LACC1 deficiency leading to juvenile arthritis and anemia.

OBJECTIVE: Juvenile arthritis caused by loss-of-function LACC1 mutations is characterized by early onset of symmetric and chronic arthritis, associated with an elevation of inflammatory markers. We aimed to describe serum cytokine levels, explore the type I interferon pathway, and evaluate the efficacy of treatment in a patient presenting with polyarthritis and anemia caused by novel compound heterozygous variations in LACC1. METHODS: Clinical data of a patient with compound heterozygous variations in LACC1 was collected. Serum cytokine levels and IFN-stimulated cytokine genes were analyzed at diagnosis, at disease flare, and after treatment. Full-length cDNA of LACC1 was checked by RNA analysis. Single-cell RNA sequencing was performed in PBMCs. RESULTS: Two novel variants in the LACC1 gene were identified in a patient presenting with polyarthritis and anemia. LACC1-cDNA was normally expressed in the healthy control, the target production at 1384 bp was not observed in the patient. Compared to nine patient controls with non-systemic juvenile idiopathic arthritis, serum interleukin(IL)-6 level was significantly elevated in the affected patient. The median IFN score for the patient, her mother, and controls were 118, 8, and 4.9, respectively. The combined treatment of JAK inhibitors with prednisone or tocilizumab led to a complete response, including remission of joint symptoms, resolution of anemia, reduced expression of IFN-stimulated cytokine genes, and normalized levels of inflammatory markers, including CRP, ESR, SAA, and serum IL-6. CONCLUSION: LACC1 may play a crucial role in multiple inflammatory signaling pathways. The combination therapy of JAK inhibitors and tocilizumab may be effective for a subset of refractory patients.

Homozygous IL37 mutation associated with infantile inflammatory bowel disease.

Interleukin (IL)-37, an antiinflammatory IL-1 family cytokine, is a key suppressor of innate immunity. IL-37 signaling requires the heterodimeric IL-18R1 and IL-1R8 receptor, which is abundantly expressed in the gastrointestinal tract. Here we report a 4-mo-old male from a consanguineous family with a homozygous loss-of-function IL37 mutation. The patient presented with persistent diarrhea and was found to have infantile inflammatory bowel disease (I-IBD). Patient cells showed increased intracellular IL-37 expression and increased proinflammatory cytokine production. In cell lines, mutant IL-37 was not stably expressed or properly secreted and was thus unable to functionally suppress proinflammatory cytokine expression. Furthermore, induced pluripotent stem cell-derived macrophages from the patient revealed an activated macrophage phenotype, which is more prone to lipopolysaccharide and IL-1ß stimulation, resulting in hyperinflammatory tumor necrosis factor production. Insights from this patient will not only shed light on monogenic contributions of I-IBD but may also reveal the significance of the IL-18 and IL-37 axis in colonic homeostasis.

Novel mutations of TYK2 leading to divergent clinical phenotypes.

BACKGROUND: TYK2 deficiency is a rare primary immunodeficiency disease caused by loss-of-function mutations of TYK2 gene, which is initially proposed as a subset of hyper-IgE syndrome (HIES). However, accumulating evidence suggests TYK2-deficient patients do not necessarily present with HIES characteristics, indicating a vacuum of knowledge on the exact roles of TYK2 in human immune system. METHOD: Pathogenic effects of patients were confirmed by qRT-PCR, Western blot, and protein stability assays. The responses to cytokines including IFN-α/ß/γ, IL-6, IL-10, IL-12, and IL-23 of peripheral blood mononuclear cells (PBMCs) from these patients were detected by Western blot, qRT-PCR, and flow cytometry. The differentiation of T and B cells was detected by flow cytometry. RESULTS: We described five more TYK2-deficient cases presenting with or without hyper-IgE levels, atopy, and distinct pathogen infection profile, which are caused by novel TYK2 mutations. These mutations were all found by high-throughput sequencing and confirmed by Sanger sequencing. The patients showed heterogeneous responses to various cytokine treatments, including IFN-α/ß/γ, IL-6, IL-10, IL-12, and IL-23. The homeostasis of lymphocytes is also disrupted. CONCLUSION: Based on our findings, we propose that TYK2 works as a multi-tasker in orchestrating various cytokine signaling pathways, differentially combined defects which account for the expressed clinical manifestations.

Talaromyces marneffei Infections in 8 Chinese Children with Inborn Errors of Immunity.

PURPOSE: Talaromyces marneffei (TM) is an opportunistic fungus leading to multi-organ damages and poor prognosis in immunocompromised individuals. TM infections in children are rare and our knowledge to TM infection is insufficient. To investigate the clinical characteristics of TM-infected children and to explore the underlying mechanisms for host against TM, we analysed TM-infected patients diagnosed in our hospital. METHODS: Eight patients with TM infections have been identified in Shenzhen Children's Hospital during 2017-2021. Clinical data were collected from medical records. Immunological features were evaluated by flow cytometry. Literatures were also reviewed to summarize the reported inborn errors of immunity (IEIs) with TM infections. RESULTS: All 8 children were HIV-negative. The most common symptom of TM infections was fever (8/8), followed by weight loss (7/8), pneumonia (7/8), hepatomegaly (7/8), splenomegaly (6/8), anemia (6/8), lymphadenopathy (5/8), thrombocytopenia (3/8), diarrhea (3/8), rashes or skin lesions (3/8), and osteolytic lesions (1/8). Five children died during the follow-ups. CD3+ T cells were decreased in 6 patients. Eight patients had reduced natural killer cells. All patients went gene sequencing and were finally diagnosed as IEIs, including STAT1 gain-of-function, IL-2 receptor common gamma chain deficiency, adenosine deaminase deficiency, CD40 ligand deficiency, and STAT3 deficiency. Another 4 types of IEIs (CARD9, IFN-γ receptor 1, RelB, and NFKB2 deficiency), have been reported with TM infections based on literature review. CONCLUSION: TM infections resulted in systemic injuries and high mortality. The spectrum of IEIs underlying TM infections indicated that T cell-mediated immunity, IFN-γ, IL-17 signalings and NF-κB pathways were important for host responses against TM infection. In reverse, for HIV-negative children without other secondary immunodeficiencies, IEIs should be considered in TM-infected children.

An Update on XMEN Disease.

"X-linked immunodeficiency with magnesium defect, Epstein-Barr virus (EBV) infection, and neoplasia" (XMEN) disease is an inborn error of glycosylation and immunity caused by loss of function mutations in the magnesium transporter 1 (MAGT1) gene. It is a multisystem disease that strongly affects certain immune cells. MAGT1 is now confirmed as a non-catalytic subunit of the oligosaccharyltransferase complex and facilitates Asparagine (N)-linked glycosylation of specific substrates, making XMEN a congenital disorder of glycosylation manifesting as a combined immune deficiency. The clinical disease has variable expressivity, and impaired glycosylation of key MAGT1-dependent glycoproteins in addition to Mg2+ abnormalities can explain some of the immune manifestations. NKG2D, an activating receptor critical for cytotoxic function against EBV, is poorly glycosylated and invariably decreased on CD8+ T cells and natural killer (NK) cells from XMEN patients. It is the best biomarker of the disease. The characterization of EBV-naïve XMEN patients has clarified features of the genetic disease that were previously attributed to EBV infection. Extra-immune manifestations, including hepatic and neurological abnormalities, have recently been reported. EBV-associated lymphomas remain the main cause of severe morbidity. Unfortunately, treatment options to address the underlying mechanism of disease remain limited and Mg2+ supplementation has not proven successful. Here, we review the expanding clinical phenotype and recent advances in glycobiology that have increased our understanding of XMEN disease. We also propose updating XMEN to "X-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect" in light of these novel findings.

Haploinsufficiency of A20 Due to Novel Mutations in TNFAIP3.

Haploinsufficiency of A20 (HA20) is a newly described immune dysregulation disease due to the loss-of-function mutation in TNFAIP3. In the present study, we report six patients from four unrelated Chinese families with distinct pathogenic mutations in TNFAIP3, including three novel variants. All of the patients presented with early-onset autoimmune/auto-inflammatory diseases, including Crohn's disease, Behcet's disease, systemic lupus erythematosus, and unclassified auto-inflammatory syndrome. Immunological phenotype tests showed elevated levels of serum pro-inflammatory cytokines, reduced naïve B cells and TFH cells, an inverted CD4:CD8 ratio, and increased susceptibility to restimulation-induced cell death (RICD) and FASL-induced apoptosis in derived T cells. Insufficient expression of A20 was found in these patients. A20 truncated protein was detected in mutant-transfected 293T cells. Upon TNF-α stimulation, the NF-κB pathway was over-activated in both derived T cells of these patients and mutant-transfected Hela cells. In conclusion, clinical manifestations are diverse in patients with HA20, even in those with the same TNFAIP3 mutation. A20 inhibits the NF-κB pathway and plays a crucial role in the regulation of cell death. Haploinsufficiency of A20 leads to defects in both innate and adaptive immunity.

Identification of a novel de novo gain-of-function mutation of PIK3CD in a patient with activated phosphoinositide 3-kinase δ syndrome.

Activated phosphoinositide 3-kinase δ (PI3Kδ) syndrome is a newly defined and relatively common primary immunodeficiency, which is caused by heterozygous gain-of-function (GOF) mutations in PIK3CD or PIK3R1. Here, we report a novel de novo GOF mutation (c.1570 T > A, p.Y524N) in PIK3CD in a 6-year-old Chinese girl. The patient suffered recurrent sinopulmonary infection, bronchiectasis, lymphoproliferation, herpesvirus infection, and distinctive nodular lymphoid hyperplasia of mucosal surfaces. Immunological analysis revealed increased CD4+ T cell senescence and B cell immaturity. Further analysis revealed an increase in almost all CD4+ T cell subsets to varying degrees, including effector T cells and Treg cells. Increased levels of plasma T cell-related cytokines corroborated these results. Hyperactivation of the PI3Kδ-Akt-mTOR signaling pathway was also confirmed. Treatment with rapamycin ameliorated the lymphoproliferative immunodeficiency caused by hyperactivation of mTOR. These results expand genetic spectrum of APDS and will facilitate further study of the genotype-phenotype correlation in those with PIK3CD mutations.

Targeted next-generation sequencing for genetic diagnosis of 160 patients with primary immunodeficiency in south China.

BACKGROUND: Primary immunodeficiency disorders (PID) is a group of heterogeneous diseases mainly characterized by severe and recurrent infections and an increased susceptibility to lymphoproliferative, atopic, and autoimmune conditions. The clinical diagnosis should preferably be complemented by a genetic diagnosis. To date, PID-related reports from China seldom attempt to make a genetic test for their patients. METHODS: Our study aimed to evaluate demographic data, clinical manifestations, and molecular diagnosis of PID patients from southern China. Moreover, by comparison with previous reports, we provide a picture of the current status of PID in mainland China. A total number of 160 pediatric PID patients (106 males and 54 females) were enrolled, and targeted next-generation sequencing was conducted using 269 PID-related genes and subsequently confirmed by Sanger sequencing and familial segregation analysis. RESULT: The autoinflammatory disease group was the most common subcategory of PID (20%), followed by immune dysregulation (17.5%) and combined immunodeficiencies (16.2%). Antibody deficiency disorders were identified in only 11.9% of the cohort. The putative causative gene was identified in 70 patients (43.8%), and an X-linked pattern was found in 45.7% of the genetically diagnosed patients. CONCLUSION: The current study provides the first collective study of PID phenotypes and genotypes in south China and provides a strong argument for the diagnostic application of targeted next-generation sequencing panels in patients with suspected PID.

[Clinical features and genetic analysis of a child with mosaic variegated aneuploidy syndrome].

OBJECTIVE: To explore the clinical phenotype, genetic variant, treatment and prognosis of a child with mosaic variegated aneuploidy syndrome (MVAS). METHODS: Immunological marker screening, chromosomal karyotyping and whole exome sequencing were carried out. RESULTS: The 1-year-11-month old girl has featured severe growth retardation, feeding difficulty, short stature, microcephaly, facial anomalies, scoliosis, visual impairment, hypotonia, chylothorax, and renal lesions. Karyotype analysis of peripheral blood lymphocytes has discovered variegated aneuploidy cells (6/11). DNA sequencing has identified compound heterozygous c.826delG (p.Asp276Metfs*21) and c.2441G>A (p.Arg814His) variants in the BUB1B gene, which were inherited from her father and mother, respectively. CONCLUSION: The compound heterozygous variants of the BUB1B gene probably underlie the pathogenesis in this patient.

[Clinical features and mutational analysis of a case with Sensenbrenner syndrome].

OBJECTIVE: To explore the clinical characteristics of a patient with Sensenbrenner syndrome (also called cranioectodermal dysplasia type 3) caused by mutation of intraflagellar transport (IFT) 43 gene. METHODS: The clinical data of the patient was retrospectively analyzed. The target genes was the patient were captured and subjected to next generation sequencing. Suspected mutations were verified through Sanger sequencing. RESULTS: The patient, a-13 year-and-5-month-old girl, was admitted for anemia and renal dysfunction for 8 months. Clinically, she has featured short stature, short limbs, brachydactylia, tooth agenesis, and retinal dystrophy, high-degree myopia, and chronic renal failure. Gene sequencing showed that she has carried a homozygous c.1A>G (p.M1V) mutation of the IFT43 gene, for which both of her parents were heterozygous carriers. CONCLUSION: c.1A>G (p.M1V) mutation of the C14ORF179/IFT43 gene is the cause for praecox chronic renal failure in children. Genetic testing can facilitate the diagnosis of this rare disorder. For affected families, prenatal diagnosis should be provided.

Canakinumab in the treatment of systemic juvenile idiopathic arthritis: a retrospective single center study in China.

Objective: Systemic juvenile idiopathic arthritis (sJIA) is characterized by excessive production of proinflammatory cytokines. As an anti-IL-1 agent, canakinumab has been approved in the USA and Europe for the treatment of sJIA patients aged ≥2 years. However, the use of canakinumab has never been reported in China. In this study, we aimed to assess the efficacy and safety of canakinumab in Chinese patients with sJIA. Methods: A total of 11 patients with sJIA who were treated with canakinumab were included in this study. Clinical data were collected retrospectively from medical records. Efficacy was evaluated by the systemic juvenile arthritis disease activity score (sJADAS). The follow-up was performed at canakinumab initiation, at months 1, 3, 6, 9 and 12, or at the last follow-up. Results: Of the 11 patients enrolled, 91.0% (10/11) had previously received treatment with tocilizumab. The mean duration of canakinumab was 9 (3-18) months. 45.5% (5/11) of patients showed complete response, 45.5% (5/11) showed partial response, and 9.0% (1/11) showed no response. 18.2% (2/11) experienced disease flare during the treatment with canakinumab. 81.8% (9/11) of patients successfully reduced the dose of corticosteroids, with six discontinuing corticosteroids. 45.6% (5/11) of patients experienced infection. No serious adverse events occurred during the treatment with canakinumab. Conclusions: Canakinumab may be effective and tolerable for Chinese sJIA patients, helping to reduce the dosage of corticosteroids. However, additional researches on large samples are required to evaluate its efficacy and safety.

Effectiveness and safety of canakinumab in cryopyrin-associated periodic syndrome: a retrospective study in China.

OBJECTIVE: Cryopyrin-associated periodic syndrome (CAPS) is characterized by excessive IL-1ß release resulting in systemic and organ inflammation. As an anti-IL-1 agent, canakinumab has been approved with all CAPS phenotypes in USA and European countries. However, the use of canakinumab in CAPS in Chinese patients was rarely reported. In this study, we aimed to assess the effectiveness and safety of canakinumab in Chinese patients with CAPS. METHODS: Patients with CAPS treated with canakinumab were included. Clinical data were collected retrospectively from medical records. Treatment response was evaluated by CAPS disease activity score, C-reactive protein (CRP), and/or serum amyloid A (SAA) levels. Data was analyzed at canakinumab initiation, at months 1, 3, 6, 9, and 12, or the last follow-up. RESULTS: A total of 10 CAPS patients were included. 40% of patients were males, the median age at disease onset was 2.5 (2.5, 6) days and the median duration of follow-up while on canakinumab was 22.5 (8.5, 27.5) months. 80% (8/10) of CAPS patients presented with moderate-severe disease activity before the canakinumab treatment. 30% (3/10) of patients required canakinumab dose increase to control disease activity. After treatments, 60% (6/10) of CAPS patients achieved complete remission without relapse and the rest showed minimal disease activity. Clinical symptoms such as fever and rash were improved significantly in most patients (80%). Although abnormal imaging in brain MRI remained in over half of those patients, neurological manifestations were all relieved. 60% (6/10) of patients received prednisone before starting canakinumab therapy and five of them discontinued prednisone later. The most common adverse event was infection (40%). No serious adverse events occurred during the treatment of canakinumab. CONCLUSIONS: Canakinumab may be effective and tolerable for Chinese CAPS patients, helping to reduce the dosage of corticosteroids. However, additional trials on large samples are required to further evaluate its efficacy and safety in China.

Characterization of a Novel Pathogenic PLCG2 Variant Leading to APLAID Syndrome Responsive to a TNF Inhibitor.

OBJECTIVE: Autoinflammation and phospholipase C (PLC) γ2-associated antibody deficiency and immune dysregulation (APLAID) syndrome is an autoinflammatory disease caused by gain-of-function variants in PLCG2. This study investigates the pathogenic mechanism of a novel variant of PLCG2 in a patient with APLAID syndrome. METHODS: Whole-exome sequencing and Sanger sequencing were used to identify the pathogenic variant in the patient. Single-cell RNA sequencing, immunoblotting, luciferase assay, inositol monophosphate enzyme-linked immunosorbent assay, calcium flux assay, quantitative PCR, and immunoprecipitation were used to define inflammatory signatures and evaluate the effects of the PLCG2 variant on protein functionality and immune signaling. RESULTS: We identified a novel de novo variant, PLCG2 p.D993Y, in a patient with colitis, pansinusitis, skin rash, edema, recurrent respiratory infections, B-cell deficiencies, and hypogammaglobulinemia. The single-cell transcriptome revealed exacerbated inflammatory responses in the patient's peripheral blood mononuclear cells. Expression of the D993Y variant in HEK293T, COS-7, and PLCG2 knock-out THP-1 cell lines showed heightened PLCγ2 phosphorylation; elevated inositol-1,4,5-trisphosphate production and intracellular Ca2+ release; and activation of the MAPK, NF-κB, and NFAT signaling pathways compared with control-transfected cells. In vitro experiments indicated that the D993Y variant altered amino acid properties, disrupting the interaction between the catalytic and autoinhibitory domains of PLCγ2, resulting in PLCγ2 autoactivation. CONCLUSION: Our findings demonstrated that the PLCG2 D993Y variant is a gain-of-function mutation via impairing its autoinhibition, activating multiple inflammatory signaling pathways, thus leading to APLAID syndrome. This study further broadens the molecular underpinnings and phenotypic spectrum of PLCγ2-related disorders.

Tocilizumab-induced hypofibrinogenemia in patients with systemic-onset juvenile idiopathic arthritis.

Systemic juvenile idiopathic arthritis (SJIA) is a chronic inflammatory disease of childhood with elevated serum IL-6 levels. As an inhibitor of IL-6R, tocilizumab (TCZ) has been approved to treat SJIA patients. TCZ-induced hypofibrinogenemia has been only reported in adult cases and limited small case series with rheumatoid arthritis or giant cell arteritis. Here, we describe the incidence of TCZ-induced hypofibrinogenemia in SJIA patients and its possible influence on bleeding risk. SJIA patients with TCZ treatment in Shenzhen Children's hospital were retrospectively reviewed. Only those with the data on serum fibrinogen levels were included. Data on clinical manifestations, laboratory parameters, management, and sJADAS10-ESR score were collected. Laboratory data were extracted following the start of TCZ therapy at 2, 4, 8, 12, and 24 weeks thereafter. Seventeen SJIA patients with TCZ treatment were included. Thirteen (76.47%, 13/17) had hypofibrinogenemia. The lowest serum fibrinogen levels were even below 1.5 g/L in seven (41.17%, 7/17) patients. Among four patients without MTX treatment, two had obvious hypofibrinogenemia. Although five patients had already stopped steroid treatment 24 weeks after TCZ treatment, three of them still had hypofibrinogenemia. Only P14 had mild nasal mucosal bleeding occasionally. Coagulation tests were regularly performed in eight patients, of these, six had hypofibrinogenemia, which occurred following one to four doses of TCZ; continuation of TCZ treatment hadn't further aggravated hypofibrinogenemia. Serum fibrinogen levels were not decreased consistently with the improvement of sJADAS10-ESR score in more than half of these eight patients. Factor XIII was detected in six patients and none was identified with Factor XIII deficiency. TCZ alone may induce hypofibrinogenemia in SJIA patients. Continuation of TCZ treatment may be safe for most SJIA patients. But for SJIA patients with indications of surgery or complicated with MAS, the risk of hemorrhage should be regularly evaluated during TCZ treatment. The association between TCZ-induced hypofibrinogenemia and factor XIII deficiency remains uncertain.Trial registration: Not applicable; this was a retrospective study.

JAK inhibitors in systemic juvenile idiopathic arthritis.

Objective: Systemic juvenile idiopathic arthritis (SJIA) is characterized by excessive and inappropriate production of proinflammatory cytokines. Janus kinase inhibitors (JAKi) can block the downstream pathway of many cytokines. The use of JAKi in SJIA or macrophage activation syndrome (MAS) has only been described in a limited number of case reports. In this study, we aimed to assess the efficacy and potential adverse effects of JAKi in SJIA patients. Methods: Patients with SJIA who received JAKi and underwent at least one assessment of efficacy and safety after JAKi initiation were eligible for this study. Data were collected retrospectively from inpatient or outpatient medical records at JAKi initiation, at 1, 3, 6, 9, and 12 months, after disease flare, after JAKi discontinuation, or at the last follow-up. Results: Ten patients with SJIA were included in the study. At the start of JAKi treatment, all patients presented with active disease; five showed variable adverse effects secondary to glucocorticoids. Seven patients received tofacitinib (one later switched to ruxolitinib). Of these, only two patients showed a complete response of persistent arthritis associated with tocilizumab; tofacitinib was used without a biological DMARD only in two patients, together with MTX, showing a partial response; three patients were nonresponders. Four patients with SJIA-related MAS or persistent hyperferritinemia were treated with ruxolitinib. Ruxolitinib allowed a good response on MAS parameters in three of them. All these four patients required an adjunction or switch to canakinumab later. The median decrease in the daily glucocorticoid dose between JAKi initiation and the last follow-up was 90.6% in patients with complete remission and 77.4% in other patients. Three patients discontinued glucocorticoid treatment after the introduction of JAKi. Severe adverse events, notably serious infection or thrombosis, were not observed during JAKi treatment. Conclusion: JAKi may be an alternative or adjuvant agent for SJIA patients, especially in those with persistently active disease, glucocorticoid-related adverse reactions, or SJIA-MAS.

Elevated serum IFN-γand IFN-γ/IL-6 ratio in Kikuchi-Fujimoto disease.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is typically a benign, self-limiting inflammatory disease. The diagnosis of KFD can be challenging for nonspecific symptoms, laboratory or imaging findings. In this study, we aimed to describe the clinical manifestations of patients with KFD and to access the potential role of serum cytokines in the diagnosis of this disease. METHODS: Patients with KFD were retrospectively enrolled from January 2015 to November 2021 at Shenzhen Children's Hospital. Clinical data were collected from inpatient or outpatient medical records. Serum cytokines were detected by the Flowcytomix technique. Serum levels of cytokines were compared between patients with KFD and SJIA, or patients with KFD and KD. The data of patients without MAS were further analyzed. A receiver operating characteristic (ROC) curve analysis was further performed to access the potential role of serum cytokines in the diagnosis of KFD. RESULTS: Serum cytokines were detected in 25 (43.8%, 25/57) patients with a histological diagnosis of KFD. Compared to SJIA or KD patients, the KFD group had a significantly higher IFN-γ/IL-6 ratio and much lower levels of serum IL-6. The median level of serum IFN-γ in KFD was 41.65 pg/ml (range, 21.04-70.74 pg/ml), which was much higher than that in SJIA (median: 3.33 pg/ml, p = 0.16) or KD (median: 2.6 pg/ml, p = 0.01). After excluding patients with MAS, there was statistical significance in all comparisons of serum IFN-γ, IFN-γ/IL-6 ratio, and serum IL-6. The cutoff values of serum IFN-γ, IL-6, and IFN-γ/IL-6 ratio for differentiating KFD from SJIA were > 8.48 pg/ml, < 47.42 pg/ml, and > 0.45, respectively. The cutoff values of serum IFN-γ, IL-6, and IFN-γ/IL-6 ratio for differentiating KFD from KD were > 8.56 pg/ml, < 50.45 pg/ml, and > 0.45, respectively. The specificity of all those cutoff values for differentiating KFD from SJIA or KD was ≥ 94.7%. CONCLUSIONS: For patients with fever of unknown etiology and lymphadenopathy, after excluding HLH or MAS, serum IFN-γ > 8.56 pg/mL and IFN-γ/IL-6 ratio > 0.45 may highly suggest the diagnosis of KFD; serum IL-6 > 50.45 pg/mL indicates that the probability of KFD may be small, and sJIA, KD, and acute infection should be excluded first.

Macrophage activation syndrome in children with Kikuchi-Fujimoto disease.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is typically a benign, self-limiting inflammatory disease. However, some patients may have a prolonged or recurrent disease course, or present with life-threatening complications such as macrophage activation syndrome (MAS). In this study, we aimed to describe the incidence and clinical features of MAS in KFD and to access potential laboratory markers for the diagnosis of KFD-associated MAS. METHODS: Patients with KFD were retrospectively enrolled from January 2015 to November 2021 at Shenzhen Children's Hospital. Clinical data were collected from inpatient or outpatient medical records. Data collected included clinical manifestations, laboratory and imaging findings, treatment, and clinical outcomes. Data were analyzed using GraphPad Prism 8.0 statistical software (GraphPad Software Inc., La Jolla, CA, USA). A receiver operating characteristic (ROC) curve analysis was further performed to access the potential predictors for the KFD-MAS diagnosis. RESULTS: Of 58 patients with a histological diagnosis of KFD, 15 (25.9%) patients had MAS. Compared to patients without MAS, patients with KFD-MAS presented with a higher proportion of skin rash (26.7%, p = 0.01), glucocorticoid treatment (80%, p = 0.003), and disease recurrence (33.3%, p = 0.04). KFD-MAS patients had lower absolute peripheral white blood cell (WBC, p = 0.02), platelet (p = 0.002), serum albumin levels (p = 0.01), and lymphocyte count (p < 0.0001), and higher lactate dehydrogenase (LDH) levels (p < 0.0001). ROC curve analysis showed that the cutoff values of absolute lymphocyte count, an absolute platelet count, serum albumin level, and serum LDH level for KFD-MAS diagnosis were < 1235/µL, < 171 × 106/µL, < 35.6 g/L, and > 679 IU/mL, respectively. CONCLUSIONS: The presence of KFD-MAS in children may be more common than previously expected, especially in those with skin rash. KFD-MAS may be associated with a higher recurrence rate. An extremely elevated serum LDH level and moderate to severe lymphopenia may be useful diagnostic markers for MAS in KFD. TRIAL REGISTRATION: Not applicable; this was a retrospective study.

Analysis of clinical characteristics of children with Aicardi-Goutieres syndrome in China.

BACKGROUND: Aicardi-Goutieres syndrome (AGS) is an inflammatory disorder belonging to the type I interferonopathy group. The clinical diagnosis of AGS is difficult, which can lead to a high mortality rate. Overall, there is a lack of large-sample research data on AGS in China. We aim to summarize the clinical characteristics of Chinese patients with AGS and provide clues for clinical diagnostic. METHODS: The genetic and clinical features of Chinese patients with AGS were collected. Real-time polymerase chain reaction was used to detect expression of interferon-stimulated genes (ISGs). RESULTS: A total of 23 cases were included, consisting of 7 cases of AGS1 with three prime repair exonuclease 1 mutations, 3 of AGS2 with ribonuclease H2 subunit B (RNASEH2B) mutations, 3 of ASG3 with RNASEH2C, 1 of AGS4 with RNASEH2A mutations, 2 of AGS6 with adenosine deaminase acting on RNA 1 mutations, and 7 of AGS7 with interferon induced with helicase C domain 1 mutations. Onset before the age of 3 years occurred in 82.6%. Neurologic involvement was most common (100%), including signs of intracranial calcification which mainly distributed in the bilateral basal ganglia, leukodystrophy, dystonia, epilepsy, brain atrophy and dysphagia. Intellectual disability, language disability and motor skill impairment were also observed. Skin manifestations (60.87%) were dominated by a chilblain-like rash. Features such as microcephaly (47.62%), short stature (52.38%), liver dysfunction (42.11%), thyroid dysfunction (46.15%), positive autoimmune antibodies (66.67%), and elevated erythrocyte sedimentation rate (53.85%) were also found. The phenotypes of 2 cases fulfilled the diagnostic criteria for systemic lupus erythaematosus (SLE). One death was recorded. ISGs expression were elevated. CONCLUSIONS: AGS is a systemic disease that causes sequelae and mortality. A diagnosis of AGS should be considered for patients who have an early onset of chilblain-like rash, intracranial calcification, leukodystrophy, dystonia, developmental delay, positive autoimmune antibodies, and elevated ISGs, and for those diagnosed with SLE with atypical presentation who are nonresponsive to conventional treatments. Comprehensive assessment of vital organ function and symptomatic treatment are important.