Th17/1 and ex-Th17 cells are detected in patients with polyarticular juvenile arthritis and increase following treatment.

BACKGROUND: A better understanding of the pathogenesis of polyarticular juvenile idiopathic arthritis (polyJIA) is needed to aide in the development of data-driven approaches to guide selection between therapeutic options. One inflammatory pathway of interest is JAK-STAT signaling. STAT3 is a transcription factor critical to the differentiation of inflammatory T helper 17 cells (Th17s). Previous studies have demonstrated increased STAT3 activation in adult patients with rheumatoid arthritis, but less is known about STAT3 activation in polyJIA. We hypothesized that Th17 cells and STAT3 activation would be increased in treatment-naïve polyJIA patients compared to pediatric controls. METHODS: Blood from 17 patients with polyJIA was collected at initial diagnosis and again if remission was achieved (post-treatment). Pediatric healthy controls were also collected. Peripheral blood mononuclear cells were isolated and CD4 + T cell subsets and STAT activation (phosphorylation) were evaluated using flow cytometry. Data were analyzed using Mann-Whitney U and Wilcoxon matched-pairs signed rank tests. RESULTS: Treatment-naïve polyJIA patients had increased Th17 cells (CD3 + CD4 + interleukin(IL)-17 +) compared to controls (0.15% v 0.44%, p < 0.05), but Tregs (CD3 + CD4 + CD25 + FOXP3 +) from patients did not differ from controls. Changes in STAT3 phosphorylation in CD4 + T cells following ex vivo stimulation were not significantly different in patients compared to controls. We identified dual IL-17 + and interferon (IFN)γ + expressing CD4 + T cells in patients, but not controls. Further, both Th17/1 s (CCR6 + CD161 + IFNγ + IL-17 +) and ex-Th17s (CCR6 + CD161 + IFNγ + IL-17neg) were increased in patients' post-treatment (Th17/1: 0.3% v 0.07%, p < 0.05 and ex-Th17s: 2.3% v 1.4%, p < 0.05). The patients with the highest IL-17 expressing cells post-treatment remained therapy-bound. CONCLUSIONS: Patients with polyJIA have increased baseline Th17 cells, potentially reflecting higher tonic STAT3 activation in vivo. These quantifiable immune markers may identify patients that would benefit upfront from pathway-focused biologic therapies. Our data also suggest that inflammatory CD4 + T cell subsets not detected in controls but increased in post-treatment samples should be further evaluated as a tool to stratify patients in remission on medication. Future work will explore these proposed diagnostic and prognostic biomarkers.

Distal extremity necrosis as a manifestation of cutaneous polyarteritis nodosa: case report and review of the acute management of a pediatric patient.

We present the case of an 8-year-old girl who presented with distal extremity necrosis of the hands, feet, nose, and ears as an acute manifestation of cutaneous polyarteritis nodosa (CPAN). She was emergently managed with intravenous steroids, nifedipine, sildenafil, pentoxifylline, nitroglycerin paste, aspirin, low-molecular-weight heparin, and intravenous gamma globulin. The necrosis was controlled, and reperfusion was attained to salvage the extremities. It is important for clinicians to be aware that acute distal extremity necrosis can be a manifestation of CPAN in children. Etiology is often not clear on presentation, but once infection is excluded, acute management with systemic steroids and systemic vasodilators is indicated regardless of the cause. Iloprost and bosentan may represent options for adjunctive vasodilators. More studies are needed to create guidelines for the acute and long-term management of these children. Close follow-up of children with CPAN, especially with a history of vaso-occlusive symptoms, is important to allow prompt intervention in the event of distal extremity infarction.