Use of interleukin-6 receptor antibodies in the second and third trimester of pregnancy: a retrospective cohort study.

BACKGROUND: A paucity of data exists to inform the use of interleukin (IL)-6 receptor antibodies (anti-IL-6) in pregnancy, particularly in the third trimester. This study aimed to describe outcomes of pregnant women and their neonates exposed to these medications given after the first trimester to treat COVID-19. METHODS: In this retrospective cohort study, we included all women with COVID-19 who were treated with an anti-IL-6 during pregnancy at two tertiary hospitals in London, UK-Guy's and St Thomas' NHS Foundation Trust and Imperial College Healthcare NHS Trust-between March 1, 2020, and Sept 30, 2022. Maternal demographics, clinical data, administered medications, and maternal and neonatal outcomes were assessed for all included women via a review of medical records and through maternal medicine networks. FINDINGS: 25 women received an anti-IL-6 for COVID-19 in pregnancy during the study period and were followed up for 12 months. The group described were a population at high risk, with 24 requiring level two or three critical care. 24 women received tocilizumab and one received sarilumab. All women were prescribed at least three concomitant medications. 16 received the anti-IL-6 in the third trimester of pregnancy and nine during the seocnd trimester. There were no women with maternal neutropenia or pancytopenia; increases in liver enzymes in 16 of 20 women with available alanine aminotransferase data were in keeping with the severity of COVID-19 reported and all three women who developed a secondary bacterial infection mounted a C-reactive protein response. There was one maternal death due to COVID-19. All pregnancies resulted in livebirths and there was one twin pregnancy. 16 of 26 babies were born preterm. One baby died at age 6 months due to complications of extreme prematurity. A transient neonatal cytopenia was described in six of 19 babies in whom a full blood count was performed. Although these findings are likely to be in keeping with prematurity alone, we cannot exclude the possibility that transplacental transfer of anti-IL-6 was contributory. INTERPRETATION: We report further data on the use of anti-IL-6 in the second and third trimesters of pregnancy for the management of COVID-19. When extrapolated, our data can inform shared decision making for individuals who would benefit from the use of anti-IL-6 into the third trimester of pregnancy for management of rheumatological disease. FUNDING: None.

The Cytokine Storm of Multicentric Castleman Disease.

As described throughout this book, different triggers can elicit a variety of different cytokine storm disorders that share overlapping clinical features (Fig. 31.1). Even within a particular cytokine storm disorder, multiple different triggers can elicit the syndrome. Like HLH, multicentric Castleman disease (MCD) serves as a great example of this as it can be caused by a viral infection, neoplastic cell population, or an unknown cause. Furthermore, the idiopathic subtype of MCD (iMCD) provides one of the first examples of a cytokine storm disorder that could be abrogated with targeted neutralization of a single cytokine when inhibition with the anti-interleukin-6 (IL-6) receptor monoclonal antibody tocilizumab was shown to effectively treat iMCD in the 1990s. Of course, this "iMCD treatment," tocilizumab, has been used in a variety of cytokine storm settings over the last 30+ years.

In vitro neutralization of IL-6 receptor exacerbates damage to intestinal epithelial cells during Mycobacterium avium paratuberculosis infection.

Like TNFα, IL-6 is upregulated in Crohn's disease (CD) especially in patients associated with Mycobacterium avium paratuberculosis (MAP) infection, and both cytokines have been targeted as a therapeutic option for the treatment of the disease despite the accepted partial response in some patients. Limited response to anti-IL-6 receptor-neutralizing antibodies therapy may be related to the homeostatic dual role of IL-6. In this study, we investigated the effects and the signaling mechanism of IL-6 involved in intestinal epithelial integrity and function during MAP infection using an in vitro model that consists of THP-1, HT-29 and Caco-2 cell lines. Clinically, we determined that plasma samples from MAP-infected CD patients have higher IL-6 levels compared to controls (P-value < 0.001). In CD-like macrophages, MAP infection has significantly upregulated the secretion of IL-6 and the shedding of (IL-6R) from THP-1 macrophages, P-value < 0.05. Intestinal cell lines (Caco-2 and HT-29) were treated with the supernatant of MAP-infected THP-1 macrophages with or without a neutralizing anti-IL-6R antibody. Treating intestinal Caco-2 cells with supernatant of MAP-infected macrophages resulted in significant upregulation of intestinal damage markers including claudin-2 and SERPINE1/PAI-1. Interestingly, blocking IL-6 signaling exacerbated that damage and further increased the levels of the damage markers. In HT-29 cells, MAP infection upregulated MUC2 expression, a protective response that was reversed when IL-6R was neutralized. More importantly, blocking IL-6 signaling during MAP infection rescued damaged Caco-2 cells from MAP-induced apoptosis. The data clearly supports a protective role of IL-6 in intestinal epithelia integrity and function especially in CD patients associated with MAP infection. The findings may explain the ineffective response to anti-IL6 based therapy and strongly support a therapeutic option that restores the physiologic level of IL-6 in patient's plasma. A new treatment strategy based on attenuation of IL-6 expression and secretion in inflammatory diseases should be considered.

IL-6 Blockade in Cytokine Storm Syndromes.

Interleukin-6 (IL-6) is a pro-inflammatory cytokine elevated in cytokine storm syndromes, including hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS). It is also elevated in cytokine release syndrome (CRS) after immune activating cancer therapies such as chimeric antigen receptor (CAR) T-cells or bispecific T-cell engagers (BITEs) and in some patients after infection with SARS-CoV-2. The interaction of IL-6 with its receptor complex can happen in several forms, making effectively blocking this cytokine's effects clinically challenging. Fortunately, effective clinical agents targeting the IL-6 receptor (tocilizumab) and IL-6 directly (siltuximab) have been developed and are approved for use in humans. IL-6 blockade has now been used to safely and effectively treat several cytokine storm syndromes (CSS). Other methods of investigation in effective IL-6 blockade are underway.

Mechanistic computational modeling of monospecific and bispecific antibodies targeting interleukin-6/8 receptors.

The spread of cancer from organ to organ (metastasis) is responsible for the vast majority of cancer deaths; however, most current anti-cancer drugs are designed to arrest or reverse tumor growth without directly addressing disease spread. It was recently discovered that tumor cell-secreted interleukin-6 (IL-6) and interleukin-8 (IL-8) synergize to enhance cancer metastasis in a cell-density dependent manner, and blockade of the IL-6 and IL-8 receptors (IL-6R and IL-8R) with a novel bispecific antibody, BS1, significantly reduced metastatic burden in multiple preclinical mouse models of cancer. Bispecific antibodies (BsAbs), which combine two different antigen-binding sites into one molecule, are a promising modality for drug development due to their enhanced avidity and dual targeting effects. However, while BsAbs have tremendous therapeutic potential, elucidating the mechanisms underlying their binding and inhibition will be critical for maximizing the efficacy of new BsAb treatments. Here, we describe a quantitative, computational model of the BS1 BsAb, exhibiting how modeling multivalent binding provides key insights into antibody affinity and avidity effects and can guide therapeutic design. We present detailed simulations of the monovalent and bivalent binding interactions between different antibody constructs and the IL-6 and IL-8 receptors to establish how antibody properties and system conditions impact the formation of binary (antibody-receptor) and ternary (receptor-antibody-receptor) complexes. Model results demonstrate how the balance of these complex types drives receptor inhibition, providing important and generalizable predictions for effective therapeutic design.

Extracellular CIRP co-stimulated T cells through IL6R/STAT3 in pediatric IgA vasculitis.

Immunoglobulin A vasculitis (IgAV) is the most common vasculitis of childhood. Disordered immune responses play important roles in its pathogenesis, but the comprehensive immune profile of the disease and the underlying mechanisms are still largely unknown. Here we found a potential disease biomarker cold inducible RNA binding protein (CIRP) in our pediatric IgAV cohort. Serum CIRP level in these patients were elevated and positively correlated with the increased early memory (CD45RA+CD62L+CD95+) T cells revealed using multicolor flow cytometry. Immune phenotyping of the patients showed they had more activated T cells with higher IL6Ra expression. T cell culture experiment showed CIRP further activated both human CD4+ and CD8+ T cells as indicated by increased perforin secretion and phosphorylation of STAT3. Blockade of IL6Rα attenuated CIRP-induced T cell toxicity in vitro. RNA-sequencing data further supported CIRP stimulation promoted human T cell activation and migration, fueled inflammation through the JAK-STAT signaling pathway. Therefore, IL6Ra-mediated T cell activation by extracellular CIRP may contribute to pathogenesis of IgAV in children, both CIRP and IL6Ra could be new therapeutic targets for IgAV.

Bioinformatics and in-silico findings reveal medical features and pharmacological targets of biochanin A against colorectal cancer and COVID-19.

Severe mortality due to the COVID-19 pandemic resulted from the lack of effective treatment. Although COVID-19 vaccines are available, their side effects have become a challenge for clinical use in patients with chronic diseases, especially cancer patients. In the current report, we applied network pharmacology and systematic bioinformatics to explore the use of biochanin A in patients with colorectal cancer (CRC) and COVID-19 infection. Using the network pharmacology approach, we identified two clusters of genes involved in immune response (IL1A, IL2, and IL6R) and cell proliferation (CCND1, PPARG, and EGFR) mediated by biochanin A in CRC/COVID-19 condition. The functional analysis of these two gene clusters further illustrated the effects of biochanin A on interleukin-6 production and cytokine-cytokine receptor interaction in CRC/COVID-19 pathology. In addition, pathway analysis demonstrated the control of PI3K-Akt and JAK-STAT signaling pathways by biochanin A in the treatment of CRC/COVID-19. The findings of this study provide a therapeutic option for combination therapy against COVID-19 infection in CRC patients.

Antibody to Interleukin-6 Receptor Inhibits In Vivo Growth of Human Colorectal Carcinoma Cell Xenografts.

BACKGROUND: Interleukin-6 receptor antibody (IL6R) inhibits colony formation and invasion by colorectal carcinoma (CRC) in vitro. We examined the effect of IL6R antibody on tumor growth of CRC xenografts in vivo. MATERIALS AND METHODS: SW480 cells inoculated subcutaneously into NU/NU mice were treated with anti-IL6R and tumor histology and growth-related signaling were subsequently estimated by hematoxylin and eosin and immunohistochemical staining. RESULTS: Tumor growth was inhibited by anti-IL6R treatment at dosages of both 0.1 and 1.0 mg/kg. Tumor cells had invaded into surrounding tissues in untreated mice, while there was no invasion of tumors in the IL6R antibody-treated mice. The expression of Ki-67, signal transducer and activator of transcription protein 3 (STAT3) and phosphor-extracellular signal-regulated kinase 1 and 2 (ERK1/2) were suppressed in anti-IL6R-treated tumors. CONCLUSION: IL6R antibody inhibited tumor growth and invasiveness in vivo by suppressing the expression of Ki-67, STAT3 and phosphor-ERK1/2. The results imply that the anti-IL6R may be a promising targeted drug for CRC.

Synergistic and additive interactions between receptor signaling networks drive the regulatory T cell versus T helper 17 cell fate choice.

CD4+ T cells differentiate into subsets that promote immunity or minimize damage to the host. T helper 17 cells (Th17) are effector cells that function in inflammatory responses. T regulatory cells (Tregs) maintain tolerance and prevent autoimmunity by secreting immunosuppressive cytokines and expressing check point receptors. While the functions of Th17 and Treg cells are different, both cell fate trajectories require T cell receptor (TCR) and TGF-ß receptor (TGF-ßR) signals, and Th17 polarization requires an additional IL-6 receptor (IL-6R) signal. Utilizing high-resolution phosphoproteomics, we identified that both synergistic and additive interactions between TCR, TGF-ßR, and IL-6R shape kinase signaling networks to differentially regulate key pathways during the early phase of Treg versus Th17 induction. Quantitative biochemical analysis revealed that CD4+ T cells integrate receptor signals via SMAD3, which is a mediator of TGF-ßR signaling. Treg induction potentiates the formation of the canonical SMAD3/4 trimer to activate a negative feedback loop through kinases PKA and CSK to suppress TCR signaling, phosphatidylinositol metabolism, and mTOR signaling. IL-6R signaling activates STAT3 to bind SMAD3 and block formation of the SMAD3/4 trimer during the early phase of Th17 induction, which leads to elevated TCR and PI3K signaling. These data provide a biochemical mechanism by which CD4+ T cells integrate TCR, TGF-ß, and IL-6 signals via generation of alternate SMAD3 complexes that control the development of early signaling networks to potentiate the choice of Treg versus Th17 cell fate.

The Importance of the Timing of Tocilizumab Administration in Moderate to Severely Ill COVID-19: Single Centered Experience Case series.

One of the main causes of death in COVID-19 is the dysregulation of the host's immune system which leads to cytokine storm, a potentially fatal systemic inflammatory syndrome. Interleukin 6 (IL-6) is a pro-inflammatory cytokine that is produced in response to infections and tissue injuries and is believed to play a pivotal role in the event of a cytokine storm, as signified by its increase in the process. Considering the role of IL-6 as a pro-inflammatory cytokine in the process of cytokine storm in COVID-19, perceiving IL-6 as a therapeutic target could prove to be promising. Tocilizumab is a monoclonal antibody that competitively inhibits the binding of IL-6 to its receptor (IL-6R). The use of IL-6R blocker is recommended for severe COVID-19 patients in the latest therapeutic guideline published by the World Health Organization (WHO), but the timing of the administration has not been specified. While previous studies about the use of tocilizumab in COVID-19 patients have shown various results, these studies do not emphasize on plasma IL-6 levels when deciding the time of tocilizumab administration. In this case series, we present three patients with moderate to severe COVID-19 infections that receive tocilizumab as an adjunct to the standard of care therapy. This case series introduces the novel idea that the timely use of tocilizumab as signified by plasma IL-6 levels in moderate to severe COVID-19 patients could potentially improve overall clinical condition and increase survival rate.

Molecular Mechanism of the Anti-Inflammatory Action of Heparin.

Our objective is to reveal the molecular mechanism of the anti-inflammatory action of low-molecular-weight heparin (LMWH) based on its influence on the activity of two key cytokines, IFNγ and IL-6. The mechanism of heparin binding to IFNγ and IL-6 and the resulting inhibition of their activity were studied by means of extensive molecular-dynamics simulations. The effect of LMWH on IFNγ signalling inside stimulated WISH cells was investigated by measuring its antiproliferative activity and the translocation of phosphorylated STAT1 in the nucleus. We found that LMWH binds with high affinity to IFNγ and is able to fully inhibit the interaction with its cellular receptor. It also influences the biological activity of IL-6 by binding to either IL-6 or IL-6/IL-6Rα, thus preventing the formation of the IL-6/IL-6Rα/gp130 signalling complex. These findings shed light on the molecular mechanism of the anti-inflammatory action of LMWH and underpin its ability to influence favourably conditions characterised by overexpression of these two cytokines. Such conditions are not only associated with autoimmune diseases, but also with inflammatory processes, in particular with COVID-19. Our results put forward heparin as a promising means for the prevention and suppression of severe CRS and encourage further investigations on its applicability as an anti-inflammatory agent.

Kinase activity profiling reveals contribution of G-protein signaling modulator 2 deficiency to impaired regulatory T cell migration in rheumatoid arthritis.

The ability of regulatory T (Treg) cells to migrate into inflammatory sites is reduced in autoimmune diseases, including rheumatoid arthritis (RA). The reasons for impaired Treg cell migration remain largely unknown. We performed multiplex human kinase activity arrays to explore possible differences in the post-translational phosphorylation status of kinase related proteins that could account for altered Treg cell migration in RA. Results were verified by migration assays and Western blot analysis of CD4+ T cells from RA patients and from mice with collagen type II induced arthritis. Kinome profiling of CD4+ T cells from RA patients revealed significantly altered post-translational phosphorylation of kinase related proteins, including G-protein-signaling modulator 2 (GPSM2), protein tyrosine kinase 6 (PTK6) and vitronectin precursor (VTNC). These proteins have not been associated with RA until now. We found that GPSM2 expression is reduced in CD4+ T cells from RA patients and is significantly downregulated in experimental autoimmune arthritis following immunization of mice with collagen type II. Interestingly, GPSM2 acts as a promoter of Treg cell migration in healthy individuals. Treatment of RA patients with interleukin-6 receptor (IL-6R) blocking antibodies restores GPSM2 expression, thereby improving Treg cell migration. Our study highlights the potential of multiplex kinase activity arrays as a tool for the identification of RA-related proteins which could serve as targets for novel treatments.

Anti-Interleukin-6 and Janus Kinase Inhibitors for Severe Neurologic Toxicity of Checkpoint Inhibitors.

BACKGROUND AND OBJECTIVES: To describe the marked clinical and biological responses of a targeted treatment with anti-interleukin-6 (IL-6)-receptor antibody and Janus kinase (JAK) inhibitors in a patient with a severe, corticoresistant CNS toxicity of immune-checkpoint inhibitor (ICI) therapy. METHODS: A 58-year-old man was admitted for subacute paraparesis, urinary retention, and ascending paresthesia. He was under treatment with ipilimumab and nivolumab for metastatic melanoma. Spine MRI disclosed multiple T2-hyperintense, contrast-enhancing longitudinally extensive lesions. A diagnosis of ICI-related acute transverse myelitis was made. RESULTS: ICIs were immediately discontinued, and the patient received high-dose glucocorticoids plus 1 session of plasma exchange, but he did not improve. Based on the marked elevation of CSF IL-6 (505 pg/mL), a second-line targeted therapy with anti-IL-6-receptor tocilizumab (8 mg/kg/mo for 3 infusions) plus JAK inhibitor ruxolitinib (50 mg/d) was administered. Patient neurologic status started to improve shortly after, with corresponding radiologic resolution. At 9 months, the patient was able to walk independently, presenting only slight residual disability while remaining in oncologic partial response. DISCUSSION: Our case suggests that some patients with severe, corticoresistant CNS immune-related toxicities of ICIs may benefit from cytokine blockade. Cytokine measurement in serum and CSF might help in selecting patients for personalized treatment strategies.

Investigation of Fascin1, a Marker of Mature Dendritic Cells, Reveals a New Role for IL-6 Signaling in CCR7-Mediated Chemotaxis.

Migration of mature dendritic cells (DCs) to lymph nodes is critical for the initiation of adaptive immunity. CCR7, a G-protein-coupled receptor for CCL19/21 chemokines, is known to be essential for chemotaxis of mature DCs, but the molecular mechanism linking inflammation to chemotaxis remains unclear. We previously demonstrated that fascin1, an actin-bundling protein, increases chemotaxis of mature mouse DCs. In this article, we demonstrated that fascin1 enhanced IL-6 secretion and signaling of mature mouse DCs. Furthermore, we demonstrated that IL-6 signaling is required for chemotaxis. Blockage of IL-6 signaling in wild-type DCs with an anti-IL-6 receptor α (IL-6Rα) Ab inhibited chemotaxis toward CCL19. Likewise, knockout of IL-6Rα inhibited chemotaxis of bone marrow-derived DCs. The addition of soluble IL-6Rα and IL-6 rescued chemotaxis of IL-6Rα knockout bone marrow-derived DCs, underscoring the role of IL-6 signaling in chemotaxis. We found that IL-6 signaling is required for internalization of CCR7, the initial step of CCR7 recycling. CCR7 recycling is essential for CCR7-mediated chemotaxis, explaining why IL-6 signaling is required for chemotaxis of mature DCs. Our results have identified IL-6 signaling as a new regulatory pathway for CCR7/CCL19-mediated chemotaxis and suggest that rapid migration of mature DCs to lymph nodes depends on inflammation-associated IL-6 signaling.

Interplay between interleukin-6 signaling and the vascular endothelium in cytokine storms.

Interleukin-6 (IL-6) plays a crucial role in host defense against infection and tissue injuries and is a bioindicator of multiple distinct types of cytokine storms. In this review, we present the current understanding of the diverse roles of IL-6, its receptors, and its signaling during acute severe systemic inflammation. IL-6 directly affects vascular endothelial cells, which produce several types of cytokines and chemokines and activate the coagulation cascade. Endothelial cell dysregulation, characterized by abnormal coagulation and vascular leakage, is a common complication in cytokine storms. Emerging evidence indicates that a humanized anti-IL-6 receptor antibody, tocilizumab, can effectively block IL-6 signaling and has beneficial effects in rheumatoid arthritis, juvenile systemic idiopathic arthritis, and Castleman's disease. Recent work has also demonstrated the beneficial effect of tocilizumab in chimeric antigen receptor T-cell therapy-induced cytokine storms as well as coronavirus disease 2019 (COVID-19). Here, we highlight the distinct contributions of IL-6 signaling to the pathogenesis of several types of cytokine storms and discuss potential therapeutic strategies for the management of cytokine storms, including those associated with sepsis and COVID-19.

Interleukin-6 receptor blockade in patients with COVID-19: placing clinical trials into context.

The pleiotropic cytokine interleukin-6 (IL-6) has been implicated in the pathogenesis of COVID-19, but uncertainty remains about the potential benefits and harms of targeting IL-6 signalling in patients with the disease. The efficacy and safety of tocilizumab and sarilumab, which block the binding of IL-6 to its receptor, have been tested in adults with COVID-19-related acute respiratory illness in randomised trials, with important differences in trial design, characteristics of included patients, use of co-interventions, and outcome measurement scales. In this Series paper, we review the clinical and methodological heterogeneity of studies of IL-6 receptor antagonists, and consider how this heterogeneity might have influenced reported treatment effects. Timing from clinical presentation to treatment, severity of illness, and concomitant use of corticosteroids are among the factors that might have contributed to apparently inconsistent results. With an understanding of the sources of variability in these trials, available evidence could be applied to guide clinical decision making and to inform the enrichment of future studies.

Comparison of efficacy between anti-IL-6 receptor antibody and other biological disease-modifying antirheumatic drugs in the patients with rheumatoid arthritis who have knee joint involvement: the ANSWER cohort, retrospective study.

OBJECTIVE: We aimed to investigate the efficacy of anti-IL-6 receptor antibody (aIL-6) and other biologic disease-modifying antirheumatic drugs (bDMARDs), such as TNF inhibitor and CTLA4-Ig in the treatment of rheumatoid arthritis (RA) in patients with knee joint involvement. METHODS: We retrospectively analyzed 1059 treatment courses of patients with RA who visited our hospitals and were treated with bDMARDs. We categorized them into two groups, with or without knee joint involvement. We investigated the clinical disease activity index (CDAI) at baseline and 12 weeks after the initiation of bDMARDs. We compared the improvement of the markers between aIL-6 and other bDMARDs. RESULTS: Treatment with aIL-6 significantly increased ΔCDAI (n = 91, 15.4 ± 1.1; mean ± SEM) in patients with knee joint involvement, compared to other bDMARDs (n = 232, 11.0 ± 0.7) at 12 weeks (P = 0.006). Following the multivariate analysis adjusted by the CDAI levels at baseline, age, gender, concomitant use of methotrexate, and the first use of bDMARDs, ΔCDAI levels were significantly higher in aIL-6, compared to other bDMARDs (P = 0.02). However, there was no significant difference in ΔCDAI improvement between aIL-6 (n = 162, 5.9 ± 0.6) and other bDMARDs (n = 573, 6.2 ± 0.4) in patients without swollen knee joints. ΔCDAI levels were equally increased in patients with shoulder and elbow joint involvement. CONCLUSION: aIL-6 was more effective in the patients with RA and knee joint involvement, compared to other bDMARDs.