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.

Changes in Frequency and Activation Status of Major CD4+ T-Cell Subsets after Initiation of Immunosuppressive Therapy in a Patient with New Diagnosis Childhood-Onset Systemic Lupus Erythematosus.

BACKGROUND: Several studies suggest that defects of regulatory T-cells (Tregs) and impaired cellular immunity are secondary to an imbalance between auto-aggressive T-cells and Tregs in lupus patients. Discrepancies in Tregs and effector T-cells (Teff) in active lupus patients are shown to be restored in patients upon receiving immunosuppressive therapy. Therefore, our main aim was to observe frequencies of these CD4+ T-cell subsets and Tregs/Teff ratio in a new diagnosis of childhood-onset systemic lupus erythematous (cSLE) before and after initiation of therapy. In addition, we monitored T-cell exhaustion status by examining responses to super-antigen staphylococcal enterotoxin B (SEB) and PD-1 expression in this patient. METHODS: Phenotyping of CD4+ T-cell subsets was carried out under basal conditions and after SEB stimulation using flow cytometry in one inactive (I-cSLE) and one active cSLE (A-cSLE) patient, as well as a healthy control (HC). The A-cSLE patient was a new diagnosis. Variables were measured at three consecutive time points in the active patient, reflecting various stages of disease activity. Activation status of CD4+ T-cells in the A-cSLE patient was compared to that of the I-cSLE patient and HC. Disease activity was measured by calculating the systemic lupus erythematous disease activity index. RESULTS: We found that the A-cSLE patient was not Tregs deficient. The patient had increased frequency of Tregs, and the Tregs/Teff ratio increased when the disease activity became less severe. CD4+ T-cells in the I-cSLE patient and in the A-cSLE patient with milder disease activity had heightened responsiveness to SEB, whereas T-cells were relatively hypo-responsive to SEB in the A-cSLE patient when disease activity was higher. The active patient exhibited higher frequencies of PD-1+ expressing Tregs, Teff, and Tnaïve/mem cells under basal conditions compared to the HC and I-cSLE patient. CONCLUSION: In the A-cSLE patient, changes in Tregs/Teff ratio correlated better with clinical improvement compared to Tregs frequencies alone and might reflect the restoration of immune homeostasis with therapy. SEB hypo-responsiveness in the A-cSLE patient when disease activity was higher paralleled with findings of greater frequencies of PD-1+ expressing Tregs, Teff, and Tnaïve/mem cells, suggests a possible global exhaustion status of CD4+ T-cells in this patient.

Diffuse Alveolar Hemorrhage as a Manifestation of Childhood-Onset Systemic Lupus Erythematosus.

BACKGROUND: Diffuse alveolar hemorrhage (DAH) is a devastating clinical syndrome characterized by a falling hematocrit, respiratory insufficiency, and radiographic evidence of pulmonary infiltrates. Literature regarding management of DAH in childhood-onset SLE (cSLE) is limited. METHODS: We reviewed the presentation, management, and outcome of DAH in a pediatric tertiary medical center with one of the largest cSLE cohorts in North America. During a 10 year period 7 of 410 children with cSLE had DAH. RESULTS: The majority of cSLE patients with DAH were male (71%) and Hispanic (57%). The median age at the time of DAH diagnosis was 14 years (range 3 -15 years). DAH was the presenting manifestation of cSLE in 29% of children; 71% presented with DAH within 3 months of their diagnosis. All patients had cough, 86% had dyspnea, and 29% had hemoptysis. All patients had anemia and 71% had thrombocytopenia. Eighty-six percent had hematuria/proteinuria, and a positive anti-double stranded DNA antibody. Chest imaging showed diffuse ground glass opacities in all events. All patients developed respiratory insufficiency (29% supplemental oxygenation and 71% mechanical ventilation). Transfusions were required in 57% of cases. All patients received corticosteroids and additional immunomodulation to achieve disease control. Eighty-six percent of our DAH/cSLE cohort survived their initial event (median follow-up 2.5 years). No survivor required supplemental oxygen or had a DAH recurrence. CONCLUSIONS: SLE should be in the hospitalist's differential diagnosis for any child with respiratory insufficiency, cytopenias, and/or urinary abnormalities. Once cSLE is identified, initiation of aggressive immune suppression with multiple agents may enhance outcomes.