Being the leading cause of mortality by a single infectious agent, tuberculosis (TB) continues as one of the most relevant issues of public health. Another pandemic disease is type 2 diabetes mellitus (T2D) is usually associated with immunodeficiency. Thus, an increased prevalence of TB-T2D comorbidity represents one of the most significant challenges for health providers. During the chronic phase of both diseases, several immunoendocrine abnormalities are occurring, but extra-adrenal production of active glucocorticoids (GCs) is a possible deleterious factor in both entities. Active GCs have been related to insulin resistance and suppression of Th1 responses, contributing to T2D and TB pathogenesis. 11-β-hydroxysteroid dehydrogenase type 1 (11-βHSD1) catalyzes the conversion of inactive GGs in their active form (cortisol or corticosterone in rodents) in the lungs and liver and could be responsible for this immunoendocrine disfunction. Dehydroepiandrosterone (DHEA) is an anabolic adrenal hormone with antagonist effects against GCs on immune cells and glucose metabolism. A synthetic analog of DHEA, the 16a-bromoepindrosterone (BEA), lacks an anabolic effect while keeping his immune and metabolic effect. The therapeutic efficiency of BEA was studied in a murine model of T2D-TB comorbidity. TB-T2D mice underwent more severe lung disease than in TB-infected but non-diabetic animals. BEA decreased the active form of GCs and 11-βHSD1 expression, while increasing 11-βHSD2 expression, which reduced hyperglycemia and liver steatosis, lung bacillary loads, and pneumonia. Thus, it seems that BEA is an efficient therapy to control metabolic and immune abnormalities caused by high active GCs production.

Autoimmune neutropenia (AIN) in childhood is characterized by chronic neutropenia and positivity for antineutrophil antibodies, resulting in the excessive destruction of neutrophils. In this study, we investigated the involvement of regulatory T cells (Tregs) in the pathogenesis of AIN in childhood. Tregs have been classified into three subpopulations based on the expressions of CD45RA and FOXP3: resting Tregs, activated Tregs, and non-suppressive Tregs. The frequency of activated Tregs (CD4+CD25+FOXP3highCD45RA− T cells) as well as that of total Tregs (CD4+CD25+FOXP3+ T cells) in peripheral blood was significantly decreased in patients with AIN. Analysis of the T cell receptor (TCR)-Vβ repertoire of CD4+ T cells revealed skewed usages in patients with AIN compared with that observed in age-matched control subjects. Regarding T cell subsets, the use of four of 24 TCR-Vβ families in Tregs and one in conventional T cells were increased in patients with AIN. The number of patients with AIN who showed skewed usages of TCR-Vβ family in conventional and Tregs was significantly higher than that reported in control subjects. When the preference between Tregs and conventional T cells in each TCR-Vβ family was individually compared, different use was prominently observed in the TCR-Vβ 9 family in patients with AIN. These results suggest that the quantitative abnormalities of Tregs and the skew of the TCR-Vβ repertoire in CD4+ T cells, including Tregs and conventional T cells, may be related to autoantibody production through a human neutrophil antigen-reactive T cell clone.

Tuberculosis kills more people than any other single infectious disease globally. Despite decades of research, there is no vaccine to prevent TB transmission. Bacille Calmette-Guerin (BCG) vaccine developed a century ago has little effect on pulmonary TB and does not control transmission. Lack of an effective vaccine emanates from lack of knowledge on correlates of protective immunity on which to base vaccine design and development. However, some household contacts who are extensively exposed to Mtb infection remain persistently negative to tuberculin skin test and interferon-gamma assay. These individuals called “resisters” clear Mtb infection early before the development of acquired immunity. The immunological basis of early Mtb clearance is yet to be established, however, innate lymphocytes such as monocytes/macrophages, dendritic cells, neutrophils and natural killer cells, and innate like T cells such as mucosal associated invariant T cells, invariant natural killer T cells and gamma-delta (γδ) T cells have been implicated in this early protection. One of the cells that has attracted increasing attention in recent years, in protection against Mtb is the natural killer cell. Emerging data from animal and epidemiological studies indicate that NK cells may play a significant role in the fight against Mtb. NK cells express various surface markers to recognize and kill both Mtb and Mtb-infected cells. In this review, recent advances in our understanding of NK cells in the fight against Mtb early during infection, with emphasis on cohort studies, will be presented.

Tissue damage associated with trauma might release a sufficient autoantigen substrate to break immune tolerance. In a previous study, we showed that the leukopenia observed following severe inflammation is related to adenosine A1-receptor (A1R) desensitization and A2AR upregulation. We hypothesized that, under destructive pathological conditions this mechanism is beneficial in reducing prevalence of autoimmunity. In this study, we aim to evaluate the protective role of A1R and A2AR in prevention of autoimmune diseases. We used two murine models of autoimmune diseases: type 1 diabetes (T1D) induced by low-dose streptozotocin and pristane-induced lupus (PIL) and on neutrophils we studied NETosis regulation by adenosine. In both the T1D and PIL models, A1R-KO mice were predisposed to the development of autoimmunity. In the PIL model, in WT mice, parallel to the decline of A1R mRNA levels, lymphocytes number dropped (-85%) 6h after pristane injection. WT mice remained without any sign of disease at 36 weeks. In contrast, following pristane 43% of A1R-KO mice suffered from lupus-like disease. Compared to A1R-KO, in WT mice at 10 days A2AR mRNA levels were significantly higher. Similar to PIL, in T1D model the presence of A1R and A2AR was protective. In addition, we found that A1R increases and A2AR suppresses NETosis. We suggest that adenosine-dependent immune suppression and reduction in neutrophil extracellular traps (NETs) limits the reactive T-cells and development of anti-double strand DNA (dsDNA) antibodies that promote autoimmunity.

Objectives: The aims of the study were to further elucidate the roles of M1 and M2 macrophages in the pathogenesis of EAE and the effects of treatment with M2 macrophages that target certain pro-inflammatory cytokines and with immunomodulatory preparations that beneficially influence the disease course should be in focus of future therapeutic trials. Results: Enhanced the total number of macrophages at the onset of clinical signs in the EAE group, consistent with an increased proportion of M1 cells and low numbers of M2 cells. As the disease progressed and the symptoms worsened, M1 cells were decreased and M2 cells were gradually increased till the peak. In the recovery stage, M2 cell numbers were gradually decreased. Treatment with M2 macrophages inhibited the NF-κb pathway, alleviated the symptoms of EAE, reduced inflammatory cell infiltration and demyelination in the central nervous system, and decreased the numbers of macrophages in the spleens. BAY-11-7082, an NF-κb blocking agent, could reduce the total number of macrophages both in vivo and in vitro, effectively prevented the EAE development, and significantly inhibited the symptoms EAE in mice. Conclusions: Macrophages may play a crucial role in the pathogenesis of EAE, while M2 macrophages have anti-inflammatory effects. Transfer of M2 macrophages to EAE mice can block the NF-κb pathway successfully and relieve the EAE symptoms. Application of NF-κb blockers is useful in the prevention and treatment of EAE.

Follicular helper T cells (Tfh) cells are generally considered critical in secondary lymphoid tissues; however, they are also identified in the circulation and in tertiary lymphoid structures in chronic inflammation. Gingival tissues with periodontitis reflect chronic inflammation so genomic footprints of Tfh cells should occur in these tissues and may differ related to aging effects. Methods: Macaca mulatta monkeys were used in a model of ligature-induced periodontitis [adult group (12-23 years of age); young group (3-7 years)]. Gingival tissue and subgingival microbiome samples were obtained at matched healthy sites, sites during ligature-induced disease, and in samples after clinical resolution. Microarray analysis examined Tfh genes (n=40) and the microbiome samples were examined using 16S MiSeq. Results: An apparent increase in the major transcription factor of Tfh cells, BCL6, was found with disease in both adult and young animals, while the master transcription markers of other T cell subsets were either decreased or showed minimal change. A number of the Tfh related genes, including surface receptors, secreted products and transcription factors were also significantly increased during disease. Unique microbial complexes showed patterns of interactions with Tfh genes that differed in health and disease. Conclusions: An increase in Tfh cell responsiveness occurred later in the progression of periodontitis, affected by age and strongly related to specific microbial complexes. The capacity of gingival Tfh cells to contribute to localized B cell activation and active antibody responses, including affinity maturation may be critical for controlling periodontal lesions and contributing to limiting and/or resolving the lesions.

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease that leads to joint destruction and disability. Despite a significant progress in administration of biological agents for RA patients, there is still a need for improved therapy. Intravenous-immunoglobulins (IVIG) , a pooled polyspecific immunoglobulin-G (IgG) extracted from 20,000 healthy subjects, showed beneficial therapeutic effect in patients with immune-deficiency, sepsis, and autoimmune diseases. The current study aim to investigate the beneficial effect of treatment with IVIG in established collagen induced arthritis in DBA/1j mice. Murine arthritis was induced in DBA/1j mice. The treatment with IVIG started when the disease was established. The clinical score was followed twice a week until day 48. The mice were bled for plasma, the paws were H&E stained. Cytokine profile in the plasma was analyzed by Luminex technology, titers of circulating anti-collagen antibodies in the plasma was tested by ELISA. Our results show that treatment with IVIG in murine, significantly rreduced the clinical arthritis score (P<0.001). Moreover, mode of action show that IVIG significantly reduced circulating level of inflammatory cytokines (IFN, IL-1β, IL-17, IL-6, TNFα) (P<0.001), inhibit anti-collagen antibodies (P < 0.001) in the plasma of CIA mice. Importantly, histopathological examination revealed that IVIG treatment prevented the migration of inflammatory immune cells into the cartilage and synovium, reduced the extent of joint damage and preserved joint architecture. Our results proved for the first time the valuable anti-inflammatory treatment of IVIG in experimental RA. We propose IVIG therapy for a subgroup of patients with as rheumatological-related diseases.

The skin is a unique immune organ that constitutes a complex network of physical, chemical, and microbiological barriers against external insults. Keratinocytes are the most abundant cell type in the epidermis. These cells form the physical skin barrier and represent the first line of the host defense system by sensing pathogens via innate immune receptors, initiating antimicrobial responses and producing various cytokines, chemokines and antimicrobial peptides, which are important events in immunity. A damaged epidermal barrier in atopic dermatitis allows the penetration of potential allergens and pathogens to activate keratinocytes. Among the dysregulation of immune responses in atopic dermatitis, activated keratinocytes play a role in several biological processes that contribute to the pathogenesis of atopic dermatitis. In this review, we summarize the current understanding of the innate immune functions of keratinocytes in the pathogenesis of atopic dermatitis, with a special emphasis on skin-derived antimicrobial peptides and atopic dermatitis-related cytokines and chemokines in keratinocytes. An improved understanding of the innate immunity mediated by keratinocytes can provide helpful insight into the pathophysiological processes of atopic dermatitis and support new therapeutic efforts.

Introduction: long-term observation of patients with ANCA-associated vasculitis (AAV) allows the identification of different longitudinal patterns of ANCA levels during follow-up. This study aimed to characterise these patterns and to determine their prognostic significance. Methods: all ANCA determinations performed in two university hospitals along a 2-year period were retrospectively reviewed. Patients were included in the analysis if they had high titers of anti-myeloperoxidase (anti-MPO) or anti-proteinase 3 (anti-PR3) antibodies at least once, they had ≥5 serial ANCA determinations, and they had AAV diagnosed by biopsy or ACR classification criteria. Patients’ time-course ANCA patterns were classified as monophasic, remitting, recurrent or persistent. Associations between ANCA patterns and prognostic variables (relapse rate and renal outcome) were analysed by univariate and multivariate statistics. Results: A total of 99 patients (55 with microscopic polyangiitis [MPA], 36 with granulomatosis with polyangiitis [GPA], and 8 with eosino¬philic granulomatosis with polyangiitis) were included. Median follow-up was 9 years. Among patients diagnosed with MPA or GPA, recurrent or persistent ANCA patterns were associated with a higher risk of clinical relapse (HR 3.7 [95% CI 1.5-9.1] and HR 2.9 [95% CI 1.1-8.0] respectively), independently of clinical diagnosis or ANCA specificity. In patients with anti-MPO antibodies, the recurrent ANCA pattern was associated with worsening renal function (OR 5.7 [95% CI 1.2-26.0]). Conclusion: Recurrent or persistent ANCA patterns are associated with a higher risk of clinical relapse. A recurrent ANCA pattern was associated with worsening renal function in anti-MPO-associated vasculitis.

The interesting report by Karagianni P et al on the finding of increased DNA methylation of H19 locus imprinting control region in saliva samples of Sjögren’s syndrome patients correlating with low complement C4 levels, may offer insights into how C4 level may be regulated in serpinopathies such as C1-inhibitor deficiency. An undetectable or low C4 level in patients with severe angioedema is a feature of C1-inhibitor deficiency (hereditary angioedema (HAE) type I with low to absent function and antigenic levels; HAE type II with point mutations in SERPING1 gene that affect the reactive centre loop affecting protein function only). However, C4 levels do not always clinically correlate with disease activity, and up to 6% patients do not have known mutations in the SERPING1 gene.

Natural Killer (NK) cell functions are regulated by diverse inhibitory and activating receptors including Killer cell Immunoglobulin-like receptors (KIR) which interact with HLA class I molecules. Some KIR/HLA genetic combinations were reported associated with spontaneous clearance (SC) of hepatitis C virus (HCV) but with discordant results, possibly reflecting KIR and/or HLA gene polymorphism according to populations. KIR/HLA genetic combinations associated with both an exhaustive NK and T cell repertoire were investigated in a cohort of HIV-HCV co-infected individuals with either SC (n=68) or chronic infection (CI, n=163) compared to uninfected blood donors (Ctrl, n=100). Multivariate analysis showed that the HLA C2C2 environment was associated with SC only in European HIV-HCV co-infected individuals (OR=4.30[1.57-12.25], p=0.005). KIR2D+ NK cell repertoire and potential of degranulation of KIR2DL1/S1+ NK cells were similar in SC European cohort compared to uninfected individuals. In contrast, decreased frequencies of KIR2DS1+ and KIR2DL2+ NK cells were detected in CI group of Europeans compared to SC and a decreased frequency of KIR2DL1/S1+ NK cells compared to controls. On the T cell side, higher frequencies of DNAM-1+ and CD57+ T cells were observed in SC in comparison to controls. Interestingly, SC subjects emphasized increased frequencies of KIR2DL2/L3/S2+ T cells compared to CI subjects. Our study underlines that the C2 environment may activate efficient KIR2DL1+ NK cells in viral context and maintain KIR2DL2/L3/S2+ mature T cell response in the absence of KIR2DL2 engagement with its cognate ligands in SC group of HCV-HIV co-infected European patients.

Innate immune sensing of viral molecular patterns is essential for development of antiviral responses. Like many viruses SARS CoV-2 has evolved strategies to circumvent innate immune detection including low CpG levels in the genome, glycosylation to shield essential elements including the receptor binding domain, RNA shielding and generation of viral proteins that actively impede anti-viral interferon responses. Together these strategies allow widespread infection and increased viral load. Despite the efforts of immune subversion SARS-CoV-2 infection does activate innate immune pathways inducing a robust type I/III interferon response, production of proinflammatory cytokines, and recruitment of neutrophils and myeloid cells. This may induce hyperinflammation or alternatively, effectively recruit adaptive immune responses that help clear the infection and prevent reinfection. The dysregulation of the renin-angiotensin system due to downregulation of angiotensin converting enzyme 2, the receptor for SARS-CoV-2, together with the activation of type I/III interferon response, and inflammasome response converge to promote free radical production and oxidative stress. This exacerbates tissue damage in the respiratory system but also leads to widespread activation of coagulation pathways leading to thrombosis. Here, we review the current knowledge of the role of the innate immune response following SARS-CoV-2 infection, much of which is based on the knowledge from SARS-CoV and other coronaviruses. Understanding how the virus subverts the initial immune response and how an aberrant innate immune response contributes to the respiratory and vascular damage in COVID-19 may help explain factors that contribute to the variety of clinical manifestations and outcome of SARS-CoV-2 infection.

The clinical application of monoclonal antibodies (mAbs) revolutionised the field of cancer therapy as it enabled the successful treatment of previously untreatable types of cancer. Different mechanisms play a role in the anti-tumour effect of mAbs and both target engagement with the Fab arm as well as Fc-mediated effector functions contribute to the efficacy of treatment. Because Ig isotypes differ in their ability to bind to FcRs on immune cells as well as in their ability to activate complement, they differ in the immune responses they activate. Therefore, the choice of antibody isotype for therapeutic mAbs is dictated by its intended mechanism of action. Considering that clinical efficacy of many mAbs is currently achieved only in subsets of patients, optimal isotype selection and Fc optimisation during antibody development may represent an important step towards improved patient outcome. Here, we discuss the current knowledge of the therapeutic effector functions of different isotypes and Fc-engineering strategies to improve mAbs application.

Background: Bacillus Calmette-Guérin (BCG) vaccination policies of countries are postulated to have effect on the course of coronavirus disease 2019 (COVID-19) pandemic. Methods: Retrospective cross-sectional study was conducted between March 11-June 10, 2020 in a chest clinic in a state hospital in Istanbul,Turkey. Adults with diagnosis of COVID-19 pneumonia confirmed with severe acute respiratory syndrome coronavirus 2 polymerase chain reaction positivity in a nasopharyngeal sample and pulmonary infiltrates in computed chest tomography were included consecutively. Sociodemographic characteristics, body-mass index, smoking status, comorbid diseases, income rates, and BCG-vaccination status were compared between severe and mild patients with COVID-19 pneumonia. Results: Study population consisted of 123 adults (mean age, 49.7 years [standard deviation, 13.3 years]; 82 (66.7%) male). The proportion of BCG-vaccinated cases was significantly lower among severe patients than mild patients with COVID-19 pneumonia (68.5% vs 88.2%; p=.026). Mean age (54.0 ± 11.5 years vs 38.3 ±10.7 years; p <.001), diabetes rate (32.6% vs 5.9%; p=.002) and low-income (84.3% vs 52.9% p<.001) are higher in patients with severe COVID-19 pneumonia than in patients with mild COVID-19 pneumonia. Multivariate logistic regression analysis showed that increasing age (odds ratio [OR], 1.112; 95% confidence interval [CI], 1.058 – 1.169; p<.001) and low income (OR, 3.369; 95% CI, 1.074 – 10.570; p =.037) are associated with severe COVID-19 pneumonia. Conclusion: Clinical data does not support that being vaccinated with BCG is associated with disease severity in COVID-19 pneumonia. Age and low-income are the major predictors for disease severity.

Chronic Granulomatous Disease (CGD) is a rare inherited disorder in which phagocytes lack NADPH oxidase activity. The most common form is the X-linked CGD (X-CGD), caused by mutations in the CYBB gene. Clinical, functional and genetic characterizations of 16 CGD cases of male patients and their relatives were done. We classified them as suffering from different variants of CGD (X910, X91− or X91+) according to NOX2 expression and NADPH oxidase activity in neutrophils. Twelve mutations were novel (10 X910-CGD and 2 X91− -CGD). One X910-CGD was due to a new and extremely rare double missense mutation Thr208Arg-Thr503Ile. We investigated the pathological impact of each single using stable transfection of each mutated cDNA in the NOX2 knock-out PLB-985 cell line. Both mutations leading to X91−-CGD were also novel; one deletion -67delT was localized in the promoter region of CYBB, the second one c.253-1879A>G mutation activates a splicing donor site, which unveils a cryptic acceptor site, leading to the inclusion of a 124-nucleotide pseudo-exon between exons 3 and 4 and responsible for the partial loss of NOX2 expression. Both X91−-CGD mutations were characterized by a low cytochrome b558 expression and a faint NADPH oxidase activity. The functional impact of new missense mutations is discussed in the context of a new 3D-model of the dehydrogenase domain of NOX2. Our study demonstrates that low NADPH oxidase activity found in both X91−-CGD patients correlates with mild clinical forms of CGD whereas X910-CGD and X91+-CGD cases remain the most clinically severe forms.

Although most autoimmune diseases are considered to be CD4 T-cell or antibody-mediated, many respond to CD20-depleting antibodies that have limited influence on CD4 and plasma cells. This includes rituximab that is used in cancer, rheumatoid arthritis and off-label in a large number of other autoimmunities, notably multiple sclerosis, where ofatumumab is in late stage development and ocrelizumab is approved for use. Recently, the COVID-19 pandemic created concerns about immunosuppression in autoimmunity, leading to cessation or a delay in immunotherapy treatments. However, based on the known and emerging biology of multiple sclerosis and COVID-19, it was hypothesised that whilst B-cell depletion should not necessarily expose people to severe SARS-CoV-2-related issues, it may inhibit protective immunity following infection and vaccination. As such, drug-induced B-cell subset inhibition that controls multiple sclerosis and other autoimmunities, would not influence innate and CD8 T-cell responses, which are central to SARS-CoV-2 elimination, nor the hyper-coagulation and innate inflammation causing severe morbidity. This is supported clinically, as the majority (mortality rate n=~5/392) of SARS-CoV-2 infected, CD20-depleted people with multiple sclerosis have recovered. However, protective neutralising-antibody and vaccination responses are predicted to be blunted, until naïve B-cells repopulate, based on B-cell repopulation-kinetics and vaccination responses, from published rituximab and unpublished ocrelizumab (NCT00676715, NCT02545868) trial data, shown here. This suggests that it may be possible to undertake dose-interruption to maintain inflammatory disease control in MS and other autoimmune diseases, whilst allowing effective vaccination against SARS-CoV-29, if and when an effective vaccine is available.

Immune response variations could define successful resistance to Hepatitis C Virus (HCV) infection. Toll-like receptors (TLR)-3 are innate detectors of dsRNA viruses while bacterial and viral unmethylated CpG motifs are recognized by TLR9. We previously reported that TLR3.rs3775290 “CC” genotype was associated with HCV chronicity, while TLR9 gene played no major role in this infection. This study identified the role of TLR3.rs3775290 (c.1377C/T), TLR9.rs5743836 (-1237T→C) and TLR9.rs352140 (G2848A) gene polymorphisms in predicting the outcome of HCV-specific cell-mediated immunity (CMI) among Egyptian healthcare workers (HCWs) and patients. We enrolled 546 subjects (409 HCWs and 137 patients) divided into four groups. Group1: 265 seronegative, aviraemic subjects; group2: 25 seronegative, viraemic subjects; group3: 87 subjects with spontaneously resolved HCV infection; and group4: 169 chronic HCV HCWs and patients. All subjects were genotyped by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis for the TLR3.rs3775290, TLR9.rs5743836 and TLR9.rs352140 SNPs. We, also, quantified HCV-specific CMI in 265 HCWs distributed among the four groups using an interferon gamma (IFN-γ) enzyme-linked immunospot (ELISpot) assay in response to nine HCV genotype 4a overlapping 15mer peptide pools covering the whole viral genome. No statistically significant difference was found between CMI responding subjects with different HCV states and TLR3.rs3775290 genotype or TLR9.rs352140. However, there was a significant relationship between the outcome of the HCV-specific CMI and the TLR9.rs5743836 genotype among the responding subjects (p=0.005) and the chronic HCV patients (p=0.044). In conclusion, TLR9.rs5743836 SNP; but not TLR3.rs3775290 or TLR9.rs352140 genotypes; could predict the outcome of HCV-specific CMI responses among genotype-4-infected Egyptians.

Follicular T helper (Tfh) and regulatory (Tfreg) cells are distinct subsets of CD4+T lymphocytes, regulating humoral immune responses in the germinal center. Dysregulated Tfh and Tfreg cells are believed to associate with autoimmunity. Here, we evaluated the frequencies of circulating CXCR5+PD-1+ Tfh (cTfh) and CXCR5+PD-1+FoxP3+CD25+ Tfreg (cTfreg) cells, and their corresponding cytokines from the peripheral blood mononuclear cells of 20 patients with relapsing-remitting multiple sclerosis (MS) and 12 age- and sex-matched healthy controls (HC). Subsets of cTfh cells by Th1 and Th17 related surface markers (CXCR3 and CCR6) were also evaluated. We found the frequency of cTfh cells was significantly higher in MS patients compared to HC (p=0.002). Conversely, cTfreg cells were downregulated in MS patients (p<0.0001). IL-21 producing cTfh cells were significantly increased in MS patients (p=0.003), while IL-10 secreting cTfreg cells were decreased in MS compared to HC (p=0.02). Among cTfh cells, cTfh17.1 cells were major subtypes that were significantly increased in MS compared to HC (p=0.002) and the frequency of IL-21 secreting cells were highest. These results suggest that an imbalanced distribution of cTfh and cTfreg exist in MS, which contributes to reciprocally altered IL-21 and IL-10 production.