September 2026 Research Update

This month, studies looking at macrophage activation syndrome (MAS) in Still's disease painted a consistent picture: treatment often starts with glucocorticoids (steroids), and many patients also receive additional immune-targeting medicines, especially anakinra and ciclosporin. The studies found that treatment choices for MAS varied depending on the underlying disease, region, and medicine availability. In one study of 64 patients, 37.5% had a complete response and 40.6% had a partial response to treatment for the first MAS episode; MAS came back in 31.3%. Together, these reports help explain why MAS care often involves more than one medicine and close follow-up when possible. [1] [2]

In a multicenter cohort of glucocorticoid-refractory MAS complicating Still's disease (mostly systemic juvenile idiopathic arthritis, with a smaller group with adult-onset Still's disease), all patients received glucocorticoids and many also received anakinra (48/64) and ciclosporin (33/64). By laboratory measures, 7 patients had a complete and 41 a partial remission; by their doctors' clinical assessment, 24 had a complete and 26 a partial response. MAS came back in 20 of the 64 patients (31%) and 7 died; estimated survival one year after the episode was about 94%. Because these were patients whose MAS had not responded to steroids alone, the results support close follow-up even after a good response. [1]

A large international physician survey reported that steroids (often intravenous methylprednisolone) were the most common first approach to MAS across rheumatologic diseases, sometimes used alone (44%) and often combined with medicines like anakinra, ciclosporin, or IVIG. The survey also highlighted that access to specific drugs differs by region, which may push some settings toward more steroid-only treatment. [2]

For patients and caregivers, the main point is that MAS is commonly treated urgently with steroids, and many real-world clinicians also use add-on medicines such as anakinra or ciclosporin, especially when MAS does not respond quickly. This body of evidence does not prove which combination is best for any one person, but it clarifies what is commonly being used and that relapse can happen even after improvement. This may matter now mainly as context for why MAS care often looks intensive and variable across hospitals, while future studies are still needed to clarify which strategies lead to the most reliable control and safety in different patient groups. [1] [2]

This month added practical information about how researchers and clinics might score adult-onset Still's disease (AOSD) activity in a more consistent way. Across two studies, several scoring tools broadly matched clinician judgments, and some appeared better at picking up change over time. This matters because reliable scoring makes it easier to compare patients across visits and to compare results across studies, even when symptoms involve different body systems. [3] [4]

In one multicenter study of 86 adults with initially active AOSD, modified versions of two scores (mDAVID and mSDAS) performed similarly to another score (SAS) when compared with a physician overall assessment. In that comparison, mDAVID showed the greatest responsiveness and sensitivity to change over time, while mSDAS appeared to line up more with the joint-related (articular) side of disease activity. [3]

In a separate validation study using 129 clinic visits, sJADAS10 showed strong agreement with a reference definition of activity and strong ability to distinguish inactive or low disease activity from moderate or high activity. The authors described this as support for using sJADAS10 in adult AOSD, which could help comparisons between adult AOSD and related pediatric disease research. [4]

For patients, these studies are mainly about tracking disease rather than changing treatment. They suggest that a few scoring approaches can reflect how active AOSD is and can capture improvement or worsening over time, including tools originally used in related pediatric disease. What remains uncertain is which score is best for all adults in routine care, since the studies used retrospective clinic data and specific reference standards. This matters most for research and for more consistent monitoring in clinics over time, rather than providing a new test or a direct change in day-to-day care right now. [3] [4]

This month, several reports focused on situations where AOSD can be hard to recognize, especially when the rash does not look typical or when other lab results confuse the picture. A small biopsy series suggested a skin finding that showed up in many confirmed AOSD cases, while case reports illustrated how AOSD can appear in very old age, can come with unusual rash patterns, and can overlap with drug-reaction scoring systems. Together, these studies reinforce that diagnosis may rely on putting multiple clues together rather than any single sign. [5] [6] [7] [8]

In a clinicopathology study of 16 adults with confirmed AOSD, superficial dyskeratotic keratinocytes (a specific type of damaged skin cell seen on biopsy) were found in 12/16 patients. The authors argued that, when symptoms and other findings already point toward AOSD, a skin biopsy could provide a relatively accessible extra piece of evidence supporting the diagnosis. [5]

Two case reports highlighted how AOSD can be missed when presentation is unusual. One described AOSD diagnosed at age 83, emphasizing that a positive ANA blood test does not rule out AOSD and that very high ferritin can still be an important clue even in older adults. Another described a patient with sequential, atypical rashes where biopsy supported AOSD, with improvement reported after IL-1 blocking medicines (anakinra and later canakinumab), although injection-site reactions occurred with anakinra. [7] [6]

A separate report described a pregnant patient with AOSD who developed eosinophilic complications and lung findings after IL-1/IL-6 receptor inhibition, with improvement reported after benralizumab (a medicine that targets eosinophils). In the same paper, a retrospective analysis of 69 AOSD patients suggested that commonly used DRESS scoring rules (RegiSCAR) can overlap substantially with AOSD features, raising the possibility of misclassification when relying on that scoring approach alone. [8]

For patients and caregivers, these studies mostly add to understanding of why diagnosis can take time, especially with atypical rashes, unusual ages, or confusing blood tests. The biopsy series suggests a skin biopsy may provide supportive evidence in the right clinical context, but it does not prove that the finding is unique to AOSD in all settings. The case reports are important signals about what can happen, including possible drug-reaction overlap and rare complications, but they come from single individuals and may not apply to most people with AOSD. This information matters most now for awareness and future research on clearer diagnostic tools, rather than as a direct change to treatment decisions. [5] [7] [6] [8]

One study this month directly compared MAS occurring in adults with Still's disease versus MAS occurring in adults with lupus, and it found that the MAS picture was not identical between diseases. The lupus group more often had very low blood counts and nervous system involvement, while the Still's disease group had higher inflammation markers like ferritin and C-reactive protein. This helps explain why the same complication name, MAS, can look and behave differently depending on the underlying disease. [9]

In this multicenter cohort (37 lupus-MAS and 37 Still's disease-MAS), most patients in both groups met MAS criteria, and ICU admission occurred in 35% of each group. IL-1 blocking medicines were used more often in Still's disease-MAS than lupus-MAS, and in the small lupus subgroup that received IL-1 blockade there was no rapid MAS resolution reported. A small imaging sub-study suggested more widespread inflammation signals on FDG-PET/CT in Still's disease-MAS. [9]

For patients, this comparison matters mostly as context: MAS is a shared complication name, but the blood tests, symptoms, and treatments used can differ by the disease it occurs with. This study does not establish the best treatment for MAS in any one disease, but it does clarify that findings common in lupus-MAS (like profound low blood counts) were less typical in Still's disease-MAS in this cohort. The results may matter later if they lead to more tailored research and better ways to recognize MAS early in different conditions, but for now they mainly add understanding rather than offering a new care approach. [9]

One study focused on whether blood markers might help predict who can successfully reduce or stop canakinumab, using patients with systemic juvenile idiopathic arthritis (a related Still's disease) who were already in remission. People who tapered successfully tended to have lower levels of several inflammation-related blood markers, and their gene activity patterns differed from those who flared during tapering. This adds early evidence that biology measured in blood may eventually help explain why some people stay well off medicine and others do not. [10]

In this randomized withdrawal trial, lower sCD163, CXCL9, IL-1RA, and IL-18 were linked with successful tapering, and a 9-gene signature was more active in those with unsuccessful tapering. The reported composite score for this gene set separated successful from unsuccessful discontinuation with an AUC of 0.71, which suggests modest discrimination rather than a perfect predictor. [10]

For patients with adult-onset Still's disease, this study is most relevant as early research because it was done in systemic juvenile idiopathic arthritis, not in adults with AOSD. It suggests that lower inflammation markers, including IL-18, may be part of the biology of staying in remission during canakinumab tapering, but it does not provide a ready-to-use test for individuals. What remains uncertain is whether the same markers work in AOSD and how reliably they would predict taper outcomes in routine care. This matters mainly for future research aimed at more personalized taper planning, rather than changing what people do now. [10]