The adverse effects of tumor necrosis factor alpha inhibitors (TNFi) are well characterized but rare adverse events are increasing day by day. We presented an 18-year-old girl with rheumatoid factor positive polyarticular juvenile idiopathic arthritis (JIA) who developed fever, headache, and nausea after the second dose of adalimumab. In addition to her suspicious complaints for meningitis, she had bilateral papilledema and partial abducens nerve palsy. Leptomeningeal contrast enhancement was noted in magnetic resonance imaging (MRI) of the brain. Brain MRI venography was normal. The cerebrospinal fluid (CSF) opening pressure was high but CSF analysis was normal. She was diagnosed with non-infectious subacute meningitis. Since brain biopsy was not performed, no definite distinction could be made between TNFi related aseptic meningitis or cerebral involvement of JIA. Due to the onset of neurological complaints after initiation of adalimumab treatment and rare cerebral involvement in JIA, the drug-associated aseptic meningitis was likely to be responsible in our patient. Adalimumab was discontinued and methylprednisolone followed by methotrexate treatment were initiated. Her symptoms resolved and control brain MRI was normal. Pediatric rheumatologists should be aware of this potentially severe side effect of anti-TNF treatment.

STING-associated vasculopathy with onset in infancy (SAVI) is a type 1 interferonopathy manifesting as a pulmonary and vascular syndrome resulting from gain-of-function mutations in TMEM173, the gene encoding STING. Familial reports in the literature are sparse. We report a case series of SAVI in a three generation kindred, with a phenotype of interstitial lung disease (ILD) and rheumatoid factor positive polyarticular juvenile idiopathic arthritis (JIA). Current and historical medical records were reviewed for clinical and laboratory information. Whole blood from cases 1 and 2, plus stored appendicectomy tissue from case 3, underwent DNA sequencing of the TMEM173 gene. Peripheral blood RNA was obtained from cases 1 and 2 for functional assessment of the TMEM173 mutation. DNA sequencing identified the same heterozygous TMEM173 mutation (c.463G > A; p.Val155Met) in all three cases, consistent with a diagnosis of the autosomal dominant condition SAVI. Functional assessment of this mutation identified a prominent interferon signature which was confirmed on repeat testing. SAVI presented in this family as ILD with early onset juvenile rheumatoid arthritis. This condition should be considered in all rheumatoid arthritis patients with early-onset ILD and in all JIA patients with ILD.

Juvenile idiopathic arthritis (JIA) comprises 7 heterogeneous categories of chronic childhood arthritides. Approximately 5% of children with JIA have rheumatoid factor (RF)-positive arthritis, which phenotypically resembles adult rheumatoid arthritis (RA). Our objective was to compare and contrast the genetics of RF-positive polyarticular JIA with those of RA and selected other JIA categories, to more fully understand the pathophysiologic relationships of inflammatory arthropathies. Patients with RF-positive polyarticular JIA (n = 340) and controls (n = 14,412) were genotyped using the Immunochip array. Single-nucleotide polymorphisms were tested for association using a logistic regression model adjusting for admixture proportions. We calculated weighted genetic risk scores (wGRS) of reported RA and JIA risk loci, and we compared the ability of these wGRS to predict RF-positive polyarticular JIA. As expected, the HLA region was strongly associated with RF-positive polyarticular JIA (P = 5.51 × 10-31 ). Nineteen of 44 RA risk loci and 6 of 27 oligoarticular/RF-negative polyarticular JIA risk loci were associated with RF-positive polyarticular JIA (P < 0.05). The RA wGRS predicted RF-positive polyarticular JIA (area under the curve [AUC] 0.71) better than did the oligoarticular/RF-negative polyarticular JIA wGRS (AUC 0.59). The genetic profile of patients with RF-positive polyarticular JIA was more similar to that of RA patients with age at onset 16-29 years than to that of RA patients with age at onset ≥70 years. RF-positive polyarticular JIA is genetically more similar to adult RA than to the most common JIA categories and thus appears to be a childhood-onset presentation of autoantibody-positive RA. These findings suggest common disease mechanisms, which could lead to novel therapeutic targets and shared treatment strategies.

Macrophage activation syndrome (MAS) is one of the serious complications associated with rheumatic diseases, especially systemic juvenile idiopathic arthritis (sJIA). Here we describe a 9-year-old girl with rheumatoid factor (RF)-positive polyarticular JIA, not sJIA, combined with pneumonia who was successfully treated by plasma exchange. She was diagnosed with RF-positive polyarticular JIA based on positive RF and multiple joint swelling and tenderness 3 years ago. She was admitted in our hospital with myalgia for 2 days and a high fever for half a day. Physical examination revealed relapsing joints symptoms and rough breathing sounds of lungs. The laboratory examination showed increased liver enzymes, elevated serum ferritin and procalcitonin (PCT), decreased percentage of nature killer (NK) cells and fibrinogen, and activated macrophage phagocytosing hematopoietic elements in bone marrow. The elevated PCT and chest computed tomography scan confirmed she also had pneumonia. Intravenous methylprednisolone and oral cyclosporine A followed by intravenous immunoglobulin were added on the basis of antibiotics therapy, but clinical symptoms and laboratory findings did not improve. Finally, we changed to plasma exchange once every other day for a total of three times. Within 1 week, the girl recovered from the MAS completely.