Interleukin-6 is currently attracting significant interest as a potential therapeutic target in systemic sclerosis (SSc). In this paper, the biology of interleukin-6 is reviewed, and the evidence for interleukin-6 dysregulation in SSc is explored. The role of inteleukin-6 classical and trans signalling pathways in SSc relevant phenomena such as chronic inflammation, autoimmunity, endothelial cell dysfunction, and fibrogenesis is discussed. The existing evidence that interventions designed to block interleukin-6 signalling are of therapeutic relevance in SSc is evaluated.

ObjectiveTo investigate whether antidrug antibodies and/or drug non‐trough levels predict the long‐term treatment response in a large cohort of patients with rheumatoid arthritis (RA) treated with adalimumab or etanercept and to identify factors influencing antidrug antibody and drug levels to optimize future treatment decisions.MethodsA total of 331 patients from an observational prospective cohort were selected (160 patients treated with adalimumab and 171 treated with etanercept). Antidrug antibody levels were measured by radioimmunoassay, and drug levels were measured by enzyme‐linked immunosorbent assay in 835 serial serum samples obtained 3, 6, and 12 months after initiation of therapy. The association between antidrug antibodies and drug non‐trough levels and the treatment response (change in the Disease Activity Score in 28 joints) was evaluated.ResultsAmong patients who completed 12 months of followup, antidrug antibodies were detected in 24.8% of those receiving adalimumab (31 of 125) and in none of those receiving etanercept. At 3 months, antidrug antibody formation and low adalimumab levels were significant predictors of no response according to the European League Against Rheumatism (EULAR) criteria at 12 months (area under the receiver operating characteristic curve 0.71 [95% confidence interval (95% CI) 0.57, 0.85]). Antidrug antibody–positive patients received lower median dosages of methotrexate compared with antidrug antibody–negative patients (15 mg/week versus 20 mg/week; P = 0.01) and had a longer disease duration (14.0 versus 7.7 years; P = 0.03). The adalimumab level was the best predictor of change in the DAS28 at 12 months, after adjustment for confounders (regression coefficient 0.060 [95% CI 0.015, 0.10], P = 0.009). Etanercept levels were associated with the EULAR response at 12 months (regression coefficient 0.088 [95% CI 0.019, 0.16], P = 0.012); however, this difference was not significant after adjustment. A body mass index of ≥30 kg/m2 and poor adherence were associated with lower drug levels.ConclusionPharmacologic testing in anti–tumor necrosis factor–treated patients is clinically useful even in the absence of trough levels. At 3 months, antidrug antibodies and low adalimumab levels are significant predictors of no response according to the EULAR criteria at 12 months.

Neutrophils are normally short-lived cells and die by apoptosis, but when recruited into tissues, their apoptosis is delayed, and they survive for much longer time periods. In inflammatory diseases, such as rheumatoid arthritis (RA), this delayed apoptosis may lead to increased tissue damage and a failure of the inflammation to resolve. However, there are conflicting reports in the literature as to whether neutrophil apoptosis is delayed or accelerated in rheumatoid joints. In this report, we show that neutrophils isolated from the synovial fluid (SF) of patients with RA show accelerated rates of apoptosis when incubated ex vivo and that SF, despite containing a variety of antiapoptotic cytokines, is proapoptotic. Paradoxically, levels of the key neutrophil survival protein Mcl-1 are elevated in freshly isolated SF neutrophils compared with matched peripheral blood samples from the same patients, indicating that delayed neutrophil apoptosis has been signaled in vivo as the cells enter the joints. However, when SF was added to neutrophils and incubated under hypoxia (1% O(2)), conditions known to exist in vivo within joints, the SF was antiapoptotic. These data reveal that the rheumatoid synovial joint contains a complex mixture of pro- and antiapoptotic factors and that the low, local oxygen tensions that exist within these joints can exert profound effects on neutrophil survival. These experiments also highlight the importance of performing in vitro experiments under laboratory conditions that closely mimic those that occur in vivo; otherwise, misleading conclusions may be drawn.

Objective. To evaluate the efficacy and tolerability of prolonged administration of quinapril, a long-acting angiotensin-converting enzyme inhibitor, in the management of the peripheral vascular manifestations of limited cutaneous systemic sclerosis (lcSSc) and in the prevention of the progression of visceral organ involvement in the disease.Methods. This was a multicenter, randomized, double-blind, placebo-controlled study evaluating quinapril 80 mg/day, or the maximum tolerated dosage, in 210 patients with lcSSc or with Raynaud's phenomenon (RP) and the presence of SSc-specific antinuclear antibodies. Treatment was for 2-3 years. The primary outcome measure was the number of new ischemic ulcers appearing on the hands; secondary measures were the frequency and severity of RP attacks, skin score, treatments for ischemia, health status (measured by the Short Form 36 instrument), measures of kidney and lung function, and echocardiographic estimates of pulmonary artery pressure. An intent-to-treat analysis was used.Results. Quinapril did not affect the occurrence of digital ulcers or the frequency or severity of RP episodes. It did not alter the treatments that were prescribed for either infected ulcers or severe RP symptoms. There was no apparent effect on the estimated tricuspid gradient. Health status was not affected by quinapril, and one-half of the patients who believed they had benefited from the trial treatment were in the placebo arm. Quinapril was not tolerated by one-fifth of the patients, with dry cough being the most frequent side effect.Conclusion. Administration of quinapril for up to 3 years had no demonstrable effects on the occurrence of upper limb digital ulcers or on other vascular manifestations of lcSSc in this patient population. ISRCTN: 57984704.