Cytokine Profiles of Korean Patients with Adult Onset Still's Disease Treated with Biologic Agents

Abstract

Background/Purpose: Adult onset Still’s disease (AOSD) is a rare inflammatory disorder of unknown etiology. Several studies have reported that pro-inflammatory cytokines including interleukin (IL)-1, IL-6, IL-18, tumor necrosis factor (TNF)-α, and interferon (INF)-γ, are involved in the pathogenesis of AOSD. Refractory AOSD patients have been treated successfully with anti-cytokine biologics. Herein, we analyzed cytokines to investigate predictors for therapeutic response of biologic drugs in refractory AOSD.

Methods: Twenty two AOSD patients who treated with anti-TNFα agents or anti-IL-6 receptor agent were recruited from a university hospital for rheumatic diseases in Korea. The dosages of anti-TNFα (infliximab in 18 patients, etanercept in 4, and adalimumab in 3) and tocilizumab in 12 were same as those of rheumatoid arthritis. Serum cytokines (TNFα, IL-1β, IL-6, IL-8, IL-17α, and INF-γ) and IL-2 receptor α were analyzed by multiplex flowcytometry. A good response to biologic agents was defined as decreased modified Pouchot score more than 2 score compared to initial treatment of biologic agents. A no response to biologic agents was defined as no decrease of modified Pouchot score. We used the Mann-Whitney test for continuous variable.

Results: Seven (36.8%) patients showed good response to anti-TNFα inhibitors and 3 (13.6%) patients showed partial response. Nine (47.4%) patients did not respond to anti-TNFα inhibitors. Three (25%) patients showed good response to tocilizumab (TCZ), 4 (33.3%) showed partial response, and 5 (41.7%) showed no response. At starting time point of anti-TNFα inhibitors, levels of TNFα, IL-1β, IL-6, and IFNγ in no responders was higher compared to those with good response, but without statistically significant differences (Table 1). At starting time point of TCZ, conversely, the levels of TNFα and IL-6 in no responders was lower compared to responders including good and partial response (Table 2). We didn’t raise the dosage of infliximab in no responders, nine patients, in whom TCZ was used as second biologic therapy. Of those, five (55.6%) patients showed improvement in clinical and laboratory findings.

Conclusion: This study showed that AOSD patients who were refractory to biologic agents might have distinct cytokine profiles. Therefore, dosage and sort of biologic agents in AOSD patients might be individualized according to pre-treatment cytokine profiles.