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BackgroundThe potential of expanded flow cytometric analysis of PBLs has not been yet been fully exploited to study JIA heterogeneity neither to monitor JIA patients' on biological treatmentsObjectivesTo analyze in depth lymphocyte subpopulations in treated JIA patients stratified by age and gender.MethodsOne hundred one patients, 69 children and 32 adult fulfilling JIA (ILAR) criteria attending HUVH rheumatology clinic were included. All patients were treated with either MTX, anti-TNFα, or a combination of both. Controls were sex/age matched volunteers either healthy or attending the clinics of HUVH for non inflammatory conditions (59 controls, 29 paediatric and 30 adult). Extended immunophenotype following FITMaN protocol that discerns 57 peripheral blood lymphocyte (PBL) subpopulations was applied. Bonferrroni's correction indicated that the cut off for significance was p<0.00041667.ResultsChanges common to each group of patients irrespective of treatment are as follows: paediatric patients showed lower percentage of CD8 effector cells (CD45RA+CCR7-) when compared to controls (10.53±5.71 vs 16.92±5.71). Percentage of total CD4 cells was higher on JIA children than in controls (42.21±7.40 vs 36.04±5.22). No differences were found on percentages nor in absolute number of Th1 (CXCR3+CCR6-), Th2 (CXCR3-CCR6-), or Th17 (CXCR3-CCR6-) CD4 cells. Interestingly all Th subpopulations showed decreased expression of HLA-DR in JIA children when compared with controls (6.06±3.08 vs 10.49±5.02; 0.81±0.51 vs 1.48±0.64; 8.57±3.81 vs 12.6±4.95; respectively). JIA adults presented no significant differences in T cells subpopulations compared to adult controls, but showed higher percentage of CD21- switch-memory B cells (IgD-IgM-CD27-) than controls (10.82±5.33 vs 4.29±4.33).In a second analysis of the JIA patients few differences were observed according to the administered therapy. Paediatric patients treated with MTX (n=27) showed a lower proportion of the effector memory (CD45RA-CCR7-) cells both CD4+ and CD8+, when compared to controls, anti-TNF, and anti-TNF plus MTX groups (20.01±7.76 vs 27.64±9.27; 20.01±7.76 vs 27.84±4.27; 20.01±7.76 vs 27.07±10.05; for CD4s and 26.42±7.23 vs 37.10±12.38; 26.42±7.23 vs 42.08±11.59; 26.42±7.23 vs 37.27±12.54 for CD8s, respectively). Percentage of CD25+ lymphocytes was higher in the anti-TNF plus MTX group. The Th1–17 (CCR6+CXCR3+) CD4 cell subpopulation was significantly increased in anti-TNF and anti-TNFα plus MTX groups compared with controls and MTX (10.45±3.14 vs 6.38±3.89; 10.45±3.14 vs 4.78±2.56 and 9.43±4.63 vs 6.38±3.89; 9.43±4.63 vs 4.78±2.56, respectively). Adult patients treated with anti-TNFα+MTX and MTX presented higher levels of CD21- naïve B cells compared to HC and to anti-TNF groups (4.86±3.24 vs 2.32±1.69; 4.86±3.24 vs 2.95±1.94 and 5.38±1.54 vs 2.32±1.69; 5.38±1.54 vs 2.95±1.94).ConclusionsIn depth phenotypic analysis of PBL in JIA showed alterations in cell subpopulations that seem dependent on age group. Our data also suggests that detailed in depth phenotypic analysis ...

BackgroundThere is some evidence that clinical response in patients with chronic arthritis treated with antiTNF agents can be influenced by their immunogenicity. This particular has not been fully studied in patients with juvenile idiopathic arthritis (JIA)ObjectivesTo evaluate the immunogenic response against antiTNF agents and its possible impact on treatment efficacy in patients with JIAMethodsSeventy-three patients (40 children and 33 adults) fulfilling ILAR criteria of JIA were included. All of them were on treatment with Etanercept (ETN), Adalimumab (ADA) or Infliximab (IFX) +/− Methotrexate (MTX). Demographical and disease characteristics were recorded at baseline. Clinical outcome was prospectively assessed every 6 months (JADAS, patient or parents VAS, physician's VAS, CHAQ/HAQ, ESR, CRP, number of swollen, painful and limited joints). Patients were tested for the presence of both, serum drug levels and antidrug antibodies levels at baseline and every 6 monthsResultsThirty-one paediatric patients (77.5%) needed combined treatment (antiTNF + MTX) vs 18 patients (54.4%) in the adult group. Furthermore, paediatric patients followed an intensified antiTNF therapy protocol more frequently than adult patients (54% vs 39.33%; p=0.044). A total of 189 determinations for the assessment of immunogenic response against antiTNF therapy were analysed. No differences were found between children and adults in the prevalence of antidrug antibodies or in the circulating antiTNF levels. No antidrug antibodies were found neither in the 107 determinations of patients following ETN treatment nor in the 6 determinations of patients on IFX. Just 5 (17%) of the 29 patients on ADA treatment produced anti-ADA antibodies at least once during the follow-up period. Regarding the 77 ADA determinations, patients who were on monotherapy with ADA produced antidrug antibodies with a significant higher frequency than patients on combined treatment with MTX (37.5% vs 8.7% of them respectively; p=0.016). Patients on monotherapy with ADA also exhibit a significant reduced serum ADA levels than patients on ADA+MTX (4.73μg/mL vs 12.73μg/mL respectively; p=0.019). However, no significant differences were observed in the ETN concentration between patients on monotherapy or on ETN+MTX treatment (1.50μg/mL vs 1.77μg/mL respectively). No correlation was observed between drug levels or the presence of antidrug antibodies and any of the clinical or biological parametersConclusionsJIA paediatric patients needed intensified and combined with MTX antiTNF therapy more frequently than adults. In spite of this, no differences were found regarding antiTNF levels between children and adults. This fact suggest that children need more therapy to maintain antiTNF concentrations to control the disease activity. No antibodies antiETN were detected in our patients. ADA in monotherapy seems to be more immunogenic than in combined therapy in JIA. We found no correlation between antiTNF levels or the presence of anti-antiTNF antibodies and the clinical outcome of JIA ...