Aspiration of acidified milk induces milk allergy by activating alveolar macrophages in mice.

BACKGROUND: Epidemiological studies have identified associations between gastroesophageal reflux (GER) and cow's milk allergy (CMA) in infants. However, the role of GER in the development of CMA remains poorly understood. Our primary objectives were to develop a mouse model that suggests GER as a potential pathogenic mechanism for CMA and to elucidate the immunological mechanisms that connect lung innate immunity with CMA. METHODS: Mice were exposed to cow's milk (CM) treated with hydrochloric acid through repeated aspiration into their airways. Subsequently, they were challenged by intraperitoneal injection of CM extract. The immunological mechanisms were investigated using comprehensive single-cell RNA sequencing (scRNA-seq) analysis of the lungs, combined with the use of genetically modified mice. RESULTS: Mice exposed to CM mixed with hydrochloric acid via airway sensitization developed CMA, as evidenced by the production of antigen-specific IgE and IgG antibodies, and the induction of anaphylaxis upon systemic antigen administration. In contrast, aspiration of CM alone did not induce CMA. scRNA-seq analysis revealed potential roles of alveolar macrophages in response to hydrochloric acid. Mice lacking the TLR4 pathway were protected from developing CMA. CONCLUSIONS: We have developed a novel mouse model for CMA that utilizes the natural antigen and follows the physiological airway sensitization pathway, thus potentially resembling clinical scenarios. This model, named the acidified milk aspiration-induced allergy model, has the potential to shed light on the role of early innate immunity by analyzing a more physiological model.

House dust mite SLIT-tablet is well tolerated in pediatric patients with controlled asthma.

BACKGROUND: : Despite the reported clinical effectiveness of house dust mite (HDM) sublingual immunotherapy (SLIT) in pediatric patients, the risk of treatment remains unclear in pediatric patients with allergic asthma. OBJECTIVE: To show a risk of adverse drug reactions (ADRs) in pediatric patient with allergic asthma during the initiation period of HDM SLIT. METHODS: We retrospectively analyzed the clinical data of pediatric patients aged ≤ 15 years who initiated allergen immunotherapy (AIT) with the SQ HDM SLIT-tablet for allergic rhinitis between February 2017 and September 2019. Asthma severity at baseline and ADRs during the first 4 weeks of the treatment were determined for each subject. RESULTS: In our study population (n = 217; median age, 8.4 years), 99 patients (45.6%) were classified as having asthma. One hundred and one patients (46.5%) in the whole cohort experienced ADRs during the first 4 weeks of therapy, but a major gap in the frequency of ADRs was not observed between an asthma group and a non-asthma group. CONCLUSIONS: The SQ HDM SLIT-tablet was well tolerated in pediatric patients with controlled HDM-driven allergic asthma. HDM-SLIT is an option to treat their allergic rhinitis without excessive concern for its ADRs.

Effect of Japanese cedar-specific sublingual immunotherapy on allergen-specific TH2 cell counts in blood.

BACKGROUND: The contribution of antigen-specific TH cells in peripheral blood to immunologic mechanisms underlying sublingual immunotherapy (SLIT) remains unclear, partly because of the lack of a standardized method for the analysis of this rare lymphocyte subset. OBJECTIVE: To clarify the role of antigen-specific TH cells during SLIT using a sensitive method analyzing activation marker CD154-positive TH cells with multicolor flow cytometry. METHODS: We assessed antigen-specific TH cells using multicolor flow cytometry based on the expression of the activation marker CD154 and intracellular cytokines in patients with Japanese cedar pollinosis receiving SLIT at baseline and during the first pollen season after the initiation of SLIT. RESULTS: A total of 18 patients between 12 and 44 years of age were enrolled in the present study. Of these, 8 patients received SLIT (SLIT group) and 10 patients received symptomatic treatment only (control group). Although seasonal pollen exposure significantly increased the number of Japanese cedar-specific interleukin 5- and interleukin 4-producing TH cells in the control group (P < .01 for both), SLIT ameliorated this increase in the SLIT group (P = .64 and P = .84, respectively). CONCLUSION: The present study indicates that allergen-specific TH2 cells in peripheral blood are involved in mechanisms underlying SLIT. The analysis of antigen-specific TH cells using multicolor flow cytometry based on the expression of the activation marker CD154 represents a sensitive and relatively simple, standardized method for monitoring peripheral antigen-specific TH cells during allergen-specific immunotherapy.

Japanese cedar pollen-based subcutaneous immunotherapy decreases tomato fruit-specific basophil activation.

BACKGROUND: Some patients with Japanese cedar pollen (JCP)-induced allergic rhinitis develop pollen-food allergy syndrome (PFAS) as a reaction to tomato fruit. Pollen allergen-specific subcutaneous immunotherapy (SCIT) is reportedly beneficial for some associated food allergies; however, the reported changes in food allergen-specific immunoglobulin (Ig)E and IgG4 levels are inconsistent. Here, we investigated immunologic reactivity to tomato fruit after JCP-based SCIT. METHODS: Twenty-three children (aged 6-17 years) with JCP-induced allergic rhinitis and sensitized to tomato (serum tomato fruit-specific IgE level >0.34 UA/ml) received JCP-based SCIT. Basophil activation by tomato and JCP extracts and serum-specific IgE and IgG4 levels against these allergens were determined before and after 4 or 5 months of maintenance SCIT. Basophil activation was assessed by monitoring CD203c upregulation on flow cytometry. RESULTS: JCP-based SCIT significantly reduced the basophil activation caused by tomato fruit (p = 0.03) and JCP (p < 0.001) extracts. JCP-specific IgG4 levels markedly increased after SCIT (p < 0.001), whereas tomato fruit-specific IgG4 levels did not. After SCIT, no significant changes were observed in specific IgE levels for tomato fruit (p = 0.11) or JCP (p = 0.19). CONCLUSIONS: Tomato fruit-specific basophil activation decreases after JCP-based SCIT, suggesting that it is efficacious in relieving and preventing the symptoms of PFAS in patients with JCP-induced allergic rhinitis.

Multicolor flow-cytometric analysis of milk allergen-specific T-helper type 2 cells revealed coexpression of interleukin-4 with Foxp3.

BACKGROUND: Allergen-specific T-helper type 2 (TH2) cells play an important role in the development of allergic inflammation; however, investigations of the properties of allergen-specific T cells have been challenging in humans. Despite clear evidence that forkhead box p3 (Foxp3) is expressed in conventional effector T cells, its function has remained unknown. OBJECTIVE: To characterize allergen-specific TH2 cells in milk allergy, with particular focus on the expression of Foxp3. METHODS: Twenty-one children with milk allergy and 11 children without milk allergy were studied. Peripheral blood mononuclear cells from subjects were stimulated with milk allergen for 6 hours and analyzed using multicolor flow cytometry to identify CD154(+) allergen-specific T-helper cells. Simultaneously, the expression of intracellular cytokines and Foxp3 was analyzed. RESULTS: The milk allergy group had significantly larger numbers of milk allergen-specific interleukin (IL)-4- and IL-5-producing CD4(+) T cells than the control group. Subjects in the milk allergy group had significantly more CD154(+)CD4(+) IL-10-producing cells and CD154(+)Foxp3(+)CD4(+) cells than those in the control group. In addition, the number of milk allergen-specific CD154(+)Foxp3(+)CD4(+) cells strongly correlated with that of CD154(+)IL4(+)CD4(+) cells. Bcl-2 expression in CD154(+)IL-4(+)Foxp3(+) T-helper cells was significantly lower compared with that in total CD4 cells. CONCLUSION: Increased numbers of IL-4-producing allergen-specific T-helper cells were found in patients with milk allergy. In addition, Foxp3 was coexpressed with IL-4 in allergen-specific TH2 cells from patients. This coexpression was associated with lower Bcl-2 levels and could contribute to the phenotype and function of TH2 cells.

Diffuse alveolar hemorrhage secondary to ANCA-associated vasculitis in a patient with Down syndrome.

Diffuse alveolar hemorrhage (DAH) is a rare disease characterized by dyspnea, cough, hemoptysis, and new alveolar infiltrates. Among the various underlying disorders, vasculitis is believed to play a significant role in the pathogenesis of DAH. Here we report the first case of a patient with Down syndrome who developed DAH secondary to anti-neutrophil cytoplasmic antibody-associated vasculitis. This case highlights the significance of vasculitis as well as pulmonary hypoplasia and vulnerability associated with Down syndrome in the development of DAH.

Effect of Japanese cedar specific immunotherapy on allergen-specific T(H)2 cells in peripheral blood.

BACKGROUND: The involvement of a shift from TH2 to TH1 responses in peripheral blood in pollen subcutaneous immunotherapy (SCIT) has been contentious, partly because of difficulties analyzing antigen-specific TH cells. OBJECTIVES: To use recent technical advances to establish a more direct and simple method to analyze antigen-specific TH cells and to clarify the involvement of a TH2/TH1 shift in peripheral blood in pollen specific immunotherapy. METHODS: After short-term (6-hour) antigen stimulation, antigen-specific TH cells in peripheral blood of Japanese children and young adults with Japanese cedar pollinosis undergoing SCIT were analyzed by multicolor flow cytometry for the presence of the activation marker CD154 and intracellular cytokines. RESULTS: Twenty-eight patients between 5 and 22 years of age were enrolled in the study; 22 had started SCIT after enrolling in the study (SCIT group), and the remaining 6 were planning to start SCIT in the next off-season (control group). The number of Japanese cedar-specific interleukin (IL) 5-, IL-4-, interferon γ-, IL-17A-, IL-10-, and tumor necrosis factor α-producing TH cells without antigen-driven cell proliferation was determined. The seasonal increase in the number of Japanese cedar-specific IL-5- and IL-4-producing TH cells seen in the control group was suppressed in the SCIT group (P < .005 and <.001, respectively). CONCLUSION: We report a powerful method for the analysis of antigen-specific TH cells in peripheral blood. This method will contribute to our understanding of immune mechanisms of immunotherapy and help us develop more sophisticated allergen specific immunotherapy.

Two cases of transplant-acquired food allergy who developed resensitization after a negative oral food challenge.

BACKGROUND: Cases of food allergy after hematopoietic stem cell and solid organ transplantation in previously nonallergic transplant recipients were reported as transplant-acquired food allergy (TAFA), but information about its long-term outcome is still limited. A phenomenon where patients reacquire food allergy by resuming daily consumption after a negative oral food challenge has not yet been reported. CASE PRESENTATION: We report two cases of TAFA after liver transplantation and cord blood transplantation. In each case, the threshold of daily consumption to cause allergic symptoms decreased when a negative oral food challenge was obtained. CONCLUSIONS: Our cases show an importance of gastrointestinal tract as a route of food sensitization because thresholds that caused allergic reactions decreased during their resuming process. We need to be careful with possible resensitization once a negative substantial dose was confirmed.

DOOR syndrome concomitant with non-convulsive status epilepticus and hyperintense cerebellar cortex on T2-weighted imaging.

We report a case study of an 11-year-old Japanese boy with complex partial status epilepticus, a type of non-convulsive status epilepticus, concomitant with DOOR syndrome. To our knowledge, this is the first report of this type of epilepsy concomitant with DOOR syndrome. Magnetic resonance (MR) imaging showed diffuse atrophy of the cerebellar cortex. The cerebellar cortex was hyperintense on T2-weighted imaging. This finding of MR imaging is rare and has been considered pathognomonic for infantile neuroaxonal dystrophy and Marinesco-Sjogren syndrome which are in the entity of metabolic disease. So this lesion may be the result of a metabolic defect occurring in conjunction with DOOR syndrome.

Acylcarnitine profiles during carnitine loading and fasting tests in a Japanese patient with medium-chain acyl-CoA dehydrogenase deficiency.

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is rare among Asian individuals, and the clinical course and biochemical findings remain unclear. We report herein a 3-year-old Japanese girl with MCADD. The diagnosis was suggested by acylcarnitine profiles and confirmed by enzyme activity and genetic analysis after clinical presentation. Our described method with high-performance liquid chromatography/tandem mass spectrometry allows quantification of levels of n-octanoylcarnitine (C8-N) and other isomers (e.g. valproylcarnitine). We examined the patient's acylcarnitine profiles in serum and urine samples during carnitine loading and 14-hr fasting tests with/without carnitine supplementation. Under hypocarnitinemia, serum level of C8-N was 0.16 micromol/l and C8-N/decanoylcarnitine (C10) ratio was 1.8, which did not correspond to the diagnostic criteria for MCADD. However, intravenous carnitine loading test (100 mg/kg/day for 3 days and 50 mg/kg/day for 1 day) led to increased serum C8-N levels and urinary excretion was obvious, strongly suggesting MCADD. In the fasting test with carnitine supplementation, marked production of acylcarnitines (C8-N > C2 >> C6 > C10) was found, compared to the fasting test without carnitine supplementation. These results indicate that carnitine supplementation may be useful for detoxification of accumulated acylcarnitines even in an asymptomatic state. Moreover, the one-point examination for serum C8-N level and/or C8-N/C10 ratio may make the diagnosis of MCADD difficult, particularly in the presence of significant hypocarnitinemia. To avoid this pitfall, attention should be given to serum levels of free carnitine, and carnitine loading may be demanded in hypocarnitinemia.