Impact of immunogenicity on clinical efficacy and toxicity profile of biologic agents used for treatment of inflammatory arthritis in children compared to adults.

The treatment of inflammatory arthritis has been revolutionised by the introduction of biologic treatments. Many biologic agents are currently licensed for use in both paediatric and adult patients with inflammatory arthritis and contribute to improved disease outcomes compared with the pre-biologic era. However, immunogenicity to biologic agents, characterised by an immune reaction leading to the production of anti-drug antibodies (ADAs), can negatively impact the therapeutic efficacy of biologic drugs and induce side effects to treatment. This review explores for the first time the impact of immunogenicity against all licensed biologic treatments currently used in inflammatory arthritis across age, and will examine any significant differences between ADA prevalence, titres and timing of development, as well as ADA impact on therapeutic drug levels, clinical efficacy and side effects between paediatric and adult patients. In addition, we will investigate factors associated with differences in immunogenicity across biologic agents used in inflammatory arthritis, and their potential therapeutic implications.

Letter to the Editor in response to Chen et al. 2020.

We would like to comment on the article entitled "Association between cytokine profiles and lung injury in COVID-19 pneumonia" by Li-Da Chen and colleagues, with respect to emerging data regarding the immunopathogenesis of COVID-19. Chen et al. demonstrated the relevance of IL-2R, IL-6 and TNF-α in the cytokine storm and IL-6 as an independent predictor for COVID-19 severity. Del Valle et al. corroborated these findings with regard to IL-6 and disease severity, however, they also showed IL-8 to be of significance. This may be explained by the varying techniques used by the two studies to determine severity. Further studies including critically ill patients and the analysis of mortality rates in this patient cohort would greatly enhance the clinical relevance of these findings. As speculated by Chen et al., early studies on the use of tocilizumab in COVID-19 patients were promising, however, full results from ongoing trials are required to confirm a survival benefit in patients treated with tocilizumab. Moreover, investigating the roles of other pro-inflammatory cytokines and their impact on disease severity could potentially inform novel therapeutic targets.