Identification and Functional Analysis of the Pre-piRNA 3' Trimmer in Silkworms.

PIWI-interacting RNAs (piRNAs) play a crucial role in transposon silencing in animal germ cells. In piRNA biogenesis, single-stranded piRNA intermediates are loaded into PIWI-clade proteins and cleaved by Zucchini/MitoPLD, yielding precursor piRNAs (pre-piRNAs). Pre-piRNAs that are longer than the mature piRNA length are then trimmed at their 3' ends. Although recent studies implicated the Tudor domain protein Papi/Tdrkh in pre-piRNA trimming, the identity of Trimmer and its relationship with Papi/Tdrkh remain unknown. Here, we identified PNLDC1, an uncharacterized 3'-5' exonuclease, as Trimmer in silkworms. Trimmer is enriched in the mitochondrial fraction and binds to Papi/Tdrkh. Depletion of Trimmer and Papi/Tdrkh additively inhibits trimming, causing accumulation of ∼35-40-nt pre-piRNAs that are impaired for target cleavage and prone to degradation. Our results highlight the cooperative action of Trimmer and Papi/Tdrkh in piRNA maturation.

The tRNAVal half: A strong endogenous Toll-like receptor 7 ligand with a 5'-terminal universal sequence signature.

Toll-like receptors (TLRs) are crucial components of the innate immune system. Endosomal TLR7 recognizes single-stranded RNAs, yet its endogenous ssRNA ligands are not fully understood. We previously showed that extracellular (ex-) 5'-half molecules of tRNAHisGUG (the 5'-tRNAHisGUG half) in extracellular vesicles (EVs) of human macrophages activate TLR7 when delivered into endosomes of recipient macrophages. Here, we fully explored immunostimulatory ex-5'-tRNA half molecules and identified the 5'-tRNAValCAC/AAC half, the most abundant tRNA-derived RNA in macrophage EVs, as another 5'-tRNA half molecule with strong TLR7 activation capacity. Levels of the ex-5'-tRNAValCAC/AAC half were highly up-regulated in macrophage EVs upon exposure to lipopolysaccharide and in the plasma of patients infected with Mycobacterium tuberculosis. The 5'-tRNAValCAC/AAC half-mediated activation of TLR7 effectively eradicated bacteria infected in macrophages. Mutation analyses of the 5'-tRNAValCAC/AAC half identified the terminal GUUU sequence as a determinant for TLR7 activation. We confirmed that GUUU is the optimal ratio of guanosine and uridine for TLR7 activation; microRNAs or other RNAs with the terminal GUUU motif can indeed stimulate TLR7, establishing the motif as a universal signature for TLR7 activation. These results advance our understanding of endogenous ssRNA ligands of TLR7 and offer insights into diverse TLR7-involved pathologies and their therapeutic strategies.

Pregnancy outcomes in patients with familial Mediterranean fever: systematic review and meta-analysis.

OBJECTIVE: The relationship between FMF and pregnancy outcomes remains unclear. This systematic review and meta-analysis aimed to clarify this association. METHODS: Electronic databases-PubMed, Web of Science, Cochrane, and EMBASE-were searched on 20 December 2022, using specific search terms. Case-control, cohort, and randomized clinical trial studies comparing patients with FMF and healthy controls were considered eligible. We excluded systematic reviews, meta-analyses, case series with fewer than five cases, republished articles without new findings on pregnancy outcomes, studies targeting paternal FMF, and those not published in English. The results were summarized in the form of odds ratios (ORs) and 95% CIs, using a random-effects model. This study was registered in the University hospital Medical Information Network Clinical Trials Registry (Japan) as UMIN000049827. RESULTS: The initial electronic search identified 611 records, of which 9 were included in this meta-analysis (177 735 pregnancies, 1242 with FMF, and 176 493 healthy controls). FMF was significantly associated with increased odds of preterm deliveries (OR, 1.67; 95% CI, 1.05-2.67; I2 = 22%) and insignificantly associated with increased odds of fetal growth restriction (OR, 1.45; 95% CI, 0.90-2.34; I2 = 0%) and hypertensive disorders during pregnancy (OR, 1.28; 95% CI, 0.87-1.87; I2 = 0%). CONCLUSION: FMF was significantly associated with preterm delivery and insignificantly associated with fetal growth restriction and hypertensive disorders. All of the included studies were observational studies. Treatment characteristics were not fully collected from the articles, and further analysis of treatments for FMF in pregnancy is still warranted.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome presenting as recurrent aseptic peritonitis in a patient receiving peritoneal dialysis: a case report.

BACKGROUND: Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is caused by mutations in the ubiquitin-activating enzyme1 (UBA1) gene and characterised by an overlap between autoinflammatory and haematologic disorders. CASE PRESENTATION: We reported a case of a 67-year-Japanese man receiving peritoneal dialysis (PD) who had recurrent aseptic peritonitis caused by the VEXAS syndrome. He presented with unexplained fevers, headache, abdominal pain, conjunctival hyperaemia, ocular pain, auricular pain, arthralgia, and inflammatory skin lesions. Laboratory investigations showed high serum C-reactive protein concentration and increased cell count in PD effluent. He was treated with antibiotics for PD-related peritonitis, but this was unsuccessful. Fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography images demonstrated intense FDG uptake in his left superficial temporal artery, nasal septum, and bilateral auricles. The working diagnosis was giant cell arteritis, and he was treated with oral prednisolone (PSL) 15 mg daily with good response. However, he was unable to taper the dose to less than 10 mg daily because his symptoms flared up. Since Tocilizumab was initiated, he could taper PSL dose to 2 mg daily. Sanger sequencing of his peripheral blood sample showed a mutation of the UBA1 gene (c.122 T > C; p.Met41Thr). We made a final diagnosis of VEXAS syndrome. He suffered from flare of VEXAS syndrome at PSL of 1 mg daily with his cloudy PD effluent. PSL dose of 11 mg daily relieved the symptom within a few days. CONCLUSIONS: It is crucial to recognise aseptic peritonitis as one of the symptoms of VEXAS syndrome and pay attention to the systemic findings in the patients.

Cluster analysis defines four groups of Japanese patients with adult-onset Still's disease.

OBJECTIVES: To define groups and characterize differences in the prognosis of patients with adult-onset Still's disease (AOSD). METHODS: We performed a retrospective cohort study. Patients with AOSD were grouped using hierarchical unsupervised cluster analysis according to age, sex, clinical features, and laboratory data. The primary endpoints were overall survival and drug-free remission rate. RESULTS: A total of 153 patients with AOSD were placed into four clusters. Those in Cluster 1 had a young onset, tended to be female, and had fewer complications and moderate ferritin concentrations. Those in Cluster 2 had a young onset and had more complications and higher ferritin concentrations. Those in Cluster 3 had a young onset, tended to be male, and had no lymphadenopathy and fewer complications. Those in Cluster 4 had an older onset, tended to be female, and had more complications and higher ferritin concentrations. Overall survival tended to be lower (P = .0539) in Cluster 4, and drug-free remission was higher in Clusters 1, 2, and 3 [hazard ratios (HRs) 2.19, 3.37, and 3.62 vs. Cluster 4, respectively]. CONCLUSIONS: Four groups of AOSD that have distinct clinical manifestations, ferritin concentrations, severity, and drug-free remission rate were identified, which were lowest in Cluster 4. Graphical Abstract.

Immune checkpoint inhibitor-induced arthralgia is tightly associated with improved overall survival in cancer patients.

OBJECTIVES: With the increased use of immune checkpoint inhibitors (ICIs) in cancer patients, arthralgia has been the most commonly reported musculoskeletal immune-related adverse event (irAE). We aimed to characterize arthralgia and its association with overall survival (OS). MATERIAL AND METHODS: Randomized controlled trials (RCTs) reporting on data for ICI-induced arthralgia from four online databases were comprehensively investigated. Odds ratios (ORs) with 95% CIs were calculated for arthralgia using a random-effects model meta-analysis. Individual patient data were reconstructed from RCTs assessing OS in patients with or without ICI-induced arthralgia. We also retrospectively collected data on the clinical features and outcomes of ICI-induced arthralgia in the Yokohama City University (YCU) registry. RESULTS: We analysed 14 377 patients from 24 RCTs. The OR of ICI-induced arthralgia was 1.37 (95% CI 1.20, 1.56). Of the 369 patients in the YCU registry, 50 (13.6%) developed ICI-induced arthralgia. Among them, 30 had other grade ≥2 irAEs, which was noticeably more frequent than in those without arthralgia (OR 1.92, 95% CI 1.04, 3.52). By irAE types, a significant difference was found for relative adrenal insufficiency (OR 3.88, 95% CI 1.80, 8.39). In the YCU registry, patients with (vs without) ICI-induced arthralgia had better OS (log-rank, P < 0.001). OS results were validated from RCT patients with matched cancer types, drugs, and time to arthralgia onset (hazard ratio 0.34, 95% CI 0.17, 0.65, P < 0.001). CONCLUSIONS: If arthralgia develops after ICIs, another irAE, such as relative adrenal insufficiency, may have developed. The incidence of arthralgia was associated with better OS, and the condition of patients with irAEs must be carefully evaluated to determine optimal management.

Infection-induced 5'-half molecules of tRNAHisGUG activate Toll-like receptor 7.

Toll-like receptors (TLRs) play a crucial role in the innate immune response. Although endosomal TLR7 recognizes single-stranded RNAs, their endogenous RNA ligands have not been fully explored. Here, we report 5'-tRNA half molecules as abundant activators of TLR7. Mycobacterial infection and accompanying surface TLR activation up-regulate the expression of 5'-tRNA half molecules in human monocyte-derived macrophages (HMDMs). The abundant accumulation of 5'-tRNA halves also occur in HMDM-secreted extracellular vehicles (EVs); the abundance of EV-5'-tRNAHisGUG half molecules is >200-fold higher than that of the most abundant EV-microRNA (miRNA). Sequence identification of the 5'-tRNA halves using cP-RNA-seq revealed abundant and selective packaging of specific 5'-tRNA half species into EVs. The EV-5'-tRNAHisGUG half was experimentally demonstrated to be delivered into endosomes in recipient cells and to activate endosomal TLR7. Up-regulation of the 5'-tRNA half molecules was also observed in the plasma of patients infected with Mycobacterium tuberculosis. These results unveil a novel tRNA-engaged pathway in the innate immune response and assign the role of "immune activators" to 5'-tRNA half molecules.

In vitro production and multiplex quantification of 2',3'-cyclic phosphate-containing 5'-tRNA half molecules.

RNA cleavages by many ribonucleases generate RNA molecules that contain a 2',3'-cyclic phosphate (cP) at their 3'-termini, and many cP-containing RNAs (cP-RNAs) are expressed as functional molecules in cells and tissues. 5'-tRNA half molecules are representative examples of functional cP-RNAs, playing important roles in various biological processes. We here show in vitro production of cP-containing 5'-tRNA half molecules that is able to prepare abundant synthetic cP-RNAs enough for functional analyses. Furthermore, we report a multiplex TaqMan RT-qPCR method which can simultaneously quantify multiple cP-containing 5'-tRNA half species. The method enabled us to efficiently quantify 5'-tRNA halves using samples with limited amounts, such as human plasma samples, revealing drastic enhancement of 5'-tRNA half levels at approximately 1,000-fold in patients infected with Mycobacterium tuberculosis. These in vitro production and multiplex quantification methods can be applied to any cP-RNAs, and they provide cost-effective, in-house techniques to accelerate expressional and functional characterizations of 5'-tRNA halves and other cP-RNAs.

Cryptococcal meningitis with atypical paradoxical inflammatory reactions after antifungal treatment in acquired immune deficiency syndrome: A case report.

Cryptococcal meningitis (CM) is a life-threatening disease that primarily affects patients with human immunodeficiency virus (HIV). Antifungal therapy with antiretroviral treatment (ART) usually leads to the clinical remission of CM; however, in some cases, these treatments exacerbate intracranial inflammation because of paradoxical inflammatory reaction or immune reconstitution inflammatory syndrome (IRIS). Here we report two CM cases that presented atypical clinical courses attributed to paradoxical inflammatory reactions. The first case was a 43-year-old man with headache and vertigo diagnosed with CM and HIV. The patient's CM not only was refractory to the antifungal combination therapy of liposomal amphotericin B (L-AMB) and fluconazole (FLCZ) but suddenly worsened because of a paradoxical inflammatory reaction after 18 days of treatment. He passed away from brain herniation on day 23. The second case was a 43-year-old man diagnosed with CM and HIV. After receiving antifungal therapy and ART, the patient's status was stable for more than 3 years with undetectable HIV-RNA. He suddenly presented with brain inflammation and was diagnosed with IRIS due to CM (CM-IRIS). His brain lesions were migratory and refractory to various antifungal therapies such as L-AMB, FLCZ, flucytosine, and intrathecal amphotericin B. Although the cryptococcal antigen in the patient's cerebrospinal fluid gradually diminished after continuous antifungal therapies, his cognitive function declined, and right hemiparesis persisted. These two cases of CM presented atypical clinical courses, presumably because of paradoxical inflammatory reactions. It should be noted that the onset of CM-IRIS may not necessarily depend on the timing of ART initiation.

Benefits and risks of haematopoietic stem cell transplantation for systemic sclerosis: A systematic review and meta-analysis.

OBJECTIVES: We aimed to evaluate the efficacy and safety of haematopoietic stem cell transplantation (HSCT) in patients with systemic sclerosis. METHODS: A systematic literature review and meta-analysis were carried out. We compared survival outcomes using the Kaplan-Meier method with patient-level data between HSCT and intravenous pulse cyclophosphamide. Additionally, the incidence rate of treatment-related deaths with HSCT was pooled using a random-effect model. RESULTS: Of the 2091 articles screened, 22 were included: 3 randomized controlled trials and 19 observational studies. HSCT studies showed significant improvement in the skin thickness score and lung function. Despite treatment-related deaths being higher in HSCT than in intravenous pulse cyclophosphamide, the Kaplan-Meier analysis showed a high survival rate of 2 years post-transplant (log-rank, P = 0.004). The pooled frequency of transplant-related death from 700 systemic sclerosis patients was 6.30% (95% confidence interval 4.21-8.38). However, the estimated frequency of treatment-related deaths has been reducing over the last decade. CONCLUSIONS: HSCT is an effective treatment for systemic sclerosis, but the optimal indications must be carefully determined by balancing the risks.

Recommendations for the management of the vascular involvement in Behçet's disease by the Japanese National Research Committee for Behçet's disease-secondary publication.

OBJECTIVES: This study aimed to develop clinical guidelines for the management of vascular Behçet's disease (BD) by the Behçet's Disease Research Committee of the Ministry of Health, Labour and Welfare of the Japanese Government. METHODS: A task force proposed clinical questions (CQs) concerning vascular BD based on a literature search. After screening, draft recommendations were developed for each CQ and brushed up in three blinded Delphi rounds, leading to the final recommendations. RESULTS: This study provides recommendations for 17 CQs concerning diagnosis and differential diagnoses, assessment of disease activity, and treatment. The guidelines recommend immunosuppressive treatments, for both arterial and venous involvement with active inflammation. Anticoagulation is also recommended for deep vein thrombosis except in high-risk patients. Surgical and endovascular therapies can be optional, particularly in patients with urgent arterial lesions undergoing immunosuppression. In addition, two sets of algorithms for diagnosis and treatment are shown for arterial and venous involvement. CONCLUSIONS: These recommendations are expected to serve as useful tools in the daily clinical practice of BD. This content has already been published in Japanese in the Guideline for the Management of Behçet's Disease 2020 and is submitted with permission from both the primary and secondary publishers.

Behçet's disease and activities of daily living.

OBJECTIVES: No large-scale registration study has comprehensively evaluated the activities of daily living (ADL) in patients with Behçet's disease. METHODS: The Japanese government provided us with a dataset of confirmed or suspected Behçet's disease cases derived from ongoing national registration. ADL were categorized and analysed into four categories in patients who satisfied the International Criteria for Behçet's Disease. RESULTS: Data from 2960 patients (men 38.9%, women 61.1%; median age 39 years) were assessed. While 1767 patients (59.7%) had normal ADL, the others had impaired ADL comprising limited but not assisted [n = 1058 (35.7%)], partially assisted [n = 116 (3.9%)] and fully assisted [n = 19 (0.6%)]. Logistic regression analysis showed that chronic ocular lesions [odds ratio (OR) 1.85 (95% CI 1.46, 2.35), P < 0.001], paralysis [OR 2.51 (95% CI 1.58, 3.97), P < 0.001], psychosis [OR 3.16 (95% CI 2.02, 4.95), P < 0.001] and arthritis [OR 1.69 (95% CI 1.44, 1.99), P < 0.001] led to the risk of impaired ADL. Chronic ocular lesions [OR 3.61 (95% CI 2.27, 5.72), P < 0.001], paralysis [OR 3.43 (95% CI 1.87, 6.30), P < 0.001] and psychosis [OR 3.60 (95% CI 2.00, 6.50), P < 0.001] were related to the requirement of physical assistance (partially or fully assisted), although arthritis [OR 1.39 (95% CI 0.93, 2.06), P = 0.108] was not a significant factor in this model. CONCLUSION: Ocular lesions, neurological manifestations and arthritis affected ADL. Patients with ocular lesions or neurological manifestations more frequently required physical assistance.

A randomised, double-blind, placebo-controlled phase III trial on the efficacy and safety of tocilizumab in patients with familial Mediterranean fever.

OBJECTIVES: To evaluate the efficacy and safety of tocilizumab (TCZ), an interleukin 6 receptor monoclonal antibody, in a subset of Japanese patients with familial Mediterranean fever (FMF). METHODS: We performed a double-blind, randomised, parallel-group trial, followed by an open-label extension trial, in patients with colchicine-resistant or -intolerant FMF (crFMF) (UMIN000028010). Patients were randomly assigned (1:1) to receive TCZ (162 mg every week) or placebo, administered subcutaneously, for 24 weeks. Rescue treatment was allowed if the rescue criteria were met. The primary endpoint was the number of fever attacks over the 24 weeks of treatment. Secondary endpoints included the frequency of accompanying symptoms during attacks, serum CRP and SAA values, and adverse events (AEs). The open-label extension study evaluated the long-term safety and efficacy of TCZ in patients who had completed the preceding study (UMIN000032557). RESULTS: We randomly assigned 23 patients to either TCZ (n=1) or placebo (n=12). The TCZ-placebo rate ratios were 0.691 (95% confidence intervals (CI), 0.189-2.531; p=0.577) for the fever attacks, based on the group rates per week. The recurrence of attacks was significantly lower in the TCZ group (hazard ratio = 0.457; 95% CI, 0.240-0.869). Fever attacks, accompanying symptoms, serum CRP and SAA values were controlled in most of the patients who received long-term TCZ. In these trials, the numbers and severity of AEs did not differ between groups. CONCLUSIONS: Although a primary endpoint was not met in the preceding trial, long-term administration of TCZ showed stable efficacy and safety for patients with crFMF.

Genome-wide identification of short 2',3'-cyclic phosphate-containing RNAs and their regulation in aging.

RNA molecules generated by ribonuclease cleavage sometimes harbor a 2',3'-cyclic phosphate (cP) at their 3'-ends. Those cP-containing RNAs (cP-RNAs) form a hidden layer of transcriptome because standard RNA-seq cannot capture them as a result of cP's prevention of an adapter ligation reaction. Here we provide genome-wide analyses of short cP-RNA transcriptome across multiple mouse tissues. Using cP-RNA-seq that can exclusively sequence cP-RNAs, we identified numerous novel cP-RNA species which are mainly derived from cytoplasmic tRNAs, mRNAs, and rRNAs. Determination of the processing sites of substrate RNAs for cP-RNA generation revealed highly-specific RNA cleavage events between cytidine and adenosine in cP-RNA biogenesis. cP-RNAs were not evenly derived from the overall region of substrate RNAs but rather from specific sites, implying that cP-RNAs are not from random degradation but are produced through a regulated biogenesis pathway. The identified cP-RNAs were abundantly accumulated in mouse tissues, and the expression levels of cP-RNAs showed age-dependent reduction. These analyses of cP-RNA transcriptome unravel a novel, abundant class of non-coding RNAs whose expression could have physiological roles.

Clinical features of Behçet's disease patients with joint symptoms in Japan: A national multicenter study.

OBJECTIVES: Approximately 30-60% of Behçet's disease patients exhibit joint symptoms. The aim of this study was to determine the clinical characteristics of such patients in Japan. METHODS: This study retrospectively analyzed 151 Behçet's disease patients with joint symptoms who had been treated at seven cooperative medical institutions from 2007 to 2017. We investigated their clinical characteristics and treatments. RESULTS: The most commonly affected joints were the knee, ankle, and proximal interphalangeal joints. Of the cases with pain and swelling, 18 of 293 joints (11 cases) displayed narrowing of the cleft or deformity by X-ray analysis. Improvement in their arthritis was observed in 80% of the patients who received steroids as initial treatment; however, the rate of improvement was lower in patients who had received prednisolone (PSL) at <10 mg/day. The recurrence of joint symptoms was significantly less common in the colchicine group than in the PSL group. CONCLUSIONS: These results suggest that PSL is effective for remission induction for the treatment of joint symptoms of Behçet's disease. Additionally, colchicine is effective in preventing the recurrence of joint symptoms in Behçet's disease. Furthermore, joint damages like joint space narrowing or with any deformity can often be observed in Behçet's disease.

Beneficial effects of apremilast on genital ulcers, skin lesions, and arthritis in patients with Behçet's disease: A systematic review and meta-analysis.

OBJECTIVES: This study aimed to determine the clinical efficacy of apremilast for oral ulcers (OUs), extra-oral manifestations, and overall disease activity in patients with Behçet's disease (BD). METHODS: A systematic literature search was performed in PubMed, Embase, Cochrane Library, and Web of Science Core Collection. Studies assessing the treatment effects of apremilast in BD were included. The odds ratios (ORs) of being symptom-free for individual manifestations and mean difference (MD) of Behçet's Disease Current Activity Form (BDCAF) scores were calculated with 95% confidence intervals (CIs) at 12 and 24 weeks using a random-model meta-analysis. RESULTS: Of 259 screened articles, eight were included. After 12 weeks of apremilast treatment the OR of symptom-free was as followings: OUs, 45.76 (95% CI, 13.23-158.31); genital ulcers, 4.56 (95% CI, 2.47-8.44); erythema nodosum, 3.59 (95% CI, 1.11-11.61); pseudofolliculitis, 2.81 (95% CI, 1.29-6.15); and arthritis, 3.55 (95% CI, 1.71-7.40). Furthermore, BDCAF scores at 12 weeks were significantly reduced (MD=-1.38; -1.78 to -0.99). However, the proportion of oral-ulcer-free patients increased at 24 weeks (OR = 14.88; 4.81 to 46.07). CONCLUSIONS: The currently accumulated data indicate an improvement in mucocutaneous and articular symptoms by short-term apremilast treatment in patients with BD.

Usefulness of the severity classification for predicting drug-free remission in Japanese patients with adult-onset Still's disease.

OBJECTIVES: To investigate the usefulness of severity classification for predicting outcomes in patients with adult-onset Still's disease (AOSD). METHODS: This was a multi-centre retrospective cohort study. AOSD patients were classified into mild, moderate, and severe groups based on severity classification (Japanese Ministry of Health, Labour and Welfare) during the initial treatment, and clinical features were compared among these groups. The primary endpoints were the AOSD-related mortality and drug-free remission rate. For comparison, the same analysis was performed in parallel for patient groups stratified by the modified Pouchot systemic score. RESULTS: According to severity classification, 49 (35%), 37 (26%), and 56 patients (39%) were classified into mild, moderate, and severe groups, respectively. Patients in the severe group showed higher frequency of severe complications and the use of biological agents. Although AOSD-related survival was not significantly different (p = .0776), four of the five fatal cases were classified into the severe group. The severe group showed a reduced rate of drug-free remission (p = .0125). Patient groups classified by systemic score did not correlate with survival or drug-free remission. CONCLUSIONS: Severity classification is useful for predicting outcomes in patients with AOSD.

Pathogenic UBA1 variants associated with VEXAS syndrome in Japanese patients with relapsing polychondritis.

OBJECTIVES: To determine clinical and genetic features of individuals with relapsing polychondritis (RP) likely caused by pathogenic somatic variants in ubiquitin-like modifier activating enzyme 1 (UBA1). METHODS: Fourteen patients with RP who met the Damiani and Levine criteria were recruited (12 men, 2 women; median onset age (IQR) 72.1 years (67.1-78.0)). Sanger sequencing of UBA1 was performed using genomic DNA from peripheral blood leukocytes or bone marrow tissue. Droplet digital PCR (ddPCR) and peptide nucleic acid (PNA)-clamping PCR were used to detect low-prevalence somatic variants. Clinical features of the patients were investigated retrospectively. RESULTS: UBA1 was examined in 13 of the 14 patients; 73% (8/11) of the male patients had somatic UBA1 variants (c.121A>C, c.121A>G or c.122T>C resulting in p.Met41Leu, p.Met41Val or p.Met41Thr, respectively). All the variant-positive patients had systemic symptoms, including a significantly high prevalence of skin lesions. ddPCR detected low prevalence (0.14%) of somatic variant (c.121A>C) in one female patient, which was subsequently confirmed by PNA-clamping PCR. CONCLUSIONS: Genetic screening for pathogenic UBA1 variants should be considered in patients with RP, especially male patients with skin lesions. The somatic variant in UBA1 in the female patient is the first to be reported.

Elevated serum gasdermin D N-terminal implicates monocyte and macrophage pyroptosis in adult-onset Still's disease.

OBJECTIVES: Elevation of serum IL-18 in adult-onset Still's disease (AOSD) and systemic JIA (sJIA) suggests the role of the inflammasome in these diseases. Gasdermin D is a pore-forming protein playing central roles in inflammasome-mediated inflammation, but its role in rheumatic disease is unknown. We aimed to elucidate the auto-inflammatory mechanisms in AOSD and sJIA. METHODS: Patients with AOSD, sJIA, hemophagocytic lymphohistiocytosis (HLH) and Behçet's disease followed at Yokohama City University (YCU), or US National Institutes of Health (NIH) were included in the study. Disease activity was evaluated by the modified Pouchot score. Ferritin and N-terminal gasdermin D levels in serum and culture supernatant were measured by ELISA. Primary monocytes (Mo) were stimulated with GM-CSF or M-CSF and differentiated into M1 macrophages (Mφ) or M2Mφ, respectively. The number of Mo/Mφ and their viability were monitored over time. RESULTS: Patients with active AOSD and sJIA had increased levels of serum gasdermin D N-terminal, which correlated with serum ferritin and IL-18 levels. Mo-derived Mφ from active AOSD patients showed reduced cell viability and increased cell death. The number of cultured Mφ cells on day nine was negatively correlated with the serum ferritin and gasdermin D levels. Higher ferritin and gasdermin D levels were observed in the M1Mφ culture supernatant of active AOSD patients. Gasdermin D inhibitors reduced the pyroptosis-mediated ferritin release in Mo. CONCLUSION: Elevation of serum gasdermin D N-terminal provides evidence for inflammasome activation triggering gasdermin D-mediated Mo and Mφ pyroptosis in AOSD and possibly sJIA.

Anti-TRIM21 antibody is associated with aberrant B-cell function and type I interferon production in systemic lupus erythematosus.

BACKGROUND: TRIM21 is a member of the tripartite motif family proteins and is one of the autoantigens which react with anti-SS-A antibody (Ab) present in sera of patients with systemic lupus erythematosus (SLE) and Sjögren's syndrome. Previous studies have shown that TRIM21 dysfunction promotes aberrant B-cell differentiation and Ab production in SLE, and anti-TRIM21 Ab may be related to the TRIM21 dysfunction in human SLE pathogenesis. Here, we examined the relationship between anti-TRIM21 Ab and clinical and immunological characteristics in SLE patients. METHODS: Twenty-seven patients with SLE (23 women and four men) before immunosuppressive therapies, who fulfilled the revised 1997 American College of Rheumatology criteria for SLE, and four healthy controls (3 women and one man) were enrolled in the study. SLE patients were divided into two groups according to the seropositivity for anti-TRIM21 Ab. Serum anti-TRIM21 Ab levels were measured using enzyme-linked immunosorbent assays. The serum levels of cytokines and immunoglobulins were measured by cytometer beads arrays. The expression levels of TRIM21 protein in peripheral mononuclear cells (PBMCs) from SLE patients were evaluated by Western blotting. RESULTS: Sixteen and 9 patients showed seronegativity and seropositivity for anti-TRIM21 Ab, respectively. There were no significant differences in the background parameters, including female ratio, age, disease duration, SLE activity, and laboratory data between the two groups. The serum levels of interferon (IFN)-ß were significantly higher in patients with anti-TRIM21 Ab as compared with those without anti-TRIM21 Ab (P = .043). The levels of IgG1 and IgA were significantly higher in SLE patients with anti-TRIM21 Ab as compared with those without anti-TRIM21 Ab (P = .0022 and .032, respectively). The PBMCs of patients with anti-TRIM21 Ab showed a significantly lower expression of TRIM21 protein as compared with those of patients without anti-TRIM21 Ab (P = .014). CONCLUSIONS: Anti-TRIM21 Ab seropositivity was related to B-cell abnormalities and type I IFN overproduction in SLE patients. These findings suggest that anti-TRIM21 Ab may have an inhibitory effect on TRIM21 functions and be a novel biomarker for the level of dependence on type I IFN overproduction and B-cell abnormalities.