Early monitoring of anti-infliximab antibodies by drug-tolerant assay predicts later immunogenicity and drug survival in rheumatic diseases.

OBJECTIVES: To investigate the appearance of anti-drug antibodies (ADA) against infliximab (IFX) determined by drug-sensitive and drug-tolerant assays and their relationship with drug levels and drug survival. METHODS: This longitudinal observational study included 45 patients with rheumatoid arthritis (RA) and 61 with spondyloarthritis (SpA). Serum samples were obtained at weeks 2, 6, 12, 24, and 52. Serum IFX levels were measured by a capture enzyme-linked immunosorbent assay (ELISA) and ADA by an in-house drug-sensitive two-site (bridging) enzyme-linked immunosorbent assay (bELISA) and a commercially available drug-tolerant ELISA (IDK, Immundiagnostik, Germany). RESULTS: Anti-drug antibodies were detected earlier by IDK than by bELISA. Once ADA appeared, positivity persisted throughout the study period. Patients who were bELISA ADA+ had higher IDK ADA levels (than bELISA ADA- patients). Circulating IFX levels were detected in all patients except those found to be bELISA ADA+. Serum IFX levels were lower in IDK ADA+ than in IDK ADA-patients.Most patients (64%) discontinued due to inefficacy. The early onset of immunogenicity was related to IFX survival. Both in RA and SpA, the median survival (years) was shorter in patients with earlier development of ADA (IDK+ before or at week 24) than those who became IDK+ later (after week 24) or never developed ADA. CONCLUSION: A drug-tolerant assay detects ADA during IFX therapy earlier and more frequently than a drug-sensitive assay. The onset of immunogenicity detected by drug-tolerant assays is related to the subsequent detection of ADA by drug-sensitive assays and drug survival.

Circulating Tfh cells are differentially modified by abatacept or TNF blockers, and predict treatment response in Rheumatoid Arthritis.

OBJECTIVE: CD4+CXCR5+PD-1hi follicular helper T (Tfh) cells dwell in the germinal centers (GCs) of lymphoid organs and participate in Rheumatoid Arthritis (RA) pathogenesis; the frequency of their circulating counterparts (cTfh-frequency) is expanded in RA and correlates with the pool of GC Tfh cells. Our objective was to study the effect of abatacept (ABT) or TNF blockers (TNFb) on the cTfh-frequency in RA. METHODS: Peripheral blood was drawn from seropositive-longstanding RA patients chronically receiving csDMARDS (n = 45), TNFb (n = 59), or ABT (n = 34), and healthy controls (HC) (n = 137). Also, patients with an incomplete response to csDMARDS (n = 41) who initiated TNFb (n = 19) or ABT (n = 22), were studied at 0 and 12 months. The cTfh-frequency was examined by cytometry. RESULTS: As compared with HC, an increased cTfh-frequency was seen in seropositive-longstanding RA chronically receiving csDMARDs or TNFb but not ABT. After escalating from csDMARDs, the cTfh-frequency did not vary in patients who were given TNFb but decreased to HC levels in those given ABT. In the ABT group, the baseline cTfh-frequency was higher for patients who attained 12M remission (12Mr), vs those who remained active (12Ma): 0m cutoff for remission >0.38% (Sens. 92%, Sp. 90%), OR 25.3. Conversely, in the TNFb group, the baseline cTfh-frequency was lower for 12Mr vs 12Ma: 0m cutoff for non-remission >0.44% (Sens. 67%, Sp. 90%), OR 8.5. CONCLUSION: ABT but not TNFb, is able to curtail the cTfh-frequency in RA. A higher baseline cTfh-frequency predicts a good response to ABT but a poor response to TNFb.

From Cell to Symptoms: The Role of SARS-CoV-2 Cytopathic Effects in the Pathogenesis of COVID-19 and Long COVID.

Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection triggers various events from molecular to tissue level, which in turn is given by the intrinsic characteristics of each patient. Given the molecular diversity characteristic of each cellular phenotype, the possible cytopathic, tissue and clinical effects are difficult to predict, which determines the heterogeneity of COVID-19 symptoms. The purpose of this article is to provide a comprehensive review of the cytopathic effects of SARS-CoV-2 on various cell types, focusing on the development of COVID-19, which in turn may lead, in some patients, to a persistence of symptoms after recovery from the disease, a condition known as long COVID. We describe the molecular mechanisms underlying virus-host interactions, including alterations in protein expression, intracellular signaling pathways, and immune responses. In particular, the article highlights the potential impact of these cytopathies on cellular function and clinical outcomes, such as immune dysregulation, neuropsychiatric disorders, and organ damage. The article concludes by discussing future directions for research and implications for the management and treatment of COVID-19 and long COVID.

Circulating CD19+CD24hiCD38hi regulatory B cells as biomarkers of response to methotrexate in early rheumatoid arthritis.

OBJECTIVE: The protagonism of regulatory B cells seems to vary along the course of the disease in murine models of inflammatory conditions. Decreased numbers of circulating regulatory CD19+CD24hiCD38hi transitional (cTr) B cells have been described in patients with long-standing RA, thus our objective was to examine the frequency and evolution of cTr B cells in the peripheral blood of early RA (ERA) patients. METHODS: Freshly isolated peripheral blood mononuclear cells from 48 steroid- and DMARD-naïve ERA patients with a disease duration of <24 weeks and 48 healthy controls (HCs) were examined by flow cytometry. Co-cultures of isolated memory B cells were established with autologous T cells in the absence or presence of Tr B cells. RESULTS: As compared with HCs, ERA patients demonstrated an increased frequency of cTr B cells. cTr B cells of ERA patients and HCs displayed an anti-inflammatory cytokine profile and were able to downregulate T cell IFN-γ and IL-21 production, together with ACPA secretion in autologous B/T cell co-cultures. Basal frequencies of cTr B cells above the median value observed in HCs were associated with a good EULAR response to MTX at 12 months [relative risk 2.91 (95% CI 1.37, 6.47)]. A significant reduction of cTr B cells was observed 12 months after initiating MTX, when the cTr B cell frequency was no longer elevated but decreased, and this was independent of the degree of clinical response or the intake of prednisone. CONCLUSION: An increased frequency of regulatory cTr B cells is apparent in untreated ERA and the baseline cTr B cell frequency is associated with the clinical response to MTX at 12 months.

Two populations of circulating PD-1hiCD4 T cells with distinct B cell helping capacity are elevated in early rheumatoid arthritis.

OBJECTIVE: A novel population of B helper cells, phenotypically CD4+CXCR5-PD-1hi, has been described in the synovial tissues and peripheral blood of seropositive RA patients, and termed 'peripheral helper T' (Tph) cells. Contrary to CD4+CXCR5+PD-1hi follicular helper T (Tfh), Tph cells are not located in lymphoid organs but accumulate in inflamed tissues. Our objective was to study the frequency of circulating Tph (cTph) and circulating Tfh cell counterparts (cTfh) in patients with early RA (eRA). METHODS: Freshly isolated peripheral blood mononuclear cells from 56 DMARD-naïve eRA patients and 56 healthy controls were examined by flow cytometry. Autologous cocultures of naïve or memory B cells were established with isolated peripheral blood Tph or Tfh cells. RESULTS: Seropositive (RF+ and/or ACPA+, n = 38) but not seronegative eRA patients (n = 18) demonstrated increased frequencies and absolute numbers of cTph and cTfh cells. cTph but not cTfh cells expressed CCR2. Those eRA patients who experienced a significant clinical improvement at 12 months demonstrated a marked decrease of their cTph cell numbers whereas their cTfh cell numbers remained unchanged. Both isolated Tph and isolated Tfh cells were able to induce maturation of memory B cells, whereas only Tfh cells could differentiate naïve B cells. CONCLUSION: Two populations of PD-1hiCD4 T cells with distinct phenotype and B cell helping capacity are increased in the peripheral blood of seropositive eRA patients. Whereas cTph cells are present only in patients with an active disease, cTfh cells seem to be constitutively elevated.

Ultrasound sensitivity to changes in gout: a longitudinal study after two years of treatment.

OBJECTIVES: The goals of our study are to evaluate the urate-lowering therapy (ULT) effect on gout ultrasound (US) lesions and to explore US sensitivity to change in gout patients. METHODS: Patients with chronic and symptomatic gout, confirmed by crystal identification, were prospectively included. Clinical and US assessments were performed at baseline and after 6, 12 and 24 months of ULT. The presence of double contour sign (DCS) and US- detectable tophi were assessed in the first metatarsophalangeals, the knees and patellar tendons. The mean and standard deviation were calculated for each parameter. The correlation between the clinical and US parameters was assessed by calculating Pearson's correlation coefficient. Sensitivity to change in the US examinations was assessed by estimating the smallest detectable difference (SDD). RESULTS: Twenty-three consecutive patients were included (96% men; mean age 59 ± 11 years). DCS and US tophi were detected in 73.9% and 91.3% of patients at baseline. A significant parallel improvement in the serum urate, clinical parameters and US lesions was found at the follow-up assessment. The SDD values for the global DCS and tophi were 0.52 and 0.69, respectively, which were smaller than the differences achieved over the course of the two years. A significant correlation between DCS and clinical parameters was observed (r =0.49, p=0.038). CONCLUSIONS: Ultrasound findings in gout patients show sensitivity to change and concurrent validity with uric acid reduction after ULT in gout patients. US can be a useful tool for gout tophus burden monitoring.

Comparing a tapering strategy to the standard dosing regimen of TNF inhibitors in rheumatoid arthritis patients with low disease activity.

OBJECTIVES: The aim of this study is to compare clinical outcomes, incidence of flares and administered drug reduction between rheumatoid arthritis (RA) patients under TNF inhibitors (TNFi) tapering strategy and RA patients on standard regimen. METHODS: Two groups of RA patients on TNFi with DAS28<3.2 were compared: the tapering group (TG: 67 pts from Spain) and the control group with standard therapy regimen (CG: 77 pts from the Netherlands). DAS28 was measured at different time points: visit 0 (prior starting TNFi), visit 1 (prior to start tapering in TG and with DAS28<3.2 in TG and CG), visit 2 (6 months after visit 1), visit 3 (1 year after visit 1), visit 4 (the last visit available after visit 1) and visit-flare (visit with the worst flare between visit 1 and visit 4). RESULTS: Despite the reduction of administered drug at visit 4 in the TG (interval elongation of 32.8% in infliximab, 52.9% in adalimumab and 52.6% in etanercept), the DAS28 remained similar between groups at the end of the study (DAS28: 2.7±0.9 in TG vs. 2.5±1 in CG, p=0.1). No differences were seen in the number of patients with flares [26/67 (38.9%) in the TG vs. 30/77 (39%) in the CG, p=0.324] and only nineteen out of 136 patients (14%) had anti-drug antibodies at the end of the study. CONCLUSIONS: The tapering strategy of TNFi in RA patients result in a reduction of the drug administered, while the disease control is not worse than patients on the standard regimen.

Reduction but not disappearance of Doppler signal after two years of treatment for gout. Do we need a more intensive treatment?

OBJECTIVES: We undertook this study to evaluate the responsiveness of Doppler ultrasound (US) to urate lowering therapy (ULT) in gout patients. METHODS: Twenty-four consecutive patients were prospectively included from an outpatient clinic. The patients underwent clinical, and US assessment at baseline and after 6, 12 and 24 months of ULT. The US assessment was made by another rheumatologist blinded to the clinical data. Standardised examinations were performed in four joints (both first metatarso-phalangeals and knees) and the patellar tendons. The Doppler signals were scored. The mean and standard deviation were calculated for each parameter. The comparison between the quantitative values was performed by Student's t-test. Sensitivity to change in the US examinations was assessed by estimating the smallest detectable difference (SDD) in the total Doppler score. RESULTS: A Doppler signal was detected in 95.8% of the patients at the baseline. A significant parallel improvement in the serum urate level, clinical parameters and in Doppler scores was found at the follow-up assessment. 62% of the patients had achieved a uric concentration level below 6 mg/dl at one year. At two years, persistence of a Doppler signal was found in 72.7% of the patients. The SDD in the Doppler score at 2 years was 1.92, lower than the difference achieved. CONCLUSIONS: The Doppler US findings show significant improvement and responsiveness after ULT in gout patients. The Doppler signal persistence after two years of treatment is marked. This finding introduces a reflection on the accuracy of the current outcome measures and treatments.

Subsequent biologic and targeted synthetic disease modifying anti rheumatic drugs after fulfilling difficult-to-treat rheumatoid arthritis criteria: a survival analysis.

OBJECTIVES: To evaluate the survival of different biologic or targeted-synthetic disease-modifying antirheumatic drugs (b/tsDMARD) administered after fulfilling difficult-to-treat rheumatoid arthritis (D2TRA) criteria, and to assess factors related to treatment discontinuation. METHODS: Retrospective study including D2TRA patients. Drug retention of the b/tsDMARD administered after fulfilling D2TRA was assessed by Kaplan-Meier plots and the log-rank test. Cox hazard models were used to identify factors affecting treatment discontinuation. RESULTS: Of the 122 patients included, 75 maintained active treatment (61.5%) with a subsequent line after D2T compared to 47 (38.5%) who discontinued and required more successive lines of b/tsDMARDs. The median survival of the treatments was 78.3(7.6) months and the treatment after D2T with the better rate of survival was rituximab, followed by JAKi and IL6Ri, while worse survival rates were associated with abatacept and TNFi. Significant differences were noted among b/tsDMARDs (log-rank p < 0.01) and to evaluate these differences, a Cox regression was performed, taking each b/tsDMARD as a reference and comparing it with the others. DAS28 values 6-months after initiation of treatment were higher in those patients who discontinued treatment [4.4(1.2) vs 3.5(1.3), p = 0.01]. The multivariate cox regression model revealed that treatment choice after D2T [HR = 1.26(95%CI 1.06-1.05)] and lower DAS28 values at 6 months [HR = 1.49(95%CI 1.16-1.52)] were independent risk factors associated with treatment discontinuation. CONCLUSIONS: Once patients met the D2TRA criteria, the subsequent line of b/tsDMARDs with the best survival rates were rituximab, JAKi and IL6Ri. Moreover, DAS28 at 6-months of treatment after D2T was an independent risk factor for drug discontinuation. Key Points • Rituximab, IL6Ri and JAKi have better retention rates in patients after fulfilling D2TRA criteria • Clinical disease activity in the first six months after fulfillment of D2TRA criteria is an independent risk factor of subsequent treatment survival.

Physico-chemical characterization of the tumour microenvironment of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive lethal malignancy that accounts for more than 90% of pancreatic cancer diagnoses. Our research is focused on the physico-chemical properties of the tumour microenvironment (TME), including its tumoural extracellular matrix (tECM), as they may have an important impact on the success of cancer therapies. PDAC xenografts and their decellularized tECM offer a great material source for research in terms of biomimicry with the original human tumour. Our aim was to evaluate and quantify the physico-chemical properties of the PDAC TME. Both cellularized (native TME) and decellularized (tECM) patient-derived PDAC xenografts were analyzed. A factorial design of experiments identified an optimal combination of factors for effective xenograft decellularization. Our results provide a complete advance in our understanding of the PDAC TME and its corresponding stroma, showing that it presents an interconnected porous architecture with very low permeability and small pores due to the contractility of the cellular components. This fact provides a potential therapeutic strategy based on the therapeutic agent size.

Patient and physician assessment in difficult-to-treat rheumatoid arthritis: patterns of subjective perception at early stages of b/tsDMARD treatment.

OBJECTIVES: To analyse the trajectories of Disease Activity Score 28 (DAS28), patient global assessment (PGA) and physician global assessment (PhGA) and to assess their predictive capabilities on difficult-to-treat rheumatoid arthritis (D2TRA) classification. METHODS: Longitudinal study of patients with rheumatoid arthritis (RA) from 2020 to 2022. Based on the D2TRA EULAR (European Alliance of Associations for Rheumatology) definition, patients were classified as D2TRA according to biological or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) failure due to inefficacy (D2TRA-inefficacy) or other reasons (D2TRA-other). Patients who did not fulfil the D2TRA criteria were classified as NoD2TRA. DAS28, PGA and PhGA scores collected every 6 months during the first 24 months of b/tsDMARD treatment were used to identify different trajectories using latent class mixed models (LCMM). RESULTS: The study population comprised 255 patients with RA, of whom 167 were NoD2TRA, 58 D2TRA-inefficacy and 30 D2TRA-other. LCMM stratified patients into two different trajectories for DAS28 and PhGA and three for PGA according to the most stable model. The most notable variation occurred during the first 6 months of treatment, thereafter remaining stable during the follow-up period. Most D2TRA-inefficacy patients fitted the trajectory, showing higher values of the studied parameters. NoD2TRA followed the trajectory with lower values, and D2TRA-other were distributed more homogeneously across all trajectories. CONCLUSIONS: The assessment of disease activity, together with patients' and physicians' perceptions, form a key element in the correct discrimination of patients who are going to develop D2TRA-inefficacy. However, identifying those patients who will be D2TRA-other remains challenging, whether by subjective or objective parameters.

Influence of immunogenicity on the efficacy of longterm treatment of spondyloarthritis with infliximab.

BACKGROUND: Infliximab (IFX) is a monoclonal antibody against tumour necrosis factor α that is effective for treating spondyloarthritis (SpA). However, after initial success of the drug some patients lose responsiveness or develop infusion reactions, which may be related to the development of antibodies against the drug. OBJECTIVE: To investigate the clinical relevance of antibodies to infliximab (ATI) formation in patients with SpA undergoing IFX treatment over a prolonged period. METHODS: 94 patients with SpA treated with IFX from 1999 to 2010 were studied. Their clinical characteristics, serum trough IFX levels and ATI status were evaluated for a mean of 6.99 (95% CI:6.28 to 7.7) years. Clinical activity and improvement were measured using the Ankylosing Spondylitis Disease Activity Score (ASDAS): inactive <1.3, moderate ≥1.3 and <2.1, high ≥2.1-≤3.5, and very high >3.5 at three time points (6 months, 12 months and >4 years). RESULTS: ATI were detected in 24 (25.5%) patients. The patients with ATI had higher ASDAS scores than those without ATI (2.55±0.89 vs 1.79±1.04, p=0.038 at 6 months; 1.95±0.67 vs 1.67±0.71, p=0.042 at 1 year; 2.52±0.99 vs 1.53±0.81, p=0.024 at >4 years). Eleven patients (12%) developed infusion-related reactions, and of these, ATI were present in eight patients (73%). The patients with infusion-related reactions had higher ATI titres (median 12 931 AU/ml, IQR 853-82 437) vs median 2454 AU/ml, IQR 449-7718, p=0.028) and shorter survival (4.25 years vs 8.19 years, p<0.001). ATI development occurred more frequently in the patients not receiving methotrexate (20/58 (34.5%) vs 4/36 (11.1%), p=0.011). CONCLUSION: In patients with SpA treated with IFX, ATI formation is associated with a poor clinical response, the appearance of infusion reactions and the discontinuation of treatment.

Value of a short four-joint ultrasound test for gout diagnosis: a pilot study.

OBJECTIVES: The goal of this study was to investigate the usefulness of a short ultrasound (US) assessment in gout. METHODS: Patients with gout, confirmed by urate crystal identification, and having at least one symptomatic flare in the last three months were included. Standardised US examinations of sixteen joints and eight tendons in the lower limbs were carried out. Six lesions were studied: hyperechoic spots in the synovial fluid, hyperechoic cloudy areas (HCA), bright stippled aggregates (BSA), the double contour sign (DCS), erosions and the Doppler signal. For reliability, inter-reader analyses were performed by five rheumatologists. With the results, a short US assessment was created. RESULTS: Twenty-nine consecutive patients were included (93% men). The Doppler signal, HCAs and BSAs appeared in 100%, 97% and 93% of the patients, respectively. The DCS was found in 69% of patients. The locations that were most affected were the first metatarsophalangeal joint (MTP) and the knee joints, both of which are in 93% of patients. Reliability analyses showed consistent results for erosions, the Doppler signal, HCAs and the DCS in the 1st MTP (k=0.818, k=0.958, k=0.739 and k= 0.697, respectively) and for the DCS in the knees (k=0.779). A six-minute US examination of four joints (knees and the 1st MTPs) detected HCAs or DCS in 97% of cases. CONCLUSIONS: A US examination of four joints for two elemental lesions (the DCS and HCAs) is feasible, reliable and has face and content validity as a diagnostic test in patients with crystal-proven gout.

The utility and sensitivity of colour Doppler ultrasound in monitoring changes in giant cell arteritis.

OBJECTIVES: To explore the sensitivity to change of colour Doppler ultrasound (CDUS) in giant cell arteritis (GCA). METHODS: This was a blind, prospective study composed of 30 consecutive patients diagnosed with GCA. In 25 of the cases this was their first episode of GCA, and 13 of the cases were relapses. All participants had presented with at least 1 branch involvement in the basal sonography, and steroid treatment had been initiated. A CDUS was performed every 2 weeks during the first month, and every 4 weeks thereafter, until halo disappearance was observed in the bilateral parietal and frontal branches of the temporal superficial artery. RESULTS: Thirty-eight episodes of GCA in 30 different patients (19 women and 11 men; mean age, 79.24±4.76 years; range 70-88) were followed. Dark halo disappearance occurred in 95% of cases. The mean time until halo disappearance was observed was around 11 weeks, with 50% of cases showing halo disappearance within the first 8 weeks. The relapse cases appeared to have less arterial wall affectation than the primary GCA cases, reduced erythrocyte sedimentation rate ESR and an earlier loss of the halo sign. Patients with a smaller number of affected branches required less time for halo disappearance. CONCLUSIONS: CDUS shows a sensitività to change in GCA. Halo disappearance is rare before two weeks, and it frequently persists during the first two months after initiating steroid therapy. Our data emphasise the advantages of using CDUS to monitor GCA activity.

Achievement rate and predictive factors of the recommended therapeutical target in patients with axial spondyloarthritis who remain on biological therapy: a prospective cohort study in Spain.

OBJECTIVES: To determine the frequency of sustained remission (R) or low diseas activity (LDA) in patients with axial spondyloarthritis (axSpA) undergoing long-term biological therapy and to analyse predictive factors for achieving these outcomes. DESIGN: Prospective, observational cohort study. SETTING: Spanish hospital. PARTICIPANTS: Patients with axSpA who initiated biological treatment between 2003 and 2017. INTERVENTION: Assessment of demographic and clinical characteristics at the beginning of treatment and disease activity every 6 months up to a maximum of 2 years. MAIN OUTCOME MEASURES: Disease activity was measured by Ankylosing Spondylitis Disease Activity Score (ASDAS) and Bath Ankylosing Spondylitis Disease Activity Index and C reactive protein (BASDAI&CRP). Sustained R was defined as ASDAS<1.3 and/or BASDAI <2 and normal CRP while sustained LDA was defined as ASDAS <2.1 and/or BASDAI <4 and normal CRP on at least three consecutive visits. RESULTS: In total 186 patients (66.1% men and 75.3% with radiographic sacroiliitis) were included. Overall, 76.8% of patients achieved ASDAS R/LDA (R53.2%/LDA23.6%) in at least one visit. Forty per cent (R17.6%/LDA22.4%) of the patients fulfilled the sustained ASDAS R/LDA state, whereas only 30.8% maintained this status (R14.8%/LDA15.9%) according to BASDAI&CRP. In the multivariate analysis, male sex (OR=4.01), younger age at the beginning of biological therapy (OR=0.96) and an HLA*B27 positive status (OR=4.30) were associated with achieving sustained ASDAS R/LDA. CONCLUSIONS: In clinical practice, around one-third of patients on biological disease-modifying antirheumatic drugs achieve a sustained R/LDA status, but these rates drop to less than one in five when targeting remission, preventing the use of the latter as a feasible target. Male sex, HLA*B27 positivity and younger age at the beginning of biological therapy are the main predictors for achieving sustained R/LDA.

Study of Plasma Anti-CD26 Autoantibody Levels in a Cohort of Treatment-Naïve Early Arthritis Patients.

In rheumatoid arthritis (RA), the identification of biomarkers to adjust treatment intensity and to correctly diagnose the disease in early stages still constitutes a challenge and, as such, novel biomarkers are needed. We proposed that autoantibodies (aAbs) against CD26 (DPP4) might have both etiological importance and clinical value. Here, we perform a prospective study of the potential diagnostic power of Anti-CD26 aAbs through their quantification in plasmas from 106 treatment-naïve early and undifferentiated AR. Clinical antibodies, Anti-CD26 aAbs, and other disease-related biomarkers were measured in plasmas obtained in the first visit from patients, which were later classified as RA and non-RA according to the American College of Rheumatology criteria. Two different isotype signatures were found among ten groups of patients, one for Anti-CD26 IgA and other for Anti-CD26 IgG and IgM isotypes, both converging in patients with arthritis (RA and Unresolved Undifferentiated Arthritis: UUA), who present elevated levels of all three isotypes. The four UUA patients, unresolved after two years, were ACPA and rheumatic factor (RF) negatives. In the whole cohort, 51.3% of ACPA/RF seronegatives were Anti-CD26 positives, and a similar frequency was observed in the seropositive RA patients. Only weak associations of the three isotypes with ESR, CRP and disease activity parameters were observed. Anti-CD26 aAbs are present in treatment-naïve early arthritis patients, including ACPA and RF seronegative individuals, suggestive of a potential pathogenic and/or biomarker role of Anti-CD26 aAbs in the development of rheumatic diseases.

Predictive model to identify multiple failure to biological therapy in patients with rheumatoid arthritis.

Background: Despite advances in the treatment of rheumatoid arthritis (RA) and the wide range of therapies available, there is a percentage of patients whose treatment presents a challenge for clinicians due to lack of response to multiple biologic and target-specific disease-modifying antirheumatic drugs (b/tsDMARDs). Objective: To develop and validate an algorithm to predict multiple failure to biological therapy in patients with RA. Design: Observational retrospective study involving subjects from a cohort of patients with RA receiving b/tsDMARDs. Methods: Based on the number of prior failures to b/tsDMARDs, patients were classified as either multi-refractory (MR) or non-refractory (NR). Patient characteristics were considered in the statistical analysis to design the predictive model, selecting those variables with a predictive capability. A decision algorithm known as 'classification and regression tree' (CART) was developed to create a prediction model of multi-drug resistance. Performance of the prediction algorithm was evaluated in an external independent cohort using area under the curve (AUC). Results: A total of 136 patients were included: 51 MR and 85 NR. The CART model was able to predict multiple failures to b/tsDMARDs using disease activity score-28 (DAS-28) values at 6 months after the start time of the initial b/tsDMARD, as well as DAS-28 improvement in the first 6 months and baseline DAS-28. The CART model showed a capability to correctly classify 94.1% NR and 87.5% MR patients with a sensitivity = 0.88, a specificity = 0.94, and an AUC = 0.89 (95% CI: 0.74-1.00). In the external validation cohort, 35 MR and 47 NR patients were included. The AUC value for the CART model in this cohort was 0.82 (95% CI: 0.73-0.9). Conclusion: Our model correctly classified NR and MR patients based on simple measurements available in routine clinical practice, which provides the possibility to characterize and individualize patient treatments during early stages.

Increased disease activity in early arthritis patients with anti-carbamylated protein antibodies.

The initial management of rheumatoid arthritis (RA) has a high impact on disease prognosis. Therefore, we need to select the most appropriate treatment as soon as possible. This goal requires biomarkers of disease severity and prognosis. One such biomarker may be the presence of anti-carbamylated protein antibodies (ACarPA) because it is associated with adverse long term outcomes as radiographic damage and mortality. Here, we have assessed the ACarPA as short-term prognostic biomarkers. The study was conducted in 978 prospective early arthritis (EA) patients that were followed for two years. Our results show the association of ACarPA with increased levels of all the disease activity measures in the first visit after arthritis onset. However, the associations were more significant with the high levels in local measures of inflammation and physician assessment than with the increases in systemic inflammation and patient-reported outcomes. More notably, disease activity was persistently increased in the ACarPA positive patients during the two years of follow-up. These differences were significant even after accounting for the presence of other RA autoantibodies. Therefore, the ACarPA could be considered short-term prognostic biomarkers of increased disease activity in the EA patients.