Publisher Correction: A predominant involvement of the triple seropositive patients and others with rheumatoid factor in the association of smoking with rheumatoid arthritis.

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Lower frequency of anti-citrullinated protein antibodies among early arthritis patients with high body mass index.

OBJECTIVES: To investigate the role of body mass index (BMI) in the phenotypic and genotypic characteristics of early arthritis patients. METHODS: We analysed the clinical and laboratory parameters from the baseline visit of patients (670 patients [78.51% women]) included in the PEARL study. The WHO definition for low weight, normal weight, overweight and obesity (BMI <18.5, 18.5-25, 25-30 or ≥30 kg/m2, respectively) was applied. Anticitrullinated protein antibodies (ACPA) were studied by ELISA and HLA-DRB1* were genotyped by sequence speci c oligonucleotide probes. The relationship between BMI classification and other variables was analysed using Kruskall-Wallis, Anova and Chi-Square tests. Then multivariate logistic regression was performed to establish the role of BMI in ACPA positivity and ordered logistic regression to establish its relationship with ACPA level. RESULTS: Among the patients studied, 255 (38.06%) were considered overweight and 136 (20.3%) obese. High BMI patients had significantly more pain perception and disability than normal weight patients, whereas no clear differences in disease activity were observed between high BMI and normal weight patients. ACPA positivity was significantly less frequent in overweight and obese patients compared to normal BMI patients. This information was confirmed by adjusting for smoking habit and the presence of shared epitope. CONCLUSIONS: Our data support the theory that high BMI patients suffer more frequently from ACPA-negative RA. Nevertheless, although no disease activity differences were observed, these patients showed higher pain and disability scores since the beginning of disease.

A predominant involvement of the triple seropositive patients and others with rheumatoid factor in the association of smoking with rheumatoid arthritis.

The major environmental risk factor for rheumatoid arthritis (RA) is smoking, which according to a widely accepted model induces protein citrullination in the lungs, triggering the production of anti-citrullinated protein antibodies (ACPA) and RA development. Nevertheless, some research findings do not fit this model. Therefore, we obtained six independent cohorts with 2253 RA patients for a detailed analysis of the association between smoking and RA autoantibodies. Our results showed a predominant association of smoking with the concurrent presence of the three antibodies: rheumatoid factor (RF), ACPA and anti-carbamylated protein antibodies (ACarPA) (3 Ab vs. 0 Ab: OR = 1.99, p = 2.5 × 10-8). Meta-analysis with previous data (4491 patients) confirmed the predominant association with the concurrent presence of the three antibodies (3 Ab vs. 0 Ab: OR = 2.00, p = 4.4 ×10-16) and revealed that smoking was exclusively associated with the presence of RF in patients with one or two antibodies (RF+1+2 vs. RF-0+1+2: OR = 1.32, p = 0.0002). In contrast, no specific association with ACPA or ACarPA was found. Therefore, these results showed the need to understand how smoking favors the concordance of RA specific antibodies and RF triggering, perhaps involving smoking-induced epitope spreading and other hypothesized mechanisms.

Rapid beneficial effect of the IL-6 receptor blockade on insulin resistance and insulin sensitivity in non-diabetic patients with rheumatoid arthritis.

OBJECTIVES: In patients with rheumatoid arthritis (RA), insulin resistance (IR), a component of the metabolic syndrome, is closely linked to the systemic inflammation induced by proinflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-6. In the present study, we aimed to assess if an intravenous administration of the anti-IL-6 receptor tocilizumab may yield a rapid improvement of IR in RA. METHODS: 50 consecutive non-diabetic patients with RA refractory to methotrexate, undergoing periodic treatment with tocilizumab, were studied. Besides disease activity, serum insulin, insulin/glucose ratio, insulin resistance (HOMA-IR) and insulin sensitivity (QUICKI) indexes were assessed immediately before and 1 hour after the end of an intravenous administration of tocilizumab (given in saline solution over 60 minutes). RESULTS: When comparing baseline data (immediately before) and 1 hour after finishing tocilizumab administration, we observed a dramatic decrease of the serum insulin levels and insulin/glucose ratio. Also, a statistically significant reduction of IR (HOMA-IR: mean± standard deviation immediately before: 2.62±2.03 vs. 1.65±1.15 1 hour after the end of the infusion (p<0.01) and a statistically significant increase of insulin sensitivity (QUICKI immediately before 0.34±0.03 vs. 0.37±0.04 1 hour after the end of tocilizumab infusion (p<0.01) was observed. CONCLUSIONS: The intravenous administration of tocilizumab yields a rapid beneficial effect on IR and insulin sensitivity in non-diabetic RA patients. These findings support the potential beneficial effect of the IL-6 blockade on the mechanisms associated with the development of metabolic syndrome and cardiovascular disease in patients with RA.

Vasoactive intestinal peptide gene polymorphisms, associated with its serum levels, predict treatment requirements in early rheumatoid arthritis.

We previously reported that early arthritis (EA) patients with low vasoactive intestinal peptide (VIP) serum levels demonstrate a worse clinical disease course. In this study, we analysed whether variants in the VIP gene correlated with its serum levels and clinical EA parameters. The VIP gene was sequenced in patients with extremely high/low VIP levels, measured by enzyme immunoassay. Sixteen single nucleotide polymorphisms (SNPs) were differentially distributed between both groups, which were subsequently genotyped in two patients' sets. We observed that patients with rs688136 CC genotype showed higher VIP levels in both discovery (n = 91; p = 0.033) and validation populations (n = 131; p = 0.007). This effect was attenuated by the presence of minor alleles rs35643203 and rs12201140, which showed a clear trend towards low VIP level association (p = 0.118 and p = 0.049, respectively). Functional studies with miR-205-5p, which has a target site in the 3' UTR close to rs688136, revealed a miRNA-mediated regulatory mechanism explaining the higher VIP gene expression in homozygous patients. Moreover, patients with an rs688136 CC genotype and no minor alleles of the other polymorphisms required less treatment (p = 0.009). We concluded that the identification of polymorphisms associated with VIP serum levels would complement the clinical assessment of the disease severity in rheumatoid arthritis patients.

Clinical Relevance of VPAC1 Receptor Expression in Early Arthritis: Association with IL-6 and Disease Activity.

BACKGROUND: The vasoactive intestinal peptide (VIP) receptors VPAC1 and VPAC2 mediate anti-inflammatory and immunoregulatory responses in rheumatoid arthritis (RA). Data on the expression of these receptors could complement clinical assessment in the management of RA. Our goal was to investigate the correlation between expression of both receptors and the 28-Joint Disease Activity Score (DAS28) in peripheral blood mononuclear cells (PBMCs) from patients with early arthritis (EA). We also measured expression of IL-6 to evaluate the association between VIP receptors and systemic inflammation. METHODS: We analyzed 250 blood samples collected at any of the 5 scheduled follow-up visits from 125 patients enrolled in the Princesa Early Arthritis Register Longitudinal study. Samples from 22 healthy donors were also analyzed. Sociodemographic, clinical, and therapeutic data were systematically recorded. mRNA expression levels were determined using real-time PCR. Then, longitudinal multivariate analyses were performed. RESULTS: PBMCs from EA patients showed significantly higher expression of VPAC2 receptors at baseline compared to healthy donors (p<0.001). With time, however, VPAC2 expression tended to be significantly lower while VPAC1 receptor expression increased in correlation with a reduction in DAS28 index. Our results reveal that more severe inflammation, based on high levels of IL-6, is associated with lower expression of VPAC1 (p<0.001) and conversely with increased expression of VPAC2 (p<0.001). A major finding of this study is that expression of VPAC1 is lower in patients with increased disease activity (p = 0.001), thus making it possible to differentiate between patients with various degrees of clinical disease activity. CONCLUSION: Patients with more severe inflammation and higher disease activity show lower levels of VPAC1 expression, which is associated with patient-reported impairment. Therefore, VPAC1 is a biological marker in EA.

Th17 polarization of memory Th cells in early arthritis: the vasoactive intestinal peptide effect.

Several studies in humans indicate the implication of Th17 cells in RA. Therapies targeting their pathogenicity, as well as their plasticity to the Th17/1 phenotype, could ameliorate the progression of the pathology. The neuroendocrine environment has a major impact on the differentiation of lymphoid cells. VIP is present in the microenvironment of the joint, and its known therapeutic effects are supported by several studies on RA. We examine the ability of VIP to modulate the differentiation of Th17 cells. Peripheral blood CD4(+)CD45RO(+) T cells from HD and eRA patients were expanded under Th17-polarizing conditions in the presence of TGF-ß. After 7 days, the higher IL-17A, IL-21, and IL-9 levels and lower IL-22 levels indicate the nonpathogenic profile for Th17 cells in HD. In contrast, Th17 cells from eRA patients produced significantly more IL-22 and IFN-γ, and these cells show a more Th17/1 profile, indicating a pathogenic phenotype. Interestingly, when VIP was present in the Th17 conditioned medium, increased levels of IL-10 and IL-9 were detected in HD and eRA patients. VIP also reduced the levels of IL-22 in eRA patients. These data suggest that VIP reduces the pathogenic profile of the Th17-polarized cells. This effect was accompanied by an increased in the Treg/Th17 profile, as shown by the increase levels of Foxp3. In conclusion, this report addresses a novel and interesting question on the effect of VIP on human Th17 cells and adds clinical relevance by analyzing, in parallel, HD and eRA patients.

Vasoactive Intestinal Peptide in Early Spondyloarthritis: Low Serum Levels as a Potential Biomarker for Disease Severity.

Spondyloarthritis (SpA) is a family of inflammatory diseases sharing clinical, genetic, and radiological features. While crucial for tailoring early interventions, validated prognostic biomarkers are scarce in SpA. We analyze the correlation between serum levels of vasoactive intestinal peptide (VIP) and disease activity/severity in patients with early chronic inflammatory back pain. The study population comprised 54 patients enrolled in our early chronic inflammatory back pain register. We collected demographic information, clinical data, laboratory data, and imaging findings. VIP levels were measured by enzyme immunoassay in serum samples from 162 visits. The association between independent variables and VIP levels was analyzed using longitudinal multivariate analysis nested by patient and visit. No significant differences were observed in VIP levels between these two groups. Lower levels of VIP were significantly associated with a higher Bath Ankylosing Spondylitis Disease Activity Index (BASFI) score, presence of bone edema in magnetic resonance imaging (MRI) scan, and lower hemoglobin levels. Coexistence of cutaneous psoriasis was independently associated with lower VIP levels, and similar trend was observed for enthesitis. We conclude that SpA patients with low serum VIP levels had worse 2-year disease outcome, suggesting that serum VIP levels could be a valid prognostic biomarker.

Serum levels of vasoactive intestinal peptide as a prognostic marker in early arthritis.

OBJECTIVE: Suitable biomarkers are essential for the design of therapeutic strategies in personalized medicine. Vasoactive intestinal peptide (VIP) has demonstrated immunomodulatory properties in autoimmune murine and ex vivo human models. Our aim was to study serum levels of VIP during the follow-up of an early arthritis (EA) cohort and to analyze its value as a biomarker predicting severity and therapeutic requirements. METHODS: Data from 91 patients on an EA register were analyzed (76% rheumatoid arthritis (RA), 24% undifferentiated arthritis, 73% women, and median age 54 years; median disease duration at entry, 5.4 months). We collected per protocol sociodemographic, clinical, and therapeutic data. VIP levels were determined by enzyme immunoassay in sera harvested from the 91 patients (353 visits; 3.9 visit/patient) and from 100 healthy controls. VIP values below the 25(th) percentile of those assessed in healthy population were considered low. To determine the effect of independent variables on VIP levels, we performed a longitudinal multivariate analysis nested by patient and visit. A multivariate ordered logistic regression was modeled to determine the effect of low VIP serum levels on disease activity at the end of follow-up. RESULTS: VIP concentrations varied considerably across EA patients. Those fulfilling the criteria for RA had the lowest values in the whole sample, although no significant differences were observed compared with healthy donors. Disease activity, which was assessed using DAS28, inversely correlated with VIP levels. After a two-year follow-up, those patients with low baseline levels of VIP displayed higher disease activity and received more intensive treatment. CONCLUSION: Patients who are unable to up-regulate VIP seem to have a worse clinical course despite receiving more intense treatment. Therefore, measurement of VIP levels may be suitable as a prognostic biomarker.

Urokinase plasminogen activator system in synovial fibroblasts from osteoarthritis patients: modulation by inflammatory mediators and neuropeptides.

Plasminogen activators are specific proteolytic enzymes implicated in a variety of basic biological processes. The expression of the urokinase plasminogen activator system components is increased in some human diseases, including osteoarthritis. We sought to study the effect of two components of the inflamed synovial microenvironment on this system, IL-1ß and fibronectin fragments, elucidating whether corticotropin-releasing factor (CRF) and vasoactive intestinal peptide (VIP) neuropeptides modulate it, and analyzing the physiological consequences in joint destruction by measuring matrix metalloproteinases-9 and metalloproteinases-13 levels in osteoarthritis fibroblast-like synoviocytes. We showed that IL-1ß and fibronectin fragments stimulated urokinase system contributing to the perpetuation of the destructive cascade in joint. VIP modulated, even at constitutive level, this system, also counteracting the effect of both inflammatory stimuli. However, CRF seemed to be ineffective in controlling the production of these proteinases. Moreover, VIP was able to reduce the constitutive expression of matrix metalloproteinase-13 and the levels of both matrix metalloproteinases after stimulation with the pro-inflammatory stimuli. Our results suggest that the presence of early and later inflammatory mediators, such as IL-1ß and fibronectin fragments, increases the urokinase system and the matrix metalloproteinases levels. Whereas CRF did not affect this system, VIP counteracts these actions supporting its therapeutic potential for the treatment of osteoarthritis.

Association of CD247 polymorphisms with rheumatoid arthritis: a replication study and a meta-analysis.

Given the role of CD247 in the response of the T cells, its entailment in autoimmune diseases and in order to better clarify the role of this gene in RA susceptibility, we aimed to analyze CD247 gene variants previously associated with other autoimmune diseases (rs1052237, rs2056626 and rs864537) in a large independent European Caucasian population. However, no evidence of association was found for the analyzed CD247 single-nucleotide polymorphisms (SNPs) with RA and with the presence/absence of anti-cyclic citrullinated polypeptide. We performed a meta-analysis including previously published GWAS data from the rs864537 variant, revealing an overall genome-wide significant association between this CD247 SNP and RA with anti-CCP (OR = 0.90, CI 95% = 0.87-0.93, Poverall = 2.1×10(-10)). Our results show for first time a GWAS-level association between this CD247 polymorphism and RA risk.

CARD8 rs2043211 (p.C10X) polymorphism is not associated with disease susceptibility or cardiovascular events in Spanish rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is a complex polygenic inflammatory disease associated with accelerated atherosclerosis, which is the main cause of increased cardiovascular (CV) morbidity and mortality in RA patients. CARD8 is a constituent of inflammasome, which regulates interleukin 1-beta production, and has been associated with a worse disease course in early RA. One thousand six hundred twenty-one patients fulfilling the 1987 ACR classification criteria for RA and 1300 matched controls, were genotyped for the CARD8 rs2043211 (30T>A, p.C10X) single-nucleotide polymorphism (SNP) using predesigned TaqMan SNP genotyping assay. The genotyping success rate in our study was greater than 94%. We assessed CARD8 rs2043211 gene polymorphism results in 1530 Spanish RA patients in whom information on CV disease and CV risk factors was available at the time of the study. Also, a subgroup of patients with no history of CV events (n=276) was assessed for the potential influence of the rs2043211 variant in the development of subclinical atherosclerosis, by measurement of carotid intima-media thickness (IMT) and presence of carotid plaques. No statistically significant differences in allele or genotype frequencies for the rs2043211 CARD8 gene variant between patients with RA and controls were seen. Similarly, CARD8 rs2043211 (30T>A, p.C10X) SNP did not influence the development of CV events or the risk of CV events throughout the time. Likewise, no significant association between this gene variant and carotid IMT or the presence of plaques was found. In summary, our results do not support a role of the CARD8 rs2043211 gene variant in susceptibility to RA or in the development of CV disease in patients with RA.

Demyelinating disease in patients treated with TNF antagonists in rheumatology: data from BIOBADASER, a pharmacovigilance database, and a systematic review.

OBJECTIVES: To estimate the rate of demyelinating diseases in patients with rheumatic diseases treated with tumor necrosis factor (TNF) antagonists and to describe the cases reported to 3 different pharmacovigilance sources. METHODS: All confirmed cases of demyelinating disease, optic neuritis, and multiple sclerosis (MS) in patients with rheumatic diseases treated with TNF-antagonists were reviewed from 3 different sources: (1) the Spanish Registry of biological therapies in rheumatic diseases (BIOBADASER); (2) the Spanish Pharmacovigilance Database of Adverse Drug Reactions (FEDRA); and (3) a systematic review (PubMed, EMBASE, and the Cochrane Library). In BIOBADASER, the incidence rate per 1000 patients was estimated with a 95% confidence interval (95% CI). RESULTS: In 21,425 patient-years in BIOBADASER, there were 9 patients with confirmed demyelinating disease, 4 with optic neuritis, and 1 with MS. In addition, 22 patients presented polyneuropathies, paresthesias, dysesthesias, facial palsy, or vocal cord paralysis without confirmed demyelination. The incidence rate of demyelinating disease in patients with rheumatic diseases exposed to TNF-antagonists in BIOBADASER was 0.65 per 1000 patient-years (95% CI: 0.39-1.1). The incidence of MS in BIOBADASER was 0.05 (95% CI: 0.01-0.33), while the incidence in the general Spanish population was 0.02 to 0.04 cases per 1000. Compared with BIOBADASER, cases in FEDRA (n = 19) and in the literature (n = 48) tend to be younger, have shorter exposure to TNF-antagonists, and recover after discontinuation of the drug. CONCLUSIONS: It is not clear whether TNF antagonists increase the incidence of demyelinating diseases in patients with rheumatic diseases. Differences between cases depending on the pharmacovigilance source could be explained by selective reporting bias outside registries.

Association of acid phosphatase locus 1*C allele with the risk of cardiovascular events in rheumatoid arthritis patients.

INTRODUCTION: Acid phosphatase locus 1 (ACP1) encodes a low molecular weight phosphotyrosine phosphatase implicated in a number of different biological functions in the cell. The aim of this study was to determine the contribution of ACP1 polymorphisms to susceptibility to rheumatoid arthritis (RA), as well as the potential contribution of these polymorphisms to the increased risk of cardiovascular disease (CV) observed in RA patients. METHODS: A set of 1,603 Spanish RA patients and 1,877 healthy controls were included in the study. Information related to the presence/absence of CV events was obtained from 1,284 of these participants. All individuals were genotyped for four ACP1 single-nucleotide polymorphisms (SNPs), rs10167992, rs11553742, rs7576247, and rs3828329, using a predesigned TaqMan SNP genotyping assay. Classical ACP1 alleles (*A, *B and *C) were imputed with SNP data. RESULTS: No association between ACP1 gene polymorphisms and susceptibility to RA was observed. However, when RA patients were stratified according to the presence or absence of CV events, an association between rs11553742*T and CV events was found (P = 0.012, odds ratio (OR) = 2.62 (1.24 to 5.53)). Likewise, the ACP1*C allele showed evidence of association with CV events in patients with RA (P = 0.024, OR = 2.43). CONCLUSIONS: Our data show that the ACP1*C allele influences the risk of CV events in patients with RA.

Demyelinating disease in patients treated with TNF antagonists in rheumatology: data from BIOBADASER, a pharmacovigilance database, and a systematic review.

OBJECTIVES: To estimate the rate of demyelinating diseases in patients with rheumatic diseases treated with tumor necrosis factor (TNF) antagonists and to describe the cases reported to 3 different pharmacovigilance sources. METHODS: All confirmed cases of demyelinating disease, optic neuritis, and multiple sclerosis (MS) in patients with rheumatic diseases treated with TNF-antagonists were reviewed from 3 different sources: (1) the Spanish Registry of biological therapies in rheumatic diseases (BIOBADASER); (2) the Spanish Pharmacovigilance Database of Adverse Drug Reactions (FEDRA); and (3) a systematic review (PubMed, EMBASE, and the Cochrane Library). In BIOBADASER, the incidence rate per 1000 patients was estimated with a 95% confidence interval (95%CI). RESULTS: In 21,425 patient-years in BIOBADASER, there were 9 patients with confirmed demyelinating disease, 4 with optic neuritis, and 1 with MS. In addition, 22 patients presented polyneuropathies, paresthesias, dysesthesias, facial palsy, or vocal cord paralysis without confirmed demyelination. The incidence rate of demyelinating disease in patients with rheumatic diseases exposed to TNF antagonists in BIOBADASER was 0.65 per 1000 patient-years (95%CI: 0.39-1.1). The incidence of MS in BIOBADASER was 0.05 (95%CI: 0.01-0.33), while the incidence in the general Spanish population was 0.02 to 0.04 cases per 1000. Compared with BIOBADASER, cases in FEDRA (n = 19) and in the literature (n = 48) tend to be younger, have shorter exposure to TNF-antagonists, and recover after discontinuation of the drug. CONCLUSIONS: It is not clear whether TNF antagonists increase the incidence of demyelinating diseases in patients with rheumatic diseases. Differences between cases depending on the pharmacovigilance source could be explained by selective reporting bias outside registries.

Characterization of serum interleukin-15 in healthy volunteers and patients with early arthritis to assess its potential use as a biomarker.

As interleukin-15 (IL-15) has been implicated in the pathophysiology of rheumatoid arthritis, we analysed the serum IL-15 (sIL-15) levels in healthy subjects and patients with early arthritis to establish a cut-off point that might serve to define elevated sIL-15. This is an initial step to determine whether sIL-15 has the potential for use as a biomarker for patients with early arthritis. The IL-15 concentration was measured in serum obtained from 161 healthy controls and from 174 patients with early arthritis, and the relationship between the expression of the two IL-15 mRNA variants and the sIL-15 levels was also assessed. In healthy controls, the median sIL-15 value was 0.83 [interquartile range (IQR) 0-8.68] pg/mL; there was no significant difference in the sIL-15 values according to gender [median level in males was 1.99 (IQR: 0-8.68) pg/mL and in females 0.50 (0-8.25) pg/mL: p = 0.821]. Moreover, sIL-15 levels did not correlate with age (r = 0.033, p = 0.685), and they did not display a clear circadian rhythm in healthy donors, with the median values for IL-15 close to zero at each time tested. In the light of these findings, we considered that sIL-15 was elevated if its concentration was above 20 pg/mL, since this cut-off point corresponded to the 90th percentile for this healthy population. We found that 30% of the patients with early arthritis had sIL-15 values > 20 pg/mL. The levels of sIL-15 did not correlate with disease duration in early arthritis patients, nor did they fluctuate with changes in disease activity over the follow-up period. In addition, the high level of sIL15 in patients was not associated with alterations in the alternative splicing of the IL-15 mRNA, favouring the variant that produces the protein with a long signal peptide for secretion. Serum IL-15 levels were increased in a subpopulation of patients with early arthritis, indicating that this measure may serve as a biomarker for this condition. Further studies will be necessary to determine whether the clinical evolution or response to treatment of patients with high sIL-15 levels differs.

[The therapeutic blockade of TNF reduces serum levels of interleukin 15 in patients with rheumatoid arthritis]. / El bloqueo terapéutico del factor de necrosis tumoral disminuye la concentración sérica de interleucina 15 en pacientes con artritis reumatoide.

OBJECTIVE: To analyze the effect of the TNF blocking agents (aTNF) on the serum levels of interleukin 15 (IL-15). To determine whether baseline IL15 serum levels or their response to aTNF therapy can predict the clinical response to this treatment. PATIENTS AND METHOD: We studied 75 patients suffering from rheumatoid arthritis that were selected to start aTNF therapy. Serum samples were obtained at baseline visit and after three months of aTNF treatment. Measurement of IL-15 serum concentration was performed through immune-enzyme assay. We collected the clinical and analytical parameters needed to calculate DAS28 both at baseline and final visit, as well as sociodemographic variables and other such as rheumatoid factor, previous disease modifying anti-rheumatic drugs (DMARD), etc. We defined remission as a DAS28 < 2.6 and clinical response when the decrease in DAS28 value was higher than 1.2. RESULTS: There was a significant correlation between IL-15 serum level and the number of previous DMARD. We also detected a significant decrease in the concentration of serum IL-15 after three months of treatment with aTNF. However, neither the baseline IL-15 serum level nor the decrease in the concentration of IL-15 were associated with a specific pattern of response to aTNF. CONCLUSIONS: Our data seem to support previous in vitro findings suggesting that TNF is involved in the regulation of IL-15 expression. Nevertheless, the measurement of IL-15 serum levels does not seem to be a useful tool to select those patients that should be treated with aTNF therapy.

Baseline serum RANKL levels may serve to predict remission in rheumatoid arthritis patients treated with TNF antagonists.

AIMS: The objective of this study was to investigate whether baseline receptor activator for nuclear factor kappaB ligand (RANKL) and osteoprotegerin (OPG) serum (s) levels can predict the therapeutic response to TNF antagonists (a-TNF). METHODS: We studied 75 rheumatoid arthritis patients (81% female) with a longstanding refractory disease. The variables of disease activity, physical function and sRANKL and sOPG levels were determined before and after both 12-14 and 28-30 weeks of a-TNF therapy (65 adalimumab, 10 infliximab). Remission was defined by a 28 joint count disease activity score (DAS28) /=1.2 at both 3- and 7-month follow-up visits. RESULTS: In most patients, disease activity was severe, as reflected by a baseline DAS28 score of 5.9+/-1 (mean+/-SD), an HAQ of 1.6 (1.1 to 2.1) (median (interquartile range (IQR))) and a CRP 15 mg/l (IQR: 9 to 24). The sRANKL levels and RANKL/OPG ratio in patients that achieved remission were significantly lower at baseline than in the remaining patients at both 3 and 7 months of follow-up. The sOPG levels correlated with the HAQ and the physician's disease assessment and diminished significantly after a-TNF treatment. However, no significant association was detected between the therapeutic response profile and sOPG levels. CONCLUSIONS: These data suggest that in patients receiving a-TNF treatment, lower serum levels of RANKL and RANKL/OPG ratio may serve to predict remission.

Interleukin-15 and interferon-gamma participate in the cross-talk between natural killer and monocytic cells required for tumour necrosis factor production.

We have characterized the lymphocyte subset and the receptor molecules involved in inducing the secretion of TNF by monocytic cells in vitro. The TNF secreted by monocytic cells was measured when they were co-cultured with either resting or IL-15-stimulated lymphocytes, T cells, B cells or natural killer (NK) cells isolated from the peripheral blood of healthy subjects and from the synovial fluid from patients with inflammatory arthropathies. Co-culture with IL-15-activated peripheral blood or synovial fluid lymphocytes induced TNF production by monocytic cells within 24 hours, an effect that was mainly mediated by NK cells. In turn, monocytic cells induced CD69 expression and IFN-gamma production in NK cells, an effect that was mediated mainly by beta2 integrins and membrane-bound IL-15. Furthermore, IFN-gamma increased the production of membrane-bound IL-15 in monocytic cells. Blockade of beta2 integrins and membrane-bound IL-15 inhibited TNF production, whereas TNF synthesis increased in the presence of anti-CD48 and anti-CD244 (2B4) monoclonal antibodies. All these findings suggest that the cross-talk between NK cells and monocytes results in the sustained stimulation of TNF production. This phenomenon might be important in the pathogenesis of conditions such as rheumatoid arthritis in which the synthesis of TNF is enhanced.

Streptococcus viridans-associated peritonitis after gastroscopy.

Transient bacteremia during and after endoscopic procedures is a well-documented phenomenon. Streptococcus viridans peritonitis is frequently associated with peritoneal dialysis, and the infection is probably attributable to hematogenous spread, dental procedures, or transluminal contamination with oral flora. To our knowledge, no reports exist of peritonitis occurring after gastroscopy in peritoneal dialysis patients. Here, we report the case of a 69-year-old male patient receiving automated peritoneal dialysis who required emergency gastroscopy and sclerotherapy plus heat-probe coagulation to control active bleeding from a duodenal ulcer The next day, this patient developed nausea and abdominal pain. The diagnosis of peritonitis was made based on a cloudy peritoneal effluent and a leukocyte count of 11,500 cells/microL with 98% neutrophils. S. viridans was identified in the peritoneal fluid culture. The patient received ceftazidime for 14 days, followed by clarithromycin for 7 days, and he recovered successfully. Patients receiving peritoneal dialysis who undergo esophagogastroduodenal endoscopy are at risk to develop peritonitis, and so antibiotic prophylaxis is desirable.