Juvenile idiopathic arthritis: Rethinking remission
New research looks at the emerging evidence on the biology of remission that holds promise for better outcomes for patients with JIA.
REVIEWED BY JANE A OSKI, MD, MPH
Juvenile idiopathic arthritis (JIA) refers to a heterogenous group of all forms of chronic arthritis in childhood with no apparent cause that begins prior to age 16 years and lasts for more than 6 weeks.1,2 It is the most common form of rheumatic disease in children, with an estimated incidence of 2 to 20 cases per 100,000 children and prevalence of 16 to 150 cases per 100,000 children worldwide.1,3 In the United States, it is estimated that more than 300,000 children currently have JIA.
Diagnosis and treatment of JIA has improved over the years with an increased understanding of the different subtypes and clinical presentations of JIA and the availability and efficacy of newer antirheumatic medications to treat these subtypes.4 The efficacy of methotrexate as first-line treatment for most patients with JIA, combined with other conventional disease-modifying antirheumatic drugs (DMARDs) and/or the more recent biologic agents as needed, has resulted in an increasing number of patients who attain longer periods of disease control and clinical remission. Despite these improvements, the response to therapy is as heterogeneous as the subtypes themselves and many children who achieve clinical remission experience recurrence and disease flares even while on continuous medication.5
What is emerging is recognition of the need to better understand the biology underlying the differences among the subtypes of JIA in terms of response to therapy and outcomes6 and the need to understand this biology to develop better individualized treatment. New data from a study that used gene expression profiling in a cohort of JIA patients suggest that current definitions of clinical remission thought to indicate a return to normal patterns of gene expression in children who attain control of disease activity do not accurately describe the underlying biology of clinical remission. Rather, the underlying biology of clinical remission seems to involve the counterbalancing of proinflammatory responses by anti-inflammatory responses.6
“Although children in remission on medication appear to be completely normal, our medications do not result in normal immune homeostasis,” according to James Jarvis, MD, clinical professor and chief, Allergy/Immunology and Rheumatology, University of Buffalo, New York, a lead investigator of the study.
The implications, he emphasized, are that although children can now achieve long-term disease-free periods when they stay on their medications, their vulnerability to disease persists. “While our findings explain why children who appear to be doing well experience disease recurrences, they don’t explain how to prevent them,” he said.
For pediatricians who see children with JIA, these new data and understanding of remission emphasize the need to continually treat children with JIA with appropriate medications for years and not just months, even when they are doing well, according to Jarvis.
To help pediatricians manage JIA in their patients, this article provides a brief primer on the subtypes of JIA and their clinical presentation; an update on the most current treatments and outcomes; and a look at the emerging issue and evidence on the biology of remission and therapeutic response that is promising to help better tailor treatment and optimize outcomes for children with JIA.