Tumour necrosis factor in sarcoidosis and its potential for targeted therapy

STAT expression and TFH1 cells in CVID granulomatosis and sarcoidosis: immunological and histopathological comparisons

Granulomatous disease is a serious complication of common variable immunodeficiency (CVID-GD) that occurs in 8-22% of these patients and can mimic sarcoidosis, with which it shares certain clinical, biological, and radiological features. However, few studies to date have compared the two pathologies immunologically and histologically. Therefore, we analyzed the immunological-histological findings for different tissue samples from ten patients with CVID-GD and compared them to those of biopsy-proven sarcoidosis. Specifically, we wanted to know whether or not the signaling abnormalities observed in sarcoidosis granulomas are also present in CVID-GD. Morphological differences were found between CVID-GD histology and classical sarcoidosis: mainly, the former's notable lymphoid hyperplasia associated with granulomas not observed in the latter. All CVID-GD involved organs contained several follicular helper-T (TFH) cells within the granulomatosis, while those cells were inconstantly and more weakly expressed in sarcoidosis. Moreover, CVID and sarcoidosis granulomas expressed the phosphorylated-signal transducer and activator of transcription (pSTAT)1 and pSTAT3 factors, regardless of the organ studied and without any significant difference between entities. Our results suggest that the macrophage-activation mechanism in CVID resembles that of sarcoidosis, thereby suggesting that Janus kinase (JAK)-STAT-pathway blockade might be useful in currently difficult-to-treat CVID-GD.

Infliximab in neurosarcoidosis: a systematic review and meta-analysis

OBJECTIVES

To evaluate the clinical outcomes and relapse rates in neurosarcoidosis patients administered infliximab.

METHODS

A systematic review was conducted using the MEDLINE, EMBASE, SCOPUS, and Cochrane Library databases. The search included studies from their inception to March 2023. We included case-series studies with at least 10 neurosarcoidosis patients undergoing any treatment type. Studies were also required to report at least one of the following outcomes: response rate, overall survival rate, or relapse rate. This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A random-effects model facilitated the analysis of proportional treatment outcomes. Study quality was evaluated using the modified Newcastle-Ottawa quality assessment scale, while a funnel plot helped detect any publication bias.

RESULTS

Seven studies comprising 237 patients with neurosarcoidosis were included in the analysis. Of these patients, 184 (77.6%) received treatment with infliximab. The pooled proportion of patients showing clinical improvement after infliximab treatment was 0.74 (95% CI 0.64-0.84, I2  = 49.73%). Relapse rates, derived from four studies, stood at 0.38 (95% CI 0.22-0.55, I2  = 56.92%). Most studies reported successful tapering or cessation of corticosteroid dosage in patients receiving infliximab. Adverse effects were reported in 52 (29.4%) patients, of which 39 out of 54 events (72.2%) were linked to infections.

INTERPRETATION

Infliximab demonstrated potential improvement in clinical outcomes for patients with refractory neurosarcoidosis and showed potential for reducing the dosage of concurrent corticosteroids. However, a degree of relapse was observed, with infections being the primary concern for adverse events.

Emerging Therapeutic Options for Refractory Pulmonary Sarcoidosis: The Evidence and Proposed Mechanisms of Action

Sarcoidosis is a systemic disease with heterogenous clinical phenotypes characterized by non-necrotizing granuloma formation in affected organs. Most disease either remits spontaneously or responds to corticosteroids and second-line disease-modifying therapies. These medications are associated with numerous toxicities that can significantly impact patient quality-of-life and often limit their long-term use. Additionally, a minority of patients experience chronic, progressive disease that proves refractory to standard treatments. To date, there are limited data to guide the selection of alternative third-line medications for these patients. This review will outline the pathobiological rationale behind current and emerging therapeutic agents for refractory or drug-intolerant sarcoidosis and summarize the existing clinical evidence in support of their use.

Effect of Nicotine on Immune System Function

As a parasympathetic alkaloid and the main substance in cigarette smoke, nicotine modulates the immune system, inhibits innate and acquired immunity and is used in treating many autoimmune diseases. It often stimulates the α7 receptor and causes an anti-inflammatory state in the body. This study is designed to evaluate the role of nicotine treatment on immune system. The results showed that nicotine affects many cells in immune system, alters the downstream intracellular mechanisms and changes lymphocytes polarization. This substance alters TLRs and STATs gene expression and thus changes in the innate immune system. All these events inhibit the secretion of pro-inflammatory cytokines and chemokines which increase angiogenesis and metastasis and exacerbates tumors due to increasing survival and cell growth. Nicotine can aggravate tumors in cancer patients, with many positive effects observed in the treating autoimmune disease, Nicotine treatment function in different conditions depends on factors such as concentration, how it is employed, treatment duration and other conditions such as body conditions affecting the immune system, hence, further studies and review of all conditions are required.

Emerging insights in sarcoidosis: moving forward through reverse translational research

Sarcoidosis is a chronic granulomatous disease of unknown etiology that primarily affects the lungs. The development of stage IV or fibrotic lung disease accounts for a significant proportion of the morbidity and mortality attributable to sarcoidosis. Further investigation into the active mechanisms of disease pathogenesis and fibrogenesis might illuminate fundamental mediators of injury and repair while providing new opportunities for clinical intervention. However, progress in sarcoidosis research has been hampered by the heterogeneity of clinical phenotypes and the lack of a consensus modeling system. Recently, reverse translational research, wherein observations made at the patient level catalyze hypothesis-driven research at the laboratory bench, has generated new discoveries regarding the immunopathogenic mechanisms of pulmonary granuloma formation, fibrogenesis, and disease model development. The purpose of this review is to highlight the promise and possibility of these novel investigative efforts.

Adalimumab for CNS sarcoidosis: single-center experience and literature review

BACKGROUND

Tumor necrosis factor (TNF) alpha is critical in the development of granulomas and multiple recent reports have highlighted the role of infliximab, an infused TNF alpha inhibitor, in the treatment of neurosarcoidosis. As a self-injected TNF alpha inhibitor, adalimumab has certain advantages over infused medications, including greater patient freedom and autonomy. Experience with adalimumab is not well reported in the literature.

OBJECTIVE

To report clinical experience with adalimumab in the treatment of central nervous system (CNS) sarcoidosis by combining observations in our center with those that have been reported in the literature.

METHODS

Patients were identified from the Mass General Brigham Research Patient Data Registry and in the literature by searching PubMed. Patients with CNS manifestations of sarcoidosis treated with adalimumab were included for retrospective review and analyzed for baseline characteristics, treatment indications, outcomes, and adverse effects.

RESULTS

Adalimumab was commonly started after failure of or intolerance to infliximab and methotrexate. Of those with adequate follow-up, 5/10 ultimately improved, remission was maintained in 3/10, and 2/10 with active disease remained stable without further worsening. One patient suffered a relapse, likely multifactorial in etiology, but has remained relapse free on adalimumab for 10 months subsequently. Three patients ultimately discontinued adalimumab.

CONCLUSIONS

Preliminary evidence suggests that adalimumab may be a reasonable therapeutic option for patients with neurosarcoidosis affecting the CNS, including those with medically refractory disease.

Sarcoidosis presenting with glazy mucoid sputum and dyspnea: a case report

BACKGROUND

Patients with pulmonary sarcoidosis commonly present with a dry cough; a productive cough suggests a complicating airway infection or an alternative diagnosis such as tuberculosis or bronchiectasis.

CASE PRESENTATION

A 36-year-old European (Frisian) woman recently diagnosed with pulmonary sarcoidosis presented with debilitating exertional dyspnea and cough productive of glazy mucoid sputum. Several different attempts including video-assisted thoracoscopic biopsies failed to reach a second or alternative diagnosis including an infectious, autoimmune or collagen-vascular condition. She responded to steroids but with poor tolerance to this treatment, which could not be tapered. After she was started on anti-tumor necrosis factor alpha (TNF-α) therapy with infliximab, 200 mg at three-monthly intervals, she has been fine for well over a decade.

CONCLUSIONS

In this patient with sarcoidosis who had a productive cough accompanied by fever, an extensive workup and prolonged follow-up, an alternative or second diagnosis could be ruled out; we therefore conclude that this highly unusual presentation is part of the clinical spectrum of sarcoidosis.

Infliximab treatment in pathology-confirmed neurosarcoidosis

Objective

To assess the efficacy and risks of treatment with infliximab (anti–tumor necrosis factor alpha) in pathology-confirmed neurosarcoidosis.

Methods

In a retrospective study in 2 tertiary referral centers in the Netherlands, we analyzed clinical characteristics, complications, and outcome of patients with neurosarcoidosis treated with infliximab.

Results

Twenty-eight patients were identified with a mean age of 42 years. Neurosarcoidosis presented with a cerebral parenchymal localization in 16 (59%), pituitary gland/hypothalamic sarcoidosis in 15 (54%), peripheral nerve involvement in 12 (43%), and chronic meningitis in 11 patients (41%). Initial treatment response after the start of infliximab was complete remission in 6 (21%) and improvement in 14 (50%), whereas 7 patients had stable disease (25%), and 1 (4%) deteriorated and died. At the end of follow-up, with a median of 32 months, 5 patients (18%) had died, and 2 (40%) were using infliximab at the time of death. Tapering or discontinuation of corticosteroids without a relapse was achieved in 19 of 28 patients (68%). In patients with decreasing dosing or discontinuation of infliximab, a relapse occurred in 5 of 19 patients (26%). Complications of infliximab were reported in 10 of 28 patients (36%) and mainly consisted of infections in 8 (29%).

Conclusion

Infliximab is an effective treatment in neurosarcoidosis leading to remission or improvement in 70%. The mortality rate in infliximab-treated patients was substantial, indicating the severity of disease and treatment-associated complications.

Classification of evidence

This study provides Class IV evidence that in people with pathology-confirmed neurosarcoidosis, infliximab is beneficial.

Nicotine and autoimmunity: The lotus' flower in tobacco

Nicotine, the major component of cigarettes, has demonstrated conflicting impact on the immune system: some authors suggest that increases pro-inflammatory cytokines and provokes cellular apoptosis of neutrophils, releasing intracellular components that act as auto-antigens; others claimed that nicotine has a protective and anti-inflammatory effects, especially by binding to α7 subunit of nicotinic acetylcholine receptors. The cholinergic pathway contributes to an anti-inflammatory environment characterized by increasing T regulatory cells response, down-regulating of pro-inflammatory cytokines and a pro-inflammatory cells apoptosis. The effects of nicotine were studied in different autoimmune disease, as multiple sclerosis, type 1 diabetes, rheumatoid arthritis, sarcoidosis, Behçet's disease and inflammatory bowel diseases. The major problems about nicotine are the addiction and the adverse effects of related to each commercialized formulation. We sought in this review to summarize the knowledge accumulated to date concerning the relationship between nicotine and autoimmunity.

Pediatric gastrointestinal sarcoidosis: Successful treatment with infliximab

Gastrointestinal sarcoidosis is a rare disease with very limited data in children. Here we report the first pediatric case of successful treatment with infliximab. The first case was an 8-year-old Saudi girl who presented with fever, weight loss, and abdominal pain that was followed in a few months with hematemesis and development of hepatosplenomegaly. The second case was a 9-year-old Sudanese boy who manifested with vomiting, epigastric pain, and weight loss. On upper endoscopy, both cases demonstrated severe erosive nodular gastric mucosa. Gastric and esophageal biopsies had shown noncaseating granulomatous inflammation. The first case had histopathological evidence of granulomatous hepatitis, and both cases demonstrated lung nodularity on computed tomography chest. The boy had elevated angiotensin-converting enzyme level. Given the multisystem involvement with significant chest findings, tissue findings of granulomatous disease, and negative workup for other causes of granulomatous inflammation, both cases were diagnosed with active disseminated sarcoidosis, and treated with corticosteroids. The girl continued to be symptom-free for 4 years after tapering steroid therapy. The boy had relapses off steroids and the disease was brought into remission for 5 years off steroid therapy by infliximab. Pediatric GI sarcoidosis is a rare disease that exhibits heterogeneity in natural course. The chronic relapsing progressive form of the disease might benefit from infliximab therapy.

Novel pharmacotherapy of sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that most commonly affects the lungs. Treatment of sarcoidosis can be challenging as it is often difficult to measure disease activity and distinguish active inflammation from fibrosis. Identifying the inflammatory mediators in sarcoidosis has led to the development and use of novel therapeutic agents. The goal of pharmacotherapy is to decrease granuloma accumulation, ameliorate symptoms and improve organ function. Systemic corticosteroids remain the first line treatment. Other immunosuppressive agents may be considered for the patients who respond poorly to corticosteroids or who experience significant adverse effects. An overview of pharmacotherapy of sarcoidosis is provided here.

TNF-α: a treatment target or cause of sarcoidosis?

Sarcoidosis is a systemic granulomatous disease that affects numerous organs, commonly manifesting at the lungs and skin. While corticosteroids remain the first line of treatment, tumour necrosis factor alpha (TNF-α) inhibitors have been investigated as one potential steroid sparing treatment for sarcoidosis. TNF-α is one of many components involved in the formation of granulomas in sarcoidosis. While there have been larger scale studies of biologic TNF-α inhibition in systemic sarcoidosis, studies in cutaneous disease are limited. Paradoxically, in some patients treated with biologic TNF-α inhibitors for other diseases, treatment can induce the development of sarcoidosis. In the light of this complexity, we discuss the role of TNF-α in granuloma formation, the therapeutic role of TNF-α inhibition and immunologic abnormalities following treatment with these TNF-α inhibitors including drug-specific alterations involving interferon-γ, lymphotoxin-α, TNF receptor 2 (TNFR2) and T-regulatory cells.

In vivo evaluation of TNF-alpha in the lungs of patients affected by sarcoidosis

INTRODUCTION

Sarcoidosis is a multisystemic granulomatous disorder characterized by multiple noncaseating granulomas involving intrathoracic lymph nodes and lung parenchyma. Recently, the use of anti-tumor necrosis factor alpha (anti-TNFα) agents has been introduced for therapy of chronic and refractory sarcoidosis with controversial results. Infliximab (Remicade) is a chimeric monoclonal antibody (mAb) that recognizes and binds TNFα, neutralizing its biological effects. In the present study,   (99m)Tc labelled infliximab was used to study the expression of TNFα in sarcoid lesions and to evaluate its role as a predictive marker in response to therapy with Remicade.

MATERIAL AND METHODS

A total of 10 patients with newly diagnosed sarcoidosis were enrolled together with 10 control patients affected by rheumatoid arthritis. All patients were studied by planar imaging of the chest with   (99m)Tc-infliximab at 6 h and 24 h and total body [(18)F]-FDG PET/CT. Regions of interest were drawn over the lungs and the right arm and target-to-background ratios were analysed for   (99m)Tc-infliximab. SUV mean and SUV max were calculated over lungs for FDG.

RESULTS AND DISCUSSION

Image analysis showed low correlation between T/B ratios and BAL results in patients despite positivity at [(18)F]-FDG PET.

CONCLUSION

In conclusion, patients with newly diagnosed pulmonary sarcoidosis, with FDG-PET and BAL positivity, showed a negative   (99m)Tc-infliximab scintigraphy.

Safety and efficacy of ustekinumab or golimumab in patients with chronic sarcoidosis

Sarcoidosis is characterised by non-caseating granulomas that secrete pro-inflammatory cytokines, including interleukin (IL)-12, IL-23, and tumour necrosis factor (TNF)-α. Ustekinumab and golimumab are monoclonal antibodies that specifically inhibit IL-12/IL-23 and TNF-α, respectively. Patients with chronic pulmonary sarcoidosis (lung group) and/or skin sarcoidosis (skin group) received either 180 mg ustekinumab at week 0 followed by 90 mg every 8 weeks, 200 mg golimumab at week 0 followed by 100 mg every 4 weeks, or placebo. Patients underwent corticosteroid tapering between weeks 16 and 28. The primary end-point was week 16 change in percentage predicted forced vital capacity (ΔFVC % pred) in the lung group. Major secondary end-points were: week 28 for ΔFVC % pred, 6-min walking distance, St George's Respiratory Questionnaire (lung group), and Skin Physician Global Assessment response (skin group). At week 16, no significant differences were observed in ΔFVC % pred with ustekinumab (-0.15, p = 0.13) or golimumab (1.15, p = 0.54) compared with placebo (2.02). At week 28, there were no significant improvements in the major secondary end-points, although a nonsignificant numerically greater Skin Physician Global Assessment response was observed following golimumab treatment (53%) when compared with the placebo (30%). Serious adverse events were similar in all treatment groups. Although treatment was well tolerated, neither ustekinumab nor golimumab demonstrated efficacy in pulmonary sarcoidosis. However, trends towards improvement were observed with golimumab in some dermatological end-points.

Approaches to the treatment of some of the troublesome manifestations of sarcoidosis

Sarcoidosis can be a major therapeutic challenge given its multiplicity of clinical presentations, variable combination of organ involvement and severity, and unpredictable longitudinal behaviour. Six manifestations of sarcoidosis are especially difficult to manage because of (i) an incomplete knowledge of causation - fatigue and small fibre neuropathy, (ii) the rare occurrence in sarcoidosis - intra-abdominal complications or (iii) the potentially life-threatening consequences in some patients - neurological disease, pulmonary hypertension and hypercalcaemia. In none of these situations have a prospective, double-blind, placebo-controlled trial of any therapy been conducted. Despite this absence of any firm evidence base to support therapeutic recommendations, these six entities can be extremely problematic for the practising clinician. It is for this reason that we have focused in this review on these six disease manifestations and provided a synopsis of each problem together with suggested treatment approaches, based on an analysis of the current literature.

Adalimumab induced pulmonary sarcoid reaction

Sarcoidosis is a multisystem granulomatous inflammatory disease of unknown etiology. There is evidence that Tumor Necrosis Factor alpha (TNF-α) antagonists are useful in the treatment of advanced or refractory disease. However, sarcoidosis-like reaction has been reported with TNF-α blockade in other inflammatory conditions. Here we report a case of sarcoid-like reaction in a patient with psoriatic arthritis shortly after initiation of adalimumab therapy. Stopping adalimumab and systemic anti-inflammatory therapy with corticosteroids resulted in resolution of pulmonary symptoms and chest radiographic findings. Though TNF-α plays a critical role in pathogenesis of sarcoidosis, the development of sarcoid reaction with TNF-α blockade is paradoxical and the mechanism of this response remains unknown. TNF-α induced sarcoid-reaction could involve multiple organs. Its development with one agent does not preclude therapy with other TNF-α blockers.

Adaptive immune responses in primary cutaneous sarcoidosis

Sarcoidosis is a multisystemic inflammatory disorder with cutaneous lesions present in about one-quarter of the patients. Cutaneous lesions have been classified as specific and nonspecific, depending on the presence of nonnecrotizing epithelial cell granulomas on histologic studies. The development and progression of specific cutaneous sarcoidosis involves a complex interaction between cells of the adaptive immune systems, notably T-lymphocytes and dendritic cells. In this paper, we will discuss the role of T-cells and skin dendritic cells in the development of primary cutaneous sarcoidosis and comment on the potential antigenic stimuli that may account for the development of the immunological response. We will further explore the contributions of selected cytokines to the immunopathological process. The knowledge of the adaptive immunological mechanisms operative in cutaneous sarcoidosis may subsequently be useful for identifying prevention and treatment strategies of systemic sarcoidosis.

Double-stranded RNA induces shedding of the 34-kDa soluble TNFR1 from human airway epithelial cells via TLR3-TRIF-RIP1-dependent signaling: roles for dual oxidase 2- and caspase-dependent pathways

TNF, an important mediator of inflammatory and innate immune responses, can be regulated by binding to soluble TNF receptors. The 55-kDa type 1 TNFR (TNFR1), the key receptor for TNF signaling, is released to the extracellular space by two mechanisms, the inducible cleavage and shedding of 34-kDa soluble TNFR1 (sTNFR1) ectodomains and the constitutive release of full-length 55-kDa TNFR1 within exosome-like vesicles. The aim of this study was to identify and characterize TLR signaling pathways that mediate TNFR1 release to the extracellular space. To our knowledge, we demonstrate for the first time that polyinosinic-polycytidylic acid [poly (I:C)], a synthetic dsRNA analogue that signals via TLR3, induces sTNFR1 shedding from human airway epithelial (NCI-H292) cells, whereas ligands for other microbial pattern recognition receptors, including TLR4, TLR7, and nucleotide-binding oligomerization domain containing 2, do not. Furthermore, poly (I:C) selectively induces the cleavage of 34-kDa sTNFR1 ectodomains but does not enhance the release of full-length 55-kDa TNFR1 within exosome-like vesicles. RNA interference experiments demonstrated that poly (I:C)-induced sTNFR1 shedding is mediated via activation of TLR3-TRIF-RIP1 signaling, with subsequent activation of two downstream pathways. One pathway involves the dual oxidase 2-mediated generation of reactive oxygen species, and the other pathway is via the caspase-mediated activation of apoptosis. Thus, the ability of dsRNA to induce the cleavage and shedding of the 34-kDa sTNFR1 from human bronchial epithelial cells represents a novel mechanism by which innate immune responses to viral infections are modulated.

Mechanisms involved in injury and repair of the murine lacrimal gland: role of programmed cell death and mesenchymal stem cells

The non-keratinized epithelia of the ocular surface are constantly challenged by environmental insults, such as smoke, dust, and airborne pathogens. Tears are the sole physical protective barrier for the ocular surface. Production of tears in inadequate quantity or of inadequate quality results in constant irritation of the ocular surface, leading to dry eye disease, also referred to as keratoconjunctivitis sicca (KCS). Inflammation of the lacrimal gland, such as occurs in Sjogren syndrome, sarcoidosis, chronic graft-versus-host disease, and other pathological conditions, results in inadequate secretion of the aqueous layer of the tear film and is a leading cause of dry eye disease. The hallmarks of lacrimal gland inflammation are the presence of immune cell infiltrates, loss of acinar epithelial cells (the secreting cells), and increased production of proinflammatory cytokines. To date, the mechanisms leading to acinar cell loss and the associated decline in lacrimal gland secretion are still poorly understood. It is also not understood why the remaining lacrimal gland cells are unable to proliferate in order to regenerate a functioning lacrimal gland. This article reviews recent advances in exocrine tissue injury and repair, with emphasis on the roles of programmed cell death and stem/progenitor cells.

Gastrointestinal and hepatic manifestations of sarcoidosis

Sarcoidosis is a multisystem disease characterized by noncaseating granulomas in the affected organs, including skin, heart, nervous system, and joints. Diagnosis of sarcoidosis is generally based upon a compatible history, demonstration of granulomas in at least two different organs, negative staining and culture for acid fast bacilli, absence of occupational or domestic exposure to toxins, and lack of drug-induced disease. Involvement of the hollow organs is rare. Rather than being due to sarcoidosis, some reported mucosal lesions may simply have incidental granulomas. Extrinsic compression from lymphadenopathy can occur throughout the gastrointestinal tract. The stomach, particularly the antrum, is the most common extrahepatic organ to be involved, while the small bowel is the least common. Liver involvement frequently occurs and ranges from asymptomatic incidental granulomas to portal hypertension from granulomas in the portal triad, usually with relatively preserved liver function. CT scans show hepatosplenomegaly and adenopathy, followed in frequency by focal low-attenuation lesions of the liver and spleen. Ascites is usually a transudate from right heart failure (because of pulmonary hypertension) or portal hypertension (because of biliary cirrhosis). Rarely, an exudative ascites may occur from studding of the peritoneum with nodules. Pancreatic involvement presents as a mass, usually in the head or a diffusely firm, nodular organ. Corticosteroids should be instituted when organ function is threatened, usually lungs, eyes, and central nervous system. Their role in the treatment of hepatic sarcoidosis is unclear. The overall prognosis is good although most patients will have some permanent organ impairment. Cardiac and pulmonary diseases are the main causes of death.

Pulmonary hypertension associated with sarcoidosis

Pulmonary involvement is common in sarcoidosis, an immune-mediated inflammatory disorder that is characterized by non-caseating granulomas in tissue. Sarcoid patients with advanced pulmonary disease, especially end-stage pulmonary fibrosis, risk developing pulmonary hypertension (World Health Organization group III pulmonary hypertension secondary to hypoxic lung disease). Increased levels of endothelin (ET)-1 in plasma and bronchoalveolar lavage of some sarcoid patients suggest that ET-1 may be driving pulmonary fibrosis and sarcoidosis-associated pulmonary hypertension. Although a relationship between raised levels of ET-1 and clinical phenotype is yet to be identified, early evidence from studies of ET-1 blockade with drugs such as bosentan is encouraging. Such therapy possibly could be combined with standard anti-inflammatory agents to improve outcome.

Sarcoidosis, role of tumor necrosis factor inhibitors and other biologic agents, past, present, and future concepts

Tumor necrosis factor is a potent cytokine involved in the inflammatory process of many diseases. Agents that block tumor necrosis factor have been used in the treatment of various immune-mediated diseases, including rheumatoid arthritis, Crohn disease, psoriatic arthritis, and ankylosing spondylitis. Sarcoidosis is an immune-mediated inflammatory disorder of unknown etiology characterized by the formation of noncaseating granulomas. Tumor necrosis factor plays a major role in the inflammatory process seen in sarcoidosis. Sarcoidosis therapies with activity against tumor necrosis factor and specific anti-tumor necrosis factor therapies have been used with variable success. The long-term safety and efficacy of such therapies are yet to be determined in well-designed clinical trials with long-term follow-up.

Linkage between Toll-like receptor (TLR) 2 promotor and intron polymorphisms: functional effects and relevance to sarcoidosis

The intracellular pathogens Propionibacterium acnes and Mycobacterium tuberculosis have been leading suspects as the cause of sarcoidosis, a systemic disorder characterized by the formation of non-caseating granulomas. Toll-like receptor (TLR) 2 is important in the innate immune response against both pathogens, and is therefore of interest in sarcoidosis research. In the present study, three single nucleotide polymorphisms and one dinucleotide repeat polymorphism in the TLR-2 gene were genotyped in 419 sarcoidosis patients, divided into a study cohort and a validation cohort, and 196 healthy controls. In the study cohort we found a significant increase in prevalence of the AA-genotype at promotor location -16934 in patients with chronic disease compared to patients with acute/self-remitting sarcoidosis (34.5% versus 15.9%, respectively, P = 0.006, P(c) = 0.019). These results could not be confirmed in our validation cohort, implicating a possible role for TLR-2 genetics in only a small percentage of sarcoidosis patients. Furthermore, linkage was found between the promotor polymorphism -16934 A/T and the number of GT repeats in intron 1 (P < 0.0001). After in vitro stimulation of peripheral blood mononuclear cells (PMBCs) with different TLR-2 agonists, a correlation between induction of TNF-alpha (P = 0.008), interleukin (IL)-12 (P = 0.008) as well as IL-6 (P = 0.02), and the number of GT repeats was observed. In conclusion, the data show that polymorphisms in TLR-2 might be important in a small group of sarcoidosis patients and that their functional consequences explain partly some of the variance in cytokine pattern observed in different clinical phenotypes of this disease.

Steroid-resistant sarcoidosis: is antagonism of TNF-alpha the answer?

Steroid-resistant sarcoidosis has conventionally been treated with various drugs, including methotrexate, azathioprine, cyclophosphamide, cyclosporine, antimalarial drugs and thalidomide, with variable success. There is a compelling need for more efficient and safer alternatives to these agents. Several lines of evidence suggest a critical role of TNF-alpha (tumour necrosis factor-alpha) in the initiation and organization of sarcoid granulomas. Inhibition of TNF-alpha with monoclonal antibodies has therefore received attention as a potential treatment option in therapy-resistant sarcoidosis. A number of case reports and small case series describe successful treatment of refractory disease with infliximab. Preliminary evidence from an RCT (randomized controlled trial) with infliximab in pulmonary sarcoidosis suggests a modest improvement in functional and radiological parameters. In contrast, the results with etanercept have been disappointing, perhaps related to differences in the mechanism of TNF-alpha blockade. The experience with adalimumab in sarcoidosis is too limited to draw conclusions. An open-label study and an RCT evaluating the efficacy of adalimumab in sarcoidosis with pulmonary and cutaneous involvement respectively, have been initiated. Although TNF-alpha antagonists appear relatively safe, especially when compared with conventional agents, caution is warranted in view of the increased incidence of tuberculosis, which may be a particular diagnostic challenge in patients with sarcoidosis. Pending publication of the RCTs, the use of TNF-alpha blockade in sarcoidosis should remain in the realm of experimental treatment.

Tumor necrosis factor receptors (TNFRs) on T lymphocytes and soluble TNFRs in different clinical courses of sarcoidosis

INTRODUCTION

The release of tumor necrosis factor (TNF-alpha) is increased in sarcoidosis patients. TNF-alpha exerts its effect by binding to specific cell surface receptors. There are only fragmentary data concerning the expression of tumor necrosis factor receptors (TNFRs) on bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) lymphocytes. The aim of the study was to evaluate TNFRI (CD120a) and TNFRII (CD120b) expression on T cells and the level of soluble TNFRs in specimens of patients with different clinical manifestation and clinical outcome of sarcoidosis.

MATERIAL AND METHODS

We examined 49 patients with newly diagnosed pulmonary sarcoidosis. TNFRI and TNFRII density on CD4+ and CD8+ BALF and PB cells surface was estimated using monoclonal antibodies and a flow cytometry technique. The level of TNFRs in PB serum and BALF cell culture supernatant (CCS) was measured using ELISA. Immunological analyses were also performed on PB samples collected from 10 healthy volunteers.

RESULTS

The level of soluble TNFRI (sTNFRI) in PB serum was similar in sarcoidosis patients and healthy subjects, whereas the concentration of sTNFRII in serum was significantly higher in the sarcoidosis group (P<0.001). Patients without acute symptoms of sarcoidosis, patients with radiological stage II/III as well as patients with further disease progression showed a tendency to higher levels of sTNFRs in PB serum and lower levels of sTNFRs in BALF CCS compared to Löfgren syndrome and radiological stage I subjects, and patients with spontaneous resolution of sarcoidosis. More than 80% of BALF and PB lymphocytes of sarcoidosis patients expressed both CD120a and CD120b antigens. The percentage of double-positive CD4+CD120a+ and CD4+CD120b+ cells in PB was significantly higher (P<0.005) in sarcoidosis patients than in healthy subjects. The highest percentage of CD4+CD120a+ and CD4+CD120b+ lymphocytes in BALF was determined in patients with acute disease, and in PB of patients with further spontaneous improvement.

CONCLUSION

The evaluation of sTNFRs and TNFRs expression on T-helper cells may be useful in the estimation of sarcoidosis activity.

Genetics of sarcoidosis: candidate genes and genome scans

Human leukocyte antigen class II allele associations and T-cell receptor beta chain bias in sarcoidosis suggest a specific disease-triggering antigen exposure in a genetically susceptible host. The cause of sarcoidosis has been elusive, but genetics provides one of the few promising avenues to further our understanding. We review the association studies and genome scans used to identify the genes involved in sarcoidosis.

Cutaneous sarcoidosis therapy updated

The widely accepted standard therapy for cutaneous sarcoidosis includes corticosteroids, antimalarials, and methotrexate. However, a better understanding of the basic immunopathogenic properties of sarcoidosis has elucidated a number of steps critical to the persistence and progression of disease that may be vulnerable to treatment by targeted therapy. This article reviews both standard and newer therapeutic options for cutaneous sarcoidosis.

Exploitation of the nicotinic anti-inflammatory pathway for the treatment of epithelial inflammatory diseases

Discoveries in the first few years of the 21st century have led to an understanding of important interactions between the nervous system and the inflammatory response at the molecular level, most notably the acetylcholine (ACh)-triggered, α7-nicotinic acetylcholine receptor (α7nAChR)-dependent nicotinic anti-inflammatory pathway. Studies using the α7nAChR agonist, nicotine, for the treatment of mucosal inflammation have been undertaken but the efficacy of nicotine as a treatment for inflammatory bowel diseases remains debatable. Further understanding of the nicotinic anti-inflammatory pathway and other endogenous anti-inflammatory mechanisms is required in order to develop refined and specific therapeutic strategies for the treatment of a number of inflammatory diseases and conditions, including periodontitis, psoriasis, sarcoidosis, and ulcerative colitis.

Sarcoidosis in chronic granulomatous disease

In addition to increased susceptibility to infections in patients with chronic granulomatous disease (CGD), a higher incidence of sterile inflammatory disorders in these patients has been noted. However, sarcoidosis has not been reported previously in CGD. In this report, we describe two patients who have CGD and a disorder consistent with sarcoidosis on the basis of unequivocal clinical-radiographic presentations, their responses to treatment, and serum angiotensin-converting enzyme levels. Serum angiotensin-converting enzyme levels were measured in 26 other patients with CGD to establish an appropriate reference range. A possible relationship between CGD and sarcoidosis is discussed.

Effect of inflammation on lacrimal gland function

The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.

Treatment of refractory sarcoidal parotid gland swelling in a previously reported unresponsive case

BACKGROUND

Sarcoidosis is a multisystem granulomatous disease that is seen occasionally in patients with characteristic bilateral parotid gland swelling. Conventional therapy has involved either no treatment because of spontaneous remission or corticosteroids when organ involvement is severe.

CASE DESCRIPTION

The authors describe a previously published case report of a patient with sarcoidosis with parotid gland swellings who did not respond to standard therapy. Despite the use of various immunosuppressive agents, the swellings failed to resolve over a three-year period. It was only after a newly recommended agent, infliximab, was used that the patient's condition was treated successfully.

CLINICAL IMPLICATIONS

It is important for dental practitioners to be familiar with manifestations of sarcoidosis, particularly its salivary gland aspects. Inherent in the knowledge of the disease is the therapeutic approach to both routine and recalcitrant

The utility of tumour necrosis factor blockade in orphan diseases

A variety of rheumatic disorders have been successfully treated with tumour necrosis factor (TNF) blockers. However, TNF blockade may be useful in a number of rare diseases. Preliminary data suggest that several forms of vasculitis appear responsive to TNF antagonists-Behcet's disease, Churg-Strauss vasculitis, polyarteritis nodosa, and giant cell arteritis, among others. Wegener's granulomatosis and sarcoidosis have been shown to improve with infliximab but not with etanercept. These results lend further support for the concept of differential mechanism(s) of action of the two antagonists with infliximab being more effective for the treatment of granulomatous diseases. Polymyositis/dermatomyositis may also be responsive to TNF blockade. TNF likely plays little role in Sjogren's syndrome as evidenced by the lack of efficacy of both TNF antagonists. Etanercept has been shown to be useful in the treatment of hepatitis C both in reducing the viral load and improving liver function. A number of other more rare disorders also may be responsive to TNF blockade. Further studies with larger numbers of well characterised patients and treatment regimens are necessary to provide more definitive evidence of the utility of the TNF antagonists in these serious and often life threatening diseases.