Identification and characteristics of patients with potential difficult-to-treat Psoriatic Arthritis: exploratory analyses of the Greek PsA registry.

OBJECTIVE: To present the characteristics of patients with potential difficult-to-treat (D2T) psoriatic arthritis (PsA). METHODS: We used data from the Greek multicentre registry of PsA patients. D2T-PsA was defined as follows: patients with at least 6-months disease duration, who have failed to at least 1 csDMARD and at least 2 bDMARDs/tsDMARDs with a different mechanism of action and have either at least moderate disease activity (MODA) defined as DAPSA > 14, and/or are not at minimal disease activity (MDA). Demographic and clinical characteristics were compared between D2T and non-D2T PsA patients. In two sensitivity analyses, patients classified as D2T solely according to the MODA or MDA criterion were examined separately. RESULTS: Among 467 patients included, 77 (16.5%) were considered D2T and 390 non-D2T PsA. Compared with non-D2T, patients with D2T PsA presented more commonly with extensive psoriasis (p< 0.0001) and were more likely to have higher BMI (p= 0.023) and a history of inflammatory bowel disease (p= 0.026). In the MODA and MDA sensitivity analyses, 7.5% and 12.5% of patients were considered D2T, respectively. In both sensitivity analyses, extensive psoriasis was again identified as an independent variable for D2T PsA (p= 0.001 and p= 0.008, respectively). Moreover, female gender (p= 0.034) in the MODA analysis and axial disease (p= 0.040) in the MDA analysis were independent variables for D2T PsA. CONCLUSION: Despite the availability of therapies, D2T PsA is common in real-life cohorts of patients with PsA and extensive psoriasis. High BMI, female gender, axial-disease, and history of IBD were also associated with D2T PsA.

JAK Inhibitors for the Treatment of Axial Spondyloarthritis.

Axial spondyloarthritis (axSpA) is a chronic disease characterized by inflammation and new bone formation that causes pain and results in functional impairment and long-term disability. Biologic agents targeting TNFα or IL-17 have been the mainstay of treatment for patients with axSpA and an inadequate response to nonsteroidal anti-inflammatory drugs. However, a proportion of axSpA patients do not respond adequately to those drugs either, creating the need to target alternative disease pathways. Janus kinase (JAK) inhibitors (JAKis) are a group of targeted synthetic disease-modifying anti-rheumatic drugs that block the intracellular signalling pathway of several proinflammatory cytokines. Given their efficacy in the management of rheumatoid arthritis and that JAKs mediate the signalling of cytokines involved in the pathogenesis of axSpA as well, JAKis have been successfully tested in a number of clinical trials in axSpA, which has led to the approval of two compounds, tofacitinib and upadacitinib for the treatment of the disease. Data from new clinical trials, long-term extensions of completed trials, and real-life observational studies that continuously emerge will shape the efficacy and safety profile and ultimately the place of JAKis in the treatment of AxSpA.

Disease Profile and Achievement of Therapeutic Goals in a Modern, Nationwide Cohort of 923 Patients with Psoriatic Arthritis.

Background: Psoriatic arthritis (PsA) is a heterogenous chronic inflammatory disease affecting skin, joints, entheses, and spine with various extra-musculoskeletal manifestations and comorbidities. The reported patient, disease and treatment characteristics in the modern therapeutic era are limited. Methods: In this cross-sectional, multi-centre, nationwide study, we recorded the demographic, clinical, and therapeutic characteristics as well as the comorbidities of patients with PsA seen for 1 year (1/1/2022-31/12/2022). Results: 923 patients (55% females) with a median (IQR) age of 57 (48-65) years and a mean disease duration of 9.5 years were enrolled. Family history of psoriasis and PsA was noted in 28.3% and 6.3%, respectively. Most patients had limited psoriasis (BSA<3: 83%) while enthesitis, dactylitis, nail and axial involvement reported in 48.3%, 33.2%, 43% and 25.9% of patients, respectively. Regarding comorbidities, approximately half of patients had dyslipidaemia (42%) or hypertension (45.4%), 36.8% were obese and 17% had diabetes while 22.7% had a depressive disorder. Overall, 60.1% received biologics and among them more patients treated with anti-IL-17 or -12/23 agents were on monotherapy (64.2%) compared to those on TNFi monotherapy (49.4%, p=0.0001). The median PsA activity as assessed by the DAPSA score was 6 (IQR: 2.3 - 13.1) with 46% of patients reaching minimal disease activity status (MDA). Conclusion: In this large, real life, modern cohort of patients with PsA with frequent comorbidities who were treated mainly with biologics, almost half achieved minimal disease activity. These results show the value of existing therapeutic approaches while at the same time highlight the existing unmet needs.

Molecular Mechanisms of New Bone Formation in Axial Spondyloarthritis.

Axial spondyloarthritis (axSpA) is a disease characterised by new bone formation. Biologic agents targeting TNFα or IL-17 are used widely and are very effective in controlling symptoms and improving quality of life in these patients. However, the effect of biologics on radiographic progression is still not entirely known. The most crucial question to be addressed is whether new bone formation in the context of axSpA is linked to the inflammatory process. If new bone formation and inflammation are interconnected, then long-term suppression of inflammation with biologic agents may eventually lead to inhibition of ankylosis. On the other hand, if these processes are totally uncoupled then biologics may not have an obvious effect on radiographic progression. In this case, targeting pathways that control new bone formation may be a more feasible approach to retard radiographic progression in axSpA. The molecular mechanisms involved in new bone formation in axSpA have been extensively investigated throughout the last years. In this narrative review we summarise the data regarding the mechanisms of new bone formation in axSpA.

Septic Arthritis Complicating a Gout Flare: Report of Two Cases and Review of the Literature.

Objective: To highlight potential pitfalls in diagnosis and management of patients with concomitant gout and septic arthritis. Methods: Presentation of two patients with concomitant gout and septic arthritis, the latter caused by Streptococcus agalactiae and Staphylococcus aureus, in one patient each. We also reviewed the English language literature on PubMed for similar cases. Results: Data on concurrent gout and septic arthritis is limited. Three case series of 14, 25, and 30 patients each where identified. The coexistence of septic arthritis and gout is an infrequent condition. Clinical appearance of the two diseases may be very similar and the presence of monosodium urate (MSU) crystals per se cannot exclude infection. On the other hand, patients with chronic tophaceous gout are prone to infection of MSU tophi and the development of biofilms on the latter may render the eradication of microbes particularly difficult. Vice versa, persistent activation of the immune system fuelled by the infection, together with prolonged hospitalisation and immobilisation, may increase the risk for a gout flare, thus initiating a vicious cycle. Conclusion: In patients with gout, a high index of suspicion for infection is needed by treating physicians, because septic arthritis is a medical emergency which can lead to rapid joint destruction.

Patient characteristics, treatment patterns and disease outcomes in patients with psoriatic arthritis followed in a combined Dermatology-Rheumatology clinic: a retrospective real-world study.

The aim of this study was to assess the patient characteristics, treatment patterns and disease outcomes in patients with psoriatic arthritis (PsA) referred to a combined Dermatology-Rheumatology (Derm-Rheum) Clinic. This was a retrospective study of patients seen in a combined Derm-Rheum Clinic (February 2018 to June 2020) in a Tertiary University Hospital. Consecutive patients with suspicious musculoskeletal symptoms or a known diagnosis of PsA referred to the Derm-Rheum Clinic were examined and followed simultaneously by experienced dermatologists and rheumatologists. Among 151 patients with psoriasis (PSO) with suspicious musculoskeletal complaints, 129 (85%) with a final diagnosis of PsA were included (56% females, mean age: 55 years, median disease duration: 14.2 years). In 62% of these patients (n = 94), PsA was diagnosed for the 1st time. At initial evaluation, 95% had peripheral arthritis, 45% nail involvement, 23% axial involvement, 12% enthesitis and 6% dactylitis with a median DAPSA and PASI scores of 20.5 and 1.6, respectively. 31% of the patients were not receiving any systemic treatment, 45% were on biologics, 29% on non-biologics and 10% on targeted synthetic agents (apremilast). At last visit (median interval time: 15 months), only 8% did not receive any systemic therapy (p < 0.001 compared to 1st visit), 62% were on biologics (p = 0.009 compared to 1st visit), 46% on non-biologics (p = 0.01 compared to 1st visit) and 10% remained on apremilast. The median DAPSA and PASI scores decreased significantly to 5.3 and 0, respectively. In conclusion, about 2/3 of patients with PSO and musculoskeletal complaints referred to a combined Derm-Rheum Clinic were diagnosed for the 1st time with PsA. During follow-up, the percentage of PsA patients on systemic therapies significantly increased with major improvement of disease activity indices. These data emphasize the value of combined Derm-Rheum Clinics for earlier referral, diagnosis, and more effective treatment of PsA patients.

Should we be Afraid of Immune Check Point Inhibitors in Cancer Patients with Pre-Existing Rheumatic Diseases? Immunotherapy in Pre-Existing Rheumatic Diseases.

BACKGROUND: Cancer immunotherapy is rapidly expanding but its clinical efficacy is hampered by immune related adverse events (ir-AE). There is a concern regarding patients with pre-existing auto-immune diseases (PAD) undergoing immunotherapy. METHODS: An electronic search was performed (Medline) to identify cases of patients with PAD treated with immune checkpoint inhibitors (ICI). RESULTS: Published data are rather limited but continue to emerge. Patients with PAD exhibit a high risk of PAD flare and/or de novo ir-AE. In most cases PAD flares and de novo irAEs were not severe and could be managed effectively with standard treatment. CONCLUSIONS: This risk in patients with PAD appears acceptable, and therefore, these patients could receive immunotherapy under close monitoring. Collaboration of oncologists and rheumatologists for the management of these patients is crucial.

New developments in ankylosing spondylitis-status in 2021.

Axial SpA (axSpA) is a common rheumatic disease characterized by inflammation leading to bone formation and functional impairment. TNF-α and IL-17 represent established targets in axSpA. TNF-α and IL-17 inhibitors have demonstrated efficacy in clinical trials and are currently approved biologic DMARDs for all subsets of the disease. Several lines of evidence implicate a role of an IL-23-IL-17 axis in the disease pathogenesis. In this light, and given the success of IL-17 blockade in axSpA, a similar good response to IL-23 was anticipated. Nevertheless, two clinical trials of anti-IL-23 monoclonal antibodies in axSpA have clearly exhibited negative results. This failure has raised theories for a degree of IL-23 independent pathway. The Janus kinase (JAK) pathway is also a potential therapeutic target, since several cytokines, including those involved in the IL-23-IL-17 axis, signal through the JAK family of tyrosine kinases. Further studies and more extended evaluation of response to cytokine inhibition across different tissues will be required to improve our understanding of SpA pathogenesis and determine its optimal management.

Hypogammaglobulinemia after rituximab for rheumatoid arthritis is not rare and is related with good response: 13 years real-life experience.

OBJECTIVES: Rituximab (RTX) use in the treatment of RA can be complicated by decrease in IgG, IgM or IgA levels (hypogammaglobulinemia-HGG). The aim of this study was to define the frequency of HGG in RA patients treated with RTX and to identify associations between its occurrence and patients' characteristics, disease outcomes and serious infections rate. METHODS: RA patients treated with RTX in two rheumatology centers from January 2007 to January 2020 were retrospectively examined. Demographical, clinical and laboratory parameters were recorded at baseline and at last visit. RESULTS: Eighty-three patients (84.3% females) with a mean age of 63.2 years were enrolled. They had baseline DAS28(CRP) of 5.2 (1.1) and received a median (range) of 8 (2-20) RTX cycles. A total of 43.4%, 24.1% and 31.3% developed 'any HGG', 'low IgG' and 'low IgM', respectively. Lower baseline IgG and IgM levels were predictors of 'low IgG' and 'low IgM' occurrence, respectively. Patients who developed 'low IgM' exhibited lower DAS28(CRP) and increased rates of remission and low disease activity compared with those with normal IgM levels. Patients who maintained normal IgG were receiving methotrexate more frequently. No differences were observed in serious infections rate among subgroups. CONCLUSION: HGG occurred in 43% of RTX-treated patients. Patients who developed low IgG or low IgM had lower baseline levels than those who did not. Concomitant DMARD and corticosteroid therapy was not associated with HGG. Low IgM, but not low IgG, development was associated with better disease outcomes. HGG was not associated with an increased incidence of serious infections.

Real Life Efficacy and Safety of Secukinumab in Biologic-Experienced Patients With Psoriatic Arthritis.

Background: Real world evidence data regarding secukinumab (SEC) use in biologic-experienced patients with psoriatic arthritis (PsA) are scarce. Objectives: To assess the real life survival, safety and efficacy of SEC in biologic-experienced patients with PsA. Methods: All biologic-experienced PsA patients treated with SEC in 2 University Rheumatology Units were included (3/2016-12/2018). Patients' and disease characteristics were recorded at baseline and during SEC therapy. Results: 75 patients were included; 76% were females with a mean age of 53.9 years, median disease duration of 6.7 years and median SEC treatment duration of 11.1 months. At baseline, 97% had peripheral arthritis, 42% axial involvement, 22% enthesitis, and 12% dactylitis. Regarding previous biologic exposure, 48 (64%) had been exposed to anti-tumor necrosis factor (TNF) agents only, 5 (7%) to the interleukin (IL)-12/23 inhibitor (Ustekinumab-UST) only while 22 (29%) both to anti-TNFs and UST. Fifty-three percent received SEC in combination with non-biologics and 35% with glucocorticoids, respectively. During follow-up, statistically significant improvement in different disease activity indices were noted (DAS28-CRP, DAPSA, BASDAI). SEC survival rate at the end of follow-up was 64% (48/75), without difference between patients exposed to anti-TNFs only (67%) vs. anti-TNFs and UST (68%) as well as to 1 vs. ≥2 anti-TNFs. The rate of serious adverse events and serious infections during follow-up was 4.8 and 1.2/100 patient-years, respectively. Discussion: In real life, in biologic-experienced patients with PsA, SEC displayed a high retention rate, regardless of the type, and number of previous biologics (anti-TNFs ± anti-IL12/23), without significant side effects.

Rheumatic Manifestations in Patients Treated with Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that activate the immune system, aiming at enhancing antitumor immunity. Their clinical efficacy is well-documented, but the side effects associated with their use are still under investigation. These drugs cause several immune-related adverse events (ir-AEs), some of which stand within the field of rheumatology. Herein, we present a literature review performed in an effort to evaluate all publicly available clinical data regarding rheumatic manifestations associated with ICIs. The most common musculoskeletal ir-AEs are inflammatory arthritis, polymyalgia rheumatica and myositis. Non-musculoskeletal rheumatic manifestations are less frequent, with the most prominent being sicca, vasculitides and sarcoidosis. Cases of systemic lupus erythematosus or scleroderma are extremely rare. The majority of musculoskeletal ir-AEs are of mild/moderate severity and can be managed with steroids with no need for ICI discontinuation. In severe cases, more intense immunosuppressive therapy and permanent ICI discontinuation may be employed. Oncologists should periodically screen patients receiving ICIs for new-onset inflammatory musculoskeletal complaints and seek a rheumatology consultation in cases of persisting symptoms.

Conversion and Reversion Rates of Tuberculosis Screening Assays in Patients With Rheumatic Diseases and Negative Baseline Screening Under Long-Term Biologic Treatment.

BACKGROUND: To determine the conversion and reversion rates of tuberculosis (TB) screening tests (Tuberculin Skin Test-TST, Interferon Gamma Release Assay-IGRA: T-SPOT.TB) during biologic treatment in patients with rheumatic diseases and negative baseline screening. METHODS: This was a long-term, longitudinal cohort study of 50 patients with rheumatic diseases and negative baseline TB screening (TST: < 5 mm, negative T-SPOT.TB) treated with tumor necrosis factor inhibitors (TNFi) or other non-TNFi biologics. Patients were rescreened at a mean time of 1.4 (first rescreening) and 6.9 (second rescreening) years from baseline, with both assays. The conversion (negative to positive) and reversion (positive to negative) rate was calculated for each TB screening test. RESULTS: Fifty patients (mean age = 60 years) with various rheumatic diseases (rheumatoid arthritis: n = 24, spondyloarthropathies: n = 23, other: n = 3) were enrolled. During the first phase (baseline to first rescreening), all patients were treated with TNFi while during the second phase (first to second rescreening), TNFi (54%) and non-TNFi (46%) were used. Fifteen patients (30%) displayed conversion of at least 1 screening assay during follow-up (10 at the first and 5 at the second rescreening). This conversion rate was higher with TST (n = 11, 22% or 3.47/100 patient-years) compared to T-SPOT.TB (n = 4, 8% or 1.74/100 patient-years). Among the 10 converters at the first rescreening, 5 received isoniazid (INH) preventive therapy and 5 did not; an equal number of patients (3/5, 60%) reverted to negative with or without INH therapy. None of the patients developed active TB during follow-up (6.9 ± 1.0 years). CONCLUSIONS: Approximately one-third of patients with rheumatic diseases and negative baseline TB screening developed conversion of at least 1 screening test during long-term biologic treatment. This occurred most often with TST and was usually a transient event. These findings do not support routine serial TB retesting in biologic-treated patients with rheumatic diseases in the absence of TB risk factors.

Targeted Biologic Therapy for Systemic Lupus Erythematosus: Emerging Pathways and Drug Pipeline.

Following the approval of belimumab, the first drug to be approved for systemic lupus erythematosus (SLE) in over 50 years, advances in our understanding of the pathogenesis of the disease have led to a remarkable number of clinical trials for investigational drugs, each with a unique mechanism of action. These include, but are not limited to, antibodies targeting B or T cells or their interaction, dendritic cells, interferon, and other cytokines. Frustratingly, this boost of studies has not been accompanied by a corresponding success and subsequent approval of novel agents, for reasons only partly attributed to the efficacy of the drugs per se. Successful phase II trials are often followed by failed phase III studies, which typically require many more patients. Nevertheless, recent successes, such as the ustekinumab and baricitinib trials and the positive results from the phase III TULIP-2 study of anifrolumab, provide room for cautious optimism. In this review, we attempt to draw the current landscape of the drug pipeline in SLE, focusing on the rationale behind each drug development, its mechanism of action, and the available preclinical and clinical data. We also highlight lessons learned from failed attempts that have helped to optimize clinical trial design for this challenging disease. We conclude with a look into the future, commenting on the surge of studies in the field of biomarkers and the use of omics technologies in lupus, which aim to pinpoint different disease phenotypes and, ideally, identify subsets of patients with disease that will respond to different biologic drugs.

Dkk1: A key molecule in joint remodelling and fibrosis.

Dickkopf-1 (Dkk-1) is a Wnt signaling pathway inhibitor that has been shown to play an important role in joint remodeling, in experimental models of arthritis and in humans. Recent data suggest that this molecule is involved in the fibrotic process as well. OBJECTIVES: This review summarizes all the available data regarding the role of Dkk-1 in joint remodeling and fibrosis. METHODS: An electronic search in literature was performed using the terms Dickkopf-1 (Dkk-1), fibrosis, Systemic Sclerosis (Scleroderma), joint remodeling, Ankylosing Spondylitis. Moreover, references in the retrieved articles were reviewed. RESULTS: Dkk1 expression seems to determine the fate of an arthritic joint, shifting the process of joint remodelling towards either an erosive/destructive phenotype, when Dkk1 is overexpressed or new bone formation when its expression is decreased. In humans, evidence suggests that Dkk-1 may be dysfunctional in patients with ankylosing spondylitis. Moreover, data from animal models indicate that Dkk-1 may be crucially involved in the fibrotic process in several organs such as the liver, lungs and kidneys. In animal models, enhanced expression of Dkk-1 had a clear suppressive effect on fibrosis suggesting that this molecule could be an attractive target in fibrotic diseases. In humans, Dkk-1 is clearly expressed in the skin. However, in patients with systemic sclerosis Dkk-1 is strikingly absent from the skin. CONCLUSION: Dkk-1 plays a critical role in joint remodeling and fibrosis and could serve as either a biomarker in diseases characterized by pathological joint remodeling or as a potential therapeutic target in fibrotic diseases.

The role of Dickkopf-1 in joint remodeling and fibrosis: A link connecting spondyloarthropathies and scleroderma?

BACKGROUND: Dickkopf-1 (Dkk-1) is a soluble inhibitor of the canonical Wnt pathway, which plays critical roles in embryonic development. Evidence suggests that this molecule regulates several aspects of both bone biology and fibrosis. OBJECTIVES: To provide an overview of our current knowledge of the role of Dkk-1 in joint remodeling and fibrosis. METHODS: We performed an electronic search (Medline) using the following key words: Dickkopf-1 (or Dkk-1), new bone formation, joint remodeling, ankylosing spondylitis, systemic sclerosis (or scleroderma), and fibrosis, supplemented by a manual search of references from retrieved articles. RESULTS: Dkk-1 is a master regulator of joint remodeling in animal models of arthritis shifting the balance toward new bone formation when its expression is decreased and toward erosion/joint destruction when its expression is increased. In humans, evidence suggests that Dkk-1 may be dysfunctional in patients with ankylosing spondylitis, a prototype bone forming disease. Moreover, data from animal models indicate that Dkk-1 has a protective role against fibrosis in several organs. Recent data suggest that inhibiting the canonical Wnt pathway by overexpression of Dkk-1 could be a way to target TGF-ß signaling in fibrotic diseases. Finally, B-cell depletion therapy in systemic sclerosis may exert its effects through TGF-ß dependent upregulation of Dkk-1. CONCLUSIONS: Dkk-1 appears to play a crucial role in both joint remodeling/ectopic ossification and fibrosis, and may be a prospective therapeutic modality for fibrotic diseases or diseases characterized by pathologic joint remodeling.

Decreased Serotonin Levels and Serotonin-Mediated Osteoblastic Inhibitory Signaling in Patients With Ankylosing Spondylitis.

Evidence suggests that serotonin is an inhibitor of bone formation. We aimed to assess: 1) serum serotonin levels in patients with ankylosing spondylitis (AS), a prototype bone-forming disease, compared with patients with rheumatoid arthritis (RA) and healthy subjects; 2) the effect(s) of TNFα blockers on serum serotonin levels in patients with AS and RA; and 3) the effect(s) of serum of AS patients on serotonin signaling. Serum serotonin levels were measured in 47 patients with AS, 28 patients with RA, and 40 healthy subjects by radioimmunoassay; t test was used to assess differences between groups. The effect of serum on serotonin signaling was assessed using the human osteoblastic cell line Saos2, evaluating levels of phospho-CREB by Western immunoblots. Serotonin serum levels were significantly lower in patients with AS compared with healthy subjects (mean ± SEM ng/mL 122.9 ± 11.6 versus 177.4 ± 24.58, p = 0.038) and patients with RA (mean ± SEM ng/mL 244.8 ± 37.5, p = 0.0004). Patients with AS receiving TNFα blockers had significantly lower serotonin levels compared with patients with AS not on such treatment (mean ± SEM ng/mL 95.8 ± 14.9 versus 149.2 ± 16.0, p = 0.019). Serotonin serum levels were inversely correlated with pCREB induction in osteoblast-like Saos-2 cells. Serotonin levels are low in patients with AS and decrease even further during anti-TNFα treatment. Differences in serotonin levels are shown to have a functional impact on osteoblast-like Saos-2 cells. Therefore, serotonin may be involved in new bone formation in AS.

Anti-TNFα treatment decreases the previously increased serum Indian Hedgehog levels in patients with ankylosing spondylitis and affects the expression of functional Hedgehog pathway target genes.

OBJECTIVE: Indian Hedgehog (Ihh) is the ligand that activates the Hedgehog pathway (HH) in the skeleton-the main controller of endochondral ossification. We aimed at assessing serum levels of Ihh in patients with ankylosing spondylitis (AS) and the effect of serum from patients with AS on HH pathway activation. METHODS: Serum Ihh levels were measured in 59 patients with AS, 70 patients with rheumatoid arthritis (RA), and 53 healthy subjects. The effect of serum from patients with AS on HH pathway activation was evaluated using an osteoblast-like cell line model. RESULTS: Patients with AS not on anti-TNFα treatment had significantly higher Ihh levels compared to patients with RA not on anti-TNFα treatment (mean ± SEM of OD: 0.370 ± 0.025 vs. 0.279 ± 0.026 for patients with AS and RA, respectively, p = 0.027) and healthy subjects (p = 0.031). Patients with AS on anti-TNFα treatment had significantly lower Ihh levels compared to patients with AS not on such treatment (p = 0.028). Patients with RA on anti-TNF treatment had higher levels of Ihh compared to patients not on such treatment (p = 0.013). PTHrP levels were similar in patients with RA, AS, and healthy subjects and were not affected by anti-TNFα treatment. We next assessed HH pathway activation in Saos2 cells following incubation with serum from AS patients prior to and following anti-TNF treatment. The HH pathway was downregulated following treatment. CONCLUSIONS: Ihh levels are increased in patients with AS and decrease following anti-TNFα treatment; this finding may have pathogenic and clinical implications.