Yohei Iwata

Erythema nodosum (EN) may be idiopathic or secondary, and usually resolves naturally within 1-2 months. In atypical EN cases, the rash extends beyond the lower limbs to the upper limbs and trunk, and histopathological findings may be accompanied by vasculitis in addition to septal panniculitis. Few studies have examined the differences in the clinical characteristics of patients with EN based on rash distribution. We retrospectively examined whether there was a correlation with clinical information, such as the presence or absence of underlying diseases, by classifying the patients into two groups: the lower limbs group (the EN rash was confined to the lower limbs) and the beyond lower limbs group (the EN rash appeared beyond the lower limbs). Among the 86 adult patients diagnosed with EN at the Dermatology Department of Fujita Medical University between 2015 and 2020, there were 65 cases of the lower limbs group and 21 cases of the beyond lower limbs group. The frequency of underlying diseases was significantly higher in the beyond lower limbs group (76.2%, 16 cases) than in the lower limbs group (40.0%, 26 cases; P < 0.005). Vasculitis was more notable in the beyond lower limbs group (P < 0.05). Significantly higher vasculitis was noted in the EN group with underlying diseases (30.2%, 13 cases) than in the idiopathic EN group without underlying diseases (11.6%, 5 cases; P < 0.05). Neutrophil extracellular traps were positive in approximately 40% of cases in both groups. In the beyond lower limbs group, the possibility of severe cases with underlying diseases, vasculitis, and inflammation must be considered for effective treatment.

Abstract is missing (Short communication)

Combination therapy with BRAF and MEK inhibitors (BRAFi/MEKi) have dramatically improved prognosis among patients with BRAF-mutant metastatic melanoma compared with traditional treatment, such as chemotherapy. However, resistance to these targeted agents occurs invariably, thereby limiting their clinical efficacy. Recently, it has been reported that the ligand-independent phosphorylation of erythropoietin-producing hepatocellular receptor A2 (EphA2) at Ser-897 signaling is a driver of BRAF inhibitor resistance in melanoma. A melanoma patient with multiple metastases was treated with dabrafenib plus trametinib therapy and maintained complete remission for more than 2 years. As brain metastasis occurred, we had switched to nivolumab plus ipilimumab therapy. However, new lesions were observed after four cycles of nivolumab plus ipilimumab therapy, she was rechallenged with encorafenib plus binimetinib therapy, and she maintained progression-free status for more than 7 months. We performed immunohistochemical staining of EphA2, phospho-EphA2 (p-EphA2; Ser-897), and epidermal growth factor receptor (EGFR) of melanoma cells before and/or after dabrafenib and trametinib therapy. Immunohistochemical examination showed higher expression of EphA2, p-EphA2, and EGFR in the melanoma cells after dabrafenib plus trametinib therapy as compared with that before therapy. Our results may indicate that EphA2, p-EphA2, and EGFR can be critical factors for resistance and reversible response of BRAFi/MEKi in metastases of melanoma. Our case presents a possible treatment that can help overcome BRAFi/MEKi resistance and improve prognosis of melanoma.

BACKGROUND: More effective treatment strategies are needed for the chronic skin ulcers. Recently, it has been reported that clinical application of stem cells improve wound healing. OBJECTIVE: We aimed to determine the dynamic time-course movement of epidermal stem cell markers especially p75 neurotrophin receptor (p75NTR) and Integrin beta-1 in wound healing process. Furthermore, we also investigated the presence of these markers in human. METHODS: Epidermal Integrin beta-1(+) and p75NTR(+) cells were counted in wound healing process in mice. Both cells were also counted in human skin specimen obtained from chronic skin ulcers and healthy controls. Growth factor gene expression levels by purified mouse epidermal p75NTR(+) cells were also analyzed using real-time RT-PCR. RESULTS: Integrin beta-1(+) and p75NTR(+) cells were proliferated from 3 days after wounding. Reepithelization was completed 7 days after wounding, and the numbers of cells were returned to the baseline levels by 14 days after wounding. Integrin beta-1(+) cells were proliferated in the basal layer, and p75NTR(+) cells were proliferated in the upper layer of epidermis. In human skin, Integrin beta-1(+) and p75NTR(+) cells were 81%±12% and 36%±15% of the basal cells, respectively. In patients with chronic skin ulcers, the percentage of Integrin beta-1(+) cells in the epidermis was identical to healthy controls. Surprisingly, p75NTR(+) cells were significantly decreased in chronic skin ulcer patients (1.2%±2.6%; p<0.0005) compared to healthy controls. Purified mouse epidermal p75NTR(+) cells expressed higher transforming growth factor-beta2 and vascular endothelial growth factor-alpha transcripts and lower epidermal growth factor transcripts than p75NTR(-) cells. CONCLUSION: These results suggest that Integrin beta-1(+) and p75NTR(+) cells play an important role in wound healing process, and that p75NTR may be a key molecule and a candidate for new therapeutic target besides preexisting molecules for chronic skin ulcer patients.

Regulatory B cells control inflammation and autoimmunity in mice, including the recently identified IL-10-competent B10 cell subset that represents 1% to 3% of spleen B cells. In this study, a comparable IL-10-competent B10 cell subset was characterized in human blood. B10 cells were functionally identified by their ability to express cytoplasmic IL-10 after 5 hours of ex vivo stimulation, whereas progenitor B10 (B10pro) cells required 48 hours of in vitro stimulation before they acquired the ability to express IL-10. B10 and B10pro cells represented 0.6% and approximately 5% of blood B cells, respectively. Ex vivo B10 and B10pro cells were predominantly found within the CD24(hi)CD27(+) B-cell subpopulation that was able to negatively regulate monocyte cytokine production through IL-10-dependent pathways during in vitro functional assays. Blood B10 cells were present in 91 patients with rheumatoid arthritis, systemic lupus erythematosus, primary Sjögren syndrome, autoimmune vesiculobullous skin disease, or multiple sclerosis, and were expanded in some cases as occurs in mice with autoimmune disease. Mean B10 + B10pro-cell frequencies were also significantly higher in patients with autoimmune disease compared with healthy controls. The characterization of human B10 cells will facilitate their identification and the study of their regulatory activities during human disease.

Immune cells are critical to the wound-healing process, through both cytokine and growth factor secretion. Although previous studies have revealed that B cells are present within wound tissue, little is known about the role of B cells in wound healing. To clarify this, we investigated cutaneous wound healing in mice either lacking or overexpressing CD19, a critical positive-response regulator of B cells. CD19 deficiency inhibited wound healing, infiltration of neutrophils and macrophages, and cytokine expression, including basic and acidic fibroblast growth factor, interleukin-6, platelet-derived growth factor, and transforming growth factor-beta. By contrast, CD19 overexpression enhanced wound healing and cytokine expression. Hyaluronan (HA), an endogenous ligand for toll-like receptor (TLR)-4, stimulated B cells, which infiltrates into wounds to produce interleukin-6 and transforming growth factor-beta through TLR4 in a CD19-dependent manner. CD19 expression regulated TLR4 signaling through p38 activation. HA accumulation was increased in injured skin tissue relative to normal skin, and exogenous application of HA promoted wound repair in wild-type but not CD19-deficient mice, suggesting that the beneficial effects of HA to the wound-healing process are CD19-dependent. Collectively, these results suggest that increased HA accumulation in injured skin induces cytokine production by stimulating B cells through TLR4 in a CD19-dependent manner. Thus, this study is the first to reveal a critical role of B cells and novel mechanisms in wound healing.

OBJECTIVE: To determine serum concentrations of pentraxin 3 (PTX3) and its clinical associations in patients with systemic sclerosis (SSc). METHODS: Serum PTX3 levels from 45 patients with diffuse cutaneous SSc (dSSc), 46 with limited cutaneous SSc (lSSc), and 20 healthy controls were examined by ELISA. PTX3 expression in the sclerotic skin from SSc patients was evaluated immunohistochemically. Normal and SSc fibroblasts were cultured and PTX3 levels in the culture medium were also examined by ELISA. RESULTS: Serum PTX3 levels were elevated in patients with SSc relative to controls. PTX3 levels in dSSc patients were significantly higher than in controls and lSSc patients. PTX3 expression in the sclerotic skin from SSc patients was more intense relative to normal skin. Elevation of serum PTX3 levels was associated with more frequent presence of pulmonary fibrosis, cardiac disease, and pitting scar/ulcer and increased serum immunoglobulin levels and erythrocyte sedimentation rates. PTX3 levels correlated positively with modified Rodnan total skin thickness score, and negatively with percentage vital capacity and percentage DLCO in patients with SSc. PTX3 levels also correlated positively with serum levels of 8-isoprostane, a marker of oxidative stress, and hyaluronan, recently identified as an endogenous ligand for Toll-like receptors. PTX3 production from cultured SSc fibroblasts was increased by stimulation with hyaluronan. CONCLUSION: These results suggest that elevated serum PTX3 levels are associated with the disease severity of SSc.

Herein, we describe five patients with necrotizing fasciitis (NF) who had variable outcomes and clinical manifestations. At the onset, all patients exhibited purpura with or without blister and ulceration accompanied by severe pain and tenderness in the affected skin. Out of five patients, three lacked inflammatory signs such as redness and heat, and two of the three patients showed fulminant progression and died despite intensive treatments including surgical debridement, antimicrobial therapy, close monitoring and physiological support. Tissue specimens from the patients without skin inflammatory signs showed mild neutrophil infiltration in addition to necrosis from the epidermis to subcutaneous fat, and variable amounts of thrombi. Furthermore, numerous bacteria were detected by Gram stain. By contrast, the remaining two patients with skin inflammatory signs revealed slower progression, and tissue specimens from both patients showed heavy neutrophil infiltration, but bacteria were hardly detected. Therefore, these cases suggest the possibility that the paucity of skin inflammatory signs, such as redness and heat, in NF may be a clinical clue to predict the fulminant type.

OBJECTIVE: To determine the prevalence, immunoglobulin subclass distribution, and clinical correlation of antibodies (Abs), especially of IgE Abs, to BP180 and BP230 in patients with bullous pemphigoid (BP). DESIGN: Retrospective case series analysis. SETTING: Department of Dermatology, Nagasaki University Graduate School of Biomedical Science. PATIENTS: Serum samples from 37 patients with BP, 6 with pemphigus vulgaris, 5 with pemphigus foliaceus, and 26 healthy controls (n = 26) were examined by enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURES: Prevalence, immunoglobulin subclass distribution, and clinical correlation of Abs, especially of IgE Abs, to BP180 and BP230. RESULTS: IgG anti-BP180 and anti-BP230 Abs were detected in 35 (95%) and 26 (70%) of the 37 BP serum samples, respectively. IgG1 and IgG4 isotypes were positive in 32 (87%) and 25 (68%), respectively, of the BP serum samples for anti-BP180 Abs, while they were detected in 16 (44%) and 26 (70%), respectively, for anti-BP230 Abs. IgE anti-BP180 and anti-BP230 Abs were equally detected in 8 (22%) of the BP serum samples. Similar to IgG anti-BP180 Abs, the presence or levels of IgE anti-BP180 Abs was associated with broader skin lesions. Furthermore, patients with BP positive for IgE anti-BP180 Abs required longer duration for remission, higher dosage of prednisolone, and more intensive therapies for remission. By contrast, this was not true for those with of IgE anti-BP230 Abs. Remarkably, when analyzed in patients with BP who had a high titer of IgG anti-BP180 Abs, the presence or levels of IgE anti-BP180 Abs, but not IgG anti-BP180 Abs, were associated with a more severe form. CONCLUSIONS: The present study suggests that IgE anti-BP180 Abs are related to the disease severity and activity of BP. Moreover, it may be possible to identify treatment-refractory patients with BP more specifically by assessing the presence or levels of IgE anti-BP180 Abs in those with a high IgG anti-BP180 Ab titer.

OBJECTIVES: To determine the prevalence and clinical correlation of autoantibody to peroxiredoxin (Prx) I, an antioxidant enzyme, in patients with systemic sclerosis (SSc). METHODS: Serum samples from SSc patients (n = 70) and healthy controls (n = 23) were examined by ELISA using human recombinant Prx I. The presence of anti-Prx I antibody was further evaluated by immunoblotting analysis. To determine the functional relevance of anti-Prx I antibody in vivo, we assessed whether anti-Prx I antibody was able to inhibit Prx I enzymatic activity using yeast thioredoxin reductase system. RESULTS: IgG anti-Prx I antibody levels in SSc patients were significantly higher than healthy controls and this autoantibody was detected in 33% of SSc patients. The presence of IgG anti-Prx I antibody was associated with longer disease duration, more frequent presence of pulmonary fibrosis, heart involvement, and anti-topoisomerase I antibody and increased levels of serum immunoglobulin and erythrocyte sedimentation rates. IgG anti-Prx I antibody levels also correlated positively with renal vascular damage and negatively with pulmonary function tests. Furthermore, anti-Prx I antibody levels correlated positively with serum levels of 8-isoprostane, a marker of oxidative stress. Immunoblotting analysis confirmed the presence of anti-Prx I antibody. Remarkably, Prx I enzymatic activity was inhibited by IgG isolated from SSc sera containing IgG anti-Prx I antibody. CONCLUSIONS: These results suggest that elevated IgG anti-Prx I autoantibody is associated with the disease severity of SSc and that anti-PrxI antibody may enhance the oxidative stress by inhibiting Prx I enzymatic activity.