A group of 34 penicillin-allergic patients was studied to determine skin test reactivity to the different penicillins involved in inducing the allergic reaction and the cross-reactivity with side-chain-related and side-chain-unrelated cephalosporins. All the subjects selected for the study had to be skin test positive to at least one of the following determinants: benzyl-penicilloyl-polylysine (BPO-PLL), minor-determinant mixture (MDM), amoxicillin (AX), or ampicillin (AMP), or to possess in vitro IgE to the following conjugates: benzyl-penicilloyl-human-serum albumin (BPO-HSA), ampicilloyl-human-serum albumin (AMP-HSA), and amoxicilloyl-human-serum albumin (AX-HSA). Cephalexin (CE) and ceftazidime (CEF) were used to assess cross-reactivity. If skin tests to any of these compounds were positive, the patient was considered to be allergic; if negative, a challenge test was performed. Sixteen patients (47%) were skin test positive to BPO and/or MDM, and nine (26%) exclusively to AX and/or AMP. In three cases (8%), the RAST was positive although the skin test was negative; one to BPO-HSA and two to AX-HSA and AMP-HSA. Six patients (17%) needed to be challenged with the penicillin involved to establish the diagnosis. In five patients (14%), the skin tests were positive to CE and in none to CEF. In all the others, the skin tests were negative to both cephalosporins, and the patients tolerated the drugs when challenged. These results indicate the relevance of side-chain-specific minor determinants in betalactams allergy and provide support for the role of this chemical structure in the evaluation of cross-reactivity between penicillins and cephalosporins.
RATIONALE: Nasally applied hydroxy-propyl-methyl cellulose (HPMC) powder, acting as mucosal barrier against particulate matter, has been used increasingly since 1994. Clinical and experimental evidence has accumulated about its effectivenes in preventing symptoms in allergic rhinitis sufferers. The aim of our study was to further explore the efficacy of HPMC in reducing the severity of different symptoms in subjects sensitized to grass allergens during the pollen season and its ability to render them symptom-free. METHODS: In a double blind placebo controlled study, 107 subjects (18-40 years of age) sensitized to grass pollen were randomized to apply nasally HPMC powder (n554) or placebo (n553) 3 times daily for 4 weeks. Daily severity of nasal congestion, rhinorrhea, sneezing, lower airway and ocular symptoms (ranked from 1 to 6) were reported as text messages every evening. RESULTS: The mean of severity scores were roughly halved in the active group for both nasal (p<0.0001), ocular (p<0.0001) and bronchial symptoms (p50.0015); the inter-group differences increased during the study period for nasal and bronchial symptoms (both p<0.0001). The number of subjects without nasal symptoms increased in the course of time (group difference p<0.0001) and the number of subjects without other symptoms was about twice as high as in the placebo group over the entire period (p<0.0001). CONCLUSIONS: HPMC powder provided extensive protection against all symptoms from both upper and lower airways in subjects with clinical allergy to grass pollens. It reduced the severity of symptoms and significantly increased the number of symptom-free subjects.
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