr12671.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146448/2/imr12671_am.pd

Exposure to the Epstein-Barr viral antigen latent membrane protein 1 induces myelin-reactive antibodies in vivo

© 2017 Lomakin, Arapidi, Chernov, Ziganshin, Tcyganov, Lyadova, Butenko, Osetrova, Ponomarenko, Telegin, Govorun, Gabibov and Belogurov. Multiple sclerosis (MS) is an autoimmune chronic inflammatory disease of the central nervous system (CNS). Cross-reactivity of neuronal proteins with exogenous antigens is considered one of the possible mechanisms of MS triggering. Previously, we showed that monoclonal myelin basic protein (MBP)-specific antibodies from MS patients cross-react with Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1). In this study, we report that exposure of mice to LMP1 results in induction of myelin-reactive autoantibodies in vivo. We posit that chronic exposure or multiple acute exposures to viral antigen may redirect B cells from production of antiviral antibodies to antibodies, specific to myelin antigen. However, even in inbred animals, which are almost identical in terms of their genomes, such an effect is only observed in 20-50% of animals, indicating that this change occurs by chance, rather than systematically. Cross-immunoprecipitation analysis showed that only part of anti-MBP antibodies from LMP1-immunized mice might simultaneously bind LMP1. In contrast, the majority of anti-LMP1 antibodies from MBP-immunized mice bind MBP. De novo sequencing of anti-LMP1 and anti-MBP antibodies by mass spectrometry demonstrated enhanced clonal diversity in LMP1-immunized mice in comparison with MBP-immunized mice. We suggest that induction of MBP-reactive antibodies in LMP1-immunized mice may be caused by either Follicular dendritic cells (FDCs) or by T cells that are primed by myelin antigens directly in CNS. Our findings help to elucidate the still enigmatic link between EBV infection and MS development, suggesting that myelin-reactive antibodies raised as a response toward EBV protein LMP1 are not truly cross-reactive but are primarily caused by epitope spreading

How “Humane” Is Your Endpoint?—Refining the Science-Driven Approach for Termination of Animal Studies of Chronic Infection

Public concern on issues such as animal welfare or the scientific validity and clinical value of animal research is growing, resulting in increasing regulatory demands for animal research. Abiding to the most stringent animal welfare standards, while having scientific objectives as the main priority, is often challenging. To do so, endpoints of studies involving severe, progressive diseases need to be established considering how early in the disease process the scientific objectives can be achieved. We present here experimental studies of tuberculosis (TB) in mice as a case study for an analysis of present practice and a discussion of how more refined science-based endpoints can be developed. A considerable proportion of studies in this field involve lethal stages, and the establishment of earlier, reliable indicators of disease severity will have a significant impact on animal welfare. While there is an increasing interest from scientists and industry in moving research in this direction, this is still far from being reflected in actual practice. We argue that a major limiting factor is the absence of data on biomarkers that can be used as indicators of disease severity. We discuss the possibility of complementing the widely used weight loss with other relevant biomarkers and the need for validation of these parameters as endpoints. Promotion of ethical guidelines needs to be coupled with systematic research in order to develop humane endpoints beyond the present euthanasia of moribund animals. Such research, as we propose here for chronic infection, can show the way for the development and promotion of welfare policies in other fields of research. Research on chronic infection relies heavily on the use of animals, as only the integral animal body can model the full aspect of an infection. That animals are generally made to develop a disease in infection studies exacerbates the tension between human benefit and animal well-being, which characterizes all biomedical research with animals. Scientists typically justify animal research with reference to potential human benefits, but if accepting the assumption that human benefits can offset animal suffering, it still needs to be argued that the same benefits could not be achieved with less negative effects on animal welfare. Reducing the animal welfare problems associated with research (“refinement” [1]) is therefore crucial in order to render animal-based research less of an ethical problem and to assure public trust in research. Studies that are designed to measure time of death or survival percentages present a particularly challenging situation in which at least some of the animals are made to die from the disease. These studies are frequent in experimental research on severe infections. The scientific community, industry, and regulatory authorities have responded to the ethical concerns over studies in which animals die from severe disease by developing new policies and guidelines for the implementation of humane endpoints as a key refinement measure (e.g., [2]–[4]). The most widely used definition considers a humane endpoint to be the earliest indicator in an animal experiment of severe pain, severe distress, suffering, or impending death [5], underlining that ideally such indicators should be identified before the onset of the most severe effects. Euthanizing animals, rather than awaiting their “spontaneous” death, is important to avoid unnecessary suffering in studies in which data on survival is thought to be required for scientific or legal reasons. However, several questions remain open regarding how humane endpoints are to be applied to address real animal welfare problems. We used TB experiments in mice as a case study to highlight the potential to establish biomarkers of disease progress that can replace survival time as a measure of disease severity.Fundação para a Ciência e Tecnologia (SFRH/BD/38337/2007)

Clinical isolates of the modern Mycobacterium tuberculosis lineage 4 evade host defense in human macrophages through eluding IL-1\u3b2-induced autophagy article

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), has infected over 1.7 billion people worldwide and causes 1.4 million deaths annually. Recently, genome sequence analysis has allowed the reconstruction of Mycobacterium tuberculosis complex (MTBC) evolution, with the identification of seven phylogeographic lineages: four referred to as evolutionarily "ancient", and three "modern". The MTBC strains belonging to "modern" lineages appear to show enhanced virulence that may have warranted improved transmission in humans over ancient lineages through molecular mechanisms that remain to be fully characterized. To evaluate the impact of MTBC genetic diversity on the innate immune response, we analyzed intracellular bacterial replication, inflammatory cytokine levels, and autophagy response in human primary macrophages infected with MTBC clinical isolates belonging to the ancient lineages 1 and 5, and the modern lineage 4. We show that, when compared to ancient lineage 1 and 5, MTBC strains belonging to modern lineage 4 show a higher rate of replication, associated to a significant production of proinflammatory cytokines (IL-1\u3b2, IL-6, and TNF-\u3b1) and induction of a functional autophagy process. Interestingly, we found that the increased autophagic flux observed in macrophages infected with modern MTBC is due to an autocrine activity of the proinflammatory cytokine IL-1\u3b2, since autophagosome maturation is blocked by an interleukin-1 receptor antagonist. Unexpectedly, IL-1\u3b2-induced autophagy is not disadvantageous for the survival of modern Mtb strains, which reside within Rab5-positive phagosomal vesicles and avoid autophagosome engulfment. Altogether, these results suggest that autophagy triggered by inflammatory cytokines is compatible with a high rate of intracellular bacilli replication and may therefore contribute to the increased pathogenicity of the modern MTBC lineages

An Interferon-Related Signature in the Transcriptional Core Response of Human Macrophages to Mycobacterium tuberculosis Infection

The W-Beijing family of Mycobacterium tuberculosis (Mtb) strains is known for its high-prevalence and -virulence, as well as for its genetic diversity, as recently reported by our laboratories and others. However, little is known about how the immune system responds to these strains. To explore this issue, here we used reverse engineering and genome-wide expression profiling of human macrophage-like THP-1 cells infected by different Mtb strains of the W-Beijing family, as well as by the reference laboratory strain H37Rv. Detailed data mining revealed that host cell transcriptome responses to H37Rv and to different strains of the W-Beijing family are similar and overwhelmingly induced during Mtb infections, collectively typifying a robust gene expression signature (“THP1r2Mtb-induced signature”). Analysis of the putative transcription factor binding sites in promoter regions of genes in this signature identified several key regulators, namely STATs, IRF-1, IRF-7, and Oct-1, commonly involved in interferon-related immune responses. The THP1r2Mtb-induced signature appeared to be highly relevant to the interferon-inducible signature recently reported in active pulmonary tuberculosis patients, as revealed by cross-signature and cross-module comparisons. Further analysis of the publicly available transcriptome data from human patients showed that the signature appears to be relevant to active pulmonary tuberculosis patients and their clinical therapy, and be tuberculosis specific. Thus, our results provide an additional layer of information at the transcriptome level on mechanisms involved in host macrophage response to Mtb, which may also implicate the robustness of the cellular defense system that can effectively fight against genetic heterogeneity in this pathogen

Токсичность и эффективность комбинации гемцитабина и nab-паклитаксела (паклитаксел + альбумин) в Российской популяции больных раком поджелудочной железы: результаты многоцентрового ретроспективного исследования

Introduction. The results of randomized MPACT study have demonstrated that the addition of nab-paclitaxel to gemcitabine leads to a statistically significant increase in life expectancy. The main objective of this retrospective study was to obtain up-to-date efficacy and toxicity data for this drug combination in Russian real-world clinical setting.Materials and methods. The study enrolled patients with morphologically confirmed locally advanced or metastatic pancreatic cancer who had ECOG Performance Status scores of 0-2 and received treatment with gemcitabine and nab-paclitaxel. Immediate and long-term outcomes, as well as treatment toxicity and dose modifications, were assessed.Results. The study included 142 patients who received treatment from 2009 to 2019 at 17 centers in 11 regions of Russia. Full dose gemcitabine and nab-paclitaxel were administered at baseline in 74 % of the cases. The median number of chemotherapy cycles was 4 (range, from 1 to 16). Nab-paclitaxel dose was reduced in 32 % of the cases, and that of gemcitabine in 23 % of them. Regression analysis revealed no prognostic factors associated with increased toxicity of gemcitabine and nab-paclitaxel administration. However, previous use of two or more chemotherapy lines had an impact on decisions made by physicians, making them reduce the baseline dose of gemcitabine and/or nab-paclitaxel (OR=6.1, 95% CI 1.5-24.2, р=0.010). An objective response was assessed in 134 subjects with positive response observed in 34 cases (25.4 %). The median time to progression was found to be 6.1 months, and the median life expectancy was 14.2 months.Conclusions. The combination of gemcitabine and nab-paclitaxel exhibits comparatively high efficacy. The acceptable toxicity profile allows its use in selected patients even with ECOG 2 and in the presence of serious comorbidities.Введение. Результаты рандомизированного исследования MPACT продемонстрировали, что добавление к гемцитабину nab-паклитаксела приводит к статистически значимому увеличению продолжительности жизни. Задачей данного ретроспективного исследования является получение актуальных данных об эффективности и токсичности данной комбинации в реальной клинической практике в России.Материалы и методы. В исследование включались пациенты с морфологически доказанным местнораспространенным или метастатическим раком поджелудочной железы, имеющие общее состояние по шкале ECOG 0-2, которым проводилась терапия гемцитабином и nab-паклитакселом. Оценивались непосредственные и отдаленные результаты лечения, а также токсичность лечения и модификации доз препаратов.Результаты. В исследование включено 142 пациента, получивших лечение в период с 2009 по 2019 гг. в 17 центрах из 11 регионов России. Гемцитабин и nab-паклитаксел назначались исходно в полных дозах в 74% случаев. Медиана числа проведенных курсов химиотерапии составила 4 (1-16 курсов). В процессе химиотерапии доза nab-паклитаксела редуцировалась в 32 % случаев, гемцитабина — в 23 % случаев. Регрессионный анализ не выявил прогностических факторов, ассоциированных с повышенной токсичностью гемцитабина и nab-паклитаксела. Однако назначение ранее двух или более линий химиотерапии влияло на решение врачей в пользу исходной редукции дозы гемцитабина и/ или nab-паклитаксела (ОШ=6,1, 95 % ДИ 1,5-24,2, р=0,010). Оценка объективного эффекта произведена у 134 пациентов. Объективный ответ зарегистрирован в 34 (25,4%) случаях. Медиана времени без прогрессирования составила 6,1 месяца, медиана продолжительности жизни составила 14,2 месяца.Выводы. Комбинация гемцитабина и nab-паклитаксела обладает сравнительно высокой эффективностью. Приемлемый профиль токсичности позволяет применять ее у отобранных пациентов даже при статусе ECOG 2 и наличии серьезной сопутствующей патологии

Сравнение эффективности и токсичности афлиберцепта и бевацизумаба в комбинации с режимом FOLFIRI во 2‑й линии лечения пациентов с метастатическим раком толстой кишки: ретроспективный анализ многоцентрового исследования

Objective: to compare the efficacy and toxicity of aflibercept and bevacizumab in combination with fOLfIRI in secondline therapy for patients with metastatic colon cancer.Materials and methods. we performed a retrospective analysis of data on patients with metastatic colon cancer treated in 9 clinics in the Russian federation. The inclusion criteria were as follows: metastatic or locally advanced colon cancer; treatment with bevacizumab or aflibercept plus fOLfIRI in the second-line therapy. The primary outcome measure was progression-free survival (PfS). Secondary outcome measures included objective response rate and incidence of adverse events.Results. A total of 271 patients with metastatic colon cancer who received second-line therapy with bevacizumab (n = 81) or aflibercept (n = 190) between 2014 and 2018 were selected for this study. Study groups were matched for main prognostic signs. The objective response rate was 18.1 % in the bevacizumab group and 20.5 % in the aflibercept group (p = 0.7). The median PfS was 5 months (95 % confidence interval 3.8–6.1) in the aflibercept group and 7 months (95 % confidence interval 0.81–2.1) in the bevacizumab group (hazard ratio 1.4; 95 % confidence interval 0.99–2.1; p = 0.04). multivariate regression analysis demonstrated that the type of the targeted drug independently had no effect on PfS (hazard ratio 1.3; 95 % confidence interval 0.9–1.9; p = 0.2). we observed no statistically significant differences in the incidence of complications of any grades between the groups (58 % vs 72 %, p = 0.1). Patients receiving aflibercept were more likely to develop grade III–Iv arterial hypertension (2 % vs 9.5 %) and diarrhea (0 % vs 5.4 %), whereas thrombotic complications were more common in the bevacizumab group (10 % vs 1.8 %).Conclusion. we observed no significant differences in objective response rate and PfS between patients with metastatic colon cancer receiving bevacizumab or aflibercept in combination with fOLfIRI as second-line therapy. The toxicity profiles were different. Our findings can be used for choosing an optimal targeted drug for second-line treatment.Цель исследования – сравнение эффективности и токсичности афлиберцепта и бевацизумаба в комбинации с режимом fOLfIRI во 2-й линии лечения пациентов с метастатическим раком толстой кишки.Материалы и методы. Проведен ретроспективный анализ базы данных пациентов с метастатическим раком толстой кишки в рамках наблюдательного исследования работы 9 клиник РФ. Критерии включения в исследование: больные метастатическим или местно-распространенным раком толстой кишки; проведение терапии с включением бевацизумаба или афлиберцепта в комбинации с режимом fOLfIRI во 2-й линии лечения. Основной критерий эффективности – выживаемость без прогрессирования (ВбП). дополнительные критерии: частота объективных эффектов, частота развития нежелательных явлений.Результаты. Отобран 271 пациент с метастатическим раком толстой кишки, которым в 2014–2018 гг. проводилась 2-я линия терапия с включением бевацизумаба (n = 81) и афлиберцепта (n = 190). группы статически значимо не различались по основным прогностическим признакам. частота объективных эффектов составила 18,1 % в группе бевацизумаба и 20,5 % в группе афлиберцепта (р = 0,7). медиана ВбП составила 5 мес (95 % доверительный интервал 3,8–6,1) в группе афлиберцепта и 7 мес (95 % доверительный интервал 0,81–2,1) в группе бевацизумаба (отношение рисков 1,4; 95 % доверительный интервал 0,99–2,1; р = 0,04). многофакторный регрессионный анализ не подтвердил независимого влияния характера таргетного препарата на ВбП (отношение рисков 1,3; 95 % дИ 0,9–1,9; р = 0,2). Не отмечено статистически значимых различий в частоте развития осложнений всех степеней (58 % против 72 %, р = 0,1); среди негематологических осложнений артериальная гипертензия III–Iv степени (2 % против 9,5 %) и диарея (0 % против 5,4 %) чаще наблюдались в группе афлиберцепта, тромботические осложнения чаще наблюдались в группе бевацизумаба (10 % против 1,8 %).Выводы. Не отмечено статистически значимых различий между бевацизумабом и афлиберцептом в сочетании с режимом fOLfIRI во 2-й линии терапии пациентов с метастатическим раком толстой кишки ни в отношении достижения объективного эффекта, ни в отношении ВбП. Профили токсических реакций были различными. Полученные данные можно учитывать при выборе таргетного препарата во 2-й линии терапии