Increased radiosensitivity and impaired DNA repair in patients with STAT3-LOF and ZNF341 deficiency, potentially contributing to malignant transformations.

STAT3 plays an important role in various complex and sometimes contradictory pathways such as proliferation, differentiation, migration, inflammation, and apoptosis. The transcriptional activity of the STAT3 gene is controlled by a transcription factor called ZNF341. There is insufficient data on radiation sensitivity and post-radiation DNA repair in STAT3- loss-of-function (LOF) patients. We aimed to investigate the radiosensitivity in patients with STAT3-LOF and ZNF341 deficiency. Twelve patients with STAT3-LOF and four ZNF341-deficiency patients were recruited from three clinical immunology centers in Turkey and evaluated for radiosensitivity by the Comet assay, comparing to 14 age- and sex-matched healthy controls. The tail length (TL) (µm), percentage of DNA in the tail (TDNA%), and olive tail moment (OTM) (arbitrary units) were evaluated at the same time for baseline (spontaneous), initial (immediately after 2 Gy irradiation), and recovery (2 h after irradiation) periods by using a computerized image-analysis system, estimating DNA damage. Except for a patient with ZNF341 deficiency who developed nasal cell primitive neuroendocrine tumor and papillary thyroid cancer during the follow-up, there was no cancer in both groups. During the recovery period of irradiation, TL, TDNA%, and OTM values of healthy controls decreased rapidly toward the baseline, while these values of patients with STAT3-LOF and ZNF341 deficiency continued to increase, implying impaired DNA repair mechanisms. Increased radiosensitivity and impaired DNA repair were demonstrated in patients diagnosed with STAT3-LOF and ZNF341 deficiency, potentially explaining the susceptibility to malignant transformation.

Clinical features of children with chronic non-bacterial osteomyelitis: A multicenter retrospective case series from Turkey.

OBJECTIVES: This study aims to evaluate demographic, clinical, and radiological characteristics of Turkish children with chronic non-bacterial osteomyelitis. PATIENTS AND METHODS: Between January 2008 and December 2018, a total of 28 patients (10 males, 18 females; median age: 12.5 years; range, 4.5 to 21 years) who were diagnosed with chronic non-bacterial osteomyelitis in three pediatric rheumatology centers were retrospectively analyzed. The demographic, clinical, and laboratory findings of the patients were recorded. RESULTS: The median age at the time of diagnosis was 10.2 years. The median time from symptom onset to diagnosis was 6.5 months. The median follow-up was 18.5 months. The most frequent symptom at onset was arthralgia (75.0%). The most frequently involved bone was the femur (67.9%). Eight (63.6%) of 12 patients had at least one Mediterranean fever gene (MEFV) mutation, indicating a significantly higher prevalence than the Turkish population (14.8%). Five of these patients fulfilled the diagnostic criteria for familial Mediterranean fever (FMF). All patients received non-steroidal anti-inflammatory drugs. Other drugs were methotrexate (46.4%), sulfasalazine (39%), corticosteroids (25%), anti-tumor necrosis factor (anti-TNF) agents (32%), pamidronate (25%), and colchicine (21.4%). Six of eight patients with MEFV mutations were administered with colchicine, and all of them responded to treatment. CONCLUSION: Clinical evolution and imaging investigations should be carefully performed to prevent any delay in the diagnosis of patients with chronic non-bacterial osteomyelitis. Based on our study results, FMF coexistence is worth investigating in patients with chronic non-bacterial osteomyelitis, particularly in the Turkish population.

Unique and shared signaling pathways cooperate to regulate the differentiation of human CD4+ T cells into distinct effector subsets.

Naive CD4(+) T cells differentiate into specific effector subsets-Th1, Th2, Th17, and T follicular helper (Tfh)-that provide immunity against pathogen infection. The signaling pathways involved in generating these effector cells are partially known. However, the effects of mutations underlying human primary immunodeficiencies on these processes, and how they compromise specific immune responses, remain unresolved. By studying individuals with mutations in key signaling pathways, we identified nonredundant pathways regulating human CD4(+) T cell differentiation in vitro. IL12Rß1/TYK2 and IFN-γR/STAT1 function in a feed-forward loop to induce Th1 cells, whereas IL-21/IL-21R/STAT3 signaling is required for Th17, Tfh, and IL-10-secreting cells. IL12Rß1/TYK2 and NEMO are also required for Th17 induction. Strikingly, gain-of-function STAT1 mutations recapitulated the impact of dominant-negative STAT3 mutations on Tfh and Th17 cells, revealing a putative inhibitory effect of hypermorphic STAT1 over STAT3. These findings provide mechanistic insight into the requirements for human T cell effector function, and explain clinical manifestations of these immunodeficient conditions. Furthermore, they identify molecules that could be targeted to modulate CD4(+) T cell effector function in the settings of infection, vaccination, or immune dysregulation.