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Publications (9)26.81 Total impact

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    ABSTRACT: Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory disorder of the skeletal system. Treatment with NSAIDs is generally effective in the majority of patients, however, a sizeable proportion of patients have persistent disease and subsequent treatment strategies are required. The aim of this study was to characterise the clinical and radiological disease course in CNO patients treated with the bisphosphonate pamidronate (PAM).
    Clinical and experimental rheumatology 07/2014; 32(4):604-9. · 2.66 Impact Factor
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    ABSTRACT: Hypophosphatasia (HPP) is a heterogeneous rare, inherited disorder of bone and mineral metabolism caused by different mutations in the ALPL gene encoding the isoenzyme, tissue-nonspecific alkaline phosphatase (TNAP). Prognosis is very poor in severe perinatal forms with most patients dying from pulmonary complications of their skeletal disease. TNAP deficiency, however, may also result in neurological symptoms such as neonatal seizures. The exact biological role of TNAP in the human brain is still not known and the pathophysiology of neurological symptoms due to TNAP deficiency in HPP are not understood in detail. In this report, we describe the clinical features and functional studies of a patient with severe perinatal HPP which presented with rapidly progressive encephalopathy caused by new compound heterozygous mutations in the ALPL gene which result in a functional ALPL "knock out", demonstrated in vitro. In contrast, an in vitro simulation of the genetic status of his currently asymptomatic parents who are both heterozygous for one mutation, showed a residual in vitro AP activity of above 50%. Interestingly, in our patient, the fatal outcome was due to progressive encephalopathy which was refractory to antiepileptic therapy including pyridoxine, rather than hypomineralization and respiratory insufficiency often seen in HPP patients. The patient`s cranial MRI showed progressive cystic degradation of the cortex and peripheral white matter with nearly complete destruction of the cerebrum. To our knowledge, this is the first MRI-based report of a deleterious neurological clinical outcome due to a progressive encephalopathy in an infant harboring a functional human ALPL "knock out". This clinical course of disease suggests that TNAP is involved in development and may be responsible for multiple functions of the human brain. According to our data, a certain amount of residual TNAP activity might be mandatory for normal CNS function in newborns and early childhood.
    Bone 02/2013; · 3.82 Impact Factor
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    ABSTRACT: Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disorder of unknown origin. We previously demonstrated that monocytes from CRMO patients fail to express the immune-modulatory cytokine interleukin-10 (IL-10) in a chromatin dependent manner. Here, we demonstrate that attenuated extracellular-signal regulated kinase (ERK)1 and 2 signaling in response to TLR4 activation results in failure to induce IL-10 expression in monocytes from CRMO patients. Attenuated ERK1/2 activation results in 1) reduced levels of Sp-1, a transcription factor that induces IL-10 expression in monocytes, and 2) impaired H3S10 phosphorylation of the IL10 promoter, an activating epigenetic mark. The pro-inflammatory cytokines tumor necrosis factor (TNF)α and IL-6 are not negatively affected, resulting in an imbalance towards pro-inflammatory cytokines. Thus, impaired ERK1/2 signaling with subsequently reduced Sp-1 expression and H3S10 phosphorylation of the IL10 promoter may centrally contribute to the pathophysiology of CRMO.
    Clinical Immunology 08/2012; 145(1):69-76. · 3.77 Impact Factor
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    ABSTRACT: To compare sensitivity of bone scintigraphy using 99mTechnetium-labelled methylene diphosphonate (Tc-99m MDP) and magnetic resonance imaging (MRI) in the detection of inflammatory bone lesions in patients with chronic non-bacterial osteomyelitis (CNO). Tc-99m MDP bone scintigraphy and MRI were performed in 32 CNO patients at the time of diagnosis and compared regarding their sensitivity in detecting inflammatory lesions in symptomatic regions of the body. Inflammatory lesions could be detected in 40 out of the 54 (74.1%) symptomatic regions by bone scintigraphy and in 53 (98.1%) of these regions by MRI (p<0.001). Sensitivity of MRI compared to bone scintigraphy was superior in detecting lesions in the long bones of the thigh and the lower legs (100% vs. 78.4%, respectively, p<0.05). Bone scintigraphy does not seem to display the whole extent of the inflammatory process in CNO. Therefore, depending on clinical relevance, MRI rather than planar bone scintigraphy should be considered for the detection of CNO lesions at diagnosis.
    Clinical and experimental rheumatology 07/2012; 30(4):578-82. · 2.66 Impact Factor
  • Bulletin du Groupèment international pour la recherche scientifique en stomatologie & odontologie. 01/2012; 51(1):e36.
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    ABSTRACT: Chronic non-bacterial osteomyelitis (CNO) is an auto-inflammatory disorder that affects the skeletal system. Interleukin (IL-)10 is an immune-modulatory cytokine that controls inflammation, and limits inflammatory cytokine responses. Dysregulation of IL-10 expression has been shown to result in autoimmune and infectious diseases. We investigated IL-10 expression by monocytic cells from CNO patients and controls. In response to stimulation with LPS, IL-10 expression from CNO monocytes was reduced (p<0.001). This was independent of IL10 promoter polymorphisms. Thus, we investigated Sp1 recruitment to the IL10 promoter and saw markedly reduced binding in CNO monocytes. This was accompanied with reduced phosphorylation of histone H3 serine 10 (H3S10), an activating epigenetic mark. Impaired recruitment of Sp1 to the IL10 promoter, and reduced H3S10 phosphorylation, may be a reflection of deficient MAPK signaling in CNO monocytes in response to LPS stimulation. Thus, we have discovered a mechanism that may be central in the pathophysiology of CNO.
    Clinical Immunology 08/2011; 141(3):317-27. · 3.77 Impact Factor
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    ABSTRACT: B cells impact the perpetuation of chronic inflammatory or autoimmune diseases in multiple ways. A role of B cells as antigen-presenting cells (APCs) in the pathogenesis of chronic arthritis in humans has been suggested; however, as of yet the presence of such B cells at the site of inflammation has not been demonstrated. This study was undertaken to investigate whether synovial B cells in patients with juvenile idiopathic arthritis (JIA) might display features of APCs. The frequency, phenotype, and immunoglobulin repertoire of synovial B cells were studied by flow cytometry and single-cell polymerase chain reaction (PCR). Cytokine expression by B cells was analyzed by real-time PCR, and interaction between B cells and T cells was investigated in a mixed lymphocyte culture. CD27+IgD- and CD27-IgD- B cells accumulated in the joints of JIA patients and displayed an activated phenotype. Both B cell subsets expressed hypermutated and class-switched immunoglobulins, indicators of memory B cells. The accumulating memory B cells expressed the costimulatory molecules CD80/CD86 and showed a higher capacity to activate allogeneic T cells and prime a Th1 phenotype than their peripheral blood counterparts. Activated immunoglobulin class-switched CD27- and CD27+ memory B cells, indicating a phenotype of APCs with expression of costimulatory molecules, accumulate in the joints of patients with JIA and might be involved in the amplification of pathogenic T cell activation. These findings provide evidence that B cells play an antibody-independent immunopathologic role in human chronic inflammatory arthritis of childhood.
    Arthritis & Rheumatology 07/2011; 63(11):3458-66. · 7.48 Impact Factor
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    ABSTRACT: Popliteal cysts, or Baker cysts, are considered rare in children and may exhibit particular features, as compared with adults. We studied data from 80 paediatric patients with 55 Baker cysts, examined over a period of 7 years, and correlated clinical presentation with findings on ultrasonography and MRI. Prevalence of popliteal cysts was 57% in arthritic knees, 58% with hypermobility syndrome, and 28% without risk factors. Only one patient had a trauma history and showed an ipsilateral cyst. Mean cyst volume was 3.4 mL; cysts were larger in boys. Patients with arthritis had echogenic cysts in 53%. Cyst communication with the joint space was seen in 64% on ultrasonography and 86% on MRI. In conclusion, Baker cysts are a common finding in a clinically preselected paediatric population. Children with Baker cysts should be assessed for underlying arthritis and inherited joint hypermobility, while sporadic Baker cysts appear to be common, as well.
    Arthritis. 01/2011; 2011:751593.
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    ABSTRACT: Chronic non-bacterial osteomyelitis CNO is an inflammatory disorder of the musculoskeletal system with unknown etiology. In addition to bone inflammation, patients may present with inflammatory involvement of other tissues including, e.g., skin. Recently, a novel syndrome due to deficiency of interleukin-1 receptor antagonist (IL1RN), DIRA has been identified. Clinically the syndrome is characterized by neonatal onset of pustular dermatosis, periostitis and chronic sterile multifocal osteomyelitis, strongly resembling CNO. Homozygous mutations of IL1RN have been identified and resulted in a truncated protein that is not secreted, hence leaving the action of interleukin-1 unopposed. Because of similar clinical, radiological and histological features of CNO and DIRA, we hypothesized that both disorders might share a common autoinflammatory process. Thus, we searched for the presence of mutations in the interleukin-1 receptor antagonist gene in 60 patients diagnosed with CNO. In one patient with chronic multifocal osteomyelitis a heterozygous missense variant: c.281G>T (p.Cys94Phe) was detected. In the other patients only frequent polymorphisms were found. Our findings were not able to confirm mutations in IL1RN being an important contributing factor to the pathogenesis of CNO.
    Clinical and experimental rheumatology 01/2011; 29(6):1040-3. · 2.66 Impact Factor