18 F-FDG PET/CT Reveals Localized Inflammation in Lupus Enteritis.

ABSTRACT: Lupus enteritis is classified into the colon poly-ulcerative type and the small intestine ischemic serositis type. Colon poly-ulcerative lupus enteritis is a disease that is mainly due to mesenteric arteritis. In recent years, 18 F-FDG PET/CT has been frequently used to assess the extent of the disease in patients with systemic vasculitis. We present the case report of 18 F-FDG PET/CT results in a 57-year-old woman with colon poly-ulcerative lupus enteritis.

Polyarteritis nodosa diagnosed in a young male after COVID-19 vaccine: A case report.

In response to the coronavirus disease 2019 pandemic, the coronavirus disease 2019 vaccine was rapidly developed and the effectiveness of the vaccine has been established. However, various adverse effects have been reported, including the development of autoimmune diseases. We report a case of new-onset polyarteritis nodosa in a 32-year-old male following the coronavirus disease 2019 vaccination. The patient developed limb pain, fever, pulmonary embolism, multiple subcutaneous nodules, and haematomas. Skin biopsy revealed necrotising inflammation accompanied by fibrinoid necrosis and high inflammatory cell infiltration in the walls of medium to small arteries. The symptoms resolved following corticosteroid treatment. Although it is difficult to prove a relationship between the vaccine and polyarteritis nodosa, similar cases have been reported and further reports and analyses are therefore necessary.

Performance of classification and diagnostic criteria for IgG4-related disease and comparison of patients with and without IgG4-related disease.

IgG4-related disease (IgG4-RD) was recently described in Japan. It is characterised by extensive organ involvement with tissue fibrosis. We assessed the performance of the 2019 American College of Rheumatology and European League Against Rheumatism (ACR/EULAR) classification criteria and the 2020 revised comprehensive diagnostic (RCD) criteria as well as differences between patients with and without IgG4-RD. In this retrospective, single-centre study of 50 patients admitted with suspected IgG4-RD, we evaluated the sensitivity and specificity of both criteria. We also compared clinical characteristics and laboratory data of patients with IgG4-RD (n = 42) and patients without IgG4-RD (n = 8). The ACR/EULAR classification criteria had 88.1% sensitivity and 87.5% specificity for IgG4-RD diagnosis. The RCD criteria had 100% sensitivity and 50% specificity. Patients with IgG4-RD had significantly more affected organs (p = 0.002). Patients with a single affected organ and IgG4-RD had significantly higher serum IgG4/IgG ratios (p = 0.027), lower serum C-reactive protein levels (p = 0.020), and lower total haemolytic complement activity (p = 0.044) than those without IgG4-RD. The ACR/EULAR classification criteria have high specificity and the RCD criteria have high sensitivity for diagnosing IgG4-RD. The number of affected organs is important for diagnosing IgG4-RD.

In lupus cystitis, is the urinary tract dilated or obstructed?

OBJECTIVES: Lupus cystitis is a rare but serious complication of systemic lupus erythematosus (SLE) that can cause permanent bladder dysfunction, leading to irreversible deterioration of kidney function. We report two cases of SLE with lupus cystitis who showed different images from the same cause of disease. METHODS: Patient 1, a 67-year-old woman diagnosed with SLE presented with persistent dysuria for 3 weeks with sudden headache and vomiting. She was hospitalized because of acute kidney injury; the serum creatinine level was 10.68 mg/dL. Computed tomography (CT) showed significant bilateral ureteral stenosis and bilateral hydronephrosis. Patient 2, a 45-year-old woman diagnosed with SLE presented with dysuria requiring self-catheterization. CT showed significant bilateral ureteral dilatation and bilateral hydronephrosis. RESULTS: In patient 1, the right kidney was afunctional. Left nephrostomy was performed on Day 2. Her serum creatinine returned to the normal range. In patient 2, After admission, she changed to an indwelling bladder catheter. Her serum creatinine level improved from 2.04 to 1.31 mg/dL. CONCLUSION: In patients with lupus cystitis, the urinary tract is commonly dilated, but stenosis has been seen in rare case. Physicians should be careful in diagnosing it.

PET/CT Reveals Localized Inflammation in the Temporal, Vertebral, and Lower Extremity Arteries in Giant Cell Arteritis.

ABSTRACT: 18 F-FDG PET/CT is increasingly being used in the diagnosis of systemic vasculitis syndromes, especially large-vessel vasculitis. We present a case of giant cell arteritis in an 84-year-old man who exhibited large-vessel lesions in the periphery but none in the trunk. This case highlights the usefulness of PET/CT for revealing localized inflammation.

Changes in anti-MDA5 antibody titres and serum cytokine levels before and after diagnosis of anti-MDA5 antibody-positive dermatomyositis.

OBJECTIVES: Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive DM is characterized by rapidly progressive interstitial lung disease and has a poor prognosis. We aimed to investigate whether anti-MDA5 antibody titres and cytokine levels predict clinical course, and evaluate changes in both parameters before and after diagnosis. METHODS: This was a retrospective, single-centre study in 38 patients with anti-MDA5 antibody-positive DM. We compared clinical characteristics and laboratory data at diagnosis between patients in the treatment response (n = 23) and non-response (n = 15) groups, and between those in the relapse (n = 5) and non-relapse (n = 24) groups. We also measured serum anti-MDA5 antibody titres and cytokine levels before and after diagnosis. RESULTS: The non-response group was older, had a higher ground-glass opacity score, lower PaO2/FiO2, higher CRP level, and higher anti-MDA5 antibody titre than the response group. No cytokines significantly differed between groups at diagnosis. The relapse group had a significantly higher anti-MDA5 antibody titre than the non-relapse group. In the survivor group, the anti-MDA5 antibody titre and levels of IFN-α, IFN-γ, monocyte chemotactic protein-1 (MCP-1), IL-6, IL-33, CRP, and ferritin were significantly lower 6 months post-treatment than at diagnosis. Macrophage-associated cytokines such as IL-6, IL-8, IL-18 and MCP-1 increased after anti-MDA5 antibody positivity in three patients who were anti-MDA5 antibody-positive before diagnosis. CONCLUSION: The anti-MDA5 antibody titre at diagnosis may predict the clinical course. Levels of macrophage-associated cytokines significantly declined at 6 months post-treatment, and they may have increased after anti-MDA5 antibody titre positivity.

Activated Mucosal-associated Invariant T Cells Have a Pathogenic Role in a Murine Model of Inflammatory Bowel Disease.

BACKGROUND & AIMS: Mucosal-associated invariant T (MAIT) cells are innate-like T cells restricted by major histocompatibility complex-related molecule 1 (MR1) and express a semi-invariant T cell receptor. Previously, we reported the activation status of circulating MAIT cells in patients with ulcerative colitis (UC) was associated with disease activity and that these cells had infiltrated the inflamed colonic mucosa. These findings suggest MAIT cells are involved in the pathogenesis of inflammatory bowel disease. We investigated the role of MAIT cells in the pathogenesis of colitis by using MR1-/- mice lacking MAIT cells and a synthetic antagonistic MR1 ligand. METHODS: Oxazolone colitis was induced in MR1-/- mice (C57BL/6 background), their littermate wild-type controls, and C57BL/6 mice orally administered an antagonistic MR1 ligand, isobutyl 6-formyl pterin (i6-FP). Cytokine production of splenocytes and colonic lamina propria lymphocytes from mice receiving i6-FP was analyzed. Intestinal permeability was assessed in MR1-/- and i6-FP-treated mice and their controls. The effect of i6-FP on cytokine production by MAIT cells from patients with UC was assessed. RESULTS: MR1 deficiency or i6-FP treatment reduced the severity of oxazolone colitis. i6-FP treatment reduced cytokine production in MAIT cells from mice and patients with UC. Although MR1 deficiency increased the intestinal permeability, i6-FP administration did not affect gut integrity in mice. CONCLUSIONS: These results indicate MAIT cells have a pathogenic role in colitis and suppression of MAIT cell activation might reduce the severity of colitis without affecting gut integrity. Thus, MAIT cells are potential therapeutic targets for inflammatory bowel disease including UC.

Inhibition of mTOR suppresses IFNα production and the STING pathway in monocytes from systemic lupus erythematosus patients.

OBJECTIVE: Increased IFNα is important in the pathogenesis of SLE. Plasmacytoid dendritic cells are considered the main producer of IFNα upon Toll-like receptor pathway activation. However, which cells produce IFNα following stimulation with cyclic GMP-AMP synthase (cGAS) and stimulator of IFN genes (STING) in SLE remains unknown. We investigated the IFNα producing capacity of myeloid cells under cGAS-STING pathway stimulation. METHODS: IFNα levels in peripheral blood mononuclear cells from SLE patients and healthy controls stimulated with 2'3'c-GAMP, a stimulator of cGAS-STING, were measured by intracellular cytokine staining and flow cytometry. STING expression and its co-localization with TBK1 were examined by flow cytometry or confocal microscopy. The effects of in vitro exposure to IFNα on IFNα production and STING expression, and in vitro rapamycin treatment on IFNα production and STING, pTBK1 and IRF3 expression were examined. RESULTS: IFNα was produced by monocytes, conventional dendritic cells and plasmacytoid dendritic cells upon cGAS-STING pathway activation. The frequency of IFNα-producing monocytes positively correlated with SLE disease activity. STING expression and its co-localization with TBK1 were increased in lupus monocytes. Prior exposure to IFNα enhanced the IFNα-producing capacity of monocytes. Inhibition of the mechanistic target of the rapamycin (mTOR) pathway suppressed IFNα production from monocytes and downregulated enhanced STING expression and its downstream molecules. CONCLUSION: Enhanced IFNα from lupus monocytes induced by augmented STING pathway activation is associated with SLE pathogenesis. Suppression of the mTOR pathway downregulated the enhanced STING expression and the subsequent IFNα production by monocytes.

Association of mucosal-associated invariant T cells with different disease phases of polymyalgia rheumatica.

OBJECTIVES: Although T cells are thought to be involved in the pathogenesis of PMR, whether innate-like T cells are involved in the process remains unknown. METHODS: The serum levels of 27 cytokines/chemokines in patients with PMR were measured by a multiplex immunoassay (Bio-Plex Assay). The cytokine-producing capacity of T and innate-like T cells was assessed by intracellular cytokine staining and flow cytometry. The frequency and activated status of T and innate-like T cells were investigated by flow cytometry and their associations with clinical parameters were assessed. RESULTS: The levels of inflammatory cytokines were associated with disease activity in PMR. The cytokine-producing capacity by CD8+ T and innate-like T cells was associated with disease activity. The frequency of HLA-DR+ CD38+ cells among CD8+ T cells was increased in patients with active disease. The frequencies of HLA-DR+ CD38+ cells among CD4+ T, mucosal-associated invariant T (MAIT) and γδ T cells were higher in patients with inactive disease. The frequency of HLA-DR+ CD38+ MAIT cells was associated with the PMR activity score and CRP levels in patients in remission. CONCLUSION: The inflammatory cytokine-producing capacity and expression of activation markers of CD8+ T and innate-like T cells were associated with the disease activity of PMR. MAIT cell activation in patients in remission may contribute to the subclinical activity of the disease.

Expanded circulating peripheral helper T cells in systemic lupus erythematosus: association with disease activity and B cell differentiation.

OBJECTIVE: Peripheral helper T (TPH) cells are a recently identified Th cell subset that promotes B cell differentiation and antibody production in inflamed tissues. This study investigated circulating TPH cells to determine their involvement in systemic lupus erythematosus (SLE). METHODS: Peripheral blood mononuclear cells collected from SLE patients and healthy individuals were analysed. TPH cells were identified as CD3+CD4+CD45RA-CXCR5- cells with a high expression of PD-1. The frequency, activation status and subsets of TPH cells were evaluated by flow cytometry. The production of IL-21 was assessed by intracellular staining and the association of TPH cells with disease activity and B cell populations was determined. RESULTS: Circulating TPH cells, identified as CD3+CD4+CD45RA-PD-1highCXCR5- cells were increased in the peripheral blood of SLE patients compared with controls. Circulating TPH cells produced similar amounts of IL-21 compared with follicular Th cells. The expansion and activation of TPH cells were correlated with SLE disease activity. Activated TPH cells, particularly Th1-type TPH cells, were associated with the promotion of B cell differentiation in SLE patients. CONCLUSION: The association of TPH cells with disease activity suggests the involvement of extrafollicular T-B cell interactions in the pathogenesis of SLE. TPH cells promote autoantibody production in aberrant lymphoid organs and therefore might be a novel therapeutic target in autoantibody-producing disorders.