Biologics for treating axial spondyloarthritis

Gut microbiota in axial spondyloarthritis : genetics, medications and future treatments

Axial spondyloarthritis, also referred to as ankylosing spondylitis, is a chronic inflammatory condition that predominantly affects the axial spine but may also present with peripheral arthritis. It falls within the umbrella of disorders known as spondyloarthropathies. In addition to axial spondyloarthritis, this group includes psoriatic arthritis, enteropathic arthritis, reactive arthritis, and undifferentiated spondyloarthropathy, with axial spondyloarthritis being one of the most common. The overall mechanisms underlying the development of axial spondyloarthritis are complex and multifactorial. There is a significant and well-recognized association between axial spondyloarthritis and the HLA-B27 gene, but there have also been non-HLA genes identified in the disease process, as well as certain inflammatory cytokines that play a role in the inflammatory process, such as tumor necrosis factor (TNF). More recently, there has been research and new evidence linking changes in the gut microbiota to the disease process of axial spondyloarthritis. Research into the role of the gut microbiota and gut dysbiosis is a large, ever-growing field. It has been associated with a multitude of conditions, including axial spondyloarthritis. This mini-review highlights the symbiotic relationship of the gut microbiota with the pathogenesis, therapeutic agents and future treatments of axial spondyloarthritis.

An Overview of Adalimumab Therapy for Ankylosing Spondylitis

BACKGROUND

Ankylosing spondylitis (AS) is a chronic inflammatory disease known for causing pain, stiffness, and reduced mobility in the axial skeleton. Adalimumab, a tumor necrosis factor (TNF) inhibitor, has emerged as a promising therapeutic option for AS.

METHODS

This systematic review involved a comprehensive search of randomized controlled trials related to AS treatment, conducted in major databases such as MEDLINE, Google Scholar, and PubMed. The search terms encompassed ankylosing spondylitis, adalimumab, methotrexate, other non-biologic DMARDs, glucocorticoids, NSAIDs, and analgesics. A total of 14 randomized controlled trials with 4,500 participants were included in the review.

RESULTS

The review's results revealed that adalimumab demonstrated notable superiority when compared to a placebo. It effectively reduced disease activity, improved physical function, and lowered inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate. Adalimumab demonstrated a favorable safety profile, with adverse events comparable to those observed with placebo.

CONCLUSION

Based on the results, adalimumab is deemed an effective treatment for AS, showcasing its potential as a first-line therapeutic option. Notably, no significant increase in adverse events was observed compared to placebo. However, the conclusion emphasizes the need for further studies with extended follow-up durations to ascertain the long-term efficacy and safety of adalimumab in AS management. This systematic review provides valuable insights supporting the use of adalimumab in the treatment of AS and underscores the importance of ongoing investigations into its long-term effects to optimize its clinical utilization in AS patients.

Measuring response to treatment in axial spondyloarthritis using quantitative imaging biomarkers: a prospective observational cohort study

OBJECTIVE

Objective assessments of disease activity and response to treatment in axial spondyloarthritis (axSpA) remain a challenge; quantitative imaging biomarkers (QIBs) of inflammation could enhance assessments of disease activity and therapeutic response. We aimed to determine the responsiveness of QIBs obtained from diffusion-weighted imaging (DW-MRI) and chemical shift-encoded MRI (CSE-MRI) using the partially automated Bone Edema and Adiposity Characterisation with Histograms (BEACH) software tool in axSpA patients undergoing biologic therapy.

METHODS

We conducted a prospective longitudinal cohort study, including 30 patients with axSpA undergoing biologic therapy. Patients were scanned before and after biologic therapy using conventional MRI, DWI and CSE-MRI at 3T. Apparent diffusion coefficient (ADC) and proton density fat fraction (PDFF) were assessed using the BEACH tool (https://github.com/TJPBray/BEACH), and conventional MR images were assessed using established visual scoring methods by expert radiologists. Responsiveness - the ability of the MRI measurements to capture changes in disease occurring as a result of biologic therapy - was assessed using the standardized response mean (SRM). Inter-reader reliability of the ADC and PDFF maps was assessed using Bland-Altman limits of agreement analysis and the intraclass correlation coefficient.

RESULTS

Responsiveness to therapy was moderate for ADC-based parameters (SRM 0.50) and comparable to established visual scoring methods for bone marrow oedema (SRM 0.53). Interobserver variability was lower for QIBs compared with conventional visual scores methods.

CONCLUSIONS

QIBs measured using the BEACH tool are sensitive to changes in inflammation in axSpA following biologic therapy, with similar responsiveness and lower interobserver variability to visual scoring by expert radiologists.

ADVANCES IN KNOWLEDGE

QIBs measured using the partially automated BEACH tool offer an objective measure of response to biologic therapy in axSpA.

Quantitative magnetic resonance imaging (qMRI) in axial spondyloarthritis

Imaging, and particularly MRI, plays a crucial role in the assessment of inflammation in rheumatic disease, and forms a core component of the diagnostic pathway in axial spondyloarthritis. However, conventional imaging techniques are limited by image contrast being non-specific to inflammation and a reliance on subjective, qualitative reader interpretation. Quantitative MRI methods offer scope to address these limitations and improve our ability to accurately and precisely detect and characterise inflammation, potentially facilitating a more personalised approach to management. Here, we review quantitative MRI methods and emerging quantitative imaging biomarkers for imaging inflammation in axial spondyloarthritis. We discuss the potential benefits as well as the practical considerations that must be addressed in the movement toward clinical translation of quantitative imaging biomarkers.

Discovery of CC-99677, a selective targeted covalent MAPKAPK2 (MK2) inhibitor for autoimmune disorders

As an anti-inflammatory strategy, MAPK-activated protein kinase-2 (MK2) inhibition can potentially avoid the clinical failures seen for direct p38 inhibitors, especially tachyphylaxis. CC-99677, a selective targeted covalent MK2 inhibitor, employs a rare chloropyrimidine that bonds to the sulfur of cysteine 140 in the ATP binding site via a nucleophilic aromatic substitutions (S_NAr) mechanism. This irreversible mechanism translates biochemical potency to cells shown by potent inhibition of heat shock protein 27 (HSP27) phosphorylation in LPS-activated monocytic THP-1 cells. The cytokine inhibitory profile of CC-99677 differentiates it from known p38 inhibitors, potentially suppressing a p38 pathway inflammatory response while avoiding tachyphylaxis. Dosed orally, CC-99677 is efficacious in a rat model of ankylosing spondylitis. Single doses, 3 to 400 mg, in healthy human volunteers show linear pharmacokinetics and apparent sustained tumor necrosis factor-α inhibition, with a favorable safety profile. These results support further development of CC-99677 for autoimmune diseases like ankylosing spondylitis.

The Treatment with Interleukin 17 Inhibitors and Immune-Mediated Inflammatory Diseases

IL-17 inhibitors (IL-17i) are medicines used to treat dermatological and rheumatic diseases They belong to a class of medicines called biological disease-modifying anti-rheumatic drugs (bDMARDs). This class of drugs has had a major impact on the therapy of autoimmune diseases, being much safer and more effective than treatment with small molecules. At the same time, they have highly beneficial effects on skin and joint changes, and their efficacy has been extensively monitored and demonstrated in numerous clinical trials. More and more such drugs are still being discovered today to ensure the best possible treatment of these patients, but more frequently and relatively constantly three agents are used. Two of them (Secukinumab and Ixekizumab) inhibit IL-17A directly, and the third, Brodamulab, inhibits the IL-17A receptor. Although they are extremely effective in the treatment of these diseases, sometimes their administration has been associated with paradoxical effects, i.e., there is an exacerbation of the inflammatory process. Tough, clinical trials of IL-17i have described cases of exacerbation or even onset of inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis, after administration of these drugs in patients previously diagnosed with psoriasis (PS), psoriatic arthritis (PsA), or ankylosing spondylitis (AS). The pathophysiological mechanism of action is not well understood at present. One explanation would be that this hyperreactive inflammatory process would be triggered by Interferon 1 derived from dendritic plasma cells. Even though there are many reports in the recent literature about the role of IL17i in the onset of IBD, conclusions of studies do not converge. Some of them show an increased incidence of IBD in patients treated with IL17i, while some others affirm their safety of them. In the near future we will surely have more data emerging from ongoing meta-analyses regarding safety of use IL17i in patients who are at risk of developing IBD. Clinical and paraclinical evaluation (inflammatory intestinal markers) are carefully advised before recommending treatment with IL-17i and after initiation of treatment, and prospective surveillance by clinical and biomarkers of patients treated with IL-17i is absolutely essential to capture the onset of IBD.

Advances in treatment of axial spondyloarthritis are associated with improved patient outcomes: data from the Ankylosing Spondylitis Registry of Ireland (ASRI)

The Ankylosing Spondylitis Registry of Ireland (ASRI) captures both radiographic and non-radiographic axial spondyloarthritis (axSpA) in a large, well characterised cohort. This is a valuable resource for studies in therapeutics and burden of disease, following a period of rapid change in the field of axSpA. This study aims to perform a focused analysis on patient outcomes and pattern of medication usage in axSpA. This is a cross-sectional study of registry data on 885 patients with confirmed axSpA as per the ASAS criteria for axSpA, as diagnosed by a Rheumatologist. Analysis was performed using IBM SPSS version 26. Patients were analysed on the basis of treatment categorised as: no medication, NSAIDs, biologics or combination therapy. Statistical significance was indicated by p value of < 0.05. Currently 885 patients are enrolled in the ASRI, made up of 72.5% (642) males and 26.9% (238) females. The majority of the cohort was categorized as radiographic axSpA 78.3% (693), with 21.7% (192) meeting criteria for non-radiographic disease. Overall 40.6% (359) reported at least one comorbidity. Older age was associated with no medications compared to those on biologic therapy (50.3 vs 45, p = 0.01). Lower levels of disease activity and higher quality of life were noted in those on biologics as compared to NSAIDs alone. This analysis provides detailed epidemiological data on axSpA from a large national registry. These results detail significant differences in prescribing patterns and impact on patient outcomes in axSpA. Ongoing development of registries provides a valuable insight into the real-world effects of axSpA.

Ixekizumab: an IL-17A inhibitor for the treatment of axial Spondylarthritis

INTRODUCTION

Axial spondyloarthritis (axSpA) is an inflammatory arthritis which affects primarily the entheses of the spine and sacroiliac joints with peripheral joint synovitis and extra-articular manifestations. In 2017, the first IL-17A inhibitor (IL-17Ai) secukinumab was approved for the treatment of radiographic axSpA not responding adequately to conventional therapies, and this was followed in 2019 by a second IL-17Ai, ixekizumab. These agents represent the first alternative class of biological treatments after the TNF inhibitor which dominated the therapeutic landscape of axSpA for over a decade.

AREAS COVERED

This review discusses the role of IL-17Ais in the treatment in axSpA focusing on the newest IL-17Ai ixekizumab. It provides a detailed overview of the drug pharmacodynamic, pharmacokinetics, and clinical trial data, including areas of future research needed in the post-marketing era.

EXPERT OPINION

Early trials of ixekizumab for axSpA have shown encouraging results and an acceptable safety profile. Future phase IV trials should focus on direct head-to-head comparisons between ixekizumab and other biologic drugs, and stratify patients according to important disease characteristics known to affect treatment response including sex, HLA-B27 status, presence of MRI bone marrow edema at baseline, disease duration and any extra-articular manifestations.

Serum IL-6 and TNF-α Levels Are Correlated with Disease Severity in Patients with Ankylosing Spondylitis

OBJECTIVE

Previous studies have shown that a number of cytokines participate in the regulation of ankylosing spondylitis (AS). To investigate the potential role of interleukin (IL)-6 and tumor necrosis factor- α (TNF-α) in AS pathogenesis, this study examined the serum levels of IL-6 and TNF-α in patients with AS and its clinical association with disease activity.

MATERIALS AND METHODS

The serum concentrations of IL-6 and TNF-α from 80 patients with AS and 46 healthy control patients (HCs) were examined by electrochemiluminescence immunoassay. The correlations between the serum IL-6 and TNF-α levels and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), computed tomography (CT) imaging-based classification, and laboratory indicators were analyzed using the Spearman correlation test.

RESULTS

Compared to HCs, patients with AS showed higher levels of IL-6 and TNF-α. There was also a positive correlation between the serum IL-6 and TNF-α levels and the BASDAI, the progression of AS, and the CT imaging-based classification. The serum levels of IL-6 correlated closely with C-reactive protein and the erythrocyte sedimentation rate. More important, patients with AS with hip joint involvement exhibited a significant elevation of serum levels of TNF-α, and higher IL-6 was detected in patients with the involvement of joints other than the hip and sacroiliac joints.

CONCLUSION

The serum levels of IL-6 and TNF-α can function as important indicators for auxiliary diagnosis and disease activity evaluation of AS.

Predicting Biologic Therapy Outcome of Patients With Spondyloarthritis: Joint Models for Longitudinal and Survival Analysis

BACKGROUND

Rheumatic diseases are one of the most common chronic diseases worldwide. Among them, spondyloarthritis (SpA) is a group of highly debilitating diseases, with an early onset age, which significantly impacts patients' quality of life, health care systems, and society in general. Recent treatment options consist of using biologic therapies, and establishing the most beneficial option according to the patients' characteristics is a challenge that needs to be overcome. Meanwhile, the emerging availability of electronic medical records has made necessary the development of methods that can extract insightful information while handling all the challenges of dealing with complex, real-world data.

OBJECTIVE

The aim of this study was to achieve a better understanding of SpA patients' therapy responses and identify the predictors that affect them, thereby enabling the prognosis of therapy success or failure.

METHODS

A data mining approach based on joint models for the survival analysis of the biologic therapy failure is proposed, which considers the information of both baseline and time-varying variables extracted from the electronic medical records of SpA patients from the database, Reuma.pt.

RESULTS

Our results show that being a male, starting biologic therapy at an older age, having a larger time interval between disease start and initiation of the first biologic drug, and being human leukocyte antigen (HLA)-B27 positive are indicators of a good prognosis for the biological drug survival; meanwhile, having disease onset or biologic therapy initiation occur in more recent years, a larger number of education years, and higher values of C-reactive protein or Bath Ankylosing Spondylitis Functional Index (BASFI) at baseline are all predictors of a greater risk of failure of the first biologic therapy.

CONCLUSIONS

Among this Portuguese subpopulation of SpA patients, those who were male, HLA-B27 positive, and with a later biologic therapy starting date or a larger time interval between disease start and initiation of the first biologic therapy showed longer therapy adherence. Joint models proved to be a valuable tool for the analysis of electronic medical records in the field of rheumatic diseases and may allow for the identification of potential predictors of biologic therapy failure.

Paradoxical gastrointestinal effects of interleukin-17 blockers

Secukinumab, ixekizumab and brodalumab are monoclonal antibody therapies that inhibit interleukin (IL)-17 activity and are widely used for the treatment of psoriasis, psoriatic arthritis and ankylosing spondylitis. The promising efficacy results in dermatology and rheumatology prompted the evaluation of these drugs in Crohn's disease and ulcerative colitis, but the onset of paradoxical events (disease exacerbation after treatment with a theoretically curative drug) prevented their approval in patients with inflammatory bowel diseases (IBDs). To date, the pathophysiological mechanisms underlying these paradoxical effects are not well defined, and there are no clear guidelines for the management of patients with disease flare or new IBD onset after anti-IL-17 drug therapy. In this review, we summarise the literature on putative mechanisms, the clinical digestive effects after therapy with IL-17 inhibitors and provide guidance for the management of these paradoxical effects in clinical practice.

Recent advances in managing axial spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease that predominantly affects the axial skeleton. The advent of biologic drugs has transformed the management of patients with axSpA. However, non-steroidal anti-inflammatory drugs remain the first-line drug treatment for axSpA. The optimal management of patients with axSpA requires a combination of pharmacological and non-pharmacological treatment modalities, namely exercise and physical therapy. This review looks at novel therapeutic options in patients with axSpA. It also summarises current evidence regarding radiographic progression and treat-to-target in axSpA.

Biologic disease-modifying anti-rheumatic drugs and patient-reported outcomes in axial SpA: a systematic review and a call for action

This paper is to assess the efficacy of different biologic DMARDs (bDMARDs) on several patient-reported outcomes (PROs) in randomized controlled trials (RCT) in axial spondyloarthritis (axSpA). A systematic literature review (SLR) was performed. MEDLINE (May 1, 2018) was used with the filters "published in the last 10 years" and "humans." The PICO criteria used were Patients: adults with radiographic axSpA (r-axSpA) or non-radiographic axSpA (nr-axSpA); Intervention: any bDMARD; Compararator: placebo (PBO)/any different drug; Outcome: the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ankylosing Spondylitis Quality of Life (ASQoL), the EuroQol-5D (EQ-5D), the Short Form 36 Health Survey physical component summary (SF36-PCS), the Short Form 36 Health Survey mental component summary (SF36-MCS), and the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F). After screening 84 initial references and manually selecting other 9, 24 publications, assessing TNF inhibitors (TNFi) or IL17A inhibitors (IL17Ai) were selected. Four RCTs quantified the minimal clinical important difference (MCID) between treatment arms. Most of the RCTs compared the mean difference of PROs between different timepoints. Overall, the treatment arm was superior to the comparator. PROs were often underreported or highly heterogeneously presented. MCID was seldom mentioned. There is a need to raise the standard of care on SpA by aiming at remission and PRO associated improvements. In order to achieve this goal, the target must be clearly defined, reported, and tested.

Comparison of the Efficacy and Safety of Adalimumab (Humira) and the Adalimumab Biosimilar Candidate (HS016) in Chinese Patients with Active Ankylosing Spondylitis: A Multicenter, Randomized, Double-Blind, Parallel, Phase III Clinical Trial

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of the biosimilar candidate of adalimumab (HS016) compared with adalimumab (Humira) for the treatment of active ankylosing spondylitis.

METHODS

A multicenter, randomized, double-blind, parallel, positive control, phase III clinical trial was conducted at 28 locations in China. Patients with active ankylosing spondylitis were randomized in a 2:1 ratio to subcutaneously receive 40 mg of either HS016 or adalimumab every other week for 24 weeks. The primary endpoint was to achieve at least a 20% improvement (ASAS20) in patients at 24 weeks according to the Assessment of Spondyloarthritis International Society criteria. The secondary endpoint included other efficacy assessment parameters, health evaluations, safety, pharmacokinetic, and immunogenicity parameters.

RESULTS

Following the random assignment of 648 patients into HS016 (n = 416) and adalimumab (n = 232) groups, no significant difference was found in the ASAS20 response rates at 24 weeks between the HS016 (364/416, 87.5%) and adalimumab (209/232, 90.1%) treatments and the difference between the response rates (- 2.59%; 90% confidence interval [CI] - 6.77 to 1.60) was within the predefined equivalence margin (± 15%). There were also no significant differences when the secondary endpoints were compared (all p > 0.05). Similarly, the rates of treatment-emergent adverse events (TEAEs) were not significantly different between the two groups, with most TEAEs being mild to moderate. Only nine severe cases were found, including seven within the HS016 group, three (0.7%) of which were tuberculosis cases. Plasma concentrations of HS016 and adalimumab from weeks 12 to 14 were similar during the steady-state period and steady-state maximal concentration (Cmax,ss) was equivalent for HS016 (7356.6 ng/mL) and adalimumab (7600.3 ng/mL). The accumulated proportion of patients with positive human anti-human antibodies (HAHAs) at week 24 was 326/412 (79.1%) in the HS016 group and 183/229 (79.9%) in the adalimumab group (p > 0.05), while the accumulated proportion of patients with positive neutralizing antibody (NAb) tests were 72/412 (17.5%) in the HS016 group and 43/229 (18.8%) in the adalimumab group (p > 0.05).

CONCLUSION

HS016 resembled adalimumab in efficacy and safety over the 24-week treatment period.

TRIAL REGISTRATION NUMBER

ChiCTR1900022520.

Emerging quantitative MR imaging biomarkers in inflammatory arthritides

PURPOSE

To review quantitative magnetic resonance imaging (qMRI) methods for imaging inflammation in connective tissues and the skeleton in inflammatory arthritis. This review is designed for a broad audience including radiologists, imaging technologists, rheumatologists and other healthcare professionals.

METHODS

We discuss the use of qMRI for imaging skeletal inflammation from both technical and clinical perspectives. We consider how qMRI can be targeted to specific aspects of the pathological process in synovium, cartilage, bone, tendons and entheses. Evidence for the various techniques from studies of both adults and children with inflammatory arthritis is reviewed and critically appraised.

RESULTS

qMRI has the potential to objectively identify, characterize and quantify inflammation of the connective tissues and skeleton in both adult and pediatric patients. Measurements of tissue properties derived using qMRI methods can serve as imaging biomarkers, which are potentially more reproducible and informative than conventional MRI methods. Several qMRI methods are nearing transition into clinical practice and may inform diagnosis and treatment decisions, with the potential to improve patient outcomes.

CONCLUSIONS

qMRI enables specific assessment of inflammation in synovium, cartilage, bone, tendons and entheses, and can facilitate a more consistent, personalized approach to diagnosis, characterisation and monitoring of disease.

Maintained Clinical Remission in Ankylosing Spondylitis Patients Switched from Reference Infliximab to Its Biosimilar: An 18-Month Comparative Open-Label Study

BACKGROUND

Switching from reference infliximab (RI) to biosimilar infliximab (BI) had no detrimental effects on efficacy and safety. However, long-term follow-up data is missing.

OBJECTIVE

To evaluate patients with Ankylosing Spondylitis (AS) in clinical remission who were switching from RI to BI, in terms of the safety and efficacy of this, in a long-term fashion.

METHODS

One hundred and nine consecutive unselected AS patients were investigated. All were naïve to other biologics and were followed-up at predefined times receiving RI. Patients in clinical remission were asked to switch from RI to BI. Those who switched to BI were compared with a matched control-group receiving continuous RI. During follow-up, several parameters were recorded for at least 18 months. Disease activity was measured using the Bath Ankylosing Spondylitis disease activity index (BASDAI), and the Ankylosing Spondylitis disease activity score (ASDAS), using the C-reactive protein. Remission was defined as BASDAI < 4 and ASDAS < 1.3.

RESULTS

Eighty-eight patients were evaluated (21 excluded for different reasons). From those, 45 switched to BI, while 43 continued receiving RI. No differences between groups regarding demographic, clinical and laboratory parameters were observed. All patients were in clinical remission. During follow-up, five patients from the BI-group and three from the maintenance-group discontinued the study (4 patients nocebo effect, 1 loss of efficacy). After 18 months of treatment, all patients in both groups remained in clinical remission. No significant adverse events were noted between groups.

CONCLUSION

BI is equivalent to RI in maintaining AS in clinical remission for at least 18 months.

Non-Radiographic Axial Spondyloarthritis (nr-axSpA): Advances in Classification, Imaging and Therapy

Non-radiographic axial spondyloarthritis (nr-axSpA) is a recently described form of axial inflammatory arthritis that has not caused substantial erosive damage to the sacroiliac joints. Nr-axSpA is associated with significant impairment in quality of life and, in a proportion of patients, it can evolve into ankylosing spondylitis (AS, also termed radiographic axSpA). The identification in the clinic of nr-axSpA has been made possible by advances in magnetic resonance imaging (MRI). Classification criteria for nr-axSpA have been proposed but there remains discussion in the international community regarding this. Studies are ongoing to further define the classification and diagnosis of nr-axSpA. There is much further research required regarding the optimal use of MRI in nr-axSpA, including distinguishing sacroiliac MRI changes in the normal population and the definition of a positive MRI in spinal disease. Non-steroidal anti-inflammatory drugs and physiotherapy are the core first-line therapy for nr-axSpA. Tumour necrosis factor inhibitors also play a very important role in treatment of patients with active nr-axSpA who do not respond to first-line therapy. Agents directed at interleukin-17, interleukin-23 and Janus kinase inhibitors are proving effective in AS with ongoing and planned studies in nr-axSpA. A great deal of active research is being undertaken in classification, imaging and therapy in nr-axSpA and so the future for improving the lives of patients with nr-axSpA is promising.

Pathogenesis and treatment of autoimmune rheumatic diseases

PURPOSE OF REVIEW

Autoimmune diseases are of unknown origin, and they represent significant causes of morbidity and mortality. Here, we review new developments in the understanding of their pathogenesis that have led to development of well tolerated and effective treatments.

RECENT FINDINGS

In addition to the long-recognized genetic impact of the HLA locus, interferon regulatory factors, PTPN22, STAT4, and NOX have been implicated in pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Smoking, ultraviolet light, diet, and microbiota exert strong environmental influence on development of RA and SLE. Metabolism has been recognized as a critical integrator of genetic and environmental factors, and it controls immune cell differentiation both under physiological and pathological conditions.

SUMMARY

With the advent of high-throughput genetic, proteomic, and metabolomic technologies, the field of medicine has been shifting towards systems-based and personalized approaches to diagnose and treat common conditions, including rheumatic diseases. Regulatory checkpoints of metabolism and signal transduction, such as glucose utilization, mitochondrial electron transport, JAK, mTOR, and AMPK pathway activation, and production of pro-inflammatory cytokines IL-1, IL-6, and IL-17 have presented new targets for therapeutic intervention. This review amalgamates recent discoveries in genetics and metabolomics with immunological pathways of pathogenesis in rheumatic diseases.