Low Circulating Natural Killer Cell Counts are Associated With Severe Disease in Patients With Common Variable Immunodeficiency

Epigenetic immune cell quantification for diagnostic evaluation and monitoring of patients with inborn errors of immunity and secondary immune deficiencies

BACKGROUND

Early detection and monitoring of primary immunodeficiencies (PID) in humans require quantitative determination of immune cells from fresh blood analyzed by flow cytometry. However, epigenetic immune cell quantification allows analysis from fresh, frozen, or dried blood samples. We demonstrate the utility of epigenetic immune cell quantification for patients with PID.

METHODS

Epigenetic quantification of basic lymphocyte subpopulations of 259 samples from PID patients were compared to flow cytometric data. Epigenetic analysis was extended to T-cell subsets (Treg, Th17, Tfh, PD-1+, CCR6+) and memory B-cells and compared between venous EDTA and dried blood.

RESULTS

A high correlation of >0.9 was observed for basic T- and B-cell subsets. Extended epigenetic analysis showed quantitative trends within PID subgroups, but individually these varied substantially within these groups. Epigenetic analysis of dried blood samples was equivalent to EDTA blood.

CONCLUSION

Epigenetic immune cell quantification is suitable for immune cell profiling in PID patients.

A nomogram based on peripheral lymphocyte for predicting 8-year survival in patients with prostate cancer: a single-center study using LASSO-cox regression

PURPOSE

The purpose of this study was to develop a functional clinical nomogram for predicting 8-year overall survival (OS) of patients with prostate cancer (PCa) primary based on peripheral lymphocyte.

PATIENTS AND METHODS

Using data from a single-institutional registry of 94 patients with PCa in China, this study identified and integrated significant prognostic factors for survival to build a nomogram. The discriminative ability was measured by concordance index (C-index) and ROC curves (Receiver Operating Characteristic Curves). And the predictive accuracy was measured by the calibration curves. Decision curve analyses (DCA) was used to measure the clinical usefulness.

RESULTS

A total of 94 patients were included for analysis. Five independent prognostic factors were identified by LASSO-Cox regression and incorporated into the nomogram: age, the T stage, the absolute counts of peripheral CD3(+)CD4(+) T lymphocytes, CD3(-)CD16(+)CD56(+) NK cells and CD4(+)/CD8(+) ratio. The area under the curve (AUC) values of the predictive model for 5-, 8-, and 10-year overall survival were 0.81, 0.76, and 0.73, respectively. The calibration curves for probability of 5-,8- and 10-year OS showed optimal agreement between nomogram prediction and actual observation. The stratification into different risk groups allowed significant distinction. DCA indicated the good clinical application value of the model.

CONCLUSION

We developed a novel nomogram that enables personalized prediction of OS for patients diagnosed with PCa. This finding revealed a relative in age and survival rate in PCa, and a more favorable prognosis in patients exhibiting higher levels of CD4 + T, CD4+/CD8 + ratio and CD3(-)CD16(+)CD56(+) NK cells specifically. This clinically applicable prognostic model exhibits promising predictive capabilities, offering valuable support to clinicians in informed decision-making process.

Peripheral T Cell Populations are Differentially Affected in Familial Mediterranean Fever, Chronic Granulomatous Disease, and Gout

Both innate errors of immunity, such as familial Mediterranean fever (FMF) and chronic granulomatous disease (CGD), and the common inflammatory disease gout are characterized by episodes of sterile inflammatory attacks in the absence of an infection. While these disorders encompass distinct pathologies due to differentially affected metabolic pathways and inflammasome activation mechanisms, their common features are the excessive production of interleukin (IL)-1ß and innate immune cell hyperreactivity. On the other hand, the role of T cells and innate-like lymphocytes such as gamma delta (γδ) T cells in these pathologies is ill-defined. In order to widen our understanding of T cell involvement in CGD, FMF and gout pathology, we developed multicolour immunophenotyping panels for flow cytometry to characterize γδ T cells as well as CD4 and CD8 T cell populations in terms of their cytokine production, activation status, memory or naive phenotypes, exhaustion status, homing receptor expression, and cytotoxic activity. Our study is the first deep immunophenotyping analysis of T cell populations in CGD, FMF, and gout patients. We found that CGD affects the frequencies and activation status of T cells, while gout impairs the cytokine production capacity of Vδ2 T cells. FMF was characterized by decreased percentages of regulatory T cells in circulation and attenuated IFN-γ production capacity by Vδ2 T cells. Autoinflammatory syndromes and congenital defects of phagocyte differentially affect T cell compartments. Future studies are warranted to assess whether these phenotypical changes are relevant for disease pathology.

Guardians of Immunity: Advances in Primary Immunodeficiency Disorders and Management

Primary immunodeficiency disorders (PIDs) are a heterogeneous group of genetic conditions profoundly impacting immune function. The investigation spans various PID categories, offering insights into their distinct pathogenic mechanisms and clinical manifestations. Within the adaptive immune system, B-cell, T-cell, and combined immunodeficiencies are dissected, emphasizing their critical roles in orchestrating effective immune responses. In the realm of the innate immune system, focus is directed toward phagocytes and complement deficiencies, underscoring the pivotal roles of these components in initial defense against infections. Furthermore, the review delves into disorders of immune dysregulation, encompassing hemophagocytic lymphohistiocytosis (HLH), autoimmune lymphoproliferative syndrome (ALPS), immune dysregulation, polyendocrinopathy, enteropathy, and X-linked(IPEX), and autoimmunity polyendocrinopathy candidiasis-ectodermal dystrophy(APECED), elucidating the intricate interplay between immune tolerance and autoimmunity prevention. Diagnostic strategies for PIDs are explored, highlighting advancements in genetic and molecular techniques that enable precise identification of underlying genetic mutations and alterations in immune function. We have also outlined treatment modalities for PIDs, which often entail a multidisciplinary approach involving immunoglobulin replacement, antimicrobial prophylaxis, and, in select cases, hematopoietic stem cell transplantation. Emerging therapies, including gene therapy, hold promise for targeted interventions. In essence, this review encapsulates the complexity of PIDs, emphasizing the critical importance of early diagnosis and tailored therapeutic interventions. As research advances, a clearer understanding of these disorders emerges, fostering optimism for enhanced patient care and management in the future.

Successful Prenatal Treatment of Cardiac Rhabdomyoma in a Fetus with Tuberous Sclerosis

Cardiac rhabdomyomas are a possible early manifestation of the Tuberous Sclerosis Complex (TSC). They often regress spontaneously but may grow and cause cardiac dysfunction, threatening the child's life. Treatment with rapalogs can stop the growth of these cardiac tumors and even make them shrink. Here, we present the case of a successful treatment of a cardiac rhabdomyoma in a fetus with TSC by administering sirolimus to the mother. The child's father carries a TSC2 mutation and the family already had a child with TSC. After we confirmed the TSC diagnosis and growth of the tumor with impending heart failure, we started treatment at 27 weeks of gestation. Subsequently, the rhabdomyoma shrank and the ventricular function improved. The mother tolerated the treatment very well. Delivery was induced at 39 weeks and 1 day of gestation and proceeded without complications. The length, weight, and head circumference of the newborn were normal for the gestational age. Rapalog treatment was continued with everolimus. Metoprolol and vigabatrin were added because of ventricular preexcitation and epileptic discharges in the EEG, respectively. We provide the follow-up data on the child's development in her first two years of life and discuss the efficacy and safety of this treatment.

Immunotherapies against human bacterial and fungal infectious diseases: A review

Nations' ongoing struggles with a number of novel and reemerging infectious diseases, including the ongoing global health issue, the SARS-Co-V2 (severe acute respiratory syndrome coronavirus 2) outbreak, serve as proof that infectious diseases constitute a serious threat to the global public health. Moreover, the fatality rate in humans is rising as a result of the development of severe infectious diseases brought about by multiple drug-tolerant pathogenic microorganisms. The widespread use of traditional antimicrobial drugs, immunosuppressive medications, and other related factors led to the establishment of such drug resistant pathogenic microbial species. To overcome the difficulties commonly encountered by current infectious disease management and control processes, like inadequate effectiveness, toxicities, and the evolution of drug tolerance, new treatment solutions are required. Fortunately, immunotherapies already hold great potential for reducing these restrictions while simultaneously expanding the boundaries of healthcare and medicine, as shown by the latest discoveries and the success of drugs including monoclonal antibodies (MAbs), vaccinations, etc. Immunotherapies comprise methods for treating diseases that specifically target or affect the body's immune system and such immunological procedures/therapies strengthen the host's defenses to fight those infections. The immunotherapy-based treatments control the host's innate and adaptive immune responses, which are effective in treating different pathogenic microbial infections. As a result, diverse immunotherapeutic strategies are being researched more and more as alternative treatments for infectious diseases, leading to substantial improvements in our comprehension of the associations between pathogens and host immune system. In this review we will explore different immunotherapies and their usage for the assistance of a broad spectrum of infectious ailments caused by various human bacterial and fungal pathogenic microbes. We will discuss about the recent developments in the therapeutics against the growing human pathogenic microbial diseases and focus on the present and future of using immunotherapies to overcome these diseases. Graphical AbstractThe graphical abstract shows the therapeutic potential of different types of immunotherapies like vaccines, monoclonal antibodies-based therapies, etc., against different kinds of human Bacterial and Fungal microbial infections.

Immune-metabolic adaptations in pregnancy: A potential stepping-stone to sepsis

Physiological shifts during pregnancy predispose women to a higher risk of developing sepsis resulting from a maladapted host-response to infection. Insightful studies have delineated subtle point-changes to the immune system during pregnancy. Here, we present an overlay of these point-changes, asking what changes and when, at a physiological, cellular, and molecular systems-level in the context of sepsis. We identify distinct immune phases in pregnancy delineated by placental hormone-driven changes in homeostasis setpoints of the immune and metabolic systems that subtly mirrors changes observed in sepsis. We propose that pregnancy immune-metabolic setpoint changes impact feedback thresholds that increase risk for a maladapted host-response to infection and thus act as a stepping-stone to sepsis. Defining maternal immune-metabolic setpoint changes is not only vital for tailoring the right diagnostic tools for early management of maternal sepsis but will facilitate an unravelling of the pathophysiological pathways that predispose an individual to sepsis.

Autoimmune disorders associated with common variable immunodeficiency: prediction, diagnosis, and treatment

INTRODUCTION

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. Due to the wide spectrum of the CVID manifestations, the differential diagnosis becomes complicated, ends in a diagnostic delay and increased morbidity and mortality rates. Autoimmunity is one of the important complications associated with CVID. While immunoglobulin replacement therapy has considerably decreased the mortality rate in CVID patients, mainly infection-related mortality, other complications such as autoimmunity appeared prevalent and, in some cases, life threatening.

AREAS COVERED

In this article, genetics, responsible immune defects, autoimmune manifestations in different organs, and the diagnosis and treatment processes in CVID patients are reviewed, after searching the literature about these topics.

EXPERT OPINION

Considering the many phenotypes of CVID and the fact that it remained undiagnosed until older ages, it is important to include various manifestations of CVID in the differential diagnosis. Due to the different manifestations of CVID, including autoimmune diseases, interdisciplinary collaboration of physicians from different fields is highly recommended, as discussed in the manuscript. Meanwhile, it is important to determine which patients could benefit from genetic diagnostic studies since such studies are not necessary for establishing the diagnosis of CVID.

Incidence, Management Experience and Characteristics of Patients with Giardiasis and Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is an antibody immunodeficiency with a wide variety of clinical and immunological manifestations, and whose genetic cause is found in about 25% of diagnosed cases. Giardia lamblia is one of the main causes of gastrointestinal infections in CVID. 5-Nitroimidazoles are the most used first-line treatment, but nitroimidazole-refractory giardiasis is increasing. Nevertheless, only a few cases of refractory giardiasis in CVID have been reported. This study aimed to determine the incidence of Giardia infection in our CVID cohort, shows our management experience and describes patients' phenotypic features. Clinical data collection, immunological, immunogenetics and microbiology assays were performed, and previous cases of giardiasis in CVID were reviewed. The incidence of symptomatic giardiasis was 12.9%. The main immunological features were undetectable or decreased IgA levels and reduced switched memory B cells. A probable PTEN pathogenic variant was detected in one. Three patients responded to metronidazole but suffered reinfections, and one was a refractory giardiasis eradicated with innovative quinacrine plus paromomycin combination. This work could contribute to the decision-making and therapeutic management of future patients with CVID and giardiasis, highlighting the importance of the early detection and treatment of infections in patients with CVID to ensure a good quality of life.

Biomimetic fabrication of nanotherapeutics by leukocyte membrane cloaking for targeted therapy

Cell membrane cloaking is an important biomimetic approach for improving drug residence time in the body due to its distinctive concealment ability, making it highly biocompatible and efficient for targeted drug delivery. Leukocytes are considered a fundamental part of the immune system. Leukocyte membrane cloaked nanoparticles offer site-specificity and can escape the opsonization process besides enhanced systemic circulation time. This review emphasizes the anatomical and physiological features of different leukocytes in addition to the preparation and characterization of leukocyte membrane cloaked nanoparticles. It also covers the recent advancements of this biointerfacing platform in cancer therapy, inflammatory disorders, multifunctional targeted therapy and hybrid membrane-coated nanoparticles. However, leukocytes are complex, nucleated cell structures and isolating their membranes poses a greater difficulty. Leukocyte membrane cloaking is an upcoming strategy in the infancy stage; nevertheless, there is immense scope to explore this biomimetic delivery system in terms of clinical transition, particularly for inflammatory diseases and cancer.

Specific Antibody and the T-Cell Response Elicited by BNT162b2 Boosting After Two ChAdOx1 nCoV-19 in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) patients have markedly decreased immune response to vaccinations. In this study we evaluated humoral and T cell-mediated responses against severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) with additional flow cytometric changes in CVID patients receiving booster vaccination with BNT162b2 after two ChAdOx1 nCoV-19. The BNT162b2 vaccine raised the anti-spike protein S immunoglobulin G over the cut-off value from 70% to 83% in CVID, anti-neutralizing antibody had been raised over a cut-off value from 70% to 80% but levels after boosting were significantly less in both tests than in healthy controls (*p=0.02; **p=0.009 respectively). Anti-SARS-CoV-2 immunoglobulin A became less positive in CVID after boosting, but the difference was not significant. The cumulative interferon-γ positive T cell response by ELISpot was over the cut-off value in 53% of the tested individuals and raised to 83% after boosting. This and flow cytometric control of cumulative CD4+ and CD8+ virus-specific T cell absolute counts in CVID were also statistically not different from healthy individuals after boosting. Additional flow cytometric measures for CD45+ lymphocytes, CD3+, and CD19+ cells have not shown significant differences from controls except for lower CD4+T cell counts at both time points (**p=0.003; **p=0.002), in parallel CD4+ virus-specific T-cell ratio was significantly lower in CVID patients at the first time point (*p: 0.03). After boosting, in more than 33% of both CVID patients and also in their healthy controls we detected a decrease in absolute CD45+, CD3+, CD3+CD4+, and CD3+CD8+, CD19+, and CD16+56+ cell counts. CD16+CD56+ cell counts were significantly lower compared to controls before and after boosting (*p=0.02, *p=0.02). CVID patients receiving immunosuppressive therapy throughout the previous year or autologous stem cell transplantation two years before vaccination had worse responses in anti-spike, anti-neutralizing antibody, CD3+CD4+T, CD19+ B, and natural killer cell counts than the whole CVID group. Vaccinations had few side effects. Based on these data, CVID patients receiving booster vaccination with BNT162b2 after two ChadOx1 can effectively elevate the levels of protection against COVID-19 infection, but the duration of the immune response together with COVID-19 morbidity data needs further investigation among these patients.

The War Is on: The Immune System against Glioblastoma—How Can NK Cells Drive This Battle?

Natural killer (NK) cells are innate lymphocytes that play an important role in immunosurveillance, acting alongside other immune cells in the response against various types of malignant tumors and the prevention of metastasis. Since their discovery in the 1970s, they have been thoroughly studied for their capacity to kill neoplastic cells without the need for previous sensitization, executing rapid and robust cytotoxic activity, but also helper functions. In agreement with this, NK cells are being exploited in many ways to treat cancer. The broad arsenal of NK-based therapies includes adoptive transfer of in vitro expanded and activated cells, genetically engineered cells to contain chimeric antigen receptors (CAR-NKs), in vivo stimulation of NK cells (by cytokine therapy, checkpoint blockade therapies, etc.), and tumor-specific antibody-guided NK cells, among others. In this article, we review pivotal aspects of NK cells’ biology and their contribution to immune responses against tumors, as well as providing a wide perspective on the many antineoplastic strategies using NK cells. Finally, we also discuss those approaches that have the potential to control glioblastoma—a disease that, currently, causes inevitable death, usually in a short time after diagnosis.

Role of rare immune cells in common variable immunodeficiency

Common variable immunodeficiency disorder (CVID) is a heterogeneous disorder and the most common symptomatic antibody deficiency disease characterized with hypogammaglobulinemia and a broad range of clinical manifestations. Multiple genetic, epigenetic, and immunological defects are involved in the pathogenesis of CVID. These immunological defects include abnormalities in the number and/or function of B lymphocytes, T lymphocytes, and other rare immune cells. Although some immune cells have a relatively lower proportion among total immune subsets in the human body, they could have important roles in the pathogenesis of immunological disorders like CVID. To the best of our knowledge, this is the first review that described the role of rare immune cells in the pathogenesis and clinical presentations of CVID.

Type 1 Innate Lymphoid Cells Limit the Antitumoral Immune Response

Natural killer (NK) cells are known to be able to kill established tumor cell lines, but important caveats remain regarding their roles in the detection and elimination of developing primary tumors. Using a genetic model of selective ILC1 and NK cell deficiency, we showed that these cells were dispensable for tumor immunosurveillance and immunoediting in the MCA-induced carcinogenesis model. However, we were able to generate primary cell lines derived from MCA-induced tumors with graded sensitivity to NK1.1⁺ cells (including NK cells and ILC1). This differential sensitivity was associated neither with a modulation of intratumoral NK cell frequency, nor the capacity of tumor cells to activate NK cells. Instead, ILC1 infiltration into the tumor was found to be a critical determinant of NK1.1⁺ cell-dependent tumor growth. Finally, bulk tumor RNAseq analysis identified a gene expression signature associated with tumor sensitivity to NK1.1⁺ cells. ILC1 therefore appear to play an active role in inhibiting the antitumoral immune response, prompting to evaluate the differential tumor infiltration of ILC1 and NK cells in patients to optimize the harnessing of immunity in cancer therapies.

Posttraumatic natural killer cell decrease is associated with septic complications

BACKGROUND

There has been paucity in prospective studies investigating trauma-induced changes in the cellular immunity of HIV-seropositive patients and their impact on the clinical outcome after trauma surgery. The role of natural killer (NK) cells especially has not yet been fully elucidated, and the function of this lymphocyte subtype in the immune defense after trauma is still under debate.

METHODS

This prospective study included patients requiring surgery for abdominal gunshot wounds. A blood specimen was obtained on admission, 48 hours after the index operation and, in case of damage control surgery, 48 hours after the first planned second look operation. The quantity and changes of T-, B- and NK cells were analyzed via flow cytometry to investigate whether these numbers had an impact on the postoperative outcome.

RESULTS

A total of 62 patients were recruited in the analysis of which 38 were HIV-negative and 24 HIV-seropositive. After surgery, HIV-negative patients had a more severe decrease of their CD4+ T cells compared to the HIV-seropositive patients. Trauma resulted in a severe decrease of NK cells irrespective of the HIV-serostatus. Patients with more extensive NK cell drop had a significantly higher postoperative complication rate.

CONCLUSIONS

Our data support the association of trauma-induced NK cell decrease with a subsequent significantly higher rate of septic and surgical complications and suggest that these immune cells might play an important role in antibacterial immunity. Strengthening the NK cell function or limiting their decrease in the postoperative course might be of therapeutic value in severely injured trauma patients.

Vitamin D in infectious complications in critically ill patients with or without COVID-19

25-hydroxyvitamin D [25(OH)D] is an important immunomodulator, whose deficiency may aggravate the incidence and outcome of infectious complications in patients admitted to the intensive care unit. The most recognized extra-skeletal action of vitamin D is the regulation of immune function. Host defense against intracellular pathogens depends upon both innate and adaptive immunity. It has been suggested that vitamin D regulates the pro-inflammatory endothelial response to lipopolysaccharide, rendering it a role in the sepsis cascade. Recent studies have indicated that vitamin D deficiency may be associated with worse outcomes in patients with coronavirus disease 2019 (COVID-19), such as more severe disease and higher mortality rates. To this end, clinical trials with vitamin D supplementation are being carried out in an effort to improve COVID-19 outcomes. In this review, we will discuss the role of vitamin D in the immune response, and more specifically its effect on immune cells. Subsequently, we will provide an overview of the studies that have investigated the predictive value of vitamin D in critical illness outcomes, and its therapeutic value as a supplement in critically ill patients. Finally, the emerging role of vitamin D deficiency in COVID-19 infection risk, and worse outcomes will be discussed.

Patients with Common Variable Immunodeficiency Complicated by Autoimmune Phenomena Have Lymphopenia and Reduced Treg, Th17, and NK Cells

Most patients with primary immune deficiency suffer from recurrent infections; however, paradoxical autoimmune phenomena can also manifest. The aim of this study was to identify immunological markers of autoimmune phenomena associated with common variable immunodeficiency (CVID). The study included 33 adults with CVID divided into two groups: (1) those with noninfectious autoimmune complications (CVID-C (n = 24)) and (2) those with only infectious symptoms (CVID-OI (n = 9)). Flow cytometry of peripheral blood was performed and compared with systemic lupus erythematosus (SLE) patients (n = 17) and healthy controls (n = 20). We found that all lymphocytes were lower in CVID-C and SLE. NK cells were lowest in CVID-C. Th17 cells were significantly reduced in CVID-C and SLE. Tregs were significantly lower in CVID-C and SLE. Bregs did not significantly differ between any groups. Class-switched memory B cells were significantly lower in CVID-C and CVID-OI. Lastly, plasmablasts were significantly higher in SLE. Among the T cell subsets, CVID-C patients had lower naive and recent thymic emigrant CD4+ T cells. In conclusion, reduced Treg, Th17, and NK cells are features of CVID with autoimmune complications, and class-switched memory B cells can help distinguish patients with different causes of autoimmunity. Future studies are needed to confirm whether reductions of Treg, Th17, and NK cells might be a biomarker of more complicated CVID cases.

Lymphocytes subsets in correlation with clinical profile in CVID patients without monogenic defects

Objectives: Common variable immunodeficiency (CVID) patients experience clinical manifestations rather than recurrent respiratory infections including autoimmunity, enteropathy, and lymphoproliferation. We evaluated the correlation of lymphocyte subpopulations with such manifestations.Methods: Twenty-six genetically unsolved CVID patients were subdivided into four phenotypes: infection only (IO), autoimmunity (AI), chronic enteropathy (CE), and lymphoproliferative disorders (LP) and examined for lymphocyte subsets by flow cytometry and TCD4⁺ proliferation by Carboxyfluorescein succinimidyl ester (CFSE) test.Results: We detected reduced memory B and increased total, effector memory (EM), cytotoxic, and activated TCD8⁺ in IO, AI and CE, decreased plasmablasts, total and naive TCD4⁺, Regulatory TCD4⁺ (Treg) and naive TCD8⁺ in IO and CE, elevated CD21^low B and terminally differentiated effector memory (T_EMRA) TCD8⁺ in IO and AI, increased helper T (Th2) and Th17 in IO, decreased Th1 in AI and defective total and naive B and central memory (CM) TCD4⁺ in CE. IO showed reduced TCD4⁺ proliferation response.Conclusions: In genetically unsolved CVID patients, increased Th2 and Th17 and reduced Treg is associated with IO, increased CD21^low B and T_EMRA TCD8⁺ and reduced Th1 is contributed to AI and reduced total and naive B, CM TCD4⁺ and naive TCD8⁺ and expanded total TCD8⁺ is correlated with CE.

Towards efficient immunotherapy for bacterial infection

The emergence of multiantibiotic-resistant bacteria, often referred to as superbugs, is leading to infections that are increasingly difficult to treat. Further, bacteria have evolved mechanisms by which they subvert the immune response, meaning that even antibiotic-sensitive bacteria can persist through antibiotic therapy. For these reasons, a broad range of viable therapeutic alternatives or conjunctions to traditional antimicrobial therapy are urgently required to reduce the burden of disease threatened by antibiotic resistance. Immunotherapy has emerged as a leading treatment option in cancer, and researchers are now attempting to apply this to infectious disease. This review summarizes and discusses the recent advances in the field and highlights current and future perspectives of using immunotherapies to treat bacterial infections.

Immune Circuits to Shape Natural Killer Cells in Cancer

Simple Summary

Natural killer (NK) cells are circulating innate lymphocytes endowed with antitumoral functions. NK cells are the innate counterpart of effector T cells and among the first cells responding to infections and tumors. In this review, the immune circuits regulating the NK cell antitumoral functions and the possible strategies to shape natural killing in cancer will be discussed.

Abstract

Natural killer (NK) cells are innate lymphoid cells playing an important role in anti-cancer immunity. NK cells are efficient in controlling the spreading of metastasis but are not very powerful in fighting against primary tumors. The NK cell capability to infiltrate and persist in the tumor microenvironment and to exert their antitumoral functions is often limited by tumor escape mechanisms. These tumor-mediated strategies not only induce NK cell tolerance but also interfere with the NK cell-dependent immune networking. This review will provide an overview of the tumor escape mechanisms impacting NK cells, identify the immune circuits regulating the NK cell-dependent antitumor immunity and revise the emerging therapeutic approaches to unleash NK cells in cancer.

Natural killer cells associated with SARS-CoV-2 viral RNA shedding, antibody response and mortality in COVID-19 patients

Coronavirus disease 2019 (COVID-19) is a novel infectious viral disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Two consecutively negative SARS-CoV-2 viral RNA test ( interval ≥ 24 hours), improved respiratory symptoms and obvious absorption of inflammation in pulmonary imaging are the discharge criteria for COVID-19 patients. The clearance profile of viral RNA in the upper respiratory tract specimens, including nasopharyngeal swab and/or oropharyngeal swabs, is related to innate immune cells such as Natural Killer cells. A total of 168 patients were included for the study. In this cohort, non-severe and severe groups showed significant differences in white blood cells, neutrophils, lymphocytes, basophils and platelets counts, as well as in infection related parameters such as CRP and serum cytokine IL-6. For lymphocyte subsets tests at admission, the severe group displayed significantly lower cell counts than the non-severe group. Higher counts of total T cells, CD4 + T cells, CD8 + T cells, and NK cells in peripheral blood showed a significant correlation with the shorter time taken to obtain the first negative viral RNA test and first positive IgM/ IgG antibody test. The number of B cells was only correlated with time to achieve the first positive IgM/IgG test. The count of NK cells was also correlated with a higher level of IgG antibody (p = 0.025). The lymphocytopenia group had a significantly worse survival rate (p = 0.022) and a longer duration (p = 0.023) of viral shedding than the normal lymphocyte count group. A lower NK cell count correlates the most with the worse survival rate (p<0.001) and a longer duration (p<0.001) of viral shedding. This study suggests the potential value of allo-Natural Killer cell therapy as an universal COVID-19 treatment strategy.

Immune Dysfunction in Mendelian Disorders of POLA1 Deficiency

POLA1 encodes the catalytic unit of DNA polymerase α, which together with the Primase complex launches the DNA replication process. While complete deficiency of this essential gene is presumed to be lethal, at least two conditions due to partial POLA1 deficiency have been described. The first genetic syndrome to be mapped to POLA1 was X-linked reticulate pigmentary disorder (XLPDR, MIM #301220), a rare syndrome characterized by skin hyperpigmentation, sterile multiorgan inflammation, recurrent infections, and distinct facial features. XLPDR has been shown to be accompanied by profound activation of type I interferon signaling, but unlike other interferonopathies, it is not associated with autoantibodies or classical autoimmunity. Rather, it is accompanied by marked Natural Killer (NK) cell dysfunction, which may explain the recurrent infections seen in this syndrome. To date, all XLPDR cases are caused by the same recurrent intronic mutation, which results in gene missplicing. Several hypomorphic mutations in POLA1, distinct from the XLPDR intronic mutation, have been recently reported and these mutations associate with a separate condition, van Esch-O'Driscoll syndrome (VEODS, MIM #301030). This condition results in growth retardation, microcephaly, hypogonadism, and in some cases, overlapping immunological features to those seen in XLPDR. This review summarizes our current understanding of the clinical manifestations of POLA1 gene mutations with an emphasis on its immunological consequences, as well as recent advances in understanding of its pathophysiologic basis and potential therapeutic options.

Iacta Alea Est: The Inexorable Advance of Tofacitinib in the Treatment of Dermatomyositis-Associated Rapidly Progressive Interstitial Lung Disease. A Case Report

Rapidly progressive interstitial lung disease is typically associated with clinically amyopathic dermatomyositis and the anti-melanoma differentiation associated gene 5 antibody, a condition with high mortality and resistance to classic immunosuppression. Recent reports have described the efficacy of the Janus kinase inhibitor tofacitinib in the treatment of rapidly progressive interstitial lung disease in anti-melanoma differentiation associated gene 5 antibody-positive clinically amyopathic dermatomyositis. It is uncertain, however, whether tofacitinib alters the course of rapidly progressive interstitial lung disease in other variants of dermatomyositis that are unrelated to the anti-melanoma differentiation associated gene 5 antibody and whether the early addition of the anti-fibrotic tyrosine kinase inhibitor nintedanib interferes with the development of fibrosis. To answer these questions, we present and discuss the case of an elderly woman who presented with a flare of dermatomyositis sine myositis. Based upon the detection of anti-Jo-1 antibodies and the absence of anti-melanoma differentiation associated gene 5 antibodies, anti-synthetase syndrome was diagnosed. While the cutaneous manifestations quickly resolved with prednisone, azathioprine and tacrolimus, the respiratory function paradoxically and rapidly deteriorated, and invoked the use of tofacitinib. Markedly raised ferritin levels and a severe numerical deficiency of circulating natural killer cells paralleled the acute lung inflammation, which was reflected by ¹⁸F-fluorodeoxyglucose hypermetabolism on positron emission tomography/CT. Tofacitinib lead to a prompt clinical recovery, with a reduction in oxygen requirement, correction of hyperferritinemia, reversal of the natural killer cell deficiency, and a decrease in ¹⁸F-fluorodeoxyglucose uptake in the affected lung segments. Subsequently, nintedanib was added at a point in time when inflammation subsided. Apart from cytomegalovirus reactivation no adverse events occurred. In conclusion, tofacitinib reversed the pronounced inflammatory component of anti-Jo-1 antibody-positive, anti-melanoma differentiation associated gene 5 antibody-negative rapidly progressive interstitial lung disease, confirming that Janus kinase signaling pathways are critically involved in the pathogenesis of rapidly progressive interstitial lung disease, apparently independently of the targeted autoantigen. Although some improvement in pulmonary function was observed, it seems premature to conclusively judge on reversibility or prevention of pulmonary fibrosis by pairing both kinase inhibitors for which an extended follow-up and ideally, prospective and controlled studies are needed.

From infections to autoimmunity: Diagnostic challenges in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most common clinically significant primary antibody deficiency diagnosed in adults. The early symptoms are not specific. They include common infections, mainly of the respiratory tract, caused by typical microorganisms, so cases can be missed in primary care. In the majority of patients increased susceptibility to infections coexists with signs or symptoms of autoimmunity, inflammation or polyclonal lymphoproliferation, which can divert diagnosis from immune deficiency. The overall incidence of malignancy is increased in CVID and certain cancers are significantly more common. Lymphomas and gastric carcinoma are the most frequently reported malignancies in CVID, so a high index of suspicion is recommended. Diagnostic delay in CVID is seen worldwide. The main goal of this paper is to increase the awareness about CVID among health care professionals. We aim to present features which can be helpful in CVID diagnosis in order to shorten the “latency” of proper management of CVID patients. We review clinical symptoms, complications and laboratory abnormalities of CVID. Immunoglobulin replacement therapy is regarded as the cornerstone of pharmacological intervention. New modes of Ig application, mainly subcutaneously and via the hyaluronidase-facilitated subcutaneous route, help to adjust therapy to patients’ needs and preferences. Still there remain unmet needs. It remains to be seen whether CVID complications can be avoided by earlier diagnosis, treatment and thorough monitoring in the context of increased risk of malignancy. Development of patient tailored protocols depending on the clinical phenotype and risk factors might be more appropriate. The most important consideration is to diagnose suspected cases and stratify patients in a precise and timely way. Work is needed to define features predictive of unfavorable prognosis.

Understanding the Role of Innate Immune Cells and Identifying Genes in Breast Cancer Microenvironment

The innate immune system is the first line of defense against invading pathogens and has a major role in clearing transformed cells, besides its essential role in activating the adaptive immune system. Macrophages, dendritic cells, NK cells, and granulocytes are part of the innate immune system that accumulate in the tumor microenvironment such as breast cancer. These cells induce inflammation in situ by secreting cytokines and chemokines that promote tumor growth and progression, in addition to orchestrating the activities of other immune cells. In breast cancer microenvironment, innate immune cells are skewed towards immunosuppression that may lead to tumor evasion. However, the mechanisms by which immune cells could interact with breast cancer cells are complex and not fully understood. Therefore, the importance of the mammary tumor microenvironment in the development, growth, and progression of cancer is widely recognized. With the advances of using bioinformatics and analyzing data from gene banks, several genes involved in NK cells of breast cancer individuals have been identified. In this review, we discuss the activities of certain genes involved in the cross-talk among NK cells and breast cancer. Consequently, altering tumor immune microenvironment can make breast tumors more responsive to immunotherapy.

Primary Humoral Immune Deficiencies: Overlooked Mimickers of Chronic Immune-Mediated Gastrointestinal Diseases in Adults

In recent years, the incidence of immune-mediated gastrointestinal disorders, including celiac disease (CeD) and inflammatory bowel disease (IBD), is increasingly growing worldwide. This generates a need to elucidate the conditions that may compromise the diagnosis and treatment of such gastrointestinal disorders. It is well established that primary immunodeficiencies (PIDs) exhibit gastrointestinal manifestations and mimic other diseases, including CeD and IBD. PIDs are often considered pediatric ailments, whereas between 25 and 45% of PIDs are diagnosed in adults. The most common PIDs in adults are the selective immunoglobulin A deficiency (SIgAD) and the common variable immunodeficiency (CVID). A trend to autoimmunity occurs, while gastrointestinal disorders are common in both diseases. Besides, the occurrence of CeD and IBD in SIgAD/CVID patients is significantly higher than in the general population. However, some differences concerning diagnostics and management between enteropathy/colitis in PIDs, as compared to idiopathic forms of CeD/IBD, have been described. There is an ongoing discussion whether CeD and IBD in CVID patients should be considered a true CeD and IBD or just CeD-like and IBD-like diseases. This review addresses the current state of the art of the most common primary immunodeficiencies in adults and co-occurring CeD and IBD.

A Method of Assessment of Human Natural Killer Cell Phenotype and Function in Whole Blood

The majority of data on human Natural Killer (NK) cell phenotype and function has been generated using cryopreserved peripheral blood mononuclear cells (PBMCs). However, cryopreservation can have adverse effects on PBMCs. In contrast, investigating immune cells in whole blood can reduce the time, volume of blood required, and potential artefacts associated with manipulation of the cells. Whole blood collected from healthy donors and cancer patients was processed by three separate protocols that can be used independently or in parallel to assess extracellular receptors, intracellular signaling protein phosphorylation, and intracellular and extracellular cytokine production in human NK cells. To assess extracellular receptor expression, 200 μL of whole blood was incubated with an extracellular staining (ECS) mix and cells were subsequently fixed and RBCs lysed prior to analysis. The phosphorylation status of signaling proteins was assessed in 500 μL of whole blood following co-incubation with interleukin (IL)-2/12 and an ECS mix for 20 min prior to cell fixation, RBC lysis, and subsequent permeabilization for staining with an intracellular staining (ICS) mix. Cytokine production (IFNγ) was similarly assessed by incubating 1 mL of whole blood with PMA-ionomycin or IL-2/12 prior to incubation with ECS and subsequent ICS antibodies. In addition, plasma was collected from stimulated samples prior to ECS for quantification of secreted IFNγ by ELISA. Results were consistent, despite inherent inter-patient variability. Although we did not investigate an exhaustive list of targets, this approach enabled quantification of representative ECS surface markers including activating (NKG2D and DNAM-1) and inhibitory (NKG2A, PD-1, TIGIT, and TIM-3) receptors, cytokine receptors (CD25, CD122, CD132, and CD212) and ICS markers associated with NK cell activation following stimulation, including signaling protein phosphorylation (p-STAT4, p-STAT5, p-p38 MAPK, p-S6) and IFNγ in both healthy donors and cancer patients. In addition, we compared extracellular receptor expression using whole blood vs. cryopreserved PBMCs and observed a significant difference in the expression of almost all receptors. The methods presented permit a relatively rapid parallel assessment of immune cell receptor expression, signaling protein activity, and cytokine production in a minimal volume of whole blood from both healthy donors and cancer patients.

Circulating activated lymphocyte subsets as potential blood biomarkers of cancer progression

The objective of this study was to predict the value of lymphocyte subsets in cancer progression. Peripheral blood was obtained from 327 untreated patients with cancer and 158 healthy volunteers. Levels of lymphocyte subsets were determined by flow cytometry. There were decreased levels of natural killer (NK) cells, CD8⁺ T cells, and naïve CD4⁺/CD4⁺ T cells in untreated patients with cancer compared to those in healthy controls. Inversely, there were elevated levels of the following T‐cell percentages in cancer patients compared to those in healthy controls: memory CD4⁺/CD4⁺, CD8⁺ T cells, HLA‐DR/CD8⁺, CD8⁺ CD38⁺/CD8⁺, and CD4⁺/CD8⁺. In addition, there are a decreasing trend in terms of CD4⁺ T‐cell counts and an increase CD8⁺ HLA‐DR/CD8⁺ T‐cell and CD8⁺ CD38⁺/CD8⁺ T‐cell percentages in the advanced stage. An increasing trend with advanced tumor stage and the percentages of CD8⁺ HLA‐DR/CD8⁺ T cells and CD8⁺ CD38⁺/CD8⁺ T cells was shown in this study. There are a negative correlation for CD4⁺ T‐cell counts and positive correlation for percentages of CD8⁺ HLA‐DR/CD8⁺ T cell and CD8⁺ CD38⁺/CD8⁺ T cells with the lymph node metastasis. In the presence of distant metastatic spread, we observed higher NK‐cell counts, CD8⁺ HLA‐DR/CD8⁺ T‐cell percentages, CD8⁺ CD38⁺/CD8⁺ T‐cell percentages, as well as lower CD4⁺ T‐cell counts than those in the absence of distant metastases spread. Abnormal levels of NK cell, CD8⁺ T cells, memory CD4⁺/CD4⁺, naïve CD4⁺/ CD4⁺, CD8⁺ HLA‐DR/CD8⁺, CD8⁺ CD38⁺/CD8⁺, and CD4⁺/CD8⁺ can be a potential blood biomarkers of cancer development. CD4+ T‐cell counts and percentages of CD8⁺ HLA‐DR/ CD8⁺ and CD8⁺ CD38⁺/ CD8⁺ can predict the cancer progression.

Immunological and Clinical Phenotyping in Primary Antibody Deficiencies: a Growing Disease Spectrum

PURPOSE

Although common variable immunodeficiency (CVID) is considered the most prevalent symptomatic primary antibody deficiency (PAD), there is a population with symptomatic PADs that do not meet criteria for CVID. We analyzed clinical and immunological profiles of patients with different PADs to better understand the differences and similarities between CVID and other PADs.

METHODS

We extracted clinical and laboratory data of patients with PADs from electronic medical records. Patients were categorized into CVID, IgG subclass 2 deficiency (IgG2D), IgG deficiency (IgGD), and specific antibody deficiency (sAbD) based on basal immunoglobulin levels and pneumococcal vaccine responses. We compared clinical and immunological characteristics in these groups.

RESULTS

All patients, regardless of PAD types, showed similar frequencies of infections, bronchiectasis, and interstitial lung disease (ILD). Hematopoietic malignancies were more frequently found in the CVID than in the IgG2D, IgGD, and sAbD groups, while the latter groups trended towards an increased frequency of connective tissue diseases (CTD). Low counts of natural killer (NK) cells were associated with malignancy, autoimmunity, and ILD in CVID but not in other PAD groups.

CONCLUSIONS

Higher frequency of hematopoietic malignancy in CVID than in the other PADs and association of lower NK cell counts with non-infectious complications in CVID suggest a relationship between immune alterations and the development of non-infectious manifestations in PADs.

Predominantly Antibody-Deficient Patients With Non-infectious Complications Have Reduced Naive B, Treg, Th17, and Tfh17 Cells

Background: Patients with predominantly antibody deficiency (PAD) suffer from severe and recurrent infections that require lifelong immunoglobulin replacement and prophylactic antibiotic treatment. Disease incidence is estimated to be 1:25,000 worldwide, and up to 68% of patients develop non-infectious complications (NIC) including autoimmunity, which are difficult to treat, causing high morbidity, and early mortality. Currently, the etiology of NIC is unknown, and there are no diagnostic and prognostic markers to identify patients at risk.

Objectives: To identify immune cell markers that associate with NIC in PAD patients.

Methods: We developed a standardized 11-color flow cytometry panel that was utilized for in-depth analysis of B and T cells in 62 adult PAD patients and 59 age-matched controls.

Results: Nine males had mutations in Bruton's tyrosine kinase (BTK) and were defined as having X-linked agammaglobulinemia. The remaining 53 patients were not genetically defined and were clinically diagnosed with agammaglobulinemia (n = 1), common variable immunodeficiency (CVID) (n = 32), hypogammaglobulinemia (n = 13), IgG subclass deficiency (n = 1), and specific polysaccharide antibody deficiency (n = 6). Of the 53, 30 (57%) had one or more NICs, 24 patients had reduced B-cell numbers, and 17 had reduced T-cell numbers. Both PAD–NIC and PAD+NIC groups had significantly reduced Ig class-switched memory B cells and naive CD4 and CD8 T-cell numbers. Naive and IgM memory B cells, Treg, Th17, and Tfh17 cells were specifically reduced in the PAD+NIC group. CD21^lo B cells and Tfh cells were increased in frequencies, but not in absolute numbers in PAD+NIC.

Conclusion: The previously reported increased frequencies of CD21^lo B cells and Tfh cells are the indirect result of reduced naive B-cell and T-cell numbers. Hence, correct interpretation of immunophenotyping of immunodeficiencies is critically dependent on absolute cell counts. Finally, the defects in naive B- and T-cell numbers suggest a mild combined immunodeficiency in PAD patients with NIC. Together with the reductions in Th17, Treg, and Tfh17 numbers, these key differences could be utilized as biomarkers to support definitive diagnosis and to predict for disease progression.

NK cell defects in X-linked pigmentary reticulate disorder

X-linked reticulate pigmentary disorder (XLPDR, Mendelian Inheritance in Man #301220) is a rare syndrome characterized by recurrent infections and sterile multiorgan inflammation. The syndrome is caused by an intronic mutation in POLA1, the gene encoding the catalytic subunit of DNA polymerase-α (Pol-α), which is responsible for Okazaki fragment synthesis during DNA replication. Reduced POLA1 expression in this condition triggers spontaneous type I interferon expression, which can be linked to the autoinflammatory manifestations of the disease. However, the history of recurrent infections in this syndrome is as yet unexplained. Here we report that patients with XLPDR have reduced NK cell cytotoxic activity and decreased numbers of NK cells, particularly differentiated, stage V, cells (CD3^–CD56^dim). This phenotype is reminiscent of hypomorphic mutations in MCM4, which encodes a component of the minichromosome maintenance (MCM) helicase complex that is functionally linked to Pol-α during the DNA replication process. We find that POLA1 deficiency leads to MCM4 depletion and that both can impair NK cell natural cytotoxicity and show that this is due to a defect in lytic granule polarization. Altogether, our study provides mechanistic connections between Pol-α and the MCM complex and demonstrates their relevance in NK cell function.

X-linked reticulate pigmentary disorder is associated with functional NK cell defect due to abnormal lytic granule polarization.

Low percentages of regulatory T cells in common variable immunodeficiency (CVID) patients with autoimmune diseases and its association with increased numbers of CD4+CD45RO+ T and CD21low B cells

BACKGROUND

Common variable immunodeficiency (CVID) is a heterogeneous group of primary antibody deficiencies defined by marked reductions in serum IgG, IgA and/or IgM levels and recurrent bacterial infections. Some patients are associated with defects in T cells and regulatory T cells (Tregs), resulting in recurrent viral infections and early-onset autoimmune disease.

METHODS

We analyzed whether there is an association between Tregs cells (CD4+CD25+CD127^low and CD4+CD25+FoxP3+); memory T cells (CD4+CD45RO+); memory B cells (CD19+CD27-IgD-); and CD21^low B cells (CD19+CD38^lowCD21^low); as well as autoimmune manifestations in 36 patients with CVID (25 women and 11 men, mean age 24 years), all by flow cytometry.

RESULTS

Fourteen patients presented with autoimmune diseases (AI) (39%), including 11 with autoimmune thrombocytopenia (ITP) (31%); two with vitiligo (6%); one with systemic lupus erythematosus (LES) (3%); and one with multiple sclerosis (MS) (3%). CVID patients with AI had a reduced proportion of Tregs (both CD4+CD25+CD127^low and FoxP3+ cells) compared with healthy controls. CVID patients with AI had expanded CD21^low B cell populations compared with patients who did not have AI. A correlation between increased CD4+CD45RO T cell populations and reduced Tregs was also observed.

CONCLUSIONS

Our results showed that 39% of patients with CVID had AI and reduced Tregs populations. Research in this area might provide noteworthy data to better understand immune dysfunction and dysregulation related to CVID.

Natural killer cells and other innate lymphoid cells in cancer

Immuno-oncology is an emerging field that has revolutionized cancer treatment. Most immunomodulatory strategies focus on enhancing T cell responses, but there has been a recent surge of interest in harnessing the relatively underexplored natural killer (NK) cell compartment for therapeutic interventions. NK cells show cytotoxic activity against diverse tumour cell types, and some of the clinical approaches originally developed to increase T cell cytotoxicity may also activate NK cells. Moreover, increasing numbers of studies have identified novel methods for increasing NK cell antitumour immunity and expanding NK cell populations ex vivo, thereby paving the way for a new generation of anticancer immunotherapies. The role of other innate lymphoid cells (group 1 innate lymphoid cell (ILC1), ILC2 and ILC3 subsets) in tumours is also being actively explored. This Review provides an overview of the field and summarizes current immunotherapeutic approaches for solid tumours and haematological malignancies.

Immunosuppressive therapy with rituximab in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary antibody deficiency in adulthood and is characterized by the marked reduction of IgG and IgA serum levels. Thanks to the successful use of polyvalent immunoglobulin replacement therapy to treat and prevent recurrent infections, non-infectious complications, including autoimmunity, polyclonal lymphoproliferation and malignancies, have progressively become the major cause of morbidity and mortality in CVID patients. The management of these complications is particularly challenging, often requiring multiple lines of immunosuppressive treatments. Over the last 5–10 years, the anti-CD20 monoclonal antibody (i.e., rituximab) has been increasingly used for the treatment of both autoimmune and non-malignant lymphoproliferative manifestations associated with CVID. This review illustrates the evidence on the use of rituximab in CVID. For this purpose, first we discuss the mechanisms proposed for the rituximab mediated B-cell depletion; then, we analyze the literature data regarding the CVID-related complications for which rituximab has been used, focusing on autoimmune cytopenias, granulomatous lymphocytic interstitial lung disease (GLILD) and non-malignant lymphoproliferative syndromes. The cumulative data suggest that in the vast majority of the studies, rituximab has proven to be an effective and relatively safe therapeutic option. However, there are currently no data on the long-term efficacy and side effects of rituximab and other second-line therapeutic options. Further randomized controlled trials are needed to optimize the management strategies of non-infectious complications of CVID.

Lymphopenic community-acquired pneumonia is associated with a dysregulated immune response and increased severity and mortality

OBJECTIVES

Lymphopenic (<724 lymphocytes/µL) community-acquired pneumonia (L-CAP) is an immunophenotype with an increased risk of mortality. We aimed to characterize the l-CAP immunophenotype though lymphocyte subsets and the inflammatory response and its relationship with severity at presentation and outcome.

METHODS

Prospective study of 217 immunocompetent patients hospitalized for CAP. Lymphocyte subsets (CD4⁺, CD8⁺, CD19⁺, and natural killer [NK] cells) and inflammatory cytokines were analyzed on days 1 and 4, and immunoglobulin subclasses were analyzed on day 1 in a nested group.

RESULTS

39% of patients showed l-CAP, with decreased levels of all lymphocyte subsets with a partial recovery of CD4⁺ and CD8⁺ cells by day 4. l-CAP patients exhibited higher initial severity and systemic levels of interleukin (IL)-8, IL-10, granulocyte colony-stimulating factor, and monocyte chemoattractant protein-1. Initial IgG2 levels were lower in patients with <724 lymphocytes/µL and positively correlated with ALC, CD4⁺, and CD19⁺ cell counts. Low CD4⁺ counts (<129 cells/µL) also independently predicted 30-day mortality after adjusting for age, gender, and the CURB-65 score.

CONCLUSIONS

l-CAP is characterized by CD4⁺ depletion, a higher inflammatory response, and low IgG2 levels that correlated with greater severity at presentation and worse prognosis. l-CAP is an immunophenotype useful for rapidly recognizing severity.

Targeting natural killer cells in solid tumors

Natural killer (NK) cells are innate lymphoid cells endowed with cytolytic activity and a capacity to secrete cytokines and chemokines. Several lines of evidence suggest that NK cells play an important role in anti-tumor immunity. Some therapies against hematological malignacies make use of the immune properties of NK cells, such as their ability to kill residual leukemic blasts efficiently after conditioning during haploidentical hematopoietic stem cell transplantation. However, knowledge on NK cell infiltration and the status of NK cell responsiveness in solid tumors is limited so far. The pro-angiogenic role of the recently described NK cell-like type 1 innate lymphoid cells (ILC1s) and their phenotypic resemblance to NK cells are confounding factors that add a level of complexity, at least in mice. Here, we review the current knowledge on the presence and function of NK cells in solid tumors as well as the immunotherapeutic approaches designed to harness NK cell functions in these conditions, including those that aim to reinforce conventional anti-tumor therapies to increase the chances of successful treatment.

Roles and regulations of the ETS transcription factor ELF4/MEF

Most E26 transformation-specific (ETS) transcription factors are involved in the pathogenesis and progression of cancer. This is in part due to the roles of ETS transcription factors in basic biological processes such as growth, proliferation, and differentiation, and also because of their regulatory functions that have physiological relevance in tumorigenesis, immunity, and basal cellular homoeostasis. A member of the E74-like factor (ELF) subfamily of the ETS transcription factor family—myeloid elf-1-like factor (MEF), designated as ELF4—has been shown to be critically involved in immune response and signalling, osteogenesis, adipogenesis, cancer, and stem cell quiescence. ELF4 carries out these functions as a transcriptional activator or through interactions with its partner proteins. Mutations in ELF4 cause aberrant interactions and induce downstream processes that may lead to diseased cells. Knowing how ELF4 impinges on certain cellular processes and how it is regulated in the cells can lead to a better understanding of the physiological and pathological consequences of modulated ELF4 activity.

Elizabethkingia miricola as an opportunistic oral pathogen associated with superinfectious complications in humoral immunodeficiency: a case report

BACKGROUND

Elizabethkingia miricola is a rare Gram-negative bacterium found in water and clinical specimens. Typical culturing methods often misidentify Elizabethkingia spp. as Flavobacterium or Chryseobacterium. Although diagnosis is based on culturing samples taken from sterile sites, such as blood, a proper identification of this bacterium requires an expertise that goes beyond the capabilities of a typical clinical laboratory.

CASE PRESENTATION

A 35-year-old woman diagnosed with common variable immunodeficiency was admitted to our center. Previous treatment with antibiotics (amoxicillin plus clavulanate, first and third generation of cephalosporins, macrolides) and systemic corticosteroids (up to 120 mg/day of prednisolone) failed to arrest the spread of inflammation. Gingival recession was observed in her oral cavity, resulting in an apparent lengthening of her teeth. In addition to typical commensal bacteria, including streptococci and neisseriae, strains of Rothia mucilaginosa and Elizabethkingia miricola were identified upon a detailed microbiological examination using a MALDI-TOF MS Biotyper system. The presence of the latter strain correlated with severe periodontitis, lack of IgA in her saliva and serum, a very low IgG concentration (< 50 mg/dl), IgM-paraproteinemia, decreases in C3a and C5a and microvascular abnormality. High-dose immunoglobulin (to maintain IgG > 500 mg/dl) and targeted levofloxacin treatment resulted in immune system reconstitution, oral healing, and eradication of the Elizabethkingia infection.

CONCLUSIONS

E. miricola rarely causes disease in healthy individuals. However, the overgrowth of commensal bacteria, lack of IgG/IgA, microvasculopathy and complement cascade activation in patients with humoral immunodeficiency may facilitate Elizabethkingia invasion. Overuse of antibiotics, particularly beta-lactams, may cause mucosal colonization by E. miricola, followed by its multiplication combined with periodontitis that prompts bacterial translocation. MALDI-TOF Biotyper analysis may become a method of choice for identification of Elizabethkingia infections.

The biology of natural killer cells during sepsis

Natural killer (NK) cells are large granular lymphocytes largely recognized for their importance in tumour surveillance and the host response to viral infections. However, as the major innate lymphocyte population, NK cells also coordinate early responses to bacterial infections by amplifying the antimicrobial functions of myeloid cells, especially macrophages, by production of interferon-γ (IFN-γ). Alternatively, excessive NK cell activation and IFN-γ production can amplify the systemic inflammatory response during sepsis resulting in increased physiological dysfunction and organ injury. Our understanding of NK cell biology during bacterial infections and sepsis is mostly derived from studies performed in mice. Human studies have demonstrated a correlation between altered NK cell functions and outcomes during sepsis. However, mechanistic understanding of NK cell function during human sepsis is limited. In this review, we will review the current understanding of NK cell biology during sepsis and discuss the challenges associated with modulating NK cell function during sepsis for therapeutic benefit.

Chronic Diarrhea in Common Variable Immunodeficiency: a Case Series and Review of the Literature

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by reduced immunoglobulin serum levels and absent or impaired antibody production. Clinical manifestations, including infections, inflammatory and autoimmune diseases, and malignancies, also involve various segments of the gastrointestinal tract. Chronic diarrhea is one of the most common gastrointestinal symptoms and may cause a wide spectrum of potentially life-threatening conditions as malabsorption and protein-energy malnutrition. We describe three female CVID adult patients presenting with chronic diarrhea, weight loss, and protein-energy malnutrition due to different underlying conditions. Our review of the literature explores the various gastrointestinal involvements in CVID and points out several histopathological findings proper of the disease, thus highlighting the relevance of the endoscopic and histological assessment in CVID patients presenting with chronic diarrhea.

Preferential Reduction of Circulating Innate Lymphoid Cells Type 2 in Patients with Common Variable Immunodeficiency with Secondary Complications Is Part of a Broader Immune Dysregulation

PURPOSE

Over a third of patients with common variable immunodeficiency (CVID) suffer from secondary complications like inflammatory organ disease, autoimmune manifestations, or lymphoproliferation contributing to increased morbidity and mortality in affected patients. Innate lymphoid cells (ILCs) have emerging roles in setting the milieu for physiological, but also pathological, immune responses and inflammation. We therefore sought to correlate the recently identified disturbed homeostasis of ILCs with alterations of the adaptive immune system in complex CVID patients (CVIDc).

METHODS

We quantified peripheral blood ILC and T helper cell subsets of 58 CVID patients by flow cytometry and compared the results to the clinical and immunological phenotype.

RESULTS

Total ILCs were significantly reduced in peripheral blood of CVIDc patients compared to healthy individuals, but not to CVID patients who suffered only from infections (CVIDio). This reduction was mainly due to a decrease in ILC2s, while ILC3s were relatively increased in CVIDc compared to CVIDio patients. This alteration in ILC phenotype was more prominent in patients with an expansion of CD21^low B cells, but we could not detect an association of the altered ILC phenotype with a T_H1-shift among circulating CD4 T cells, which was also prominent in CVIDc patients.

CONCLUSION

We confirm a relative shift in ILCs of CVIDc patients towards ILC3s which was associated with the expansion of CD21^low B cells, but not overtly with the relative expansion of T_H1-like T cells. Given the relative abundance of T_H1-like T cells compared to ILCs, these probably represent a more prominent source of the observed IFNγ-signature in CVIDc patients.

Carnosic acid induces apoptosis of hepatocellular carcinoma cells via ROS-mediated mitochondrial pathway

Carnosic acid (CA), an important bioactive phenolic diterpene mainly found in labiate plants, exerts various biological functions, including antioxidant, anti-inflammatory, antitumor, and neuroprotective activities. In the present study, we proved the deleterious effects of CA against hepatocellular carcinoma (HCC) in both in vitro and in vivo models. In vitro, CA significantly decreased cell viability, inhibited cell proliferation and migration, enhanced apoptosis, and increased caspase-3, -8, and -9 activities in HepG2 and SMMC-7721 cells. Specifically, CA led to a decreased mitochondrial membrane potential (MMP) and increases in intracellular reactive oxygen species (ROS) levels and apoptosis-related protein expression. Pre-incubation of HCC cells with N-Acetyl-l-cysteine (NAC), a ROS inhibitor, strongly suppressed CA-induced apoptotic phenomena, including reduced cell viability, excessive ROS levels, MMP decreases, and abnormal protein expression, suggesting an association of CA-induced apoptosis with oxidative stress-mediated mitochondrial pathways. In HepG2-and SMMC-7721-xenograft tumor mouse models, treatment with CA inhibited tumor growth and modulated apoptosis-related protein expression, confirming the anti-HCC effects of this chemical. Moreover, the CA-mediated anti-HCC effects associated with oxidative stress provide experimental evidence to support the potential use of CA as a drug therapy for HCC.

Human CD56dimCD16dim Cells As an Individualized Natural Killer Cell Subset

Human natural killer (NK) cells can be subdivided in several subpopulations on the basis of the relative expression of the adhesion molecule CD56 and the activating receptor CD16. Whereas blood CD56^brightCD16^dim/− NK cells are classically viewed as immature precursors and cytokine producers, the larger CD56^dimCD16^bright subset is considered as the most cytotoxic one. In peripheral blood of healthy donors, we noticed the existence of a population of CD56^dimCD16^dim NK cells that was frequently higher in number than the CD56^bright subsets and even expanded in occasional control donors but also in transporter associated with antigen processing-deficient patients, two familial hemophagocytic lymphohistiocytosis type II patients, and several common variable immunodeficiency patients. This population was detected but globally reduced in a longitudinal cohort of 18 HIV-1-infected individuals. Phenotypically, the new subset contained a high percentage of relatively immature cells, as reflected by a significantly stronger representation of NKG2A⁺ and CD57⁻ cells compared to their CD56^dimCD16^bright counterparts. The phenotype of the CD56^dimCD16^dim population was differentially affected by HIV-1 infection as compared to the other NK cell subsets and only partly restored to normal by antiretroviral therapy. From the functional point of view, sorted CD56^dimCD16^dim cells degranulated more than CD56^dimCD16^bright cells but less than CD56^dimCD16⁻ NK cells. The population was also identified in various organs of immunodeficient mice with a human immune system (“humanized” mice) reconstituted from human cord blood stem cells. In conclusion, the CD56^dimCD16^dim NK cell subpopulation displays distinct phenotypic and functional features. It remains to be clarified if these cells are the immediate precursors of the CD56^dimCD16^bright subset or placed somewhere else in the NK cell differentiation and maturation pathway.

Complement factor P is a ligand for the natural killer cell-activating receptor NKp46

Innate lymphoid cells (ILCs) are involved in immune responses to microbes and various stressed cells, such as tumor cells. They include group 1 [such as natural killer (NK) cells and ILC1], group 2, and group 3 ILCs. Besides their capacity to respond to cytokines, ILCs detect their targets through a series of cell surface-activating receptors recognizing microbial and nonmicrobial ligands. The nature of some of these ligands remains unclear, limiting our understanding of ILC biology. We focused on NKp46, which is highly conserved in mammals and expressed by all mature NK cells and subsets of ILC1 and ILC3. We show here that NKp46 binds to a soluble plasma glycoprotein, the complement factor P (CFP; properdin), the only known positive regulator of the alternative complement pathway. Consistent with the selective predisposition of patients lacking CFP to lethal Neisseria meningitidis (Nm) infections, NKp46 and group 1 ILCs bearing this receptor were found to be required for mice to survive Nm infection. Moreover, the beneficial effects of CFP treatment for Nm infection were dependent on NKp46 and group 1 NKp46+ ILCs. Thus, group 1 NKp46+ ILCs interact with the complement pathway, via NKp46, revealing a cross-talk between two partners of innate immunity in the response to an invasive bacterial infection.