Characterization of the immune response in the synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome

SAPHO Syndrome: Current Developments and Approaches to Clinical Treatment

SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, and osteitis) is a rare autoimmune disease which, due to its clinical presentation and symptoms, is often misdiagnosed and unrecognized. Its main features are prominent inflammatory cutaneous and articular manifestations. Treatments with immunosuppressive drugs have been used for the management of SAPHO with variable results. To date, the use of anti-TNF-α agents has proved to be an effective alternative to conventional treatment for unresponsive or refractory SAPHO cases. TNF-α is a pro-inflammatory cytokine and pivotal regulator of other cytokines, including IL-1 β, IL-6, and IL-8, involved in inflammation, acute-phase response induction, and chemotaxis. IL-1 inhibition strategies with anakinra have shown efficacy as first and second lines of treatment. In this review, we will describe the main characteristics of biological drugs currently used for SAPHO syndrome. We also describe some of the promising therapeutic effects of ustekinumab, an antibody against the p40 subunit of IL-12 and IL-23, after failure of multiple drugs including anti-TNF-α and anakinra. We discuss the use and impact of the new anti-IL-1 antagonists involved in the IL-17 blockade, in particular for the most difficult-to-treat SAPHO cases.

Extra-Articular Symptoms in Constellation with Selected Serum Cytokines and Disease Activity in Spondyloarthritis

Objectives. In this study, we assessed the extra-articular symptoms in constellation with selected serum cytokines and disease activity in spondyloarthritis (SpA). Patients and Methods. We studied 287 SpA patients: 131 had AS, 110 had PsA, and 46 had SAPHO. We assessed extra-articular symptoms in all cases. In 191 SpA patients, we measured serum interleukin-6 (IL-6), interleukin-18 (IL-18), interleukin-23 (IL-23), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). Results. Patients with acute anterior uveitis (AAU) had higher VAS (P = 0.0008), BADSDAI (P = 0.0001), ASDAS-ESR (P = 0.04), CRP (P = 0.006), IL-6 (P = 0.02), and IL-18 (P = 0.03) levels. Patients with inflammatory bowel disease (IBD) had higher VAS (P = 0.03), CRP (P = 0.0009), and IL-6 (P = 0.0003) levels. Patients with skin psoriasis had lower VAS (P = 0.001) and BASDAI (P = 0.00007) levels. Patients with psoriatic onycholysis had lower VAS (P = 0.006), BASDAI (P = 0.00001), and CRP (P = 0.02) and higher IL-23 (P = 0.04) levels. Patients with PPP had lower BASDAI (P = 0.04) and higher ET-1 (P = 0.001) levels. Conclusions. SpA patients with increased serum IL-18 and decreased serum ET-1 had an increased risk of extra-articular symptoms. In SpA patients, increased disease activity was associated with an increased risk of AAU and IBD and a decreased risk of skin psoriasis, psoriatic onycholysis, and PPP.

Subcorneal Pustular Dermatosis: A Review of 30 Years of Progress

Subcorneal pustular dermatosis (SPD), also known as Sneddon-Wilkinson disease, is a rare, benign yet relapsing pustular dermatosis. Its incidence and prevalence have not been well studied. It characteristically presents as hypopyon pustules on the trunk and intertriginous areas of the body. SPD is similar to two other disease entities. Both SPD-type immunoglobulin (Ig)-A pemphigus and annular pustular psoriasis clinically and histologically present similarly to SPD. Immunologic studies separate SPD-type IgA pemphigus from SPD and pustular psoriasis. However, there is still an unclear designation as to whether SPD is its own entity distinct from pustular psoriasis, as the once thought characteristic histologic picture of psoriasis does not hold true for pustular psoriasis. SPD has been reported to occur in association with several neoplastic, immunologic, and inflammatory conditions. Dapsone remains the first-line treatment for SPD, although dapsone-resistant cases have been increasingly reported. Other therapies have been used singly or as adjunctive therapy with success, such as corticosteroids, immunosuppressive agents, tumor necrosis factor inhibitors, and ultraviolet light therapy. This article provides a review of the last 30 years of available literature, with a focus on successful treatment options and a suggestion for reappraisal of the classification of SPD.

Pyoderma gangrenosum and its syndromic forms: evidence for a link with autoinflammation

Pyoderma gangrenosum is a rare inflammatory neutrophilic dermatosis manifesting as painful ulcers with violaceous, undermined borders on the lower extremities. It may occur in the context of classic syndromes like PAPA (pyogenic arthritis, pyoderma gangrenosum and acne) and SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis), as well as in a recently described entity named PASH (pyoderma gangrenosum, acne and suppurative hidradenitis). Pyoderma gangrenosum has recently been included within the spectrum of autoinflammatory diseases, which are characterized by recurrent episodes of sterile inflammation, without circulating autoantibodies and autoreactive T cells. In PAPA syndrome, different mutations involving the PSTPIP1 gene, via an increased binding affinity to pyrin, induce the assembly of inflammasomes. These are molecular platforms involved in the activation of caspase 1, a protease that cleaves inactive prointerleukin (pro-IL)-1β to its active isoform IL-1β. The overproduction of IL-1β triggers the release of a number of proinflammatory cytokines and chemokines, which are responsible for the recruitment and activation of neutrophils, leading to neutrophil-mediated inflammation. In SAPHO syndrome, the activation of the PSTPIP2 inflammasome has been suggested to play a role in inducing the dysfunction of the innate immune system. Patients with PASH have recently been reported to present alterations of genes involved in well-known autoinflammatory diseases, such as PSTPIP1, MEFV, NOD2 and NLRP3. Pyoderma gangrenosum and its syndromic forms can be regarded as a single clinicopathological spectrum in the context of autoinflammation.

Serum Interleukin-18, Fetuin-A, Soluble Intercellular Adhesion Molecule-1, and Endothelin-1 in Ankylosing Spondylitis, Psoriatic Arthritis, and SAPHO Syndrome

To examine serum interleukin 18 (IL-18), fetuin-A, soluble intercellular adhesion molecule-1 (sICAM-1), and endothelin-1 (ET-1) levels in ankylosing spondylitis (AS), psoriatic arthritis (PsA), and Synovitis Acne Pustulosis Hyperostosis Osteitis syndrome (SAPHO). We studied 81 AS, 76 PsA, and 34 SAPHO patients. We measured serum IL-18, fetuin-A, sICAM-1, ET-1, IL-6, IL-23, vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). IL-18 levels were higher in AS (p = 0.001), PsA (p = 0.0003), and SAPHO (p = 0.01) than in controls, and were positively correlated with CRP (p = 0.03), VEGF (p = 0.03), and total cholesterol (TC, p = 0.006) in AS and with IL-6 (p = 0.03) in PsA. Serum fetuin-A levels were lower in AS (p = 0.001) and PsA (p = 0.001) than in controls, and negatively correlated with C-reactive protein (CRP) in AS (p = 0.04) and SAPHO (p = 0.03). sICAM-1 positively correlated with CRP (p = 0.01), erythrocyte sedimentation rate (ESR, p = 0.01), and IL-6 (p = 0.008) in AS, and with IL-6 (p = 0.001) in SAPHO. Serum ET-1 levels were lower in AS (p = 0.0005) than in controls. ET-1 positively correlated with ESR (p = 0.04) and Disease Activity Score 28 (DAS28, p = 0.003) in PsA. In spondyloarthritis, markers of endothelial function correlated with disease activity and TC.

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome - A challenging diagnosis not to be missed

SAPHO syndrome manifests as chronic inflammation of bones and joints, which may or may not be accompanied by skin changes. The term SAPHO is an acronym that stands for synovitis, acne, pustulosis (usually palmoplantar), hyperostosis and osteitis. The bones most commonly affected are those in the anterior chest wall (mainly the sternum, clavicles and sternocostoclavicular joints), the vertebrae and the sacroiliac joints, but peripheral and flat bones may also be involved, especially in children. There are no validated diagnostic criteria for SAPHO, and diagnosis is based on clinical and radiological findings. One of the main challenges in diagnosis is that the clinical features may occur many years apart. Additionally, patients may not develop all manifestations. Delayed diagnosis, as a result of a lack of awareness of SAPHO, can lead to patients suffering ongoing pain and disfiguring skin manifestations. One theory is that Propionibacterium acnes (isolated from bone biopsies in many SAPHO patients) triggers an auto-immune mediated chronic inflammation in genetically predisposed individuals. Treatment involves the use of nonsteroidal anti-inflammatory drugs, intra-articular steroids, bisphosphonates and biologicals. The course of SAPHO is often prolonged but, despite the challenges in diagnosis and treatment, the long-term prognosis is good.

SAPHO Syndrome: Current Developments and Approaches to Clinical Treatment

SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, and osteitis) is a rare autoimmune disease which, due to its clinical presentation and symptoms, is often misdiagnosed and unrecognized. Its main features are prominent inflammatory cutaneous and articular manifestations. Treatments with immunosuppressive drugs have been used for the management of SAPHO with variable results. To date, the use of anti-TNF-α agents has proved to be an effective alternative to conventional treatment for unresponsive or refractory SAPHO cases. TNF-α is a pro-inflammatory cytokine and pivotal regulator of other cytokines, including IL-1 β, IL-6, and IL-8, involved in inflammation, acute-phase response induction, and chemotaxis. IL-1 inhibition strategies with anakinra have shown efficacy as first and second lines of treatment. In this review, we will describe the main characteristics of biological drugs currently used for SAPHO syndrome. We also describe some of the promising therapeutic effects of ustekinumab, an antibody against the p40 subunit of IL-12 and IL-23, after failure of multiple drugs including anti-TNF-α and anakinra. We discuss the use and impact of the new anti-IL-1 antagonists involved in the IL-17 blockade, in particular for the most difficult-to-treat SAPHO cases.

The salivary proteome profile in patients affected by SAPHO syndrome characterized by a top-down RP-HPLC-ESI-MS platform

SAPHO syndrome is a rare and often unrecognized disease with prominent inflammatory cutaneous and articular symptoms characterized by musculoskeletal manifestations (synovitis, hyperostosis, osteomyelitis) associated with dermatological conditions (severe acne and pustulosis). The acidic soluble fraction of whole saliva from 10 adult women affected by SAPHO syndrome and from a group of 28 healthy women was analysed by RP-HPLC-ESI-MS with the aim of discovering salivary biomarkers of the disorder. The levels of the oral proteins and peptides were correlated with clinical data. The following proteins showed a significant decreased concentration in saliva of SAPHO subjects with respect to controls: cystatin S1 and SN, histatins, the major acidic PRPs, P-C and P-B peptides. The cystatin SN abundance lowered according to the disease duration and histatins showed positive correlations with the C reactive protein. Statistical analysis performed excluding one patient with a different pattern of salivary proteins/peptides highlighted a positive relationship between cystatin S1, histatins 3, histatin 5, and the neutrophil count. Moreover, histatin 3 correlated positively with the total white cell count and negatively with the erythrocyte sedimentation rate. Levels and frequency of S100A12 protein showed a trend to increase in SAPHO patients. The high expression of this pro-inflammatory protein is probably related to the inflammatory response and to the altered neutrophil responses to functional stimuli that characterize SAPHO syndrome suggesting a possible application as a salivary biomarker.

Cefcapene Pivoxil Hydrochloride Is a Potentially New Treatment for Palmoplantar Pustulosis with Pustulotic Arthro-Osteitis

Pustulosis palmaris et plantaris or palmoplantar pustulosis (PPP) is a refractory pustular eruption of the palms and soles with unknown etiology. In addition to skin lesions, PPP patients may present with severe joint pain and pustulotic arthro-osteitis (PAO), especially of the sternoclavicular joint. PAO is sometimes regarded as a variant of synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome. Hence, macrolide and tetracycline antibiotics are used for the treatment of PPP with PAO. We report 3 cases of PPP with PAO that did not improve upon administration of macrolide antibiotics with NSAIDs. After administration of cefcapene pivoxil hydrochloride (CFPN-PI), a third-generation cephalosporin, the swelling and sternoclavicular joint pain were promptly reduced and dramatically improved in all 3 cases. We review the conventional antibiotic treatments used currently and propose CFPN-PI as a potentially new therapy for PPP or PPP + PAO.

Gingival pustules and sterile diffuse sclerosing osteomyelitis as a feature of synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome

Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome represents the rare co-occurrence of sterile inflammatory osteoarticular disease in association with a variety of cutaneous manifestations. Oral involvement is uncommon. The etiology of SAPHO is complex and is likely the combined result of infectious, genetic, and immunologic factors. Due to diverse clinical presentations, SAPHO is difficult to diagnose. Here, we describe the case of a 74-year-old man, who had a history of SAPHO syndrome and presented with gingival pustules and sterile diffuse sclerosing osteomyelitis of the mandible. This is the first case report describing neutrophilic mucositis as a feature of SAPHO.

[SAPHO syndrome]

The SAPHO syndrome, an acronym for synovitis, acne, pustulosis, hyperostosis and osteitis, is a rare disease which affects bones, joints and the skin. The main osteoarticular features are hyperostosis and osteitis. Osteoarticular symptoms predominantly occur on the anterior chest wall but the spine and the peripheral skeleton can also be involved. The most important skin affections are palmoplantar pustulosis and severe acne. The etiology of this syndrome remains unclear but infectious, immunological and genetic factors are involved. The diagnostic features of SAPHO syndrome are clinical and radiological. The most important diagnostic procedure is Tc-99 m bone scintigraphy but conventional x-rays as well as computed tomography (CT) and magnetic resonance imaging (MRI) can also contribute to the final diagnosis. Bone histology and positron emission tomography CT (PET-CT) may help to differentiate SAPHO syndrome from malignancies and infectious osteomyelitis. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the cornerstone of treatment. The results obtained using antibiotics and disease-modifying antirheumatic drugs (DMARDs), such as sulfasalazine and methotrexate are inconsistent. Bisphosphonates and anti-tumor necrosis factor (anti-TNF) drugs have shown promising results in small studies but further research is still necessary.

SAPHO syndrome: a review

INTRODUCTION

Synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) is an acronym for various osteoarticular and dermatological manifestations that can appear in the same patient. It is a rare syndrome, but since its awareness has increased, there have been more and more such reports in the literature.

AIMS

The objectives of this review are to summarize the current state of knowledge on pediatric and adult-onset SAPHO syndrome, and to discuss treatment strategies that should be considered.

RESULTS

The SAPHO syndrome can affect patients of any age, and its etiology is still not known. The syndrome has its cognizable radiological characteristics that are most important in making the diagnosis. There are several diagnostic criteria as well, but they need further validation. No standard treatment protocols are available and current treatment options are not evidenced-based due to the rarity of the syndrome. Therapy is empirical and aimed at easing pain and modifying the inflammatory process. It includes nonsteroidal anti-inflammatory drugs (NSAIDs) as the first-line agents. Antibiotics, corticosteroids, disease-modifying anti-rheumatic drugs, biologicals targeting tumor necrosis factor alpha or interleukin-1, and bisphosphonates have all been used with variable success. Surgery is reserved to treat complications. Even though it is a disease with good long-term prognosis, its treatment remains a challenge and the results are known to be disappointing, especially with the skin component of the disease.

CONCLUSION

It is expected that these patients present at the time of diagnosis and the treatment should be as early, effective, and safe as possible in order to prevent osteoarticular progression and to limit the adverse events associated with pharmacological drugs.

Increased neutrophil infiltration, IL-1 production and a SAPHO syndrome-like phenotype in PSTPIP2-deficient mice

OBJECTIVE

Proline-serine-threonine-phosphatase-interacting protein 2 (PSTPIP2) is involved in macrophage activation, neutrophil motility and osteoclast differentiation. However, the role of PSTPIP2 in inflammation and autoinflammatory diseases is still not clear. In this study, we generated PSTPIP2 knockout (Pstpip2(-/-)) mice to investigate its phenotype and role in autoinflammatory diseases.

METHODS

We constructed a Pstpip2-targeting vector and generated Pstpip2(-/-) mice. The phenotype and immunopathology of Pstpip2(-/-) mice were analysed.

RESULTS

All Pstpip2(-/-) mice developed paw swelling, synovitis, hyperostosis and osteitis, resembling SAPHO syndrome, an inflammatory disorder of the bone, skin and joints. Multifocal osteomyelitis was found in inflamed paws, with increased macrophage and marked neutrophil infiltrations in the bone, joint and skin. Profound osteolytic lesions with markedly decreased bone volume density developed in paws and limbs. Neutrophil-attracting chemokines and IL-1β were markedly elevated in inflamed tissues.

CONCLUSION

Our study suggests that PSTPIP2 could play a role in innate immunity and development of autoinflammatory bone disorders, and may be associated with the pathogenesis of human SAPHO syndrome.

Diffuse sclerosing osteomyelitis (DSO) of the mandible in SAPHO syndrome: a novel approach with anti-TNF therapy. Systematic review

Diffuse sclerosing osteomyelitis of the mandible is now considered a local manifestation of SAPHO syndrome. This rare condition is thought to be of auto-inflammatory origin. The myriad of treatments shown in the literature, are basically empirical and reflect its unknown origin. We present a clinical case of refractory DSO treated with an anti-TNF drug (etanercept) with complete clinical remission. We advise against radical surgery and an interdisciplinary approach is recommended. A systematic literature review was also conducted.

TH17 cells are increased in the peripheral blood of patients with SAPHO syndrome

To assess whether the immune derangement previously observed in SAPHO syndrome could be linked to variations in blood TH1, TH2 or TH17 lymphocytes frequency. Seven SAPHO patients with a protracted course of the disease were studied ex-vivo for intracellular cytokines production by means of flow-cytometry and compared with matched groups of Psoriatic Arthritis patients and healthy controls. The Kruskal-Wallis test on the median of the three categories showed that there is a significant association between the TH17 levels and the category (p value = 0.02474). The mean and variance for the proportion of IL-17 producing CD4+ cells were compared between groups showing significant differences between SAPHO versus PsA subgroup (p = 0.05) and SAPHO versus healthy controls (p = 0.008). Interestingly, activation of TH17 axis, but not of TH1 and TH2, has been found, and can be observed both in patients with different activity of the disease or treated with different drugs. The TH17 increase in peripheral blood of our SAPHO subjects resembles the one recently found in patients with different AIDs. Novel therapeutic options in these patients may therefore include IL-17 blockade.

Severe inflammation associated with synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome was markedly ameliorated by single use of minocycline

We describe the case of a 63-year-old female who presented with severe inflammatory spondylitis, refractory to various antibiotics. Mycobacterial and fungal osteomyelitis were unlikely. Although asymptomatic, she also had osteomyelitis in the sternocostoclavicular region, and was suspected of having synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome, against which minocycline showed marked efficacy. The presence of severe inflammatory SAPHO, albeit rare, together with the marked efficacy of tetracycline, should be noted.

Acne as a chronic systemic disease

Acne is the most common skin disorder. In the majority of cases, acne is a disease that changes its skin distribution and severity over time; moreover, it can be a physically (scar development) and psychologically damaging condition that lasts for years. According to its clinical characteristics, it can be defined as a chronic disease according to the World Health Organization criteria. Acne is also a cardinal component of many systemic diseases or syndromes, such as congenital adrenal hyperplasia, seborrhea-acne-hirsutism-androgenetic alopecia syndrome, polycystic ovarian syndrome, hyperandrogenism-insulin resistance-acanthosis nigricans syndrome, Apert syndrome, synovitis-acne-pustulosis-hyperostosis-osteitis syndrome, and pyogenic arthritis-pyoderma gangrenosum-acne syndrome. Recent studies on the Ache hunter gatherers of Paraguay detected the lack of acne in association with markedly lower rates of obesity, diabetes mellitus, hyperlipidemia, and cardiovascular diseases, a finding that indicates either a nutritional or a genetic background of this impressive concomitance.

[Uncommon acne-associated syndromes and their significance in understanding the pathogenesis of acne]

Acne is an intriguing model for the study of interactions between hormones, innate immunity, inflammation and wound healing (scarring). The manifestations and involvement of acne in different systemic diseases and some rare syndromes demonstrate its multifaceted nature. Synovitis-Acne-Pustulosis-Hyperostosis-Osteitis (SAPHO) and Pyogenic Arthritis-Pyoderma gangrenosum-Acne (PAPA) syndromes, both regarded as autoinflammatory diseases, highlight the attributes of inflammation in acne. While SAPHO syndrome can be used to explore the pathogenic role of Propionibacterium acnes in acne, PAPA syndrome and Apert syndrome can help understand the genetic influence on acne. The genetic defects in the gain-of-function of FGFR2 mutations in Apert syndrome and acne nevus of Munro lend further support to the hypothesis that the interaction of forkhead box class O (FoxOs)-mediated transcriptional regulation with androgen receptor transactivation and insulin/insulin like growth factor-1(IGF-1)-signaling is crucial in acne pathogenesis. Novel biologics, such as tumor necrosis factor (TNF) blockers and IL-1 inhibitors, appear promising in opposing the inflammation associated with SAPHO and PAPA syndromes, but it remains to seen if they can also improve severe acne particularly in the long term.

Pustulotic arthro-osteitis associated with palmoplantar pustulosis

Palmoplantar pustulosis (PPP) is a chronic inflammatory disorder characterized by sterile pustules predominantly involving the palms and soles of middle-aged women. PPP frequently develops or exacerbates following focal infections, such as tonsillitis, odontogenic infection and sinusitis, either with or without arthralgia and/or extra-palmoplantar lesions. Pustulotic arthro-osteitis (PAO) is a joint comorbidity of PPP, most often affecting the anterior chest wall. PAO is sometimes regarded as the same entity as synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome, and may be a subtype or incomplete type of SAPHO syndrome; however, there are several differences. In Japanese patients, PPP with PAO is frequently seen, whereas SAPHO syndrome in the true meaning is rare. A difference of incidence depending on race suggests that different genetic backgrounds may be responsible for susceptibility to these disorders. Bacterial infection, especially Propionibacterium acnes, is suggested to play an important role in the pathogenesis of SAPHO syndrome. P. acnes is responsible for acne, however, bacterium is unassociated with PPP skin lesions which are characterized by sterile pustules. On the other hand, PAO is frequently triggered by focal infection, and treatment of focal infection results in dramatic effects on the release of joint pain. This paper reviews current insights into the clinicopathophysiology of PAO, and discusses its possible mechanisms in comparison with SAPHO syndrome.

Should we start treating chronic low back pain with antibiotics rather than with pain medications?

For those of us who have read the 2 recently published articles by a Danish - British research group, it might appear that we are observing an impending paradigm shift on the origins of chronic low back pain. The results of this research indicate, that chronic low back pain associated with bone marrow edema in vertebral endplates that are adjacent to herniated intervertebral discs may be caused by infections with anaerobic bacteria of low virulence. According to these articles, treatment with certain antibiotics is significantly more effective than placebo against this low back pain. If these findings are to hold true in repeat studies by other researchers, they stand to fundamentally change our concepts of low back pain, degenerative disc disease and in consequence the suitable therapies for these entities. It may in fact require pain specialists to become familiarized with the details of antibiotic treatments and their specific risks in order to be able to properly counsel their patients. While this seems hard to believe at first glance, bacteria have been implicated in the pathogenesis of other conditions that do not primarily impose as infectious diseases such as gastric ulcers. While the authors refer to a few previous studies pointing into the same direction, the relevant research is really only from one group of collaborating scientists. Therefore, before we start prescribing antibiotics for chronic low back pain, it is imperative that other researchers in different institutions confirm these results.

Autoinflammatory bone diseases

Autoinflammatory bone disease is a new branch of autoinflammatory diseases caused by seemingly unprovoked activation of the innate immune system leading to an osseous inflammatory process. The inflammatory bone lesions in these disorders are characterized by chronic inflammation that is typically culture negative with no demonstrable organism on histopathology. The most common autoinflammatory bone diseases in childhood include chronic nonbacterial osteomyelitis (CNO), synovitis, acne, pustulosis, hyperostosis, osteitis syndrome, Majeed syndrome, deficiency of interleukin-1 receptor antagonist, and cherubism. In this article, the authors focus on CNO and summarize the distinct genetic autoinflammatory bone syndromes.

The SAPHO syndrome

OBJECTIVE

To review the epidemiology, presentation, diagnosis, treatment, pathogenesis, and genetics of the syndrome known under the acronym of SAPHO for Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis to heighten awareness of this entity.

METHODS

We conducted a Medline search using SAPHO syndrome, chronic recurrent multifocal osteitis/osteomyelitis, and related terms as keywords and extracted further relevant articles from the retrieved references.

RESULTS

The SAHPO acronym identifies a syndrome encompassing a variety of osteoarticular disorders that are frequently accompanied by dermatoses characterized by neutrophilic pseudoabscesses, but can also occur in isolation. SAPHO syndrome is rare, although probably underrecognized because its diagnosis may be challenging because of the wide variability in its musculoskeletal and cutaneous manifestations. This is especially true when atypical sites are involved and when specific skin lesions are absent. There are no standardized treatment protocols available. Current treatments are empirical and have the objective of providing relief from the at times debilitating pain associated with SAPHO syndrome. They include nonsteroidal anti-inflammatory drugs and analgesics as first-line agents. Systemic corticosteroids, disease-modifying anti-rheumatic drugs, biologicals targeting tumor necrosis factor alpha and interleukin-1, and bisphosphonates have all been beneficial in some patients, but ineffective in others. This suggests that the pathogenesis of SAPHO syndrome is multifactorial, but this aspect remains poorly explored, although bacteria and immunological dysfunction are hypothesized to play a role.

CONCLUSIONS

The early recognition, diagnosis, and prompt treatment of SAPHO syndrome can prevent the unnecessary use of long-term antibiotics or invasive procedures, while rapidly alleviating pain in a majority of affected patients.

Diagnosing the SAPHO syndrome: a report of three cases and review of literature

SAPHO, an acronym for synovitis, acne, pustulosis, hyperostosis and osteitis, is a heterogeneous entity with myriad presentations and features overlapping with other entities. It is a differential in patients presenting with skin and bone symptoms, either singly or in combination. Often misdiagnosed radiologically as a malignancy or infection, the diagnosis is seldom thought of. We present three cases referred to us for evaluation of findings unrelated to the presenting symptoms. After evaluation, a (99)Tc bone scan was ordered, which showed the 'bull's head sign' in all the three cases, confirming the diagnosis. We review the literature for SAPHO. It has a few features which point to its diagnosis and can help us to distinguish it from other seronegative arthritis. The clinician should be aware of this entity and should not hesitate to order a (99)Tc bone scan. We conclude that SAPHO is not rare, but rather, it is underdiagnosed. High index of suspicion is necessary for diagnosis. A (99)Tc bone scan is diagnostic and should be ordered in patients having any of the presenting features of the syndrome. We put forward the suggestion of using (99)Tc bone scintigraphy to define a 'pre-MRI' stage of ankylosing spondylitis.

SAPHO syndrome

SAPHO syndrome is a disorder characterized by Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis. As the osteoarticular and skin manifestations often do not occur simultaneously and there are no validated diagnostic criteria, the diagnosis can be difficult. Clinical and imaging investigation is necessary to establish the many differential diagnoses of SAPHO syndrome. The etiopathogenesis involves infectious (probably Propionibacterium acnes), immunologic, and genetic factors. Treatment is based on information gathered from case reports and small series, and is related to specific skin or articular symptoms.

Chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disease occurring primarily in children and adolescents. Episodes of systemic inflammation occur due to immune dysregulation without autoantibodies, pathogens or antigen-specific T cells. CRMO is characterised by the insidious onset of pain with swelling and tenderness over the affected bones. Clavicular involvement was the classical description; however, the metaphyses and epiphyses of long bones are frequently affected. Lesions may occur in any bone, including vertebrae. Characteristic imaging includes bone oedema, lytic areas, periosteal reaction and soft tissue reaction. Biopsies from affected areas display polymorphonuclear leucocytes with osteoclasts and necrosis in the early stages. Subsequently, lymphocytes and plasma cells predominate followed by fibrosis and signs of reactive new bone forming around the inflammation. Diagnosis is facilitated by the use of STIR MRI scanning, potentially obviating the need for biopsy and unnecessary long-term antibiotics due to incorrect diagnosis. Treatment options include non-steroidal anti-inflammatory drugs and bisphosphonates. Biologics have been tried in resistant cases with promising initial results. Gene identification has not proved easy although research in this area continues. Early descriptions of the disease suggested a benign course; however, longer-term follow up shows that it can cause significant morbidity and longer-term disability. Although it has always been thought of as very rare, the prevalence is likely to be vastly underestimated due to poor recognition of the disease.

Intra-articular glucocorticosteroid injection into sternocostoclavicular joints in patients with SAPHO syndrome

OBJECTIVE

Painful swelling of the anterior chest wall caused by osteitis and hyperostosis in the sternocostoclavicular region are characteristically observed in patients suffering from SAPHO syndrome. Autoimmune triggering of inflammation and bacterial infection is hypothesized to be involved in the pathogenesis. Promising treatment modalities include antirheumatic and antibiotic medications.

METHODS

Ten patients with SAPHO syndrome and symptomatic osteitis in the sternocostoclavicular region were treated by a single instillation of glucocorticosteroids (20 mg triamcinolone) into the sternocostoclavicular joints. The disease activity was evaluated on the basis of a questionnaire asking for osteitis activity (quantified for complains on a scale of 0-6), by Health Assessment Questionnaire (HAQ) score, erythrocyte sedimentation rate, C-reactive protein, and magnet resonance imaging (MRI) scanning of the sternocostoclavicular region (osteitis scores quantified for inflammation on a scale of 0-2 by the radiologist) prior to injection and after 12 weeks. No changes of the preexisting antirheumatic therapy were allowed during the observation interval.

RESULTS

All patients continued the study during the follow-up. The osteitis score changed from 4.2 (mean; standard error (SE) ±0.3) to 3.2 (±0.4), [P = 0.062], the erythrocyte sedimentation rate from 19.0 (range from 12 to 30) to 19.9 (from 12 to 27), [P = 0.430], and the MRI score from 1.6 (±0.2) to 1.5 (±0.2) [P = 1.0]. One patient developed an increase of the clinical osteitis activity from 3 to 5 according the scoring system; only 2 patients showed a reduction of the MRI activity score from 2 to 1.

CONCLUSIONS

Intra-articular glucocorticosteroid instillation does not appear to reduce osteitis in the sternocostoclavicular region in patients with SAPHO syndrome.

The SAPHO syndrome--are microbes involved?

The syndrome of synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) includes a rare group of chronic, relapsing, inflammatory osteoarticular disorders that is conventionally associated with manifestations in the skin. Diagnostic dilemmas can arise due to incomplete manifestations or confusion generated through mimicking of other conditions, such as osteomyelitis. The aetiology of this syndrome remains unclear, but probably involves genetic, immunological and infectious mechanisms. The possible pathogenetic role of infectious agents in genetically predisposed individuals, resulting in a 'reactive osteitis', has been suggested because microbes such as Propionibacterium acnes have been recovered from bone biopsy samples. However, this hypothesis has not been demonstrated as yet. Current knowledge with regard to treatment of this syndrome is based on results reported from small case studies and, thus, is still empiric. The use of antibiotics, instituted based on the isolation of Propionibacterium acnes, has been reported to show conflicting results. Promising results for potential future application have recently been reported for treatment of SAPHO with bisphosphonates and antagonists of tumour necrosis factor-α. This review aims to evaluate the existing knowledge on the SAPHO syndrome and to provide information on symptoms, diagnosis and treatment options for this disease.

Chronic mandibular osteomyelitis with suspected underlying synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome: a case report

Chronic mandibular osteomyelitis is an intractable disease. In recent years, some case reports have related this disease process to synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, which is chronic with frequent remissions and exacerbations. This report describes a case of chronic mandibular osteomyelitis suspected to be SAPHO syndrome. A 68-year-old woman presented with pain on the left side of the mandible. On the basis of clinical and radiological findings, chronic mandibular diffuse sclerosing osteomyelitis was initially diagnosed. We administrated oral clarithromycin (400 mg daily) and levofloxacin (500 mg daily), and her pain subsequently resolved. On (99m)Tc-labeled methylene diphosphonate scintigraphy, tracer uptake in the asymptomatic mandible was unchanged, but there was increasing tracer uptake in the sternocostal and sternoclavicular joints, compared with (99m)Tc-labeled methylene diphosphonate scintigraphic findings of the first visit. We diagnosed SAPHO syndrome and administrated oral sodium risedronate hydrate (2.5 mg daily). Although there has been no pain or swelling in the area of the left mandibular lesion, we have followed up on other skin and osteoarticular manifestations in conjunction with other medical departments.

Long-term treatment of severe SAPHO syndrome with adalimumab: case report and a review of the literature

SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome defines an association of inflammatory cutaneous disorders with osteoarticular manifestations and represents a clinical and therapeutic challenge. We report a case of severe SAPHO syndrome with acne conglobata and a diffuse involvement of the anterior chest wall and sacroiliac joints that required treatment with isotretinoin and adalimumab, a new fully human anti-tumor necrosis factor (TNF)-α monoclonal antibody. Combination treatment determined a complete clinical remission of cutaneous and osteoarticular manifestations after 48 weeks. Despite maintenance of clinical remission, follow-up imaging studies after 24 months of adalimumab monotherapy revealed osteoarticular disease progression, with features of inflammatory osteitis. TNFα antagonists have been used as third-line therapy for SAPHO syndrome in single case reports or case series, but these lack consistent long-term follow-up. SAPHO syndrome can present an intermittent-favorable course in the majority of cases as well as a chronic-progressive course, the latter requiring aggressive combination treatment with TNFα antagonists and conventional systemic agents.

The dark side of SAPHO syndrome

SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis and osteitis) is a relatively rare entity. The therapeutic approach of patients with SAPHO syndrome has included multiple drugs with varying success and incoherence responses. The therapy is still empirical today. SAPHO syndrome is commonly treated with non-steroidal anti-inflammatory drugs, bisphophonates and non-biologic disease modifying antirheumatic drugs. Recent reports showed successful treatment with tumour necrosis factor α (TNF α) antagonists, but there is still a dark side of SAPHO syndrome including a subgroup of patient's refractory to all the treatments that have been empirically experienced. A clinical report of a patient with SAPHO syndrome with 12 years of evolution is described. All the therapeutic approaches, including anti TNF α therapy, have not prevented the clinical and radiographic progression of the disease. Given that the disease affects mostly younger patients, new therapeutic strategies are necessary in order to avoid potentially irreversible joint and bone lesions.

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome with review of the relevant published work

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is characterized by various dermatological manifestations and osteoarthropathy frequently localized to the anterior chest wall. Dermatologists should be familiar with this syndrome. Its early diagnosis is important to avoid prolonged antibiotic treatments and unnecessary invasive procedures. We report a new case of this syndrome with review of the relevant published work.

SAPHO syndrome with TMJ involvement: review of the literature and case presentation

Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome is a rare group of sterile, inflammatory osteoarticular disorders classically associated with skin manifestations. The etiology is unknown but probably involves genetic, infectious, and immunological components. The characteristic feature of the disease is found in the bone lesions, which typically involve the anterior chest wall and axial skeleton. In the literature review, six case reports discussed involvement of the TMJ. Treatment of SAPHO is geared toward symptom management as there is no cure. Surgery for mandibular lesions is usually a last resort as results are reported to be temporary with symptoms recurring within a year. Surgery appears to be performed early after diagnosis of TMJ related pathology; probably because lesions affecting the TMJ involve some limitation in mouth opening with varying degrees of ankylosis. The authors provide a literature review and describe a case of SAPHO syndrome with ankylosis of the left TMJ. The patient was treated with joint reconstruction using a patient-fitted total joint prosthesis (TMJ Concepts Inc., Ventura CA) in single stage surgery. This paper is the first to report maxillary involvement in SAPHO syndrome.

SAPHO syndrome with bacillus Calmette-Guerin (BCG) immunotherapy for bladder cancer

The authors describe a case of SAPHO syndrome with bacillus Calmette-Guérin (BCG) immunotherapy for bladder cancer. The patient had undergone transurethral resection (TUR) and was treated with BCG immunotherapy following TUR. Two years after treatment for bladder cancer, the patient had palmoplantar pustulosis, and in the past 1 month suffered from pain localised to the anterior chest wall. The bone scintigraphy showed a strong focal enrichment in the right chest wall, suggesting spondyloarthropathy rather than malignant disease. On the basis of clinical and scintigraphy findings, SAPHO syndrome was diagnosed. The patient was treated with topical therapy and non-steroidal anti-inflammatory drugs and symptoms improved. The authors suggest that SAPHO syndrome might be caused by an association with BCG immunotherapy.

Does inflammatory acne result from imbalance in the keratinocyte innate immune response?

Acne is a multifactorial chronic disease affecting around 80% of teenage population. The pathogenesis of acne involves inflammatory reactions and colonization by the Propionibacterium acnes (P. acnes) strain. P. acnes stimulates the keratinocytes involved in the innate immune response, the intensity of which could be influenced either by bacterial intrinsic factors or by endogenous factors of the host.

Biologic therapy in refractory chronic non-bacterial osteomyelitis of childhood

OBJECTIVE

To date there is no uniformly effective treatment for either chronic recurrent multifocal osteomyelitis (CRMO) or synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome. We report on our clinical experience of using biologic therapy to treat children with these conditions.

METHODS

Retrospective descriptive case series of four children with refractory disease treated with biologics. Disease activity was assessed at predetermined time points (T = 0, T = 6 weeks and T = 12 months after the start of biologic therapy, and at latest follow-up) using a combination of clinical examination and radiological findings: a 10 cm pain and physician visual analogue scale; the Childhood Health Assessment Questionnaire as an assessment of disability; and changes in markers of systemic inflammation.

RESULTS

There was an initial improvement in all parameters assessed for all three children treated with TNF-alpha blockade, although the third case had to discontinue the therapy due to a suspected (but unconfirmed) fungal skin infection. Anakinra treatment alleviated the symptoms in the fourth patient at 6 weeks, but there was no sustained response to treatment at 1-year follow-up.

CONCLUSION

We present our preliminary experience of using biological therapies to treat children with CRMO and SAPHO in conjunction with other immunosuppression. Further studies are needed to establish the role of these therapies in refractory CRMO and SAPHO.

Prevalence of autoantibodies in SAPHO syndrome: a single-center study of 90 patients

OBJECTIVE

To determine the prevalence of the most often tested autoantibodies in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

METHODS

We identified 90 patients seen in our unit between June 2002 and June 2009, and diagnosed according to the proposed criteria for SAPHO syndrome. Demographic and clinical data were collected as well as immunological results, including antinuclear, antithyroid peroxydase (TPO), antithyroid globulin (Tg), antigastric parietal cell, antismooth muscle, antimitochondria, and anti-liver-kidney microsome (LKM) antibodies. Anticyclic citrullinated peptide (CCP) antibodies were analyzed in 69 patients, antibodies to soluble extractable nuclear antigens in 43, anti-double-stranded DNA (dsDNA) antibodies in 22 [depending on the type of fluorescence of antinuclear antibody (ANA)], and antiendomysium antibodies in 55.

RESULTS

Autoantibodies were found in 20 patients (22.2%): 14 patients (15.5%) had positive ANA (titer >/= 1/160); among them, 10 (11%) patients never took a lupus-inducing drug. Antithyroid antibodies (anti-TPO and/or anti-Tg antibodies) were found in only 3 patients (3.3%). Three patients (3.3%) were positive for antigastric parietal cell antibodies and 4 (4.4%) were weakly positive for antismooth muscle antibodies. Antimitochondria and LKM antibodies were negative in all 90 patients. Anti-CCP and anti-dsDNA antibodies were negative in the 69 and 22 patients tested, respectively. One out of 43 patients (2.3%) had anti-SSA antibodies. Antiendomysium antibodies were negative in the 55 patients tested.

CONCLUSION

Our study indicates an increased prevalence of autoantibodies in SAPHO syndrome, with no specific profile. We failed to confirm the reports of an increased prevalence of antithyroid antibodies. These results tend to support a link between autoimmunity and SAPHO syndrome.

Genetic Susceptibility Factors in a Cohort of 38 Patients with SAPHO Syndrome: A Study of PSTPIP2, NOD2, and LPIN2 Genes

Objective.

The SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, and osteitis) is a rare disorder that mainly affects bone and skin. Chronic multifocal osteitis is the main diagnostic feature. Genetic studies of HLA genes have shown no role for these class II antigens, whereas studies of 2 mouse models (cmo and Lupo) point to a role of the PSTPIP2 gene. We analyzed the PSTPIP2 gene in patients with SAPHO syndrome.

Methods.

In a cohort of 38 patients with SAPHO we analyzed PSTPIP2 and 2 other candidate genes, NOD2/CARD15 (Crohn's disease occurs in about 10% of SAPHO patients), and LPIN2 (clinical similarities of SAPHO with Majeed syndrome).

Results.

Rare variants of the 3 genes observed in patients with SAPHO were not specific or were not found more frequently compared to controls, suggesting no major pathogenetic role of these genes in the SAPHO syndrome.

Conclusion.

We found no association between PSTPIP2, NOD2, and LPIN2 variants and the SAPHO syndrome.