Interleukin-18 in adult-onset Still's disease: treatment target or disease activity indicator?

Systematic review on the use of biologics in adult-onset still's disease

This systematic review (SR) describes the efficacy and safety of biologic disease modifying anti-rheumatic drugs (bDMARDs) for patients with adult-onset Still's disease (AOSD). Three randomised controlled trials (RCTs), one retrospective case series of multiple interventions, and 17 case series of single interventions met the inclusion criteria for this SR. Comparisons of biologic therapy in AOSD were only available against conventional DMARDs in one RCT and against placebo in two RCTs. There was a lack of common assessment criteria, meaning treatment efficacy across studies could not be compared. Uncontrolled retrospective case series suggested that bDMARDs have an effect for patients with AOSD, but these studies did not provide comparative data to show whether bDMARDs were more effective than other interventions or, whether any bDMARD was more effective than another bDMARD. However, there was evidence that bDMARDs could reduce steroid dose. Safety data from all included studies showed that bDMARDs appear to be a safe alternative to conventional DMARDs. This SR has highlighted the need for larger comparative studies in AOSD and has shown the need to standardize the definition of therapeutic response in AOSD. This would allow comparisons between studies in order to gain clarity on which bDMARDs may be more effective treatments for AOSD.

Treatment of adult-onset Still's disease: a review

Adult-onset Still's disease (AOSD) is a rare inflammatory disorder that has been recently classified as a polygenic autoinflammatory disorder. The former classification, based on the disease course, seems to be quite dated. Indeed, there is accumulating evidence that AOSD can be divided into two distinct phenotypes based on cytokine profile, clinical presentation, and outcome, ie, a "systemic" pattern and an "articular" pattern. The first part of this review deals with the treatments that are currently available for AOSD. We then present the different strategies based on the characteristics of the disease according to clinical presentation. To do so, we focus on the two subsets of the disease. Finally, we discuss the management of life-threatening complications of AOSD, along with the therapeutic options during pregnancy.

Interleukin 1 inhibition with anakinra in adult-onset Still disease: a meta-analysis of its efficacy and safety

BACKGROUND

Anakinra is the first interleukin-1 inhibitor to be used in clinical practice, and recent evidence showed that interleukin-1 plays a pivotal role in the pathogenesis of adult-onset Still disease (AoSD). However, data concerning efficacy with anakinra use in different clinical trials has not been evaluated, and the overall remission of AoSD with anakinra treatment has not been well defined.

METHODS

We conducted a search on Embase, PubMed, and the Cochrane Library for relevant trials. Statistical analyses were conducted to calculate the overall remission rates, odds ratios (OR), and 95% confidence intervals (CI), by using either random effects or fixed effect models according to the heterogeneity.

RESULTS

Of the 273 articles that were identified, 265 were excluded. Eight studies were eligible for inclusion. The overall remission rate and complete remission rate of anakinra in AoSD patients were 81.66% (95% CI: 69.51%-89.69%) and 66.75% (95% CI: 59.94%-75.3%), respectively. Compared with the controls, the use of anakinra was associated with a significant remission in AoSD, with an OR of 0.16 (95% CI: 0.06-0.44, P=0.0005). There were also significant reductions of the dosage of corticosteroid (mean difference =21.19) (95% CI: 13.2-29.18, P<0.0001) from anakinra onset to the latest follow up time. Clinical and laboratory parameters were all improved, and anakinra was well tolerated in patients with AoSD. No evidence of publication bias was observed.

CONCLUSION

Our study has shown that anakinra is effective in remitting the manifestations of AoSD, with reduction of the dose of corticosteroid in patients with AoSD. Further, anakinra therapy was not associated with increased risk of adverse events, and it was well tolerated in patients with AoSD. Further research is still recommended to investigate these findings.

Adult onset Still's disease (AOSD) in the era of biologic therapies: dichotomous view for cytokine and clinical expressions

Adult onset Still's disease (AOSD) is a rare inflammatory disorder characterized by hectic spiking fever, evanescent rash and joint involvement. Prognosis is highly variable upon disease course and specific involvements, ranging from benign and limited outcome to chronic destructive polyarthritis and/or life-threatening events in case of visceral complications or reactive hemophagocytic lymphohistiocytosis (RHL). AOSD remains a debatable entity at the frontiers of autoimmune diseases and autoinflammatory disorders. The pivotal role of macrophage cell activation leading to a typical Th1 cytokine storm is now well established in AOSD, and confirmed by the benefits using treatments targeting TNF-α, IL-1β or IL-6 in refractory patients. However, it remains difficult to determine predictive factors of outcome and to draw guidelines for patient management. Herein, reviewing literature and relying on our experience in a series of 8 refractory AOSD patients, we question nosology and postulate that different cytokine patterns could underlie contrasting clinical expressions, as well as responses to targeted therapies. We therefore propose to dichotomize AOSD according to its clinical presentation. On the one hand, 'systemic AOSD' patients, exhibiting the highest inflammation process driven by excessive IL-18, IL-1β and IL-6 production, would be at risk of life-threatening complications (such as multivisceral involvements and RHL), and would preferentially respond to IL-1β and IL-6 antagonists. On the other hand, 'rheumatic AOSD' patients, exhibiting pre-eminence of joint involvement driven by IL-8 and IFN-γ production, would be at risk of articular destructions, and would preferentially respond to TNF-α blockers.

Adult-onset Still's disease

First described in 1971, adult-onset Still's disease (AOSD) is a rare multisystemic disorder considered as a complex (multigenic) autoinflammatory syndrome. A genetic background would confer susceptibility to the development of autoinflammatory reactions to environmental triggers. Macrophage and neutrophil activation is a hallmark of AOSD which can lead to a reactive hemophagocytic lymphohistiocytosis. As in the latter disease, the cytotoxic function of natural killer cells is decreased in patients with active AOSD. IL-18 and IL-1β, two proinflammatory cytokines processed through the inflammasome machinery, are key factors in the pathogenesis of AOSD; they cause IL-6 and Th1 cytokine secretion as well as NK cell dysregulation leading to macrophage activation. The clinico-biological picture of AOSD usually includes high spiking fever with joint symptoms, evanescent skin rash, sore throat, striking neutrophilic leukocytosis, hyperferritinemia with collapsed glycosylated ferritin (<20%), and abnormal liver function tests. According to the clinical presentation of the disease at diagnosis, two AOSD phenotypes may be distinguished: i) a highly symptomatic, systemic and feverish one, which would evolve into a systemic (mono- or polycyclic) pattern; ii) a more indolent one with arthritis in the foreground and poor systemic symptomatology, which would evolve into a chronic articular pattern. Steroid- and methotrexate-refractory AOSD cases benefit now from recent insights into autoinflammatory disorders: anakinra seems to be an efficient, well tolerated, steroid-sparing treatment in systemic patterns; tocilizumab seems efficient in AOSD with active arthritis and systemic symptoms while TNFα-blockers could be interesting in chronic polyarticular refractory AOSD.