Food-Induced Anaphylaxis among Children Weighing <15 kg: A Single-Center Case Series of the Pediatric Emergency Department.

INTRODUCTION: Food-induced anaphylaxis among infants shows an increasing prevalence; however, the prescription of epinephrine auto-injectors (EAIs) for children weighing <15 kg is associated with issues of the needle length and the epinephrine dose. Several studies have shown age-related differences in food-induced anaphylaxis, although little is known about the weight-related differences in food-induced anaphylaxis. This study aimed to reveal the incidence, clinical characteristics, and management of food-induced anaphylaxis in children weighing <15 kg. METHODS: This chart review included children who visited the pediatric emergency department (ED) of the National Center for Child Health and Development (Tokyo, Japan) from January 2014 to December 2016 and were diagnosed with food-induced anaphylaxis. The severity of anaphylaxis was evaluated using the Sampson Grading Scale. RESULTS: Of 89,232 ED visits, 444 visits included patients with food-induced anaphylaxis, after excluding cases of food-induced anaphylaxis related to oral desensitization therapy. The incidence was 4.98 per 1,000 visits. More than half of the children (n = 247/444, 55.6%) weighed <15 kg. The proportion of grade 3 and higher severity anaphylactic symptoms was 74.5% (184/247) in children weighing <15 kg and 79.2% (156/197) in children weighing 15 kg or more. The recurrence rate of food-induced anaphylaxis was 22.3% (55/247) in children weighing <15 kg and 48.7% (96/197) in children weighing 15 kg or more. Among the children weighing <15 kg, the proportion of those with recurrent food-induced anaphylaxis was 4 times higher in children weighing 10-15 kg than in those weighing <10 kg (32.2% [47/146] vs. 7.9% [8/101]). The proportion of patients who were prescribed EAIs before each visit was 25.5% (14/55) in children weighing <15 kg with a history of food-induced anaphylaxis. CONCLUSION: Food-induced anaphylaxis among children weighing <15 kg occurred as frequently and was as severe as that among children weighing 15 kg or more. However, the proportion of patients prescribed EAIs was very low in children weighing <15 kg with food-induced anaphylaxis. The potential need for EAIs is suggested among children weighing <15 kg, especially among children weighing 10 kg or more but <15 kg.

Urinary lipid profile of atopic dermatitis in murine model and human patients.

Atopic dermatitis (AD) is the most common inflammatory skin disease in children. The serum level of thymus and activation-regulated chemokine (TARC) is a useful AD index to reflect disease severity; however, it requires blood collection from young children. In comparison, urine samples are easier to collect in a pediatric clinical setting. Here, we analyzed the lipids excreted in urine to identify a diagnostic biomarker for AD. We generated a murine dermatitis model by repeated topical application of 2,4-dinitrofluorobenzene (DNFB) or tape-stripping the dorsal skin. Lipid metabolites excreted in the urine were comprehensively analyzed using liquid chromatography-tandem mass spectrometry. To corroborate our findings, we also analyzed urine samples from patients with AD. DNFB application induced AD-like skin lesions, including epidermal thickening, infiltration of eosinophils and T cells, and an increase in Th2 cytokine levels. Assessment of lipids excreted in urine showed a dominance of prostaglandins (PGs), namely, a PGF2α metabolite (13,14-dihydro-15-keto-tetranor-PGF1α ), a PGE2 metabolite (13,14-dihydro-15-keto-tetranor-PGE2 ), and a PGD2 metabolite (13,14-dihydro-15-keto PGJ2 ). mRNA and protein expression of PGF2α , PGE2 , and PGD2 synthase was upregulated in DNFB-treated skin. The tape-stripping model also caused dermatitis but without Th2 inflammation; urine PGF2α and PGD2 metabolite levels remained unaffected. Finally, we confirmed that the urinary levels of the aforementioned PG metabolites, as well as PGI2 metabolite, 6,15-diketo-13,14-dihydro-PGF1α and arachidonic acid metabolite, 17-hydroxyeicosatetraenoic acid (17-HETE) increased in patients with AD. Our data highlights the unique urinary lipid profile in patients with AD, which may provide insight into novel urinary biomarkers for AD diagnosis.

Early aggressive intervention for infantile atopic dermatitis to prevent development of food allergy: a multicenter, investigator-blinded, randomized, parallel group controlled trial (PACI Study)-protocol for a randomized controlled trial.

BACKGROUND: Atopic dermatitis is the first clinical manifestation of the atopic march, with the highest incidence in the first year of life. Those affected often go on to develop other allergic diseases including food allergy, asthma, and allergic rhinitis. Recent evidence suggests that sensitization to foods may occur through a defective skin barrier which is common in atopic dermatitis in early life. We hypothesize that therapeutic aggressive intervention to treat new onset atopic dermatitis may prevent the development of later allergen sensitization, and associated food allergy, asthma, and allergic rhinitis. METHODS: This study is a multi-center, pragmatic, two-parallel group, assessor-blind, superiority, individually randomized controlled trial. Atopic dermatitis infants (N = 650) 7-13 weeks old who develop an itchy rash within the previous 28 days are randomly assigned to the aggressive treatment or the conventional treatment in a 1:1 ratio. The primary outcome is oral food challenge-proven IgE-mediated hen's egg allergy at the age of 28 weeks. DISCUSSION: This is a novel pragmatic RCT study to examine the efficacy of early aggressive treatment for atopic dermatitis to prevent later food allergy. If our hypothesis is correct, we hope that such a strategy might impact on disease prevention in countries where food allergy is common, and that our results might reduce the frequency and associated costs of all food allergies as well as hens egg food allergy. Long-term follow and other similar studies will help to determine whether such a strategy will reduce the burden of other allergic diseases such as asthma and allergic rhinitis.Trial registration UMIN-CTR: UMIN000028043.

HTLV-I-infected breast milk macrophages inhibit monocyte differentiation to dendritic cells.

Human T-cell leukemia virus type I (HTLV-I), a causative agent of adult T-cell leukemia (ATL), is transmitted from mother to child, predominantly by breastfeeding. Oral HTLV-I infection and infection early in life are associated with a subsequent risk of ATL. Although the pathogenic mechanisms of ATL remain largely unknown, the host immune system seems to play an important role in HTLV-I pathogenesis. Previous studies have shown that monocytes from ATL patients had reduced capacity for dendritic cell (DC) differentiation. Therefore, we performed the present study to clarify the mechanisms responsible for the impairment of DC differentiation using HTLV-I-infected breast milk macrophages (HTLV-BrMMø). We found that when CD14⁺ monocytes were cultured with GM-CSF and IL-4 in the presence of HTLV-BrMMø, they altered the surface phenotype of immature DCs and the stimulatory capacity of T-cell proliferation. The presence of HTLV-BrMMø significantly blocked the increased expression of CD1a, CD1b, CD11b, DC-SIGN, and HLA-DR; however, increased expression of CD1d and CD86 was observed. These effects could be partially replicated by incubation with culture supernatants from HTLV-BrMMø. The impairment of monocyte differentiation might be not due to HTLV-I infection of monocytes, but might be due to unknown soluble factors. Since other HTLV-I-infected cells exhibited similar inhibitory effects on monocyte differentiation to DCs, we speculated that HTLV-I infection might cause the production of some inhibitory cytokines in infected cells. Identifying the factors responsible for the impairment of monocyte differentiation to DCs may be helpful to understand HTLV-I pathogenesis.

Induction of CD56+ T cells after prolonged activation of T cells in vitro: a possible mechanism for CD4+ T-cell depletion in acquired immune deficiency syndrome patients.

The pathogenic mechanisms responsible for depletion of CD4(+) T cells in aquired immune deficiency syndrome (AIDS) are not fully understood. Systemic immune activation mediated by persistent infection of human immunodeficiency virus (HIV) seems to be one of the predictors of disease progression. We predicted that certain lymphocytes responsible for CD4(+) T-cell depletion could be induced in patients during prolonged activation of lymphocytes. Therefore, we have established an in vitro long-term culture system for peripheral blood mononuclear cells with PHA-P stimulation and Herpesvirus saimiri infection, and examined what types of cells having strong cytotoxic activity to be emerged under the activated conditions. We observed that percentage of CD56(+) T cells was gradually increased in cultures from 30 days after stimulation and exhibited a cytotoxic activity against both autologous and allogeneic targets. Interestingly, HIV-1 infection enhanced the susceptibility of CD4(+) T cells to their cytotoxic effectors, and CD4(+) T cells from HIV-1-infected individuals showed decreased survival rate in the presence of autologous CD56(+) T cells. These findings raised the possibility that induction of autoreactive CD56(+) T cells in consequence of immune activation might be contributed to the depletion of CD4(+) T cells in HIV-1-infected patients.

An asymptomatic heterozygous female with fabry disease: implications for enzyme replacement therapy.

We report an asymptomatic female with Fabry disease immunohistochemically diagnosed by renal biopsy. She was initially diagnosed as having nephrotic syndrome, and renal biopsy was performed for pathological diagnosis. The renal specimen revealed non-specific findings (minor glomerular abnormalities) for nephrotic syndrome. Numerous laminated bodies in glomerular epithelial cells in electron microscopic findings and accumulations of ceramidetrihexoside immunohistochemically were observed and she was diagnosed with Fabry disease. However, no other laboratory data or clinical findings supported the diagnosis of Fabry disease. Since the efficacy of recombinant human alpha-galactosidase replacement therapy in this disease has been reported, whether enzyme replacement therapy for subclinical Fabry female patients is indicated or not is an important issue.