Immunological Medicine最新文献

Most children with acute hepatitis A virus (HAV) or hepatitis E virus (HEV) infection are asymptomatic. Bystander CD8⁺ T-cell activation has garnered attention owing to its possible pathophysiological role in adult hepatitis. However, no reports have studied it in pediatric hepatitis. Herein, we describe the case of a three-year-old girl with acute hepatitis by HEV genotype 1. She had a history of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections, and HEV hepatitis occurred shortly after asymptomatic HAV infection. Peripheral immunophenotyping revealed activation of non-HEV-specific CD8⁺ T cells which include EBV-specific and CMV-specific CD8⁺ T cells, during the acute phase. While alanine-aminotransferase levels declined after admission, the total number of activated CD8⁺ T cells increased for four days after admission and decreased thereafter. In contrast, activation of EBV-specific and CMV-specific CD8⁺ T cells was almost at the maximal level at the time of admission, which suggest development of activated bystander CD8⁺ T cells in the early stage. This case highlights the significance of the bystander CD8⁺ T-cell activation even in pediatric hepatitis and the size of the CD8⁺ T cell memory pool in the individuals for the development of hepatitis, given the patient's history of infections with EBV, CMV and HAV.

Type I interferons (IFN-Is) play a significant role in systemic lupus erythematosus (SLE) pathogenesis. Double-filtration plasmapheresis (DFPP) is a treatment option for SLE; however, its effect on IFN-Is remains unclear. Therefore, we investigated the effects of DFPP on IFN-Is. Plasma from patients with SLE (n = 11) who regularly underwent DFPP was analysed using a cell-based reporter system to detect the bioavailability and inducing activity of IFN-I. The concentration of plasma dsDNA was measured, and western blotting analysis was used to assess the phosphorylation of the STING pathway. A higher IFN-I bioavailability and inducing activity were observed in patients compared to healthy controls, and both parameters decreased after DFPP. The reduction in IFN-I-inducing activity was particularly prominent in patients with high disease activity. Notably, this reduction was not observed in STING-knockout reporter cells. Additionally, plasma dsDNA levels decreased after DFPP treatment, suggesting that inhibition of the STING pathway was responsible for the observed decrease in activity. Western blotting analysis revealed suppression of STING pathway phosphorylation after DFPP. DFPP reduced IFN-I bioavailability and the inducing activity of plasma. This reduction is likely attributable to the inhibition of the STING pathway through the elimination of dsDNA.

Immune reconstitution inflammatory syndrome (IRIS) experienced in rheumatology practice is diverse and includes opportunistic infections such as herpes zoster (HZ). This study aimed to explore the risk of HZ in patients with rheumatic diseases in the perspective of IRIS. The study retrospectively reviewed the clinical courses of 20 patients with HZ and investigated the IRIS triggers such as the reduction or discontinuation of immunosuppressive drugs within 3 months and coronavirus disease 2019 (COVID-19) vaccination within 4 weeks prior to HZ development. Disease activity of the underlying rheumatic disease at HZ onset was evaluated using the physician's global assessment. Thirteen patients developed HZ after reducing or discontinuing immunosuppressive drugs, with mild and stable disease activity. In four of these cases, disease activity increased after dose reduction or discontinuation, and HZ subsequently developed. Two of the seven patients who did not reduce or discontinue immunosuppressive drugs received the COVID-19 vaccination. Fifteen patients (75%) had at least one of the two IRIS triggers. Four of the five patients who developed HZ without any IRIS triggers were at HZ risk. To conclude, IRIS, caused by the reduction or discontinuation of immunosuppressive drugs, may be involved in the development of HZ in rheumatology practice.

This study investigated the clinical features and prognostic relevance of decreased serum complement levels in patients with idiopathic inflammatory myositis (IIM). The clinical information of IIM patients with less than normal serum complement levels (L-Com) and that of those with normal serum complement levels (N-Com) was compared. In patients with interstitial lung disease (ILD), regression analyses were used to investigate the implication of L-Com in their PaO₂/FiO₂ (P/F) ratio. Prognostic outcomes of ILD were evaluated using the log-rank test. Of 94 IIM patients, 26 with L-Com (median age, 56.0 years) and 68 with N-Com (56.5 years) were included. The prevalence of women was significantly higher in patients with L-Com (92.3%) than in those with N-Com (67.6%). ILD was observed in 17 (65.4%) patients with L-Com and in 46 (67.6%) with N-Com. Among patients with ILD, the P/F ratio was significantly lower in those with L-Com than in those with N-Com. Serum C3 levels were correlated with decreased P/F ratio. Inferior prognosis of ILD was significantly demonstrated in patients with L-Com, especially in those positive for anti-melanoma differentiation-associated protein 5 antibody. L-Com may be implicated in reduced arterial oxygen levels and a poorer prognosis in patients with IIM-related ILD.

Kabuki syndrome (KS) is a genetic disorder caused by gene mutations in either lysine-specific methyltransferase 2D (KMT2D) or lysine demethylase 6A (KDM6A). This congenital disorder exhibits characteristic facial features, developmental delays in psychomotor skills, and skeletal abnormalities. Moreover, it is classified as a congenital immunodeficient disorder under the category of combined immunodeficiency, leading to hypogammaglobulinemia and the onset of autoimmune diseases. Here, we present the first case of KS complicated by idiopathic pulmonary hemosiderosis (IPH). The KS patient, a 2-year-old Japanese girl with a history of hypoplastic left heart syndrome and recurrent bacterial infection, developed severe respiratory distress and anemia. She had autoimmune hemolytic anemia and gouty nephropathy. Hemophagocytic macrophages with hemosiderin ingestion were identified in bronchoalveolar lavage fluid, excluding differential diagnoses and leading to the diagnosis of idiopathic pulmonary hemosiderosis. Intravenous prednisolone (2 mg/kg/day) was administered, but symptoms did not improve. However, pulmonary hemorrhage disappeared with methylprednisolone pulse therapy. IPH warrants consideration in cases where individuals with KS manifest idiopathic pneumonia and concurrent anemia.

Although rapidly progressive glomerulonephritis (RPGN) is the main renal phenotype of microscopic polyangiitis (MPA), we aim to clarify the clinical features of slowly progressive MPA. This retrospective observational study included 12 patients diagnosed with MPA in our hospital between January 2012 and February 2022. We investigated the differences in surrogate markers, rate of decline of estimated glomerular filtration rate (eGFR) between the slowly progressive and rapidly progressive MPA groups. Of the 12 patients with MPA, 3 (25.0%) had slowly progressive MPA: MPA within 30% decrease in eGFR 3 months pretreatment, all of whom developed RPGN during the course. Patients with slowly progressive MPA had lower levels of C-reactive protein, myeloperoxidase anti-neutrophil cytoplasmic antibodies, and interleukin-6; higher levels of sialylated carbohydrate antigen KL-6. Slowly progressive MPA is not uncommon in our hospital. A linear relationship was found between slower rate of eGFR decline and lower surrogate markers of disease activity. Some MPA cases have slowly progressive glomerulonephritis leading to RPGN, which may be clinically characterized by low disease activity. It may be useful to measure myeloperoxidase anti-neutrophil cytoplasmic antibody in chronic kidney disease with concomitant urinary abnormalities to diagnose MPA with slowly progressive glomerulonephritis.

Postural orthostatic tachycardia syndrome (POTS) is characterized by exaggerated orthostatic tachycardia in the absence of orthostatic hypotension. The pathophysiology of POTS may involve hypovolemia, autonomic neuropathy, a hyperadrenergic state, and cardiovascular deconditioning, any of which can co-occur in the same patient. Furthermore, there is growing evidence of the role of autoimmunity in a subset of POTS cases. In recent years, investigators have described an increased rate of autoimmune comorbidities as evidenced by the finding of several types of neural receptor autoantibody and non-specific autoimmune marker in patients with POTS. In particular, the association of the disease with several types of anti-G protein-coupled receptor (GPCR) antibodies and POTS has frequently been noted. A previous study reported that autoantibodies to muscarinic AChRs may play an important role in POTS with persistent, gastrointestinal symptoms. To date, POTS is recognized as one of the sequelae of coronavirus disease 2019 (COVID-19) and its frequency and pathogenesis are still largely unknown. Multiple autoantibody types occur in COVID-related, autonomic disorders, suggesting the presence of autoimmune pathology in these disorders. Herein, we review the association of anti-GPCR autoantibodies with disorders of the autonomic nervous system, in particular POTS, and provide a new perspective for understanding POTS-related autoimmunity.

This study aimed to elucidate the clinical features, outcomes and risk factors of flares in patients with systemic lupus erythematosus (SLE). Data were collected from patients with newly diagnosed SLE at the Fukushima Medical University Hospital between 2011 and 2022. Patients who experienced a flare during the study period constituted the flare group, and their clinical features were compared with those of the no-flare group. The cumulative flare-free survival regarding several clinical items was compared between the two groups using Kaplan-Meier's curves. Among 387 patients with SLE, 83 patients with newly diagnosed SLE were included. Their mean age was 37.9 years, and 29 patients experienced flares during the study period. The general characteristics were similar between the two groups, with the exception of the observation period and anti-SS-A antibody positivity. Regarding therapy, a significantly increased frequency of hydroxychloroquine intake and combination with immunosuppressive agents were observed in the no-flare group. The Kaplan-Meier analysis revealed a significantly higher cumulative flare-free survival in the anti-SS-A negative group and combination immunosuppressive therapy group. In conclusion, anti-SS-A positivity may be a risk factor for SLE flare. In turn, combination immunosuppressive therapy may be beneficial for SLE treatment in daily clinical practice.

Although the clinical efficacy of tofacitinib has been reported in adult patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive (Ab+) dermatomyositis, data on its use in refractory juvenile dermatomyositis (JDM) are scarce. We describe two female Japanese patients with anti-MDA5 Ab + JDM and rapidly progressive interstitial lung disease who achieved remission by adding tofacitinib to existing immunosuppressive drugs and present a literature review. While both patients received various immunosuppressive or anti-inflammatory treatments for induction therapy, remission could not be achieved. Subsequently, tofacitinib was administered to reduce the Krebs von den Lungen-6 level 5 months after diagnosis in one patient; the other patient received tofacitinib 4 months after diagnosis to reduce ferritin levels and skin manifestations. Subsequently, both patients achieved remission, and prednisolone was withdrawn. Tofacitinib reduced the interferon signature associated with dermatomyositis/JDM disease progression and exerted a therapeutic effect on dermatomyositis/JDM. We found six published cases from five articles of tofacitinib for refractory anti-MDA5 Ab + JDM. Except for one case of herpes simplex meningitis, the other cases, including ours, had improved disease activity without severe adverse events, and steroids and immunosuppressive medicines could be tapered. Tofacitinib could be considered an available therapy for refractory anti-MDA5 Ab + JDM.

Anti-nuclear matrix protein 2 (NXP2) antibody-positive dermatomyositis (DM) is characterized by extensive and severe myositis. In this study, we evaluated which cytokines/chemokines involved with the activity of the myositis. We performed quantitative immunoassays using the MILLIPLEX^® Multiplex Assays Using Luminex to evaluate serum levels of interferon-γ, interleukin (IL)-1β, IL-6, IL-8, IL-12p40, and tumor necrosis factor-α in samples collected over time from a 9-year-old female with anti-NXP2 antibody-positive DM. In our case, the serum level of IL-8 was elevated when the myositis worsened, and decreased in accordance with the improvement of myositis, suggesting that the serum IL-8 levels were correlated with the myositis activity. Serum levels of IL-8 in samples from five patients with anti-NXP2 antibody-positive DM and five patients with anti-transcriptional intermediary factor 1γ (TIF1γ) antibody-positive DM without both interstitial lung disease (ILD) and malignancy before starting treatments, along with five healthy controls, were also evaluate by an enzyme-linked immunosorbent assay. Serum IL-8 levels were significantly elevated in anti-NXP2 or anti-TIF1γ antibody-positive DM patients with myositis but not ILD, than healthy controls. It was suggested that serum levels of IL-8 correlate with the activity of myositis in DM including anti-NXP2 antibody-positive DM.