[MACULOPAPULAR CUTANEOUS MASTOCYTOSIS HARBORING A KIT MUTATION (ASP419DEL): A CASE REPORT].

A 2-year-old, male patient presented with an 18-month history of scattered, brown macules and nodules up to 2 cm in size on his trunk and extremities. These macules were accompanied by pruritus and were positive for Darier's sign. A skin biopsy of a brown macule on the left thigh revealed a dense accumulation of CD117-positive, round or oval cells with amphophilic cytoplasm within the upper to middle dermis. The patient was otherwise healthy and had normal laboratory and imaging test results. Sequence analysis of genomic DNA from a skin biopsy demonstrated the presence of an Asp419del mutation in exon 8 of the KIT gene. Based on these findings, maculopapular cutaneous mastocytosis (MPCM) was diagnosed. The patient received H 1-antihistamine. Although the pruritus resolved, the brown macules remained for one year after the initial treatment. To the best of our knowledge, only three cases of cutaneous mastocytosis (CM) with an Asp419del mutation, including the present case, have been reported in the Japanese literature to date; moreover, while the previous two cases were of DCM, the present case was the first instance of MPCM. Normally, the symptoms of childhood-onset MPCM are dormant until puberty. However, a recent study reported that many MPCM patients may experience persistent or exacerbated symptoms. The present study therefore evaluated 53 Japanese cases of childhood onset MPCM with a KIT gene mutation and discussed the patients' clinical outcomes.

[TWO CASES OF ALLERGY WITH MUNG BEAN SPROUTS].

Patient 1 was a female patient in her teens who presented with swelling of the lips and oral discomfort after consuming mung bean sprouts. She had a history of this reaction since the age of 6 years and showed positive on a prick-to-prick test for mung bean sprouts. Patient 2 was a male patient in his twenties who also showed positive for mung bean sprouts as well as soybean sprout. Both patients were positive for IgE specific to birch, Gly m4, and Bet v1.Mung beans belong to the PR-10 family because they contain the allergenic component, Vig r1. A cross reaction to mung bean may occur in a patient with birch allergy as in the present cases. Mung bean sprouts are a cheap and common dietary item in Japan where, however, only a few cases of mung bean sprouts allergy have been reported. Mung bean sprouts allergy should be diagnosed with appropriate testing; if the patient has allergic reactions for this food item, an allergologist should provide detailed dietary guidance for avoiding pollen-food allergy syndrome.

[ANALYSIS OF 201 PATIENTS WITH ATOPIC DERMATITIS RECEIVING DUPILUMAB AT TOKYO MEDICAL UNIVERSITY HOSPITAL].

OBJECTIVE: The present study aimed to assess the course of patients with atopic dermatitis (AD) receiving dupilumab treatment. METHODS: The present, retrospective survey enrolled 201 patients with AD between May 2018 and May 2022 to examine their previous treatment, skin score, percentage of self-injections, EASI improvement rate, treatment continuation rate, number of treatment interruptions, and reasons for the interruptions. RESULTS: The average EASI severity score was 39.5±18.1, and the self-injection rate was 83%. The percentage of improvement in patients with an EASI-75 was 63% at week 16 and EASI 100 was 15.9% at week 60. At week 16 of treatment, the patients were divided by their improvement rate into an EASI-75, < 50 group. The EASI-75 group maintained their improvement rate until week 60. In the EASI< 50% group achieved 73.4% at week 60. The treatment continuation rate was 82.6%, and 35 patients discontinued the treatment, in most cases shortly after commencement. CONCLUSION: Dupilumab has revolutionized AD treatment, markedly improving skin symptoms. The present study was the first in Japan to demonstrate a treatment continuation rate of 82.6% at week 60 at a single center. Clear guidelines on long-term, complete maintenance treatment with dupilumab await formulation.

Pediatric Cutaneous Mastocytosis With Motor and Intellectual Delay.

Pediatric mastocytosis is a relatively rare disorder and most commonly occurs as isolated cutaneous lesions. Although autism spectrum disorders have been reported to be associated with mastocytosis, no clear association between mastocytosis and motor and intellectual delay has been reported with the exception of the case that detected de novo monoallelic mutations in the GNB1 gene. Herein, we describe the case of a Japanese male pediatric patient aged two years and six months who had cutaneous mastocytosis accompanied by motor and intellectual delay without the presence of GNB1 mutation.

Topical application of imatinib mesylate suppresses vitamin D3 analog-induced dermatitis in Balb/c mice.

Atopic dermatitis (AD) is an allergic disease mediated by Th2 cells. In AD, externally stimulated keratinocytes release inflammatory cytokines, such as IL-33 and TSLP. Inflammatory cells infiltrate skin tissue and increase vascular permeability. Therefore, we hypothesized that imatinib mesylate (IMT), which suppresses vascular permeability, may be a candidate therapeutic agent for AD. A vitamin D3 analog (MC903) was administered daily to both ears of Balb/c mice to create a murine AD model to which IMT was applied. The skin lesions were evaluated histopathologically and by immunostaining. Cytokine expression in the skin was assessed by using real-time polymerase chain reaction (PCR) and immunostaining and was investigated using Evans Blue to determine whether IMT suppressed vascular permeability due to histamine. The suppressive effect of TNF-α/IL-4-induced TSLP expression in primary mouse keratinocytes (MKCs) treated with IMT was then investigated. Tslp gene and protein expression in the lesion was measured using real-time PCR and ELISA. The activation of signal transduction was analysed by western blotting. Topical application of IMT significantly reduced ear thickness, Evans blue leakage, and scratch onset. IMT suppressed the number of infiltrating cells (CD4+ T cells, eosinophils, and basophils), and the expression of IL-13, IL-33, and TSLP in a MC903-induced, murine AD model and inhibited TNF-α/IL-4-induced TSLP expression via downregulation of ERK phosphorylation in MKCs. IMT reduced the skin symptoms in a MC903-induced, murine AD model, suggesting that it may have potential as a new treatment for AD.

[A CHILD CASE OF DIFFUSE CUTANEOUS MASTOCYTOSIS].

Cutaneous mastocytosis (CM) usually appears in childhood and improves substantially before adolescence. The c-KIT mutation of D816V is present in 36% and 20% of patients with childhood-onset CM and diffuse cutaneous mastocytosis (DCM), respectively. In some cases of childhood-onset DCM, the disease can progress to systemic mastocytosis; in others, it resolves spontaneously. Thus, assessing the prognosis is difficult. Herein, we described a case of DCM in an 11-month-old, male patient without a c-KIT mutation. The patient presented with dark brown macules and sporadic erythema topped by bullous lesions. A skin biopsy of the macule on the abdomen revealed accumulation of mast cells which were round to oval-shaped with amphophilic cytoplasm within the upper dermis. The patient had received H1 inhibitor until age 3 years and continued to experience blisters on the trunk. However, no severe symptoms, such as anaphylaxis, occurred. Included in this manuscript is a review of previous reports of childhood-onset DCM in Japan and cases specifically seen at our dermatology clinic.

Recent trends of ocular complications in patients with atopic dermatitis.

PURPOSE: To elucidate the recent trends in prevalence and characteristics of ocular complications of atopic dermatitis (AD). STUDY DESIGN: Cross-sectional observational study. METHODS: Among AD patients who visited our department between 2012 and 2015, 70 patients (140 eyes; recent AD group) who gave informed consent to participate in the study were analyzed. Following a medical interview, ophthalmological examinations were conducted for ocular complications related to AD. The data were compared to those of 280 AD patients (560 eyes) analyzed in a similar study conducted at our department in 1991-1993 (previous AD group). RESULTS: Blepharitis was found in 58 eyes (41%) in the recent AD group, and the frequency was significantly lower compared to the previous AD group (294 eyes, 53%) (p < 0.05). Tears in retina or pars plana ciliaris occurred in 22 eyes (4%) in the previous AD group, compared with none in the recent AD group (p < 0.01). Retinal detachment was observed in 12 eyes (2%) in the previous AD group, and none in the recent AD group (p < 0.01). Atopic keratoconjunctivitis (AKC) increased significantly in the recent AD group compared to the previous AD group (74.3% vs. 39.5%) (p < 0.001). Patients with a habit of slapping around the eye decreased significantly from 32.5% in the previous AD group to 12.1% in the recent AD group (p < 0.001). CONCLUSIONS: Ocular complications in AD patients show a trend of decrease in recent years, which presumably is attributed to educational activities to increase patient awareness and advances in therapeutic strategy.

[THE ANALYSIS OF ANAPHYLAXIS DIAGNOSED AT DERMATOLOGY OF TOKYO MEDICAL UNIVERSITY HOSPITAL].

OBJECTIVE: There are few epidemiological reports of anaphylaxis since childhood. We herein examined cases of anaphylaxis diagnosed in our department. METHODS: One hundred-thirty-two patients who were examined at the Dermatology Department of Tokyo Medical University Hospital between January 2011 and March 2017 and were prescribed epinephrine autoinjector (EpiPen®) for treatment were enrolled. The referral institution if any, severity of anaphylaxis, diagnostic method, causative antigen, and recurrence rate was examined. RESULTS: The referral rate was 54% while 46% of patients requested examination of their own accord. Anaphylaxis severity was mild to moderate in 75% of cases. Food allergy accounted for 71% of the symptoms, with wheat as the most common causative antigen, followed by Anisakis allergy. After diagnosis only 37% of patients continued periodic consultations, and 16 patients recurred anaphylaxis of the diagnosis. CONCLUSION: Wheat and WDEIA were the most frequent causes of anaphylaxis diagnosed in our department. We also found that as many as 15% of patients had Anisakis allergy, suggesting that it may be an important item in antigen testing.

IL-33 promotes ICAM-1 expression via NF-kB in murine mast cells.

BACKGROUND: IL-33, a member of the IL-1 cytokine family, binds to heterodimeric receptors ST2 and IL-1 receptor accessory protein, and activates Th2-type immune responses. The signals from the ST2 receptor are mediated by the two major pathways, including AP-1 and NF-κB molecules. The present study examined whether IL-33 induced ICAM-1 expression in bone marrow-derived mast cells (BMMCs). METHODS: BMMCs from C57BL/6J mice, cultured in media containing IL-3 (20 ng/ml), were treated with IL-33 (50 ng/ml) for up to 72 h. ICAM-1 expression with mRNA and protein, degranulation of siRNA ICAM-1 transfected BMMCs, and cell adhesion were analyzed. In the in vivo part of the experiment rIL-33 (500 ng) was injected intradermally into the ear pinnae of mice and any resulting pathological changes were assessed. RESULTS: ICAM-1 mRNA expression was increased one hour after IL-33 stimulation while ICAM-1 protein attained maximum expression levels 24 h after IL-33 stimulation. Moreover, IL-33-treated BMMCs showed increased cell adhesion to the LFA-1-coated plate. However, siRNA ICAM-1 transfected BMMCs did not affect Ag/IgE-mediated degranulation level compared to the wild control siRNA. Pre-treatment with a NF-κB inhibitor dramatically reduced ICAM-1 expression in IL-33-treated BMMCs, suggesting the involvement of NF-κB in the process. In vivo study, at 6 h after IL-33 treatment, MCs histologically showed up-regulated ICAM-1 expression though the number of tryptase-positive cells did not change. CONCLUSIONS: These data suggest that MCs increase ICAM-1 expression and activate LFA-1 positive cells in the early phase of skin inflammation in response to IL-33.

IL-33 promotes MHC class II expression in murine mast cells.

Mast cells (MCs), recognized as tissue-resident cells of hematopoietic origin, are involved in cellular and pathological manifestations of allergic disorders including atopic dermatitis. IL-33, a member of the IL-1 cytokine family, activates Th2-type immune responses, and promotes the degranulation and maturation of MCs. However, it is uncertain whether IL-33 treatment induces mature mast cells to acquire the characteristics of the monocyte-dendritic cell lineage.We investigated the effect of IL-33 on the MHC class II expression and function of murine mast cells. IL-33-treated mature murine bone marrow-derived mast cells (BMMCs) were analyzed by FACS, real-time PCR, chromatin immunoprecipitation (ChIP) assay, and Western blotting. The morphology and degranulation activity of BMMCs and T-cell activation by BMMCs were also examined. BMMCs treated with IL-33 for 10 days induced cell surface expression of the MHC class II protein, whereas the expression of FcεRI and c-kit was not affected by IL-33. The expression of CIITA, driven from pIII and pIV, was up-regulated in IL-33-treated BMMCs. The amount of PU.1 mRNA and protein significantly increased in IL-33-treated BMMCs. The ChIP assay showed PU.1 binding to CIITA pIII, and enhanced histone acetylation due to IL-33 treatment. Syngeneic T cells were activated by co-culture with IL-33-treated BMMCs, although the expression of the co-stimulatory molecules, CD40, CD80, CD86, and PDL-1, was not detected. Mast cells express MHC class II after prolonged exposure to IL-33, probably due to enhanced recruitment of PU.1 to CIITA pIII, resulting in transactivation of CIITA and MHC class II. IL-33 is an important cytokine in allergic disorders. Mast cells have the ability to express MHC class II after prolonged exposure to IL-33 in a murine model. IL-33 holds a key to understanding the etiology of atopic dermatitis.