Tocilizumab reduces complement C3 and C4 serum levels in rheumatoid arthritis patients

Systemic Immune Factors and Risk of Allergic Contact Dermatitis: A Bidirectional Mendelian Randomization Study

Skin inflammation and immune regulation have been suggested to be associated with allergic contact dermatitis (ACD) progression, but whether the system's immune regulation is a cause or a potential mechanism is still unknown. This study aims to assess the upstream and downstream of systemic immune factors on ACD within a bidirectional Mendelian-randomization design. A bidirectional two-sample MR analysis was employed to implement the results from genome-wide association studies for 52 system immune factors and ACD. Genetic associations with systemic immune factors and ACD were obtained from the IEU Open GWAS project database. The inverse-variance weighted (IVW) method was adopted as the primary MR analysis, MR-Egger, weighted median, MR-pleiotropy residual sum, and outlier (MR-PRESSO) was also used as the sensitivity analyses. Only Tumor necrosis factor ligand superfamily member 11 (TNFS11) from among 52 systemic immune factors was associated with a protective effect of ACD. However, ACD was associated with a decrease in Interleukin-9 (IL9) and an increase in C-X-C motif chemokine 1 (GROα), Tumor necrosis factor ligand superfamily member 10 (TRAIL), C4, and complement factor B of the assessed systemic immune factors. This study identified TNFS11 as the upstream regulator and IL9, GROα, TRAIL, C4, and complement factor B as the downstream regulator of ACD, providing opportunities for new therapeutic exploitation of ACD. Nonetheless, these associations of systemic immune factors need to be verified in vivo.

The effect of immunosuppressive therapies on the endothelial host response in critically ill COVID-19 patients

While several effective therapies for critically ill patients with COVID-19 have been identified in large, well-conducted trials, the mechanisms underlying these therapies have not been investigated in depth. Our aim is to investigate the association between various immunosuppressive therapies (corticosteroids, tocilizumab and anakinra) and the change in endothelial host response over time in critically ill COVID-19 patients. We conducted a pre-specified multicenter post-hoc analysis in a Dutch cohort of COVID-19 patients admitted to the ICU between March 2020 and September 2021 due to hypoxemic respiratory failure. A panel of 18 immune response biomarkers in the complement, coagulation and endothelial function domains were measured using ELISA or Luminex. Biomarkers were measured on day 0-1, day 2-4 and day 6-8 after start of COVID-19 treatment. Patients were categorized into four treatment groups: no immunomodulatory treatment, corticosteroids, anakinra plus corticosteroids, or tocilizumab plus corticosteroids. The association between treatment group and the change in concentrations of biomarkers was estimated with linear mixed-effects models, using no immunomodulatory treatment as reference group. 109 patients with a median age of 62 years [IQR 54-70] of whom 72% (n = 78) was male, were included in this analysis. Both anakinra plus corticosteroids (n = 22) and tocilizumab plus corticosteroids (n = 38) were associated with an increase in angiopoietin-1 compared to no immune modulator (n = 23) (beta of 0.033 [0.002-0.064] and 0.041 [0.013-0.070] per day, respectively). These treatments, as well as corticosteroids alone (n = 26), were further associated with a decrease in the ratio of angiopoietin-2/angiopoietin-1 (beta of 0.071 [0.034-0.107], 0.060 [0.030-0.091] and 0.043 [0.001-0.085] per day, respectively). Anakinra plus corticosteroids and tocilizumab plus corticosteroids were associated with a decrease in concentrations of complement complex 5b-9 compared to no immunomodulatory treatment (0.038 [0.006-0.071] and 0.023 [0.000-0.047], respectively). Currently established treatments for critically ill COVID-19 patients are associated with a change in biomarkers of the angiopoietin and complement pathways, possibly indicating a role for stability of the endothelium. These results increase the understanding of the mechanisms of interventions and are possibly useful for stratification of patients with other inflammatory conditions which may potentially benefit from these treatments.

Overview on the Link Between the Complement System and Auto-Immune Articular and Pulmonary Disease

Complement system (CS) dysregulation is a key factor in the pathogenesis of different autoimmune diseases playing a central role in many immune innate and adaptive processes. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by ta breach of self-tolerance leading to a synovitis and extra-articular manifestations. The CS is activated in RA and seems not only to mediate direct tissue damage but also play a role in the initiation of RA pathogenetic mechanisms through interactions with citrullinated proteins. Interstitial lung disease (ILD) represents the most common extra-articular manifestation that can lead to progressive fibrosis. In this review, we focused on the evidence of CS dysregulation in RA and in ILD, and highlighted the role of the CS in both the innate and adaptive immune responses in the development of diseases, by using idiopathic pulmonary fibrosis as a model of lung disease. As a proof of concept, we dissected the evidence that several treatments used to treat RA and ILD such as glucocorticoids, pirfenidone, disease modifying antirheumatic drugs, targeted biologics such as tumor necrosis factor (TNF)-inhibitors, rituximab, tocilizumab, and nintedanib may act indirectly on the CS, suggesting that the CS might represent a potential therapeutic target in these complex diseases.

Dietary Supplementation with Boswellia serrata, Verbascum thapsus, and Curcuma longa in Show Jumping Horses: Effects on Serum Proteome, Antioxidant Status, and Anti-Inflammatory Gene Expression

Intense exercise can cause inflammation and oxidative stress due to the production of reactive oxygen species. These pathophysiological processes are interdependent, and each one can induce the other, creating a vicious circle. A placebo-controlled blind study was carried out in show jumping horses (n. 16) to evaluate the effects of a commercial dietary supplement (Dolhorse® N.B.F. Lanes srl, Milan, Italy) containing Verbascum thapsus leaf powder (1.42%), Curcuma longa (14.280 mg/kg), and Boswellia serrata (Roxb ex Colebr) (14.280 mg/kg) extracts. Before and after 10 days of dietary supplementation, blood samples were collected to evaluate the protein levels, antioxidants, and inflammatory responses by proteomic analysis or real-time Reverse Transcriptase-Polymerase Chain Reaction (real-time RT-PCR). A total of 36 protein spots, connected to 29 proteins, were modulated by dietary supplementation, whereas real-time RT-PCR revealed a significant downregulation of proinflammatory cytokines (interleukin 1α (p < 0.05) and interleukin-6 (0.005), toll-like receptor 4 (p < 0.05), and IKBKB (p < 0.05) in supplemented sport horses. Immunoglobulin chains, gelsolin, plasminogen, vitamin D binding protein, apolipoprotein AIV, and filamin B were overexpressed, whereas haptoglobin, α-2-HS-glycoprotein, α2-macroglobulin, afamin, amine oxidase, 60S acidic ribosomal protein, and complement fragments 3, 4, and 7 were reduced. No effect was observed on the antioxidant defense systems. The present results suggest this phytotherapy may reinforce the innate immune responses, thus representing a valid adjuvant to alleviate inflammation, which is a pathophysiological process in sport horses.

Hypocomplementemia during tocilizumab treatment: Long-term follow-up results

Hypocomplementemia has been reported in patients with rheumatoid arthritis treated with tocilizumab (TCZ), but its long-term consequences are unknown. We assessed the long-term outcome of patients treated with TCZ who developed hypocomplementemia regarding serious bacterial infections or autoimmune diseases (AID).The charts of patients treated with TCZ at two rheumatology centers were reviewed retrospectively. Data regarding patients' age, gender, disease duration, autoantibodies status, previous or concomitant treatments, blood counts, liver enzymes, C3 and C4 levels at baseline and during TCZ treatment, episodes of infections, allergic reactions, and AID were analyzed. Univariate analysis was used to compare patients with low C3, C4 levels versus patients with normal C3, C4 levels. Variables that were statistically significant associated or tended to be associated with low C3 or C4 were included in multiple variable logistic regression.Of 132 patients treated with TCZ, 108 had serial measurements of serum complement concentration. Thirty-three (30%) patients developed low C4 levels and 23 (21%) had also low C3. Mean TCZ treatment period was 4.9 years (range, 1-14 years). All patients had normal complement levels at baseline. Leukopenia occurred in 18 (16.7%) patients, 14 of whom (77%) had low complement. Persistent leukopenia was observed in 8% and 5.3% of patients with normal C3 and C4 levels, respectively, as opposed to 47% and 42% of patients with low C3 or low C4, respectively. Low C3, C4 levels correlated with prolonged TCZ treatment retention time and effectiveness. There were no serious bacterial infections or new onset AID.Hypocomplementemia during TCZ treatment was accompanied by leukopenia that correlated with treatment duration. Hypocomplementemia was not associated with serious bacterial infections or new onset AID. Decreased complement levels were associated with treatment longevity. The role of monitoring complement level in predicting treatment response or assessing disease activity deserves further investigation.

Analysis of Hepatic Lipid Metabolism and Immune Function During the Development of Collagen-Induced Arthritis

The liver is essential for metabolic and immune functions and has been linked to systemic inflammatory diseases. However, the role of the liver is still elusive during the development of rheumatoid arthritis (RA), although there have been indeed some reports. We used label-free quantitative proteomics and experimental verification in this study to reveal the hepatic lipid metabolism and immune function during collagen-induced arthritis (CIA) development. The proteomics results revealed that the role of the liver differs in different phases of CIA rats. In terms of specific performance, hepatic lipid metabolism, which is primarily concerned with cholesterol, triacylglycerol, and phospholipid, was significantly influenced in the CIA induction phase, whereas the immune function, which includes binding of granulocytes, adhesion of immune cells, etc., was affected considerably at the peak phase of CIA rats compared to normal rats. Finally, the hepatic dynamic changes in CIA rats were further confirmed using targeted metabolomics and ELISA. We found that most fatty acids of the liver in the CIA induction phase were significantly decreased, and proteins related to complement activation and migration or adhesion of immune cells including C3, MMP-8, CTSZ, and S100A9 were significantly increased in the liver of CIA rats in the peak phase. Our findings indicated that the lipid metabolism and immune function of the liver were influenced in CIA rats. Thus, the conditions of the liver during RA development should be considered in therapeutic and nutritional interventions.

Utility of serum complement factors C3 and C4 as biomarkers during therapeutic management of giant cell arteritis

OBJECTIVE

There is a strong unmet need for biomarkers in giant cell arteritis (GCA), as C-reactive protein (CRP) may be unreliable in patients treated with Tocilizumab (TCZ). We aimed to assess whether C3 and C4 are useful biomarkers in GCA patients, particularly in those treated with TCZ.

METHOD

We retrospectively enrolled all patients who underwent C3 and C4 measurement at baseline. All patients were evaluated at 3, 6, 12, and 24 months after diagnosis, as part of routine follow-up. Two assessments after the end of the observational period, in case of further relapses, were also included.

RESULTS

At baseline, mean ± sd levels (mg/dL) of C3 (133 ± 28.99) and C4 (25.9 ± 9.04) were within normal ranges. During follow-up, C3 and C4 decreased in patients attaining remission (107.07 ± 19.86, p = 0.0006; 19.86 ± 10.27, p = 0.01, respectively) and sustained remission (95.85 ± 18.04, p = 0.001; 15.61 ± 9.75, p = 0.006). In TCZ-treated patients, even stronger decreases in C3 (83.11 ± 19.66, p = 0.001) and C4 (8.26 ± 3.83, p < 0.0001) were observed, and their values were not correlated with CRP or erythrocyte sedimentation rate.

CONCLUSION

C3 and C4 do not seem useful in the diagnosis of GCA, as normal values do not rule out active vasculitis. However, C3 and C4 correlate with disease activity. As the low C4 levels found in TCZ-treated patients are not correlated with CRP, C4 should be evaluated as a potential biomarker of disease activity and treatment response.

Tocilizumab for massive refractory pleural effusion in an adolescent with systemic lupus erythematosus

BACKGROUND

Pleural effusion in systemic lupus erythematous (SLE) is a common symptom, and recent studies demonstrated that IL-6 has a pivotal role in its pathogenesis.

CASE PRESENTATION

We report a case of a 15 years old Caucasian boy with a history of persistent pleural effusion without lung involvement or fever. Microbiological and neoplastic aetiologies were previously excluded. Based on the presence of pleuritis, malar rash, reduction of C3 and C4 levels and positivity of antinuclear antibody (ANA) and anti-double stranded DNA (dsDNA), the diagnosis of juvenile SLE (JSLE) was performed. Treatment with high dose of intravenous glucocorticoids and mycophenolate mofetil was started with partial improvement of pleural effusion. Based on this and on adults SLE cases with serositis previously reported, therapy with intravenous tocilizumab (800 mg every two weeks) was started with prompt recovery of pleural effusion.

CONCLUSION

To the best of our knowledge, this is the first case of JSLE pleuritis successfully treated with tocilizumab.

Complement C4, Infections, and Autoimmune Diseases

Complement C4, a key molecule in the complement system that is one of chief constituents of innate immunity for immediate recognition and elimination of invading microbes, plays an essential role for the functions of both classical (CP) and lectin (LP) complement pathways. Complement C4 is the most polymorphic protein in complement system. A plethora of research data demonstrated that individuals with C4 deficiency are prone to microbial infections and autoimmune disorders. In this review, we will discuss the diversity of complement C4 proteins and its genetic structures. In addition, the current development of the regulation of complement C4 activation and its activation derivatives will be reviewed. Moreover, the review will provide the updates on the molecule interactions of complement C4 under the circumstances of bacterial and viral infections, as well as autoimmune diseases. Lastly, more evidence will be presented to support the paradigm that links microbial infections and autoimmune disorders under the condition of the deficiency of complement C4. We provide such an updated overview that would shed light on current research of complement C4. The newly identified targets of molecular interaction will not only lead to novel hypotheses on the study of complement C4 but also assist to propose new strategies for targeting microbial infections, as well as autoimmune disorders.

Serum complement C3 and α2-macroglobulin are potentially useful biomarkers for inflammatory bowel disease patients

Aims

Ulcerative colitis (UC), characterized by chronic inflammation and its recurrence in the large intestine, is well known as inflammatory bowel disease (IBD). Suitable biomarkers specific for UC are poorly understood till date. We aimed to discover novel serum biomarkers for UC and identify good indicators that reflected the severity of UC.

Main methods

Serum samples were obtained from out-patients with IBD (n = 101) and healthy volunteers (HVs, n = 101). Serum proteins were subjected to high performance liquid chromatography (HPLC) and sodium dodecyl sulfate-electrophoresis (SDS-PAGE) analysis. After electrophoresis, proteins in the gel were identified by mass spectrometry. Further, the protein concentration was measured by enzyme-linked immunosorbent assays (ELISAs). Based on the results, correlations between the serum levels of these proteins and the disease activity index scores for UC were statistically evaluated.

Principal findings

HPLC showed that chromatograms of serum proteins from HVs apparently differed from those of patients with IBD. Eleven protein bands, which were different in their protein concentrations from those in HVs, were separated by SDS-PAGE accordingly. Among them, complement C3 (c-C3) and α₂-macroglobulin (α₂-MG), with high protein scores, were identified by mass spectrometry. The serum concentration of c-C3 in patients with IBD was higher than that in HVs. However, the level of α₂-MG in patients with IBD was significantly lower than that in HVs. Hence, the serum levels of c-C3 and α₂-MG could be good indicators of the severity of UC.

Conclusion

Serum c-C3 and α₂-MG are suitable biomarkers for monitoring the condition of patients with UC.

Tailoring biologic therapy for real-world rheumatoid arthritis patients

Introduction: The cornerstone of rheumatoid arthritis (RA) therapy relies on the treat-to-target strategy, which aims at dampening inflammation as soon as possible in order to achieve persistent low disease activity or, ideally, remission, according to validated disease activity measures. Traditional disease-modifying antirheumatic drugs (DMARDs) may be chosen in monotherapy or in combination as first-line therapy; in case of an unsatisfactory response after a 3-6-month trial, biologic therapy may be commenced.Areas covered: Real-life RA patients may present with concomitant comorbidities/complications or be in peculiar physiological states which raise more than one question as to which biotherapy may be more well suited considering the whole clinical picture. Therefore, a thorough literature search was performed to identify the most appropriate biologic therapy in each setting considered in this review.Expert opinion: Here we provide suggestions for the use of biologic drugs having a predictable better outcome in specific real-world conditions, so as to ideally profile the patient to the best of the current knowledge.

Immunosuppressive Agents and Infectious Risk in Transplantation: Managing the "Net State of Immunosuppression"

Successful solid organ transplantation reflects meticulous attention to the details of immunosuppression, balancing risks for graft rejection against risks for infection. The 'net state of immune suppression' is a conceptual framework of all factors contributing to infectious risk. Assays which measure immune function in the immunosuppressed transplant recipient relative to infectious risk and allograft function are lacking. The best measures of integrated immune function may be quantitative viral loads to assess the individual's ability to control latent viral infections. Few studies address adjustment of immunosuppression during active infections. Thus, confronted with infection in solid organ recipients, the management of immunosuppression is based largely on clinical experience. This review examines known measures of immune function and the immunologic effects of common immunosuppressive drugs and available studies reporting modification of drug regimens for specific infections. These data provide a conceptual framework for the management of immunosuppression during infection in organ recipients.

Tocilizumab-induced immunocomplex glomerulonephritis: a report of two cases

We report here two cases of membranoproliferative glomerulonephritis that developed during treatment of rheumatoid arthritis with tocilizumab. In both cases, the initial findings were proteinuria and haematuria, followed by development of bilateral lower leg oedema. One of the patients was weakly positive for anti-nuclear antibody; both had hypocomplementaemia. The patients' renal impairment gradually resolved with discontinuation of tocilizumab followed by treatment with moderate doses of oral prednisolone. Pathological examination of renal biopsies resulted in diagnoses of immunocomplex glomerulonephritis and immunofluorescence staining revealed depositions of IgG, IgA, and IgM, accompanied by C3. Tocilizumab rarely induces autoimmune disorders; therefore, the underlying mechanism is unknown. One patient with immunocomplex glomerulonephritis that may have been associated with tocilizumab therapy for rheumatoid arthritis has been reported previously; that patient and our two are similar in their clinical courses and pathological findings. We conclude that such glomerulonephritis can occur during tocilizumab treatment, but this is rare. Clinicians should be aware of the possibility of paradoxical development of autoimmune diseases during tocilizumab therapy.

Tocilizumab treatment effectively improves coronary artery involvement in patients with Takayasu arteritis

OBJECTIVE

Coronary artery involvement in Takayasu arteritis (TAK) leads to poor prognosis and high mortality. Tocilizumab (TCZ) has been used to effectively treat large vessel vasculitis. However, the efficacy of TCZ in resolving coronary artery involvement in TAK is unclear. The aim of this retrospective study was to evaluate the efficacy of TCZ in the treatment of coronary artery involvement in TAK.

METHODS

Clinical features and manifestations of coronary artery lesions in 11 TAK patients were evaluated before and after TCZ treatment, and the results were compared with those of 11 patients treated with traditional disease-modifying antirheumatic drugs (DMARDs).

RESULTS

C-reactive protein (p = 0.006), erythrocyte sedimentation rate (ESR) (p = 0.011), and Kerr score (p = 0.007) were significantly decreased post-TCZ treatment for 6 months. The Indian Takayasu Clinical Activity Score (ITAS) 2010 (p = 0.019) and ITAS-A (p = 0.019) were significantly lower in patients treated with TCZ compared with those treated with traditional DMARDs. The glucocorticoid (GC) dose was tapered to 2.50 (0.00, 7.50) mg day^-1 after TCZ treatment for 6 months, which was significantly lower than the GC dose after traditional DMARDs treatment [10.0 (5.00, 11.25) mg.day^-1, (p = 0.033)]. After 6-month TCZ treatment, the total number of coronary artery lesions was reduced from 23 to 15 in 6 patients. Vascular wall thickening was remarkably improved in 2 lesions (in the ostia of the left main and right coronary arteries).

CONCLUSION

TCZ may decrease the disease activity and improve coronary artery lesion in patients with TAK. Key Points • TCZ treatment significantly decreased the disease activity in TAK patients with coronary artery involvement. • TCZ treatment significantly reduces the dosage of GC. • TCZ treatment led to an improvement in imaging findings of TAK patients with coronary artery involvement.

Complement-Mediated Events in Alzheimer's Disease: Mechanisms and Potential Therapeutic Targets

An estimated 5.7 million Americans suffer from Alzheimer's disease in the United States, with no disease-modifying treatments to prevent or treat cognitive deficits associated with the disease. Genome-wide association studies suggest that an enhancement of clearance mechanisms and/or promotion of an anti-inflammatory response may slow or prevent disease progression. Increasing awareness of distinct roles of complement components in normal brain development and function and in neurodegenerative disorders align with complement-mediated responses, and thus, thorough understanding of these molecular pathways is needed to facilitate successful therapeutic design. Both beneficial and detrimental effects of C1q as well as contributions to local inflammation by C5a-C5aR1 signaling in brain highlight the need for precision of therapeutic design. The potential benefit of β-amyloid clearance from the circulation via CR1-mediated mechanisms is also reviewed. Therapies that suppress inflammation while preserving protective effects of complement could be tested now to slow the progression of this debilitating disease.

Tocilizumab-Associated Reversible Cerebral Vasoconstriction: A Case Report

OBJECTIVES

To report a case of reversible cerebral vasoconstriction syndrome (RCVS) possibly precipitated by tocilizumab.

BACKGROUND

Immunosuppressant drugs are a rare cause of reversible cerebral vasoconstriction, a syndrome characterized by segmental vasospasm. However, although it is considered a reversible process that resolves within 3 months, the cerebral vasoconstriction over time may lead to severe complications such as strokes.

RESULTS

We describe a 53-year-old woman who presented with a reversible vasoconstriction syndrome possibly associated with tocilizumab, an inhibitor of IL-6 receptor used in inflammatory diseases such as rheumatoid arthritis. The patient developed a cerebellar infarction as the major complication of the vasoconstriction syndrome.

CONCLUSION

Tocilizumab could be a trigger of RCVS. It is important to bear in mind the role of tocilizumab as a possible precipitating factor in order to remove it and reduce complications such as strokes. It is, to our knowledge, the first reversible vasoconstriction syndrome possibly precipitated by tocilizumab published to date.