Comparison of weight per volume and protein nitrogen units in non-standardized allergen extracts: implications for prescribing subcutaneous immunotherapy.

BACKGROUND: Allergen extracts used in subcutaneous immunotherapy can be standardized or non-standardized. Standardized extracts are available in specific biological potencies, presumably making their biological activity more consistent. The majority of allergen extracts are non-standardized and may have less consistent potencies. Non-standardized extracts are labeled as weight per volume or protein nitrogen units (PNUs). Neither method provides direct information regarding the extract's biologic potency. The purpose of this study was to compare weight per volume versus PNU concentrations for 4 non-standardized allergen extracts prepared by two allergen manufacturers. The potencies were compared to current North American practice recommendations. METHODS: The weight per volume and PNU values were provided for 4 non-standardized extracts-birch, short ragweed, dog hair and Alternaria-from HollisterStier and Stallergenes Greer. Weight per volume and PNU concentrations were compared for each of these extracts from both manufacturers. From the raw data, we calculated the corresponding PNU values for a weight per volume of 1:100 and 1:200 for each extract. Similarly, we calculated the corresponding weight per volume including a range of PNU values, for 1000, 2000, 3000, 4000 and 5000 PNU/ml. RESULTS: Birch extract has low PNU concentration, below 5000, for a weight per volume of 1:200 for both HollisterStier and Stallergenes Greer. In contrast, for both HollisterStier and Stallergenes Greer ragweed extract, a weight per volume of 1:200 corresponds to a PNU concentration greater than 5000. Dog extract for a weight per volume of 1:200, and even for 1:100, corresponds to very low PNUs for both companies. For Alternaria, corresponding PNU concentrations for HollisterStier is low at only 500 while over 5000 for Stallergenes Greer. CONCLUSIONS: Our results show variability when comparing weight per volume and PNU concentrations for both Hollister-Stier and Stallergenes Greer products. We suggest selecting a PNU dose that corresponds to a weight per volume of 1:200 as this may improve patient safety. Our recommendations for starting PNU dose for the four non-standardized extracts are 1500 for birch, 5000 for ragweed, 25 for dog, and 500 for Alternaria when using HollisterStier products; 2300 for birch, 5000 for ragweed, 1200 for dog, and 5000 for Alternaria when using Stallergenes Greer products. If the starting PNU concentration is considerably below 5000 for a weight per volume of 1:200 slow up-titration is advised. Conversely, for PNU concentrations above 5000 for weight per volume of 1:200 we suggest a maintenance dose of 5000 PNU.

Tracheobronchomegaly, cough and recurrent chest infection: Mounier-Kuhn syndrome.

Mounier-Kuhn Syndrome (MKS) is a rare disease characterised by recurrent chest infections, and dilation of the trachea and main bronchi, most likely to due to atrophy of elastic fibres https://bit.ly/3azhDjr.

Evaluation of peroxisome proliferator-activated receptor agonists on interleukin-5-induced eosinophil differentiation.

Peroxisome proliferator-activated receptor (PPAR) agonists have been suggested as novel therapeutics for the treatment of inflammatory lung disease, such as allergic asthma. Treatment with PPAR agonists has been shown to inhibit airway eosinophilia in murine models of allergic asthma, which can occur through several mechanisms including attenuated generation of chemoattractants (e.g. eotaxin) and decreased eosinophil migrational responses. In addition, studies report that PPAR agonists can inhibit the differentiation of several cell types. To date, no studies have examined the effects of PPAR agonists on interleukin-5 (IL-5) -induced eosinophil differentiation from haemopoietic progenitor cells. Non-adherent mononuclear cells or CD34(+) cells isolated from the peripheral blood of allergic subjects were grown for 2 weeks in Methocult(®) cultures with IL-5 (10 ng/ml) and IL-3 (25 ng/ml) in the presence of 1-1000 nm PPARα agonist (GW9578), PPARß/δ agonist (GW501516), PPARγ agonist (rosiglitazone) or diluent. The number of eosinophil/basophil colony-forming units (Eo/B CFU) was quantified by light microscopy. The signalling mechanism involved was assessed by phosphoflow. Blood-extracted CD34(+) cells cultured with IL-5 or IL-5 + IL-3 formed Eo/B CFU, which were significantly inhibited by rosiglitazone (100 nm, P < 0·01) but not GW9578 or GW501516. In addition, rosglitazone significantly inhibited IL-5-induced phosphorylation of extracellular signal-regulated kinase 1/2. We observed an inhibitory effect of rosiglitazone on eosinophil differentiation in vitro, mediated by attenuation of the extracellular signal-regulated kinase 1/2 signalling pathway. These findings indicate that the PPARγ agonist can attenuate tissue eosinophilia by interfering with local differentiative responses.

IL-25 and IL-25 receptor expression on eosinophils from subjects with allergic asthma.

BACKGROUND: Allergic asthma is an inflammatory airway disease in which Th2 cytokines play an important role. Epithelial-derived interleukin (IL)-25 has been suggested to be important in the maintenance of Th2-type responses. The effects of IL-25 are mediated by the IL-25 receptor, composed of two subunits, IL-17RA and IL-17RB. Eosinophils are effector cells in allergic asthma. The role of IL-25 in eosinophil function is unknown. This study examined the expression of IL-25 and its receptor on eosinophils in allergic asthmatics compared to atopic nonasthmatics and normal controls. METHODS: The expression of IL-25, IL-17RA and IL-17RB on eosinophils, and levels of plasma IL-25 were measured in 14 normal control subjects, 15 atopic nonasthmatics and 14 mild allergic asthmatics. RESULTS: The expression of IL-17RB on eosinophils was significantly higher in allergic asthmatics (43.08%, range 33.96-59.98%) than in atopic nonasthmatics (11.98%, range 6.33-27.11%, p = 0.002) and normal controls (17.70%, range 10.97-38.9%, p = 0.01). IL-17RA expression was also significantly higher in the allergic asthmatic group. No differences were observed in the intracellular expression of IL-25. The concentration of IL-25 in plasma was significantly increased in the allergic asthmatics (145 ng/ml, range 64-290 ng/ml) when compared to the normal controls (21 ng/ml, range 0-116 ng/ml, p = 0.012), but not compared to atopic nonasthmatics. There was a significant negative correlation between FEV1 % predicted and the IL-25 level in the plasma (r = -0.443, p = 0.003). CONCLUSIONS: The increased IL-25 levels in plasma and the expression of IL-17RA and IL-17RB on eosinophils in allergic asthma patients suggests that IL-25 may activate eosinophils during allergic inflammation.

Natural regulatory T cells in isolated early responders compared with dual responders with allergic asthma.

BACKGROUND: Natural regulatory T (Treg) cells are implicated in the regulation of the inflammatory response in patients with allergic asthma. OBJECTIVES: We sought to determine changes in Treg cell numbers in the airways and peripheral blood of isolated early responder (IER) versus dual responder (DR) subjects with mild allergic asthma before and after allergen challenge. METHODS: Induced sputum was collected from 22 subjects with allergic asthma (10 IERs and 12 DRs) and peripheral blood collected from 8 DRs with allergic asthma at 0, 7, and 24 hours after allergen challenge. Treg cells were identified by using fluorescently labeled antibodies to CD4 and forkhead box protein 3 and enumerated by using flow cytometry. RESULTS: There was a significant increase in the percentage of sputum CD4(+) cells 24 hours after allergen challenge in both IERs and DRs. The percentage of sputum Treg cells significantly decreased 24 hours after challenge in DRs but not IERs. This change was significantly correlated with the magnitude of the late asthmatic response. There was also a significant increase in the absolute number of sputum CD4(+) cells and Treg cells at 24 hours in DRs only. The ratio of the number of Treg cells to CD4(+) cells at 24 hours was significantly smaller in DRs compared with that in IERs. None of the above changes were observed in peripheral blood. CONCLUSIONS: DRs exhibit a diminished percentage of airway Treg cells after allergen challenge that is not observed in IERs and a significantly lower ratio of Treg cells to CD4(+) cells, which might contribute to the development of the late asthmatic response.

Inhibition of allergen-induced basophil activation by ASM-024, a nicotinic receptor ligand.

BACKGROUND: Nicotinic acetylcholine receptors (nAChRs) were identified on eosinophils and shown to regulate inflammatory responses, but nAChR expression on basophils has not been explored yet. OBJECTIVE: We investigated surface receptor expression of nAChR α4, α7 and α1/α3/α5 subunits on basophils. Furthermore, we examined the effects of ASM-024, a synthetic nicotinic ligand, on in vitro anti-IgE and in vivo allergen-induced basophil activation. METHODS: Basophils were enriched from the peripheral blood of allergic donors and the expression of nAChR subunits and muscarinic receptors was determined. Purified basophils were stimulated with anti-IgE in the presence of ASM-024 with or without muscarinic or nicotinic antagonists for the measurement of CD203c expression and histamine release. The effect of 9 days of treatment with 50 and 200 mg ASM-024 on basophil CD203c expression was examined in the blood of mild allergic asthmatics before and after allergen inhalation challenge. RESULTS: nAChR α4, α7 and α1/α3/α5 receptor subunit expression was detected on basophils. Stimulation of basophils with anti-IgE increased CD203c expression and histamine release, which was inhibited by ASM-024 (10(-5) to 10(-)(3) M, p < 0.05). The effect of ASM-024 was reversed in the presence of muscarinic and nicotinic antagonists. In subjects with mild asthma, ASM-024 inhalation significantly inhibited basophil CD203c expression measured 24 h after allergen challenge (p = 0.03). CONCLUSION: This study shows that ASM-024 inhibits IgE- and allergen-induced basophil activation through both nicotinic and muscarinic receptors, and suggests that ASM-024 may be an efficacious agent for modulating allergic asthma responses.

Myeloid and plasmacytoid dendritic cells in induced sputum after allergen inhalation in subjects with asthma.

BACKGROUND: Dendritic cells are professional antigen presenting cells that mediate the response to inhaled allergens. In animal models, the induction and maintenance of allergic airway inflammation is primarily a function of myeloid dendritic cells, whereas the tolerization to inhaled allergens is likely a function of plasmacytoid dendritic cells. OBJECTIVE: To investigate changes in sputum myeloid and plasmacytoid dendritic cells after allergen inhalation in subjects with asthma. Also, the number of myeloid and plasmacytoid dendritic cells expressing both CCR6 and 7 and their chemokine ligands macrophage inflammatory protein (MIP)-3alpha and 3beta were measured in sputum supernatants. METHODS: Sputum was induced from 12 dual-responder subjects with allergic asthma before and 7 hours, 24 hours, and 72 hours after inhalation of diluent and allergen. Dendritic cells were enumerated via flow cytometry and the chemokines by using ELISAs. RESULTS: The number of sputum myeloid dendritic cells was significantly higher 24 hours after allergen challenge compared with diluent. Similarly, sputum plasmacytoid dendritic cells increased significantly at 24 hours after allergen challenge. Also, a significant increase in CCR6(+) myeloid dendritic cells numbers occurred 72 hours after allergen challenge. In contrast, CCR7(+) myeloid dendritic cells, as well as the number of CCR6(+) and CCR7(+) plasmacytoid dendritic cells, were not different between challenges. Finally, allergen challenge increased sputum levels of MIP-3alpha, but not MIP-3beta, compared with baseline. CONCLUSIONS: Both myeloid and plasmacytoid dendritic cells increase in the sputum of subjects with asthma after allergen challenge, suggesting that both subsets are involved in the pathogenesis of allergen responses in asthma.