Bacterial flagellin is a well-known agonist of the innate immune system that induces proinflammatory responses through the TLR5 and Naip5/6 recognition pathways. Several clinical trials investigating flagellin fusion proteins have demonstrated promising results for inducing protective immunity toward influenza virus, which has been largely attributed to flagellin’s ability to activate TLR5. Our laboratory previously demonstrated that the Salmonella enterica serovar Typhimurium flagellin protein, FliC, induces Ab responses in mice through a third pathway that is independent of TLR5, Casp1/11, and MyD88. In this study, we further define the structural features of FliC that contribute to this unknown third pathway. By destroying the Naip5/6 and TLR5 recognition sites, we demonstrate that neither were required for the TLR5-, inflammasome- and MyD88-independent Ab responses toward FliC. In contrast, deletion of FliC’s D3 or D0/D1 domains eliminated primary anti-flagellin Ab responses. For optimal primary and secondary anti-flagellin Ab responses we show that TLR5, inflammasome recognition, and the D3 domain of FliC are essential for flagellin’s robust immunogenicity. Our data demonstrate that the D3 domain of FliC influences immunogenicity independent of the known innate recognition sites in the D0/D1 domains to augment Ab production. Our results suggest full-length FliC is critical for optimal immunogenicity and Ab responses in flagellin-based vaccines.

Patients who have symptoms of sicca, such as dry eyes and mouth, may have Sjögren's syndrome (SS). However, the conservative culture makes patients hesitate to undergo an invasive biopsy, which contributes to the difficulty of confirming a diagnosis. We aimed to identify the characteristics of patients with sicca symptoms to develop a better predictive value for each item included in the three different diagnostic criteria for SS and clarify the best diagnostic tools for the local population. This is a single-center retrospective case-control study from January 2016 to December 2017. Patients who underwent sialoscintigraphy because of clinical symptoms of xerostomia and xerophthalmia at one medical center were reviewed via the patients' electronic medical records. Of 515 patients enrolled, the severity of results for sialoscintigraphy and Schirmer's test was correlated with a diagnosis of SS and generated receiver operator characteristic curve. The area under curve (AUC) was 0.603 for positive Schirmer's test, 0.687 for positive anti-Ro/La results, 0.893 for a positive salivary gland biopsy. The AUC was 0.626 and 0.602 for Schirmer's test which is redefined as <10 mm/5 minutes in either eye and according to 2016 the American College of Rheumatology/ European League Against Rheumatism criteria, respectively. Our results indicate the cut-off point for defining a positive test result in the Schirmer's test is worth modified to <10 mm/5 minutes in either eye.

Secondary hypogammaglobulinemia (SHG) is characterized by reduced serum immunoglobulin (Ig) levels and is typically caused by immunosuppressive therapy or certain diseases. Patients with systemic autoimmune rheumatic diseases (SARDs) and hematological malignancies are particularly susceptible to developing SHG due to underlying diseases and the use of immunosuppressive medications, such as B‐cell‐targeted agents. Consequently, SHG significantly contributes to increased risks of severe infections and mortality in SARDs patients. Considering the lack of a unified strategy for managing SHG, the Taiwan College of Rheumatology (TCR) aimed to formulate consensus recommendations for the screening, diagnosis, and management of SHG. These recommendations were developed based on emerging evidence during a face‐to‐face meeting of the TCR committee (nine immunologists and rheumatologists), and utilizing the modified Delphi process. This meeting involved a comprehensive review of the current evidence, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Thirteen consensus recommendations were developed to emphasize the importance of early detection and optimal treatment of SHG. Furthermore, effective prevention of infections through risk assessment alongside timely and regular monitoring of IgG levels was highlighted. The recommendations also included anti‐infective therapies and intravenous Ig replacement, offering valuable guidance to rheumatologists in managing SHG. This consensus will be regularly updated as newer evidence emerges.

Adult-onset Still disease (AOSD) is a rare systemic inflammatory disease of unknown etiology characterized by evanescent salmon-pink rash, spiking fever, arthralgia/ arthritis, and lymphadenopathy. AOSD sometimes was fatal when it is complicated by macrophage activation syndrome (MAS) or hemophagocytic lymphohistiocytosis (HLH). Nonetheless, the literature provides no recommendations for treatment of AOSD patients with severe sepsis. A previously healthy 65-year-old man with history of AOSD was referred to our hospital for persistent right lower quadrant abdominal pain for 2 days. One week later, an abdominal wall abscess and hematoma developed by extravasation from the inferior epigastric vessels, complicated by necrotizing fasciitis of the right thigh and groin region. To our best knowledge, this case was the first reported case of a perforated appendix complicated with necrotizing fasciitis in a patient with AOSD. The patient was diagnosed as acute appendicitis complicated with necrotizing fasciitis and abdominal wall abscess. This case received intravenous tigecycline injection and daily 10 mg prednisolone initially, and shifted to daily intravenous hydrocortisone 200 mg for suspected MAS or HLH. This patient underwent surgical intervention and debridement for necrotizing fasciitis. The patient's symptoms progressed worse rapidly. He died from cytomegalovirus viremia and bacterial necrotizing fasciitis complicated by septic shock. (1) The steroid dose was difficult to titrate when AOSD complicated by sepsis. The differential diagnosis from MAS/HLH with bacterial/viral infection related severe sepsis was difficult but critical for decision making from clinicians and rheumatologists. (2) The conservative treatment with antibiotics for perforated appendix is safe but has a higher failure rate in immunocomprised patients such as systemic lupus erythematosus and AOSD. Early surgical intervention might contribute to better outcome. (3) The abdominal wall abscess can be spread from intra-abdominal lesion through the inferior epigastric vessels which were as weak points of abdominal wall. Imaging examinations contribute to acute diagnosis and help surgeons perform surgical interventions to prevent morbidity and mortality.

Multidrug-resistant Acinetobacter baumannii (MDRAB) pneumonia with severe sepsis in a patient with rheumatoid arthritis (RA), who is predisposed after treatment with tumor necrosis factor inhibitor (TNFI), is a rare severe infection and can be successfully treated with prompt antibiotics. A 75-year-old woman was diagnosed with RA >30 years previously. After inadequate treatment responses to conventional disease-modifying antirheumatic drugs (DMARDs), she developed progressive RA, including swollen joints in both hands, and had a high disease activity score of 4.96 when presenting at our rheumatology clinic. She had started taking the TNFI, golimumab (50 mg/month), 3 years before and developed a productive cough 4 weeks before this admission. One week after admission, she developed fever, dyspnea, hypoxemia, tachycardia, and increased serum C-reactive protein level. Chest plain film (CxR) and computed tomography of the chest showed hospital-acquired pneumonia; microbial examination of the sputum showed the presence of MDRAB. She was prescribed a full course of antibiotics with cefoperazone sulbactam. CxR showed complete remission of pneumonia. Biological DMARDs, such as TNFI, act as a double-edged sword: these drugs are used to treat autoimmune diseases, but they increase the risk of infection. The trend toward antibiotic resistance and persistent environmental survival of MDRAB is an emerging problem in countries with high rates of antibiotic abuse. TNFI may affect intestinal immunity by inducing dysbiosis, which affects T helper 17–mediated mucosal immunity and can contribute to A baumannii colonization and the development of MDRAB in frequently hospitalized patients.

Background and Objectives: Adult-onset Still’s disease (AOSD) is a rheumatic disease characterized by systemic inflammatory symptoms, including intermittent spiking fever, polyarthritis and a distinctive salmon-colored rash. Corticosteroids are the first-line treatment for AOSD. However, corticosteroids are potentially hepatotoxic in certain cases and may complicate the course of the disease. Materials and Methods: A 29-year-old female suffering from fever of unknown origin for two weeks was diagnosed with AOSD according to Yamaguchi’s criteria. She received corticosteroids as the first-line treatment for AOSD and developed acute severe hepatitis. A diagnostic protocol has been performed. Results: Corticosteroid-induced liver injury was confirmed by clinical observation and rechallenge of the drug in this case. The result of liver biopsy also supported the diagnosis. Mycophenolic acid, a disease-modifying antirheumatic drug (DMARD) was chosen as an alternative treatment. AOSD remission was achieved under this treatment after three months. Conclusions: Severe acute hepatitis induced by corticosteroids, although very rare, may be observed in patients with AOSD. Drug-induced liver injury needs to be kept in mind when unexpected acute hepatitis is found. Mycophenolic acid could be a proper substitute medication in these cases.