The clinical characteristics of children with Behçet's disease like trisomy 8 (T8-BD) diagnosed and treated in multi-centers were summarized, so as to improve the understanding and treatment ability of clinicians.

Clinical data of children with T8-BD who were hospitalized in the First Hospital of Jilin University, Children's Hospital of Fudan University and Peking Union Medical College Hospital from January 2016 to June 2022 were retrospectively collected, and then based on the literature, to summarize their general data, symptoms and signs, auxiliary examination results, and treatment and prognosis.

A total of 6 children with T8-BD hospitalized in the First Hospital of Jilin University, Children's Hospital of Fudan University and Peking Union Medical College Hospital and 13 children with T8-BD recorded in 10 literature reports were included. Among the 19 children with T8-BD, there were 4 males (21.1%) and 15 females (78.9%). The median age of onset was 8 years (range: 0-16 years). The main clinical manifestations were oral ulcer (94.7%), vulvar ulcer (57.9%) and fever (57.9%, including 4 cases with periodic fever-like manifestations). There were 14 cases (73.7%) of malignant hematologic diseases, 9 cases (47.4%) of digestive tract lesions, 7 cases (36.8%) of skin lesions, and 1 case (5.3%) of cerebrospinal fluid pressure elevation. There were 7 cases (36.8%) of abnormal development, including 5 cases of developmental delay, 3 cases of deep folds, 3 cases of joint deformity, 1 case of special facial appearance, 1 case of intellectual impairment, and 1 case of agenesis of corpus callosum. Auxiliary examination showed hemocytopenia in 11 cases (57.9%); C-reactive protein increase in 11 cases (57.9%), and erythrocyte sedimentation rate increase in 9 cases (47.4%). In terms of treatment, 11 cases (57.9%) were treated with glucocorticoid, 9 cases (47.4%) with traditional immunosuppressant, 6 cases (31.6%) with biological agents, 6 cases (31.6%) with hematopoietic stem cell transplantation and 3 cases (15.8%) with chemical agents. In terms of prognosis, 4 cases (21.1%) died, all of which were complicated with hematologic malignancies.

The common clinical symptoms of T8-BD are oral ulcers, vulvar ulcers and fever, which can be combined with digestive tract lesions, skin lesions, hematologic malignancies and developmental abnormalities. However, some children are accompanied by other atypical manifestations at the onset of the disease, to which clinicians should pay attention to identify. Overall, the prognosis of children with T8-BD is reasonable, but patients with hematologic malignancies have poor response to immunosuppressive therapy and increased risk of death.

To investigate the clinical features and treatment outcomes of chronic non-bacterial osteomyelitis (CNO) from five tertiary pediatric rheumatology services in China and provide possible treatment options for clinicians.

In this multicenter, retrospective study, pediatric patients diagnosed with CNO in Children's Hospital of Fudan University, Peking Union Medical College Hospital, Children's Hospital of Nanjing Medical University, Children's Hospital of Chongqing Medical University and the First Hospital of Jilin University from March 2014 to August 2022 were included. According to the treatment plan, the patients were divided into nonsteroidal anti-inflammatory drugs (NSAID) group, traditional disease modifying anti-rheumatic drugs (DMARD) group, tumor necrosis factor inhibitor (TNF-i) group, bisphosphonate group, and bisphosphonate+TNF-i group, and physician global assessment score was used to evaluate the efficacy.

Retrospective data analysis showed that the disease was more common in boy sthan girls(31 vs. 27), and the average age at onset of symptoms was 8.5±3.4 years, the mean age of diagnosis was 9.8±3.2 years, and the Median follow-up was 10.9(5.0, 30.1) months. A total of 46 cases (79.3%) were diagnosed in the last 3 years. Bone pain and / or arthralgia was the predominant symptom in 54(93.1%) patients followed by fever in 31(53.4%) patients. Raised inflammatory markers (ESR and CRP) were present in 87.9% and 77.6% of the patients. The most frequently affected bones were lower limb bones, including 42 cases of femur and 41 cases of tibia; 3 patients had compression fractures of the vertebrae at the time of diagnosis. Bone biopsy was conducted in 33 cases, and subacute or chronic osteomyelitis manifested with inflammatory cells infiltration were detected. The remission rate was not statistically different between treatment groups (P=0.562), with the remission rate at 11 months in the bisphosphonate+TNF-i group being 60.0%, 55.6% and 33.3% in the NSAID and DMARD groups respectively; 66.7% and 52.4% in the NSAID and TNF-i groups respectively at 12 months. A total of 40 patients were followed up for ≥6 months, with the remission rate of 81.3%.

Our multicenter study describes the features and outcomes of CNO patients in China. The characteristics of CNO children from multiple centers in China were lack of specificity. Bone pain and/or arthralgia were the main clinical symptoms, accompanied by fever, normal white blood cells, and raised inflammatory markers (CRP and/or ESR). Although anti-inflammatory treatment regimens were different, the efficacy of the treatment groups was similar. Anti-inflammatory therapy is currently the first choice.

To analyze the clinical and immunological characteristics of the first case of FOXN1 haploinsufficiency in China and summarize the clinical characteristics of previous reported cases in other countries.

The whole-exome sequencing(WES) and Sanger sequencing were conducted to verify the mutation of FOXN1.The T cell receptor rearrangement excision circles(TRECs)and κ-deleting recombination excision circles(κRECs)copies, peripheral blood lymphocyte subsets and T cell receptor (TCR) Vβ repertoire were further detected。A literature search was conducted using PubMed, Wangfang Med Online and CNKI with search terms "FOXN1 deficiency" and "FOXN1 haploinsufficiency".

A 1-year-old girl manifested with recurrent autoimmune hemolytic anemia, hair loss and nail dystrophy. Genetic mutation of FOXN1 (c.1392_1401delTCCTGGACCC, p.P465Rfs*82) was confirmed by WES and Sanger sequencing. The TRECs were 0.35 copies/μL, κRECs were normal. The TCR Vβ repertoire in this patient was markedly oligoclonal. Lymphocytes subsets revealed a predominate decrease of CD4⁺ T cell and Naïve CD4⁺ T, and an increase of effector memory helper T cells. A total of 5 publications were included (5 English and 0 Chinese). Thus far, 41 cases have been reported worldwide who mostly manifested with the decrease of T cells in early childhood.

FOXN1 haploinsufficiency deficiency is a kind of combined immunodeficiency disease, which is mainly manifested by the decrease of T cells and repeated infection in infants and young children, and may also be accompanied by hair loss, nail dystrophy and autoimmune disease, which cannot be cured by hematopoietic stem cell transplantation.