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RAST Inhibition (rast + inhibition)
Selected AbstractsHypersensitivity reactions to penicillins: studies in a group of patients with negative benzylpenicillin G skin testJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 3 2009H.-L. Qiao MD PhD Summary Background:, Although skin tests are usually employed to evaluate current penicillin allergy status, a negative result does not exclude hypersensitivity. There is a need for accurate in vitro tests to exclude hypersensitivity. A radioallergosorbent test (RAST) is a potentially good supplementary approach, but there is little information on the suitability of this method to diagnose penicillin hypersensitivity in subjects with a negative skin test to benzylpenicillin. Methods:, A total of 133 patients with a negative skin test to benzylpenicillin G (PG) and all of whom developed allergic reactions to PG were studied. RAST was used to detect eight kinds of specific IgE antibodies to penicillins in serum, which included four kinds of major and minor antigenic determinants to four penicillin drugs. The combination sites for the specific IgE antibodies were studied by RAST inhibition test. Results:, The rate of positive reactions for the specific IgE antibodies was 59·40% (79/133). Of the eight kinds of antigenic determinants, the positive rates for specific IgE against the major and minor determinants were 39·10% (52) and 42·86% (57) respectively. Of the four drugs, positive cases only to PG were 10 (7·5%), were significantly fewer than the cross-reacting positive cases (36) to PG (P < 0·01). In the RAST inhibition studies all drugs exhibited good inhibitory potencies, and in some instances the side-chain of the penicillins could induce specific responses with a variable degree of cross-reactivity among the different penicillins. Conclusion:, Radioallergosorbent test is a good complementary test in persons who are skin-test negative with PG, and the sensitivity of RAST increaes with increasing specificity of IgE antibodies to be detected. 6-APA and the groups, making part of the different side-chains on penicillins, all contributed to the cross-reactivity. [source] Role of minor determinants of amoxicillin in the diagnosis of immediate allergic reactions to amoxicillinALLERGY, Issue 5 2010M. J. Torres To cite this article: Torres MJ, Ariza A, Fernández J, Moreno E, Laguna JJ, Montañez MI, Ruiz-Sanchez AJ, Blanca M. Role of minor determinants of amoxicillin in the diagnosis of immediate allergic reactions to amoxicillin. Allergy 2010; 65: 590,596. Abstract Background:, Skin testing of subjects with immediate hypersensitivity to amoxicillin is performed using major and minor determinants of benzylpenicillin plus amoxicillin. However, sensitivity is not optimal, and other determinants need to be considered. We assessed the sensitivity of stable, well-characterized minor determinants of amoxicillin in subjects with immediate allergic reactions to amoxicillin to improve skin test sensitivity. Methods:, Amoxicillin, amoxicilloic acid, and diketopiperazine were prepared and characterized by reverse-phase HPLC, tested in vivo by skin testing and in vitro by basophil activation test and RAST inhibition assay. Results:, Patients with immediate hypersensitivity to amoxicillin were selected: Group A (n = 32), skin test positive just to amoxicillin; Group B (n = 19), skin test positive to benzylpenicillin determinants; Group C (n = 10), skin test negative and amoxicillin drug provocation test positive. In Group A, 27 subjects (81.8%) were skin test positive to amoxicillin, ten (30.3%) to amoxicilloic acid, two (6.1%) to diketopiperacine, and six (18.2%) negative. In Group B, nine (50%) were positive to amoxicillin, eight (42.1%) to amoxicilloic acid, none to diketopiperacine, and nine (50%) negative. In Group C, skin tests were negative. BAT was positive to amoxicillin in 26 patients (50.9%), to amoxicilloic acid in 15 (29.1%), and diketopiperazine in four (7.8%). RAST inhibition studies showed > 50% inhibition in all sera, with the highest concentration of amoxicillin and amoxicilloic acid. Conclusions:, The combination of minor determinants of amoxicillin, amoxicilloic acid, and diketopiperazine seems to be of no greater value than the use of amoxicillin alone. Further efforts are needed to find new structures to improve sensitivity in the diagnosis of immediate hypersensitivity to betalactams. [source] Skin testing for immediate hypersensitivity to betalactams: comparison between two commercial kitsALLERGY, Issue 8 2006J. L. Rodríguez-Bada Introduction:, Skin testing with major and minor determinants of benzylpenicillin is the recommended standard practice to evaluate subjects with immediate hypersensitivity to betalactams. The withdrawal of these products from the market has set us back to the early days, before the introduction of reagents for in vivo testing. Objectives:, To compare a recently released kit of benzylpenicillin conjugated to poly- l -lysine (PPL) and minor determinants mixture (MDM) with the previously existing kit in a positive control group of subjects sensitized to major and/or minor determinants of benzylpenicillin. Methods:, Skin tests with both kits were made in a group of positive subjects previously diagnosed with immediate hypersensitivity to penicillins and with positive results to PPL and/or MDM and in a negative control group. Radioallergosorbent test (RAST) inhibition assays with a pool of sera and individual samples were carried out to compare the inhibition capacity of PPL and MDM of both kits. Results:, Of 22 cases selected from our historical group, 14 were positive: eight to PPL, three to MDM and three to both. These results were equivalent for both kits. RAST inhibition studies showed similar potencies in the inhibition of PPL and MDM. Conclusions:, Both tests show similar results in terms of RAST inhibition assays and skin tests sensitivity and specificity in the groups selected. The new assay can be used for the same purpose and indications as the previous test. [source] Dual sensitization to rat and mouse urinary allergens reflects cross-reactive molecules rather than atopyALLERGY, Issue 6 2009H. Jeal Background:, Sensitization to rats and mice can develop in laboratory animal workers exposed to only one species. Reasons for this dual sensitization are unclear but may reflect a genetic predisposition to developing allergy (atopy) or alternatively cross-reactivity between rat and mouse urinary allergens. We examined cross-reactivity between rat and mouse urine and the effect atopy has on dual sensitization in laboratory animal workers. Methods:, In a cross-sectional study the frequency of sensitization to rat and/or mouse was analysed in 498 employees exposed to both rat and mouse at work and 220 to rat only. RAST inhibitions, western blots and blot inhibitions were carried out on a subset of five individuals to assess cross-reactivity. Results:, Fourteen per cent of workers were sensitized to rats and 9% to mouse. Over half (62%) of rat sensitized individuals were also mouse sensitized and the majority (91%) of mouse sensitized individuals were also rat sensitized. IgE cross-reactivity was demonstrated between rat and mouse urine using RAST inhibitions. Rates of atopy did not differ between rat only sensitized individuals compared with those sensitized to both species. Sensitization to cats and rabbits was more common amongst those with dual sensitization. Conclusions:, Dual sensitization to rat and mouse reflects IgE cross-reactivity rather than atopy. Individuals with dual sensitization are more likely to be sensitized to other animal allergens. These findings will have implications for individuals working with only one rodent species who develop sensitization and symptoms to be aware of the potential for allergy to other species. [source] | ||||||||||