Activating killer immunoglobulin-like receptors genes are associated with increased susceptibility to ankylosing spondylitis.

The aim of this study was to analyse the association of specific killer cell immunoglobulin-like receptors (KIR) genes and haplotypes with susceptibility to ankylosing spondylitis (AS) and its different clinical manifestations in a Spanish population. The presence or absence of all KIR genes was studied for their association with AS. A total of 176 patients with AS and 435 healthy control subjects were selected for this study based on clinical criteria. The commercial KIR-sequence-specific oligonucleotides (SSO) typing kit was used to investigate KIR typing. Frequencies of KIR2DS1 and KIR3DS1 genes were increased significantly in patients compared with healthy controls [52·8 versus 38·2%, PBonf < 0·01, odds ratio (OR) = 1·81 (1·28-2·59); 51·7 versus 37·5%, PBonf < 0·01, OR = 1·79 (1·25-2·54)]. Moreover, the frequency of activating genotypes in the AS patient group was significantly higher than in the healthy control group (P < 0·05). KIR2DS1 and KIR3DS1, in addition to human leucocyte antigen (HLA)-B27, may play an important role in the pathogenesis of AS. However, we show that the contribution of the KIR genes to AS susceptibility extends beyond the association with individual KIRs, with an imbalance between activating and inhibitory KIR genes seeming to influence the susceptibility to AS.

Validity of the ankylosing spondylitis disease activity score (ASDAS) in patients with early spondyloarthritis from the Esperanza programme.

OBJECTIVES: To evaluate the validity of the Ankylosing Spondylitis Disease Activity Score (ASDAS) in early spondyloarthritis (SpA) in comparison with conventional clinical measures of disease activity. METHODS: Six hundred and seventy-six incident cases of early SpA from the Esperanza programme were included. Patients were categorised into high and low disease activity states based on patient and physician global assessment scores and on the physician's decision to start treatment with a disease-modifying antirheumatic drug or tumour necrosis factor blocker. The discriminant ability of ASDAS-C-reactive protein (CRP) and ASDAS-erythrocyte sedimentation rate (ESR) was tested using standardised mean differences between patients with high and low disease activity. Convergent validity was tested by Pearson correlation between ASDAS versions and other measures of disease activity. RESULTS: ASDAS-ESR and ASDAS-CRP showed good correlation with BASDAI (r=0.79 and 0.74, respectively). Both indices correlated well with the patient global assessment (r=0.70 in both indices) and moderately with the physician global score (r=0.46 and 0.47, respectively). CRP and ESR showed poor correlation with patient- and physician-derived measures. ASDAS performed similarly across the global SpA sample, ankylosing spondylitis (AS), non-radiographic axial SpA and peripheral SpA. CONCLUSIONS: ASDAS performed as a valid activity score even being slightly better than the Bath Ankylosing Spondylitis Disease Activity Index in its ability to discriminate between high and low disease activity in early SpA. ASDAS performed similarly in AS, early forms of SpA, non-radiographic axial SpA and peripheral SpA.

The C677T polymorphism in the MTHFR gene is associated with the toxicity of methotrexate in a Spanish rheumatoid arthritis population.

OBJECTIVE: Methotrexate (MTX) is the first-choice drug for the treatment of rheumatoid arthritis (RA) patients. However, 30% of RA patients discontinue therapy within 1 year, usually because of adverse effects. Previous studies have reported conflicting results on the association of polymorphisms in the MTHFR gene with the toxicity of MTX in RA. The aim of this study was to assess the involvement of the C677T and A1298C polymorphisms in the MTHFR gene in the toxicity of MTX in a Spanish RA population. METHODS: The study included retrospectively 468 Spanish RA patients treated with MTX. Single nucleotide polymorphism (SNP) genotyping was performed using the oligonucleotide microarray technique. Allele and genotype association analyses with regard to MTX toxicity and a haplotype association test were also performed. RESULTS: Eighty-four out of the 468 patients (18%) had to discontinue therapy due to adverse effects or MTX toxicity. The C677T polymorphism (rs1801133) was associated with increased MTX toxicity [odds ratio (OR) 1.42, 95% confidence interval (CI) 1.01-1.98, p = 0.0428], and the strongest association was shown in the recessive model (OR 1.95, 95% CI 1.08-3.53, p = 0.0246). The A1298C polymorphism (rs1801131) was not associated with increased MTX toxicity (OR 0.94, 95% CI 0.65-1.38, p = 0.761). A borderline significant risk haplotype was found: 677T-1298A (OR 1.40, 95% CI 1.00-1.96, p = 0.0518). CONCLUSION: These results demonstrate that the C677T polymorphism in the MTHFR gene is associated with MTX toxicity in a Spanish RA population.

Fibromyalgia in patients with ankylosing spondylitis: prevalence and utility of the measures of activity, function and radiological damage.

OBJECTIVES: To determine the prevalence of fibromyalgia (FM) in ankylosing spondylitis (AS). To evaluate the effect of FM on the measures of activity in AS. To analyse predictive factors in order to identify this group of patients. PATIENTS AND METHODS: A cross-sectional study based on 462 patients with definite ankylosing spondylitis included in the REGISPONSER. Sociodemographic data, clinical features, Bath AS disease activity index (BASDAI), Bath AS functional index (BASFI), Bath AS radiology index (BASRI), Stoke modified index (Sasss-m), laboratory data, Short-Format 12 (SF-12), AS specific quality of life (ASQoL), Fibromyalgia Impact Questionnaire (FIQ) and treatments used were all documented. To diagnose FM, the ACR 1990 criteria had to be fulfilled. All statistical tests were performed using STATA. RESULTS: The prevalence of fibromyalgia in all AS was 4.11%. Among the women with AS, the prevalence of FM increased to 10.83%. The BASDAI, BASFI and total BASRI were strongly influenced by the presence of FM. The inverse relationship between BASDAI or BASFI and total BASRI was taken to generate a ratio. Accordingly, if the patient presented BASDAI/BASRI ≥1.5 or BASFI/BASRI ≥1.08, the probability of having FM was very high. CONCLUSIONS: There is an increased risk of FM in females with AS. The fact of having FM distorts the measures of activity and functional damage of AS. As a result, it is possible that some patients with AS and FM are being overtreated. The BASDAI/BASRI and BASFI/BASRI ratios are very useful to identify these patients.

Relationship between spinal mobility and disease activity, function, quality of life and radiology. A cross-sectional Spanish registry of spondyloarthropathies (REGISPONSER).

OBJECTIVE: To determine the relationship between anthropometric measurements and disease activity, functional capacity, quality of life and radiology in Spanish patients with ankylosing spondylitis (AS). PATIENTS AND METHODS: A cross-sectional study was made of 842 patients with definite ankylosing spondylitis (REGISPONSER). Sociodemographic data, spinal mobility measurements, Bath AS disease activity index (BASDAI), nocturnal pain, Bath AS radiology index (BASRI), Bath AS functional index (BASFI), the Short-Format 12 (SF-12) and the AS specific quality of life (ASQoL) questionnaire were applied. Pearson correlation coefficient analysis and regression models were constructed. RESULTS: There was moderate correlation between fingertip-to-floor distance and lateral cervical rotation with the BASFI (p<0.01). Good correlation was evident between wall-occiput distance and lateral cervical rotation with the BASRI (p<0.01). Moderate correlation was found between chest expansion, the Schober modified test and fingertip-to-floor distance with the total BASRI (p<0.01). The anthropometric measurement with the lowest correlation value was lateral lumbar flexion. Significant association was found between the Schober modified test and BASFI, BASDAI and BASRI (R(2) = 0.37; p<0.001); chest expansion and BASFI, BASDAI and BASRI (R(2) = 0.25; p<0.001); wall-occiput distance and BASFI, BASRI and ASQoL (R(2) = 0.44; p<0.001); fingertip-to-floor distance and BASFI and BASRI (R(2) = 0.30; p<0.001); and lateral cervical rotation and BASFI and BASRI (R(2) = 0.34; p<0.001). CONCLUSION: In our study, wall-occiput distance and lateral cervical rotation showed the strongest correlation to BASRI. Similarly, fingertip-to-floor distance and lateral cervical rotation exhibited the closest correlation to BASFI.

Influence of several fungicides on the antioxidant activity of red wines (var. Monastrell).

The antioxidant activity of wines obtained from grapes treated with six fungicides (famoxadone, fenhexamid, fluquinconazole, kresoxim-methyl, quinoxyfen and trifloxystrobin) was investigated. Two field trials in triplicate were carried out for each formulation of the fungicide at the recommended dose of the manufacturer. The first trial was carried out under good agricultural practices (GAP), following the recommended pre-harvest interval, and the second one under critical agricultural practices (CAP) that involves treating the same field just before the harvest. The residue levels were determined by gas and liquid chromatography coupled to mass detectors (GC-MS and LC-MS). The antioxidant activity was determined in the wines obtained from the thirteen trials including one control, six from treated grapes obeying the pre-harvest interval, and six from grapes treated at the day of harvest or at most unfavorable conditions. Elimination of 40-100% of the initial fungicide residues present in grapes was observed during the wine-making process. It can be inferred from the results that the use of these fungicides did not produce any decrease of the antioxidant activity in the wines (7.19 +/- 0.22 mmol Trolox/L for the blank wine versus a range of 6.45 +/- 0.82 mmol Trolox/L to 10.06 +/- 0.59 mmol Trolox/L for the treated wines) at the pre-harvest interval and most unfavorable conditions. Nevertheless, the presence of famoxadone, kresoxim-methyl and quinoxyfen increased the antioxidant activity and this was directly related to their residue levels in the grapes. Also, the wine phenolic composition was altered in variable intensity by the presence of the fungicide residues.

The IL23R Arg381Gln non-synonymous polymorphism confers susceptibility to ankylosing spondylitis.

OBJECTIVES: Recent results have shown that the IL23R gene, coding for a subunit of the interleukin-23 receptor, is strongly associated with autoimmunity. The aim of the current study was to investigate, for the first time, the possible involvement of the IL23R gene in genetic susceptibility to ankylosing spondylitis (AS). METHODS: We carried out a case-control association study in which 365 patients with AS and 500 blood bank donors were included. Eight single nucleotide polymorphisms (SNPs) spanning the IL23R gene were selected as genetic markers for our association study and were genotyped using a Taqman 5' allelic discrimination assay. RESULTS: Interestingly, we observed association of two of eight IL23R genotyped SNPs. The strongest effect was conferred by the non-synonymous rs11209026 (Arg381Gln) SNP (odds ratio 0.46 95% confidence interval 0.2 to 0.7 p = 0.001). Similarly, the IL23R rs1343151 SNP showed association with AS genetic susceptibility (odds ratio 0.68 95% confidence interval 0.55 to 0.83 p = 0.0002). After a conditional case-control test we observed that the effect of these two genetic variants was independent of linkage disequilibrium. CONCLUSIONS: These results suggest that the IL23R gene seems to be involved in AS genetic predisposition.

Alteration of the Saccharomyces cerevisiae COX2 mRNA 5'-untranslated leader by mitochondrial gene replacement and functional interaction with the translational activator protein PET111.

The ability to replace wild-type mitochondrial DNA sequences in yeast with in vitro-generated mutations has been exploited to study the mechanism by which the nuclearly encoded PET111 protein specifically activates translation of the mitochondrially coded COX2 mRNA. We have generated three mutations in vitro that alter the COX2 mRNA 5'-untranslated leader (UTL) and introduced them into the mitochondrial genome, replacing the wild-type sequence. None of the mutations significantly affected the steady-state level of COX2 mRNA. Deletion of a single base at position -24 (relative to the translation initiation codon) in the 5'-UTL (cox2-11) reduced COX2 mRNA translation and respiratory growth, whereas insertion of four bases in place of the deleted base (cox2-12) and deletion of bases -30 to -2 (cox2-13) completely blocked both. Six spontaneous nuclear mutations were selected as suppressors of the single-base 5'-UTL deletion, cox2-11. One of these mapped to PET111 and was shown to be a missense mutation that changed residue 652 from Ala to Thr. This suppressor, PET111-20, failed to suppress the 29-base deletion, cox2-13, but very weakly suppressed the insertion mutation, cox2-12. PET111-20 also enhanced translation of a partially functional COX2 mRNA with a wild-type 5'-UTL but a mutant initiation codon. Although overexpression of the wild-type PET111 protein caused weak suppression of the single-base deletion, cox2-11, the PET111-20 suppressor mutation did not function simply by increasing the level of the protein. These results demonstrate an intimate functional interaction between the translational activator protein and the mRNA 5'-UTL and suggest that they may interact directly.

Bioavailability of insect growth regulators in citrus and stone fruits.

The aim of this study was to offer data about the bioavailability of flufenoxuron, lufenuron, pyriproxyfen and fenoxycarb in common commodities like mandarin, apricot and peach. The in vitro bioavailability of the compounds was studied not only in fresh fruit but also in standards and canned food in order to establish possible differences according to the matrix. The gastric digestion was simulated with porcine pepsin at pH 2, for 2 h in a shaking water bath at 37 degrees C. The intestinal digestion was simulated with porcine pancreatin at pH 7, for 2 h in a shaking water bath at 37 degrees C. The intestinal absorption was simulated with cellulose dialysis tubing filled with a solution of sodium carbonate. No in vitro bioavailability was observed in mandarin, peach and apricot samples spiked at the concentrations generally found in the market for the raw and processed commodities. In standards, the dialysis started at the level of 0.25 mg/kg. This is an approximation to the pesticide digestion and absorption in humans.

Roux-en-Y Gastric Bypass.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is considered the gold standard for gastric bypass, displaying better results for metabolic disorders than other surgical procedures over the long term. The aim of this study was to determine the effects of bariatric surgery, in particular the RYGB technique, on metabolic syndrome (MS) and other biochemical parameters implicit in the comorbid conditions associated with obesity, as well as to explore the influence of this surgical procedure on psychiatric comorbidity in the study population. METHOD: An observational retrospective cohort study based on 146 clinical records of patients having undergone RYGB between January 1, 2011, and January 1, 2014, was performed. Data related to metabolic and psychiatric comorbidity were gathered at three stages: prior to surgery and at 3 and 9 months following surgery. RESULTS: There was a progressive and statistically significant reduction of all biochemical parameters analyzed at 3 and 9 months following surgery except high-density lipoprotein cholesterol, which significantly increased (beneficial) in value. These changes imply a remission of >90% for all metabolic disorders and the consequent tendency toward a reduction in prescribed pharmacological treatments, with MS found in only one subject at 9 months. There was, however, no significant reduction in pharmacological treatments for psychiatric comorbidities. CONCLUSION: Findings suggest that RYGB is an effective treatment for MS and other metabolic disorders but not for psychiatric comorbidities accompanying MS.

Oxidative stress in Alzheimer patients in different stages of the disease.

Increasing evidence demonstrates that oxidative stress causes damage to cell function with aging and is involved in a number of age-related disorders including atherosclerosis, arthritis, and neurodegenerative disorders. Cellular changes show that oxidative stress is a condition that precedes the appearance of the hallmark pathologies of the disease, neurofibrillary tangles and senile plaques. The aim of this article is to analyze the different biomarkers of oxidative stress in Alzheimer patients, in different stages of the illness, and compare the results with a control group. A nutritional evaluation was carried out, including anthropometric and biological measures and a 3 day dietary record. The concentration of substances which react to thiobarbituric acid (TBARS) was measured as a marker of the degree of peroxidation using the HPLC method. The oxidation of proteins was analyzed by measuring the carbonyl groups in plasma. In addition, measurements were made of the total antioxidant activity in plasma and the activity of endogenous antioxidant enzymes such as gluthatione peroxidase, gluthatione reductase and superoxide dismutase. The total antioxidant plasmatic status of the patients with Alzheimer both in light-moderate phase and in advanced phase was lower than in the control. No significant differences were observed between the different stages of the disease in protein oxidation levels. Peroxidation was higher in patients in the advanced stage of the disease than in the control group. However, no significant differences were observed between the different stages of the disease. In this preliminary study, it was observed that Alzheimer patients in the light-moderate stage already present oxidative stress levels above those of the control group.

Oligomeric structure of hepatic lipase: evidence from a novel epitope tag technique.

The subunit structure of purified rHL (rHL) was determined by gel filtration chromatography, density gradient ultracentrifugation studies and a novel approach using epitope-tagged rHL. By gel filtration studies, native rHL had an apparent molecular weight of 179 kDa whereas enzyme treated with 6 M guanidine hydrochloride (GuHCl) for 22 h at room temperature gave a protein peak at 76 kDa. Using milder conditions for denaturation of rHL, such as 1 M GuHCl for 2 h, rHL eluted in two distinct peaks, one at 179 kDa and the other at 76 kDa. In addition, both protein peaks produced under mild denaturing conditions possessed detectable catalytic activity. Consistent with studies on lipoprotein lipase, the denatured rHL eluted from heparin-Sepharose at a lower salt concentration of 0.42 M NaCl than the native rHL which eluted at 0.72 M NaCl. By density gradient ultracentrifugation studies, the estimated molecular weight of native rHL was determined to be 113 kDa. Together, the data suggest that native rHL exists as a dimer that can be denatured into monomers by GuHCl and that a fraction of the denatured enzyme has detectable enzyme activity. To confirm these results, we designed two different rHL constructs that were epitope-tagged with either the myc or flag epitope and transfected them into 293 cells. The addition of the tag was shown not to alter enzyme secretion rate or specific activity of the lipase. Partially purified lipase from media of cotransfected cells was used to establish a dimer assay which employed a sandwich ELISA. This assay firmly established the presence of a rHL species which contained both the myc and flag tags, supporting an oligomeric subunit structure for rHL. Furthermore, the data using the epitope-tagged enzyme shows that this method could be a useful tool not only in identifying the region of the lipase responsible for dimer formation but also to study other protein-protein interactions.

PET111 acts in the 5'-leader of the Saccharomyces cerevisiae mitochondrial COX2 mRNA to promote its translation.

PET111 is a yeast nuclear gene specifically required for the expression of the mitochondrial gene COX2, encoding cytochrome c oxidase subunit II (coxII). Previous studies have shown that PET111 activates translation of the COX2 mRNA. To map the site of PET111 action we have constructed, in vitro, genes coding for chimeric mRNAs, introduced them into mitochondria by transformation and studied their expression. Translation of a chimeric mRNA with the 612-base 5'-untranslated leader of the COX3 mRNA fused precisely to the structural gene for the coxII-precursor protein is independent of PET111, but does require a COX3 mRNA-specific translational activator known to work on the COX3 5'-leader. This result demonstrates that PET111 is not required for any post-translational step. Translation of a chimeric mRNA with the 54-base 5'-leader of the COX2 mRNA fused precisely to the structural gene for cytochrome c oxidase subunit III was dependent on PET111 activity. These results demonstrate that PET111 acts specifically at a site in the short COX2 5'-leader to activate translation of downstream coding sequences.

Influence of anti-VEGF about cardiovascular biomarkers in age related macular degeneration.

Systemic VEGF inhibition disrupts endothelial homeostasis and accelerates the atherogenesis, suggesting that these events contribute to the clinical cardiovascular adverse events of VEGF-inhibiting therapies. The objective of the current study was to analyze the effect of anti-VEGF therapy on cardiovascular risk factors in patients with exudative age related macular degeneration. A total of 73 patients with exudative age related macular degeneration (without previous anti-VEGF therapy) were treated with two anti-VEGF: Ranibizumab and Pegaptanib sodium. The follow up was 6 months. The following parameters were determined before and after treatment: homocysteine, lipids (total cholesterol, triglycerides, HDL-c, LDL-c), C-Reactive Protein and fibrinogen. There were not statistically significant differences in parameters studied before and after treatment with both Pegaptanib sodium and Ranibizumab, except C-Reactive Protein. Of all patients analyzed, only 3 of them have initially C-Reactive Protein levels above normal levels and after antiangiogenic therapy, there was a significant increase in C-Reactive Protein. We have not found results in our study who to suspect that treatment with anti-VEGF in the patients with exudative age related macular degeneration increases cardiovascular risk predictors. However, after therapy was increased the CRP and fibrinogen may mean that anti-VEGF contribute an alteration of endothelial homeostasis in exudative AMD.

Phenolic compounds and antioxidant activity of red wine made from grapes treated with different fungicides.

The effect of treating grapes with six fungicides, applied under critical agricultural practices (CAP) on levels of phenolic compounds and antioxidant activity of red wines of Monastrell variety was studied. Vinifications were performed through addition of active dry yeast (ADY). Measurement of phenolic compounds was made with HPLC-DAD. Determination of antioxidant activity was through reaction of the wine sample with the DPPH radical. The wine prepared from grapes treated with quinoxyfen shows a greater increase of phenolic compounds than the control wine. In contrast, the wine obtained from grapes treated with trifloxystrobin showed lower total concentration of phenolic compounds, including stilbenes, whilst treatments with kresoxim-methyl, fluquinconazole, and famoxadone slightly reduced their content. Hence, the use of these last four fungicides could cause a decrease in possible health benefits to consumers. Antioxidant activity hardly varied in the assays with quinoxyfen, fluquinconazole and famoxadone, and decreased in the other wines.

Role of the new azoles in the treatment of fungal osteoarticular infections.

OBJECTIVES: To analyze the usefulness of the new azoles for the treatment of fungal osteoarticular infections, and to report three cases of fungal knee arthritis treated with fluconazole in our unit. METHODS: The medical literature was reviewed for all cases of osteoarticular infection caused by fungi and treated with fluconazole or itraconazole registered in the MedLine Silver Platter database from 1972 to 1997. RESULTS: The total number of patients included in this review was 56; 19 were treated with fluconazole and 37 with itraconazole. The most frequent causative agents implicated were fungi of the genuses Candida and Aspergillus. There were eight therapeutic failures, and there were no statistically different findings among the patients in terms of their health status. Adverse effects were unusual. CONCLUSIONS: Controlled studies are necessary to establish the true role of the new azole drugs in the treatment of fungal osteoarticular infections, but they seem to be a promising therapeutic option.

Catastrophic antiphospholipid syndrome (CAS): a rare manifestation of the antiphospholipid antibody syndrome.

During the last decade, antiphospholipid antibodies and their clinical manifestations have given rise to increasing interest and have been associated with a wide spectrum of clinic expression, including arterial and venous thrombosis, thrombocytopenia, recurrent fetal wastage, Coombs positive haemolysis, livedo reticularis and neurological abnormalities, commonly present as isolated recurrent events, and rarely characterized by fatal outcome. Recently, an acutely disseminated vasculopathy, the so-called "catastrophic antiphospholipid syndrome" (CAS) characterized by non-inflammatory vascular occlusion and frequency of fatal outcome, has been described. We present yet another case report of this new and poorly understood entity and review its antecedents, clinical manifestations, serological profile, treatment and outcome.

Lupus erythematosus with an erythema multiforme-like eruption.

We describe a patient diagnosed with lupus erythematosus (LE) who developed an acute generalized eruption characterized by erythema multiforme (EM)-like lesions. Biopsy specimen showed foci of vacuolar alteration at the dermo-epidermal junction and frequent necrotic keratinocytes. Laboratory tests disclosed a speckled-homogenous antinuclear antibody titer of 1:640, leucopenia and hypocomplementemia. Anti-Ro/anti-La antibodies and rheumatoid factor were negative. Treatment with high-dose oral prednisone and azathioprine led to complete remission of the cutaneous lesions, although eruption recurred two years later. We believe that this patient presented a subacute cutaneous lupus eythematous with a distinctive erythema multiforme-like eruption. This case could be included in the so-called Rowell's syndrome, although it does not fit all the immunological characteristics reported in the original description, as in many of the previously reported cases. At the present time there seems to be enough evidence to classify Rowell's syndrome within the subacute cutaneous lupus erythematosus subset. Finally, a coexistence of LE and EM can not be completely discarded in our patient, although no causative factor was found.

[Still's disease in adults and polymyositis. An infrequent association]. / Enfermedad de Still del adulto y polimiositis. Una asociación infrecuente.

A case of coexistence of adult onset Still's disease and idiopathic inflammatory myopathy is reported in a patient with antecedent of Graves-Basedow disease. Although myalgias are common during the flares of adult onset Still's disease, a review of literature only disclosed two previous cases of polymyositis associated to adult onset Still's disease. A high index of suspicion is needed in order to diagnose such a rare association which has relevant prognostic and therapeutic implications. Treatment with methotrexate was started in order to control myopathy, resulting in improvement of both polymyositis and adult onset Still disease. A possible role of methotrexate in the management of adult onset Still's disease is suggested.

Intra-articular osteoid osteoma at the elbow: report of a case and review of the literature.

Osteoid osteoma is a benign tumor that may occur in almost any part of any bone. Diagnosis can be difficult, particularly when it is intra-articular. In these cases, osteoid osteoma may present initially with symptoms suggestive of inflammatory arthritis, degenerative joint disease, neoplasm, or infection. We report a case of intra-articular osteoid osteoma in a teenager who presented with a monoarthritis of the elbow. The patient did not have a typical pattern of pain, did not have the typical relief with anti-inflammatory agents, and misinterpretation of the radiographs led to a delay in the diagnosis and definitive treatment. Surgical excision confirmed the diagnosis and resulted in resolution of the monoarthritis. Intra-articular osteoid osteoma must be taken into account in cases of unexplained chronic monoarthritis, with a sterile and relatively noninflammatory synovial fluid. A definitive diagnosis depends on surgical excision and histologic confirmation. Ahigh index of suspicion is necessary to make the diagnosis.