Introduction: The objective of this study was to investigate the effects of tumor necrosis factor (TNF)-α inhibitors on circulating T helper-type 17 (Th17) cells and Th17-related cytokines in patients with rheumatoid arthritis (RA). Methods: The frequencies of circulating Th17 cells and serum levels of Th17-related cytokines were determined using flow cytometry analysis and ELISA, respectively, in 48 RA patients both before (baseline) and six months after anti-TNF-α therapy. Therapeutic response was evaluated using European League Against Rheumatism (EULAR) response criteria. Results: Significantly higher baseline frequencies of circulating Th17 cells and serum levels of interleukin (IL)-6, IL-17, IL-21, IL-23 and TNF-α were observed in active RA patients than in 12 healthy controls (all P < 0.001). After anti-TNF-α therapy, 36 patients (75%) were EULAR responders (20 good responders and 16 moderate responders) and 12 (25.0%) were non-responders. The mean levels of circulating Th17 cells and IL-17 significantly decreased (1.13% vs. 0.79%; 43.1 pg/ml vs. 27.8 pg/ml; respectively, both P < 0.001) in parallel with clinical remission in responders. Levels of IL-6, IL-21, IL-23 and TNF-α were significantly decreased after anti-TNF-α therapy in responders. In contrast, the mean levels of circulating Th17 cells and IL-17 significantly increased after anti-TNF-α therapy (2.94% vs. 4.23%; 92.1 pg/ml vs. 148.6 pg/ml; respectively, both P < 0.05) in non-responders. Logistic regression analysis identified a high baseline level of IL-17 as a significant predictor of poor therapeutic response. Conclusions: The beneficial effect of anti-TNF-α therapy might involve a decrease in Th17-related cytokines in responders, whereas rising levels of circulating Th17-cells and IL-17 were observed in patients with an inadequate response to anti-TNF-α therapy.

Objective To investigate the association between the risk of rheumatoid arthritis (RA) and a history of periodontitis. Methods This nationwide, population-based, case–control study used administrative data to identify 13 779 newly diagnosed patients with RA (age ≥16 years) as the study group and 137 790 non-patients with RA matched for age, sex, and initial diagnosis date (index date) as controls. Using conditional logistic regression analysis after adjustment for potential confounders, including geographical region and a history of diabetes and Sjögren's syndrome, ORs with 95% CI were calculated to quantify the association between RA and periodontitis. To evaluate the effects of periodontitis severity and the lag time since the last periodontitis visit on RA development, ORs were calculated for subgroups of patients with periodontitis according to the number of visits, cumulative cost, periodontal surgery and time interval between the last periodontitis-related visit and the index date. Results An association was found between a history of periodontitis and newly diagnosed RA (OR=1.16; 95% CI 1.13 to 1.21). The strength of this association remained statistically significant after adjustment for potential confounders (OR=1.16; 95% CI 1.12 to 1.20), and after variation of periodontitis definitions. The association was dose- and time-dependent and was strongest when the interval between the last periodontitis-related visit and the index date was <3 months (OR=1.64; 95% CI 1.49 to 1.79). Conclusions This study demonstrates an association between periodontitis and incident RA. This association is weak and limited to lack of individual smoking status.

Objective To evaluate the use of prospective screening for the HLA-B*58:01 allele to identify Taiwanese individuals at risk of severe cutaneous adverse reactions (SCARs) induced by allopurinol treatment. Design National prospective cohort study. Setting 15 medical centres in different regions of Taiwan, from July 2009 to August 2014. Participants 2926 people who had an indication for allopurinol treatment but had not taken allopurinol previously. Participants were excluded if they had undergone a bone marrow transplant, were not of Han Chinese descent, and had a history of allopurinol induced hypersensitivity. DNA purified from 2910 participants’ peripheral blood was used to assess the presence of HLA-B*58:01. Main outcome measures Incidence of allopurinol induced SCARs with and without screening. Results Participants who tested positive for HLA-B*58:01 (19.6%, n=571) were advised to avoid allopurinol, and were referred to an alternate drug treatment or advised to continue with their prestudy treatment. Participants who tested negative (80.4%, n=2339) were given allopurinol. Participants were interviewed once a week for two months to monitor symptoms. The historical incidence of allopurinol induced SCARs, estimated by the National Health Insurance research database of Taiwan, was used for comparison. Mild, transient rash without blisters developed in 97 (3%) participants during follow-up. None of the participants was admitted to hospital owing to adverse drug reactions. SCARs did not develop in any of the participants receiving allopurinol who screened negative for HLA-B*58:01. By contrast, seven cases of SCARs were expected, based on the estimated historical incidence of allopurinol induced SCARs nationwide (0.30% per year, 95% confidence interval 0.28% to 0.31%; P=0.0026; two side one sample binomial test). Conclusions Prospective screening of the HLA-B*58:01 allele, coupled with an alternative drug treatment for carriers, significantly decreased the incidence of allopurinol induced SCARs in Taiwanese medical centres.

Objective To investigate the kinetics of hepatitis B virus (HBV) viral loads and HBV reactivation in rheumatoid arthritis (RA) patients undergoing therapy with tumour necrosis factor alpha (TNFα) inhibitors. Methods The authors investigated the virological, serological and biochemical evidence of HBV reactivation in 88 RA patients receiving anti-TNFα therapy. Levels of HBV surface (HBs) antigen (Ag), anti-HBV core (HBc)-IgG and anti-HBs antibody (Ab) were detected by electrochemiluminescence immunoassay, and viral loads were determined by real-time PCR assay. Results In a total of 88 HBcAb-positive patients, 18 (20.5%) patients were HBsAg-positive, 12 (13.6%) patients were HBsAg-negative/HBsAb-negative and 58 (65.9%) patients were HBsAg-negative/HBsAb-positive before starting anti-TNFα therapy. Among HBsAg-positive patients receiving anti-TNFα therapy, HBV reactivation was documented in none of 10 patients who received lamivudine pre-emptive therapy and serum viral loads significantly decreased (mean±SEM, 153 860±80 120 IU/ml at baseline vs 313±235 IU/ml after 12 months antiviral therapy, p<0.001), paralleling the decrease in serum aminotransferase levels. In contrast, five (62.5%) of eight patients without antiviral prophylaxis developed HBV reactivation, viral loads significantly increased after anti-TNFα therapy (9375±5924 IU/ml vs 49 710 000±40 535 000 IU/ml, p<0.001), and markedly declined after antiviral therapy (49 710 000±40 535 000 IU/ml vs 6382±2424 IU/ml, p<0.001). Baseline viral loads were detectable in four (33.3%) of 12 patients who had HBsAg-negative/HBsAb-negative status, and one developed HBV reactivation after anti-TNFα therapy. Conclusion HBV reactivation can occur in both HBsAg-positive and HBsAg-negative/HBcAb-positive patients with detectable HBV DNA, so-called occult HBV infection, during anti-TNFα therapy. Antiviral prophylaxis may effectively reduce HBV reactivation in HBsAg-positive RA patients undergoing anti-TNFα therapy.

JNK pathway-associated phosphatase (JKAP, also known as DUSP22 or JSP-1) is a JNK activator. The in vivo role of JKAP in immune regulation remains unclear. Here we report that JKAP directly inactivates Lck by dephosphorylating tyrosine-394 residue during T-cell receptor (TCR) signalling. JKAP-knockout T cells display enhanced cell proliferation and cytokine production. JKAP-knockout mice show enhanced T-cell-mediated immune responses and are more susceptible to experimental autoimmune encephalomyelitis (EAE). In addition, the recipient mice that are adoptively transferred with JKAP-knockout T cells show exacerbated EAE symptoms. Aged JKAP-knockout mice spontaneously develop inflammation and autoimmunity. Thus, our results indicate that JKAP is an important phosphatase that inactivates Lck in the TCR signalling turn-off stage, leading to suppression of T-cell-mediated immunity and autoimmunity.