SAPHO Syndrome and Pustulotic Arthro-Osteitis (PAO)

An integrated transcriptomics and network pharmacology approach to explore the mechanism of Wang-Bi tablet against SAPHO syndrome

BACKGROUND

SAPHO syndrome is recognized as a rare entity with damage to skin and bones due to inflammation. Currently, the treatment for SAPHO syndrome is still a challenge in clinical practice. In this study, an integrated transcriptomics and network pharmacology approach was applied to explore the therapeutic effect and mechanism of Wang-Bi tablet (WBT) on SAPHO syndrome.

METHODS

The main components of WBT and their targets, as well as the targets of SAPHO syndrome, were collected from databases. Network visualization was performed using Cytoscape software. The GO and KEGG enrichment analysis was executed by David dataset. Then, the molecular mechanism of WBT improving SAPHO syndrome was validated by transcriptomics of peripheral blood neutrophils in SAPHO syndrome. Finally, the above results were validated by molecular docking.

RESULTS

The Network Pharmacology results showed there are 152 core targets for WBT treatment on SAPHO syndrome. RNA-seq data showed 442 differentially expressed genes (DEGs) in peripheral blood neutrophils of SAPHO patients. Intriguingly, NIK/NF-kappaB-, MyD88-dependent toll-like receptor-, and MAPK pathway were included in the enrichment results of network pharmacology and RNA-seq. Moreover, we verified that the core components of WBT have good affinity with the core targets of NIK/NF-kappaB-, MyD88-dependent toll-like receptor-, and MAPK pathway by molecular docking.

CONCLUSIONS

This study illustrated that the possible mechanisms of WBT against SAPHO syndrome may be related to NIK/NF-kappaB-, MyD88-dependent toll-like receptor-, and MAPK pathway, and further experiments are needed to prove these predictions.

Paediatric pustulotic arthro-osteitis patient with an IL36RN variant, heterozygous c.115+6T>C, who was successfully treated with tonsillectomy: A case report and literature review

Pustulotic arthro-osteitis (PAO) is an infrequent condition, with its manifestation in children being even rare. Some reports propose an association between genetic variants and the onset of PAO. Currently, no definitive treatment protocol exists for paediatric patients with PAO. In this study, we present the paediatric case of PAO with an IL36RN variant who was successfully treated with tonsillectomy.

Treatment and monitoring of SAPHO syndrome: a systematic review

BACKGROUND AND OBJECTIVES

Synovitis acne pustulosis hyperostosis osteitis (SAPHO) is a rare heterogeneous disease of unknown aetiopathology. Externally validated and internationally agreed diagnostic criteria or outcomes and, as a result, prospective randomised controlled trials in SAPHO are absent. Consequently, there is no agreed treatment standard. This study aimed to systematically collate and discuss treatment options in SAPHO.

METHODS

Following 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' guidance, a systematic literature search was conducted using PubMed, Scopus and Web of Science databases. Prospective clinical studies and retrospective case collections discussing management and outcomes in SAPHO involving five or more participants were included. Articles not published in English, studies not reporting defined outcomes, and studies solely relying on patient-reported outcomes were excluded.

RESULTS

A total of 28 studies (20 observational, 8 open-label clinical studies) reporting 796 patients of predominantly European ethnicity were included. Reported therapies varied greatly, with many centres using multiple treatments in parallel. Most patients (37.1%) received non-steroidal anti-inflammatory drugs alone or in combination. Bisphosphonates (22.1%), conventional (21.7%) and biological (11.3%) disease-modifying antirheumatic drugs were the next most frequently reported treatments. Reported outcomes varied and delivered mixed results, which complicates comparisons. Bisphosphonates demonstrated the most consistent improvement of osteoarticular symptoms and were associated with transient influenza-like symptoms. Paradoxical skin reactions were reported in patients treated with TNF inhibitors, but no serious adverse events were recorded. Most treatments had limited or mixed effects on cutaneous involvement. A recent study investigating the Janus kinase inhibitor tofacitinib delivered promising results in relation to skin and nail involvement.

CONCLUSIONS

No single currently available treatment option sufficiently addresses all SAPHO-associated symptoms. Variable, sometimes descriptive outcomes and the use of treatment combinations complicate conclusions and treatment recommendations. Randomised clinical trials are necessary to generate reliable evidence.

Palmoplantar pustulosis and pustulotic arthro-osteitis associated with multiple venous occlusion: A case report and literature review

Pustulotic arthro-osteitis (PAO) is a rare chronic inflammatory arthropathy associated with palmoplantar pustulosis. The pathogenesis of PAO remains unclear. The most common musculoskeletal involvement in PAO is ossification of the sternoclavicular joints. A combination of parietal inflammation and hyperostosis-induced mechanical compression in this region is hypothesized to contribute to multiple venous thrombosis. Here, we present a 66-year-old man with PAO-associated multiple venous occlusion who was successfully treated with guselkumab. We also discuss its clinical manifestation and cause by reviewing the literature.

An update on therapeutic options for palmoplantar pustulosis: a narrative review and expert recommendations

INTRODUCTION

Palmoplantar pustulosis (PPP) is a chronic inflammatory skin disease belonging to the localized form of pustular psoriasis. It is characterized by sterile pustule formation in palms and soles and a recurrent disease course. Although we have many treatments for PPP, there is no authoritative guidance.

AREAS COVERED

A thorough search of PubMed was conducted to identify studies in PPP from 1973 onwards, with additional references to specific articles. Any treatment methods were outcomes of interest, including topical treatment, systemic treatment, biologics, other targeted treatments, phototherapy, and tonsillectomy.

EXPERT OPINION

Topical corticosteroids are suggested as first-line therapy. Oral acitretin has become the most applied systemic retinoid recommended in PPP without joint involvement. For patients with arthritis, immunosuppressants like cyclosporin A and methotrexate are more recommended. UVA1, NB-UVB, and 308-nm excimer laser are effective phototherapy options. The combinations of topical or systemic agents and phototherapy may enhance the efficacy, particularly in recalcitrant cases. Secukinumab, ustekinumab, and apremilast are the most investigated targeted therapies. However, heterogeneous reported outcomes in clinical trials provided low-to-moderate quality evidence of their efficacy. Future studies are required to address these evidence gaps. We suggest managing PPP based on the acute phase, maintenance phase, and comorbidities.

Pro and contra: is synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) a spondyloarthritis variant?

PURPOSE OF REVIEW

The purpose of this review is to present the up-to-date evidence on the epidemiology, pathogenesis, musculoskeletal manifestations, and imaging of the synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and to discuss its relationship with spondyloarthritis (SpA).

RECENT FINDINGS

SAPHO is a rare inflammatory disorder of bone, joints, and skin, with a worldwide distribution that predominantly affects the middle-age adults. The hallmark of the syndrome is a constellation of sterile inflammatory osteitis, hyperostosis, and synovitis involving the anterior chest wall, associated with acneiform and neutrophilic dermatoses, such as palmoplantar pustulosis and severe acne. The axial skeleton, sacroiliac, and peripheral joints can be involved in a similar fashion to SpA. The pathogenesis of the syndrome is multifactorial. The diagnosis is mainly based on the clinical and typical radiological features. The treatment approach is based on the off-label use of antibiotics, bisphosphonates, disease-modifying antirheumatic drugs, and anticytokine biologics.

SUMMARY

The SAPHO syndrome shares common features with SpA-related diseases, yet also shows some unique pathogenetic and clinical features. The nosology of SAPHO remains a subject of controversy, awaiting further research into the pathogenetic and clinical aspects of this syndrome. A better understanding of these aspects will improve the diagnostics and clinical care of patients with SAPHO.