The Status Of Vitamin D In Juvenile Idiopathic Arthritis (JIA), The Immune Mechanism Of T Cells In Arthritis Mice, And The Effectiveness Of Biological Agents In The Treatment Of JIA

PART 1: ASSOCIATION BETWEEN DISEASE ACTIVITY WITH VITAMIN D CONCENTRATIONS OF JUVENILE IDIOPATHIC ARTHRITIS PATIENTSObjective: We examine serum 25(OH)D3 in children with juvenile idiopathic arthritis,in order to find the association between the disease activity with vitamin D of JIA.Methods: 110 patients patients with juvenile idiopathic arthritis(52 males,58 females;Mean age was 9.04±3.37 years[range,3.02-16.60 years])were enrolled.Patients underwent laboratory tests of serum 25(OH)D3 by HPLC,plasma parathyroidhormone,initial dual energy X-ray absorptiometry scan of the lumbar spine.JIA patients were categorized as having active disease or inactive dieasse by ACR standard in 2011,and measured the disease activity by using JADAS-27.We analyzed the relationship between serum 25(OH)D3 level and other index.Results: The mean serum 25(OH)D3 level of 110 JIA patients is 19.9±6.1ng/ml.Vitamin D deficiency was detected in 59 patients(53.6%),insufficiency in 43 patients(39.1%)and sufficiency in 8 patients(5.6%).Patients with active disease had significantly reduced serum 25(OH)D3 levels compared to patients with inactive disease(p < 0.005),but there is no significant association between serum 25(OH)D3 level and JADAS-27.JIA patients with vitamin D deficiency showed a significantly lower bone mineral density than those with normal 25(OH)D3 level(p < 0.001).Patients using glucocorticoid show significantly lower 25(OH)D3 level than thoese never used glucocorticoid(p < 0.001).Conclusion: JIA patients have reduced serum 25(OH)D3,particularly thoese with onset in early age or/and active disease or/and using glucocorticoid.Serum 25(OH)D3 affects the bone mineral density.But the Serum 25(OH)D3 level has no statistical difference in each sbutype.PART 2:INCIDENCE OF COLLAGEN INDUCED ARTHRITIS(CIA)IN DIFFERENT MICE STRAINS AND THE ROLE OF IP-10 AND IP-10 RECEPTOR CAUSE TH17/TREG IMBALANCE IN CIA PATHOGENESISObjective: To compare the incidence of collagen induced arthritis(CIA)mice models in different strains,and to explore the role of IP-10 and its receptor of Th17/Treg imbalance in the pathogenesis of CIA mice.Methods: DBA1 mice,C57 / B6 mice and IL-17 gene knockout mice of different ages(16 for each strain)were randomly divided into experimental group and control group.Bovine type ? collagen and complete Freund's adjuvant were mixed and emulsified at 1: 1.and the experimental group were injected with 100?l via the tail vein for the primary immunization.The same method was used for the second immunization after 21 days.The 8 mice(in same strain with experimental group)in the control group were treated with the same amount of PBS.Arthritis score was performed to observe the incidence of arthritis.All mice were sacrificed in 42 days after the second immunization.The spleen cells were isolated and the percentage of cells of the two groups were detected by flow cytometry.Results: In experimental group,seven DBA1 mice showed varying degrees of joint swelling and decreased activity(7 / 8,87.5%).Four C57 / B6 mice developed arthritis symptoms(4/8,50.0%),IL-17 knockout mice did not develop arthritis(0 / 8,0%).There was no case of arthritis in the control groups.The arthritis index(AI)was evaluated at 2 weeks and 3 weeks after the second immunization.The average results showed that AI of DBA1 mice was significantly higher than that of C57 / B6 mice(mean 2.0 & 0.6).In CIA group,the percentage of CD183 + Th17 cells of spleen cells was significantly increased and the proportion of CD183 + Treg cells was significantly decreased,which was significantly different from that of control group.Conclusion: The incidence of bovine type?collagen induced arthritis(CIA)modeling is closely related to the selection of mouse strain.DBA1 mice had the highest success rate,and IL-17 gene knockout mice were unsuccessful.It was confirmed that IL-17 might play an important role in the pathogenesis of arthritis.Chemokine IP-10 may cause imbalance of Th17/Treg by expression of CXCR3(CD183 +)on Treg and Th17 cells,which may be an important cause of CIA.PART 3:THE EFFICACY AND SAFETY OF TOCILIZUMAB FOR REFRACTORY SYSTEMIC JUVENILE IDIOPATHIC ARTHRITISObjective: To examine the efficacy and adverse events(AE)associated with tocilizumab as a treatment for refractory s JIA.Study design: This observational study compared the efficacy and safety of tocilizumab with that of glucocorticoids as a treatment for Chinese patients with refractory active s JIA.The Juvenile Arthritis Disease Activity Score 27(JADAS27)was used to measure disease activity at Weeks 6,12,and 24.Results: Sixty refractory s JIA patients were enrolled: 36 received tocilizumab combined with NSAIDs and(or)glucocorticoids,and 24 received glucocorticoids combined with NSAIDs.Patients were followed for 24 weeks.Symptoms(fever,rash),severity of arthritis,and inflammatory markers were measured at Weeks 6,12,and 24 and compared with baseline values.The JADAS27,ESR,and CRP levels in both groups improved significantly at all time points tested(P<0.05).However,at Weeks 6,12,and 24,the JADAS-27 score in the tocilizumab group was significantly lower than the glucocorticoid group(P<0.05).At Weeks 6 and 12,the ESR in the tocilizumab group was significantly lower than the glucocorticoid group(P<0.05).At Weeks 12 and 24,CRP levels were significantly lower than the glucocorticoid group(P<0.05).The most common AE associated with tocilizumab were infection,rash,a transient increase of aminotransferase levels,and an infusion reaction.Glucocorticoid-related AE,such as infections and growth retardation,were more common and more serious.Conclusion: Tocilizumab is an effective treatment for refractory s JIA and is superior to glucocorticoids.AE associated with tocilizumab,especially the incidence of infections,were lower than glucocorticoids.