Library

Notes: Chironomid midges are small (2–15 mm) non-biting flies, characteristically seen swarming by water at dusk. Allergens of the “green nimitti” midge, Cladotanytarsus lewisi (Freeman) (Diptera: Chironomidae), a cause of widespread hypersensitivity in the Sudan, were isolated and partially characterized by Sephacryl S200 chromatography. The allergenicity of the fractions was identified by “rocket” autoradiography, RAST inhibition, skin “prick” tests, and the immunoblot technique. The fractions were further analysed by isoelectric focusing and SDS-PAGE. Two major allergens with pI's ranging from 4.3 to 6.0 were identified and had molecular weights of approximately 17,000 and 32,000 daltons, sizes compatible with their being monomeric and dimeric haemoglobins. Since chironomids occur in nuisance numbers worldwide and their haemoglobins have been shown to produce severe hypersensitivity reactions in man, they should be seen as an important potential cause of environmental and occupational allergy.

Notes: Background:  We previously showed that overlapping Fel d 1-derived T-cell peptides inhibited surrogate markers of allergy (i.e. early and late-phase skin reactions and T-cell function) in cat allergic subjects. The present pilot study was designed to determine whether this treatment affected clinically relevant outcome measurements such as the allergen-induced nasal and bronchial reactions, and asthma/rhinitis quality of life (QOL).Methods:  Sixteen cat-allergic asthmatic subjects who gave a dual (early and late) asthmatic response (DAR) to inhaled cat allergen were randomly assigned to receive either Fel d 1 peptides (approximately 300 μg in increasing, divided doses) or placebo (8 active : 8 placebo). Twelve single early responders (SER) were also studied in an open fashion design. Allergen-induced bronchial and nasal measurements as well as the QOL was measured at baseline, 4–8 weeks (follow-up 1 (FU1)) and 3–4 months (FU2).Results:  In the active, but not placebo, group there were significant decreases in the late asthmatic reaction (LAR) to whole cat dander (P = 0.03) at FU2 but with no between group difference. There were also significant improvements in asthma quality of life (QOL) scores [asthma-activity limitation (P = 0.014); rhinitis-sleep (P = 0.024), non-nose/non-eye symptoms (P = 0.031), nasal problems (P = 0.015)]. In the open study Fel d 1 peptide treatment resulted in significant decreases in number of sneezes (P = 0.05), weight of nasal secretions (P = 0.04) and nasal blockage (P = 0.01) following allergen challenge.Conclusions:  Multiple, short, overlapping Fel d 1 T-cell peptides have potential for inhibiting upper and lower airway outcome measurements in cat allergic patients. Larger, dose-ranging, studies are required before firm conclusions on clinical efficacy of peptide allergen therapy can be made.

Notes: There now exists compelling evidence of a role for cell-mediated immunity in the pathogenesis of adult asthma, but little information is available as to what extent this process participates in the pathogenesis of childhood asthma. We hypothesised that asthma in children is associated with the activation of T-lymphocytes whose products regulate, at least in part, the mobilisation and recruitment of eosinophils and thereby disease severity. Our aims, therefore, were to compare the expression of activation markers, including CD45 isoforms, on peripheral blood T-lymphocytes from asthmatic and non-asthmatic, allergic control children matched for age and atopic status, and to attempt to correlate the percentages of activated T-lymphocytes in the asthmatics with the numbers of peripheral blood eosinophils and with disease severity. Seventeen children with moderate to severe chronic asthma were compared with 8 non-asthmatic, allergic children matched for age and atopic status. Expression of the activation markers CD25, HLA-DR and VLA-1 and the CD45 isoforms CD45RA and CD45RO on peripheral blood CD4 and CD8 T-lymphocytes was measured using dual fluorescence flow cytometry. Peripheral blood eosinophils were measured using an automated laser cytometer. Asthma severity was assessed by a symptom score, spirometry and measurement of histamine PC20. The absolute numbers of eosinophils in the peripheral blood of the asthmatics were elevated as compared to the non-asthmatic, allergic controls (p 〈 0.01), whereas the absolute numbers of both CD4+ and CD8+ T-lymphocytes were not significantly different. The percentages and absolute numbers of CD4+ T-lymphocytes expressing CD25 and HLA-DR and CD8+ T-lymphocytes expressing CD25 also were significantly elevated in the asthmatics as compared with the controls (p 〈 0.04 in each case). However, the percentages and absolute numbers of CD4+ T-lymphocytes expressing VLA-1 and CD8+ T-lymphocytes expressing HLA-DR and VLA-1 did not significantly differ between the asthmatics and controls. Similarly, the percentages and absolute numbers of both CD4+ and CD8+ T-lymphocytes expressing the CD45 isoforms CD45RA and CD45RO were not significantly different in the asthmatics and controls. In the asthmatics, the numbers of peripheral blood eosinophils correlated with disease severity as measured by histamine PC20 (p = 0.02). The percentages of CD4+ T-lymphocytes expressing HLA-DR correlated both with the numbers of peripheral blood eosinophils and with disease severity (histamine PC20 (p 〈 0.03)). In addition, the percentages of CD8+ T-lymphocytes expressing CD25 correlated positively with disease severity as measured by a symptom and therapy score (p = 0.03). Finally, the percentages of CD8+ T-lymphocytes expressing HLA-DR correlated with histamine PC20 (p = 0.03). These observations are consistent with the hypothesis that activated T-lymphocytes play a role in the pathogenesis of childhood asthma at least in part through their influence on eosinophil recruitment.

Notes: Using the micropore filter technique of Boyden, the eosinophil chemotactic responses to an ECF-A tetrapeptide (Val-Gly-Ser-Glu) and histamine were studied in thirty-two patients with a peripheral blood eosinophilia. The eosinophilia was associated with extrinsic asthma (twelve patients), neoplasia (seven), helminth disease (five) and a miscellaneous group (eight) which included three patients with pulmonary eosinophilia, one of whom also had asthma. Both the tetrapeptide and histamine gave two types of dose–response. With Val-Gly-Ser-Glu this was either a single peak at 10-8, or two peaks at 10-4 and 10-7 mol/1, respectively. Histamine gave either a linear dose–response with maximal chemotaxis at the highest concentration or a peak response at 10-5 mol/1 with inhibition at higher doses. The two types of response given by the peptide were not related to the disease state and were reproducible when tested on more than one occasion. However, with histamine, linear dose–responses were observed in ten out of twelve patients with asthma, four out of five with helminth disease and two of the three with pulmonary eosinophilia. This was also reproducible when tested on subsequent occasions. Therefore, in these diseases, which are known to be associated with exogenous antigens and raised IgE levels, eosinophils from 80% of the patients studied (sixteen out of twenty) gave a linear rather than a ‘bell-shaped’ response to histamine. In contrast, only four of twelve patients(33%) with eosinophilia in association with other diseases (which included seven with neoplasia) gave this type of response. If this observation can be confirmed with larger numbers of patients it may be useful diagnostically in eosinophilia of unknown origin.

Notes: Background Eoswinophil granule proteins may contribute to hyperresponsiveness in asthma.Objective To measure eosinophil cationic protein (ECP) and eosinophil protein X (EPX) in sereum and bronchial lavage fluid from 20 asthmatics and 16 control subjects. To asses the effect on these eosinophil proteins of corticosteroid treatment of asthma. To determine ehether serum ECP and EPX measured weekly in a longitudina study for 10 weeks reflected changes in lung function.Methods Eosinophil granule proteins were measured by radiommunoassy of bronchial wash (BW), bronchoalveolar lavage (BAL) serum.Results Eosinophils were elevated in BAL(P〈0.01), BW (P〈0.01) and blood (P〈0.01) from asthmatic compared with control subjects. Eosinophil cationic protein concentration was significantly elevated in BAL (P〈0.05) and BW from asthmatics (P〈0.01) and EPX was increased in BAL (P〈0.05)and BW (P〈0.01). These changes were also reflected in elevated serum ECP(P〈0.01) and EPX (P〈0.01)concentrations is asthmatic subjects. There was no significant difference between sujects receiving prednisolone and the placebo group, but there was a fall in ECP in BW (P〈0.05) and serum (P〈0.01) and in EPX in BW (P〈0.01) and serum (P〈0.01) within the group receiving prednisolone. In the longitudinal study there was only significant difference between ECP values associated with highest and lowest peak expiratory flow rate (PEFR) (P〈0.05).Conclusion These data confirm a role for cosinophil activation in the airway in asthma pathogenesis, and add some support to the hypothesis that corticosteroids may inhibit cosinophil activation in asthma.

Notes: We have examined the effect of prolonged treatment with topical corticosteroid on allergen-induced early and late nasal responses and the associated inflammatory cell infiltrate in grass pollen sensitive allergic rhinitics. Following a randomized double-blind 6 week treatment period with fluticasone propionate 200 μg aqueous nasal spray twice daily or matched placebo spray, nasal provocation was performed using Timothy grass pollen extract. Nasal symptoms were recorded at intervals from 0 to 24 h. Nasal biopsies were performed before treatment and at 24 h after allergen and processed for immunohistology. When corticosteroid-treated patients were compared with the placebo group there was an approximately 50% decrease in the size of the early (0-60 min) response and almost complete inhibition of late (1–24 h) nasal symptoms after allergen challenge. After allergen challenge markedly fewer T lymphocytes and CD25+ (interleukin-2 receptor bearing) cells were observed in both the epithelium and submucosa in fluticasone treated patients compared with the placebo group. Significantly less total and activated eosinophils were observed, particularly within the nasal epithelium. Submucosal mast cell counts were decreased, whereas increased numbers of submucosal neutrophils were observed. These results confirm that topical corticosteroid treatment inhibits allergen-induced early and late nasal responses. This may possibly occur following a decrease in T lymphocytes and/or mast cells and their products and a consequent reduction in tissue eosinophilia.