Low pH condition impairs BP-IgG binding to the basement membrane zone.

Bullous pemphigoid (BP), an autoimmune subepidermal blistering disease, shows tense blisters associated with urticarial erythema. Tissue-bound Immunoglobulin G (IgG) at the basement membrane zone (BMZ) detected by direct immunofluorescence (DIF) is strong evidence for a diagnosis of BP. The sensitivity of DIF is higher in complement component 3 (C3) than in IgG, but the reason for this different sensitivity is not fully understood. In this study, we performed several ex vivo studies to investigate the possible mechanism of IgG negativity and C3 positivity at the BMZ by DIF in some BP cases. First, sera from BP patients showing IgG negativity by DIF were found to clearly react to the BMZ in their own DIF skin samples. Next, indirect immunofluorescence (IIF) was performed using sera diluted with different pH phosphate-buffered saline (PBS), pH 7.4, 6.0, and 3.0. Patients' sera diluted with pH 7.4 PBS showed linear staining at the BMZ, but sera diluted with pH 6.0 PBS and pH 3.0 PBS showed lower fluorescence intensities. Finally, sections of skin from BP patients were pre-incubated with different pH PBS (pH 3.0, 6.0, and 7.4), followed by staining with anti-human IgG and C3. The fluorescence intensities were notably lower for IgG and C3 that had been pre-incubated with pH 3.0 PBS and pH 6.0 PBS than for IgG and C3 that had been pre-incubated with pH 7.4 PBS. These results suggest that a low pH condition hinders the binding of autoantibodies to the BMZ, that is, the drop in tissue pH induced by inflammation inhibits autoantibodies from depositing at the BMZ. Furthermore, the drop in tissue pH causes tissue-bound autoantibodies to detach from the BMZ. Complement fragments are activated not only on IgG but also on the cell surface of cells close to IgG during complement activation. IgG may detach from the BMZ under low pH condition induced by inflammation, but some complement fragments remain at the BMZ. These phenomena may help to explain why C3 is more sensitive than IgG when DIF is used to diagnose BP.

Papular Umbilicated Granuloma Annulare in a Patient With Systemic Lupus Erythematosus.

Granuloma annulare (GA) is characterized by palisading granuloma, which is histopathologically distinguished by histiocytes arrayed in a palisade configuration encircling insoluble entities associated with degenerated collagen fibrils. The present case demonstrated multiple cutaneous papules showing palisading granuloma in a patient with SLE. A 39-year-old woman has been taking oral prednisolone daily, hydroxychloroquine sulfate, and belimumab for systemic lupus erythematosus (SLE). A few papules appeared on the lateral side of the left arm and gradually increased around both sides. Physical examination found multiple firm skin-colored papules ranging in diameter from 2 to 3 mm on both forearms. Some of the papules had umbilicated tops. Histopathological examination showed degenerated collagen fibers with mucin deposition surrounded by histiocyte infiltrates in the dermis. These findings are characteristic of palisading granuloma. There are several GA variants, such as generalized, subcutaneous, and perforating GA. We considered several possibilities of the mechanisms underlying characteristic histological changes; atypical generalized GA variants, dermatofibroma, and granuloma associated with cutaneous vasculitis. We made the final diagnosis of papular umbilicated GA in the context of SLE.

A case of VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) with decreased oxidative stress levels after oral prednisone and tocilizumab treatment.

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome has recently been described as an autoinflammatory disease associated with severe adult-onset inflammatory manifestations. The various clinical manifestations include recurrent high-grade fever, neutrophilic dermatoses, cutaneous vasculitis, chondritis of the ear and nose, pulmonary infiltrates, cytopenia, uveitis, gastrointestinal pain or inflammation, aortitis, hepatosplenomegaly, and hematological disorders. VEXAS syndrome is caused by somatic mutations of the ubiquitin-like modifier activating enzyme 1 (UBA1) gene in myeloid-lineage cells. It is characterized by vacuolated myeloid and erythroid progenitor cells seen by bone marrow biopsy. We report the case of a 64-year-old Japanese man with VEXAS syndrome. At age 63, he was referred to us with a recurrent erythema on the hands associated with a general fever of 38-40°C that had persisted for 4 or 5 days and had recurred about once a month for a year. The skin rash appeared 2 or 3 days after the onset of each fever episode. Computed tomography (CT) of the chest revealed bilateral hilar lymphadenopathy (BHL), and the mediastinal lymph nodes were swollen. Sarcoidosis was suspected but was ruled out by several tests. Laboratory examinations showed elevated inflammatory markers. Bone marrow examination showed the vacuolization of myeloid precursor cells. A skin biopsy revealed dense dermal, predominantly perivascular, infiltrates. These consisted of mature neutrophils admixed with myeloperoxidase-positive CD163-positive myeloid cells, lymphoid cells and eosinophils. Sequencing analysis identified the somatic UBA1 variant c.122T > C, which results in p.Met41Thr. Treatment with oral prednisone (15 mg/day) and monthly intravenous tocilizumab injections (400 mg) completely resolved the symptoms. Neutrophils are a major source of reactive oxygen species, and the present case demonstrated numerous neutrophilic infiltrates. We hypothesize that the patient might have had elevated derivatives of reactive oxygen metabolites (d-ROMs). d-ROM quantification is a simple method for detecting hydroperoxide levels, and clinical trials have proven it useful for evaluating oxidative stress. In this study, we measured serum d-ROM before and after oral prednisone and tocilizumab treatment. The levels decreased significantly during treatment.

MicroRNA-30c attenuates fibrosis progression and vascular dysfunction in systemic sclerosis model mice.

Systemic sclerosis (SSc) is characterized by peripheral circulatory disturbance and fibrosis in skin and visceral organs. We recently demonstrated that α2-antiplasmin (α2AP) is elevated in SSc dermal fibroblasts and SSc model mice, and is associated with fibrosis progression and vascular dysfunction. In the present study, we predicted that α2AP could be a target of microRNA-30c (miR-30c) using TargetScan online database, and investigated the effect of miR-30c on the pathogenesis of SSc using a bleomycin-induced SSc model mice. miR-30c attenuated α2AP expression, and prevented the pro-fibrotic changes (increased dermal thickness, collagen deposition, myofibroblast accmulation) and the vascular dysfunction (the reduction of vascular endothelial cells (ECs) and blood flow) in the skin of SSc model mice. Furthermore, miR-30c suppressed pulmonary fibrosis progression in the SSc model mice. miR-30c exerts the anti-fibrotic and anti-angiopathy effects on SSc model mice, and might provide a basis for clinical strategies for SSc.

Decrease in matrix metalloproteinase­3 activity in systemic sclerosis fibroblasts causes α2­antiplasmin and extracellular matrix deposition, and contributes to fibrosis development.

Systemic sclerosis (SSc) is a connective tissue disease of autoimmune origin characterized by fibrosis of the skin and visceral organs, and peripheral circulatory disturbance. α2­antiplasmin (α2AP) is the major circulating inhibitor of plasmin and is a key regulator of fibrinolysis. It has been demonstrated that the expression of α2AP is elevated in dermal fibroblasts obtained from patients with SSc patients. It has also been determined that α2AP is associated with the development and progression of fibrosis in SSc. The present study assessed the relationship between α2AP and matrix metalloproteinase­3 (MMP­3), an extracellular matrix (ECM)­degrading enzyme. Serum levels of α2AP and MMP­3 were measured in healthy controls and patients with SSc using ELISA. No significant differences were determined between these two groups. α2AP, MMP­3 and tissue inhibitor of metalloproteinase­1 (TIMP­1) expression was subsequently evaluated in normal and SSc fibroblasts via western blotting. The results revealed that α2AP expression increased in SSc dermal fibroblasts, while the ratio of MMP­3/TIMP­1 decreased. Additionally, incubation of recombinant α2AP with MMP­3 caused α2AP degradation. The mixture of recombinant α2AP with MMP­3 was subsequently added to normal fibroblasts prior to western blotting. The results revealed decreased α­smooth muscle actin (α­SMA; a marker of the myofibroblast phenotype) and type I collagen expression. The stimulation of SSc fibroblasts with MMP­3 decreased protein levels of α2AP, α­SMA and type I collagen, thus reversing the pro­fibrotic phenotype of SSc fibroblasts. SSc fibroblast transfection with microRNA­29a resulted in a decreased TIMP­1 expression, but also decreased the protein expression of α2AP. The results indicated that MMP­3 attenuated fibrosis progression by degrading α2AP and ECM, and might therefore contribute to a novel therapeutic approach for SSc treatment.

Alternatively activated macrophages are associated with the α2AP production that occurs with the development of dermal fibrosis : The role of alternatively activated macrophages on the development of fibrosis.

BACKGROUND: Fibrotic diseases are characterized by tissue overgrowth, hardening, and/or scarring because of the excessive production, deposition, and contraction of the extracellular matrix (ECM). However, the detailed mechanisms underlying these disorders remain unclear. It was recently reported that α2-antiplasmin (α2AP) is elevated in fibrotic tissue and that it is associated with the development of fibrosis. In the present study, we examined the mechanism underlying the production of α2AP on the development of fibrosis. METHODS: To clarify the mechanism underlying the production of α2AP on the development of fibrosis, we focused on high-mobility group box 1 (HMGB1), which is associated with the development of fibrosis. The mouse model of bleomycin-induced fibrosis was used to evaluate the production of α2AP on the development of fibrosis. RESULTS: We found that HMGB1 induced the production of α2AP through receptor for advanced glycation end products (RAGE) in fibroblasts. Next, we showed that macrophage reduction by a macrophage-depleting agent, clodronate, attenuated the progression of fibrosis and the production of α2AP and HMGB1 in the bleomycin-induced mice. We also showed that IL-4-stimulated alternatively activated macrophages induced the production of HMGB1, that IL-4-stimulated alternatively activated macrophage conditioned media (CM) induced pro-fibrotic changes and α2AP production, and that the inhibition of HMGB1 and RAGE attenuated these effects in fibroblasts. Furthermore, the blockade of IL-4 signaling by IL-4Rα neutralizing antibodies attenuated the progression of fibrosis and the production of α2AP and HMGB1 in the bleomycin-induced mice. CONCLUSION: These findings suggest that alternatively activated macrophage-derived HMGB1 induced the production of α2AP through RAGE and that these effects are associated with the development of fibrosis. Our findings may provide a clinical strategy for managing fibrotic disorders.

Newly designed soft prelooped cap for endoscopic mucosal resection of gastric lesions.

BACKGROUND: Endoscopic mucosal resection with a cap-fitted panendoscope is a useful, effective, and safe technique. The effectiveness and safety of a newly designed larger but softer cap was compared in this study with the conventional hard cap. The soft cap has a significantly larger diameter (18 mm) compared with that of the hard cap (16.5 mm). METHODS: Eighty-three patients who underwent mucosal resection of gastric lesions were included in analysis. The diameter, resection specimen depth, and the rate of en bloc resection were compared. The operability of the endoscope with the cap attached, patient tolerance, and safety of the procedure were analyzed. RESULTS: Mean diameter (+/- SEM) of specimens resected with the soft cap was larger: 22.1 (+/- 0.7) versus 15.8 (+/- 0.3) mm (p < 0.001). The specimen was also thicker: 1.54 (+/- 0.10) versus 1.08 (+/- 0.11) mm (p < 0.001). Use of the soft cap led to higher rate of en bloc resection: 66.7% versus 43.2% (p < 0.05). The operability of the endoscope with the larger, softer cap attached was similar to that when the hard cap was used. Both caps were equally safe. CONCLUSION: The soft cap is safe and useful for mucosal resection of larger gastric lesions. Its use increases the rate of en bloc resection.