Nonirritant intradermal skin test concentrations of ciprofloxacin, clarithromycin, and rifampicin.

BACKGROUND: Intradermal skin testing of the clinically important antibiotics ciprofloxacin, clarithromycin, and rifampicin in the case of suspected allergies to antibiotics is poorly standardized. For clinical practice, standardized procedures and protocols are desired. METHODS: Fifteen healthy volunteers were tested with different concentrations of the antibiotics as well as with appropriate controls. Test readings included wheal area measured by digital image analysis and blood flow increase measured by laser Doppler flowmetry (LDF). To reduce interpersonal variability, test results were normalized with the individual controls using a novel protocol. RESULTS: Nonirritating concentrations of the three antibiotics (ciprofloxacin ~0.0067 mg/ml, clarithromycin ~0.05 mg/ml, rifampicin ~0.002 mg/ml) could be defined for healthy volunteers. Laser Doppler flowmetry generates comparable results to wheal area measurement. Normalization of the test results is necessary and can be applied in a practical algorithm. CONCLUSIONS: Standardized skin testing to detect sensitization to broadly used nonbetalactam antibiotics was presented and should be applied in truly sensitized patients. This approach should help to minimize the inter- and intraindividual differences in reactivity.

Oral desensitization to milk: how to choose the starting dose!

A renewed interest in oral desensitization as treatment for food allergy has been observed in the last few years. We studied a novel method based on the end point skin prick test procedure to establish the starting dose for oral desensitization in a group of 30 children highly allergic to milk. The results (in terms of reactions to the first dose administered) were compared with a group of 20 children allergic to milk as well. Such control group started to swallow the same dose of 0.015 mg/ml of milk. None reacted to the first dose when administered according to the end point skin prick test. On the other side, ten out of 20 children (50%) from the control group showed mild allergic reactions to the first dose of milk. In conclusion the end point skin prick test procedure results safe and easy to be performed in each single child in order to find out the starting dose for oral desensitization to milk, also by taking into account the individual variability.

Validation of a Multiplex Assay for Measuring Specific IgG4.

PURPOSE: Specific IgG4 (sIgG4) increases with allergen specific immunotherapy and may reflect a state of immune tolerance in food allergy. While ImmunoCAP® has been widely used to measure sIgG4 to a single allergen, PROTIA™ Specific IgG4® has been designed as a multiplex assay for measuring sIgG4. This study sought to validate this assay in comparison to ImmunoCAP®. MATERIALS AND METHODS: Measurements of sIgG4 were compared between PROTIA™ Specific IgG4® and ImmunoCAP® using sera from 519 allergy patients (asthma: 114, allergic rhinitis: 318, food allergy: 146) with 731 paired tests. sIgG4 was measured against nine inhalant allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat dander, dog dander, birch pollen, oak pollen, ragweed pollen, mugwort pollen, and Alternaria alternata spores) and nine food allergens (egg white, casein, wheat, peanut, walnut, crab, shrimp, apple, and peach). RESULTS: PROTIA™ Specific IgG4® showed 95.6% agreement rate with ImmunoCAP® in the positivity comparison. For sIgG4 positivity to each individual allergen, an agreement rate of more than 84.8% was observed. In Cohen's kappa analysis, these assays displayed substantial correlations [Cohen's kappa coefficient (κ) ≥0.699], except for shrimp (κ=0.448). Furthermore, both assays displayed strong correlations in quantitative comparisons [correlation coefficients value (ρ) ≥0.8014], except for apple (ρ=0.6571, p=0.175). Serial dilution tests also showed consistency between the assays. CONCLUSION: PROTIA™ Specific IgG4® showed high consistency with ImmunoCAP® in measuring sIgG4. This assay is applicable to various clinical fields, including allergen immunotherapy and food allergy.

Oral desensitization in children with immunoglobulin E-mediated cow's milk allergy--follow-up at 4 yr and 8 months.

Until now, the basic treatment for food allergy has been to avoid the offending item. This approach is difficult in the case of common foods and in the case where there is a risk of severe reaction after consuming the offending food, even inadvertently. This is the follow-up of a previous study aimed at desensitizing 21 children with immunoglobulin E (IgE)-mediated cow's milk (CM) allergy. This protocol was totally or partially successful in 85% of cases, but failed in the remaining 15%. Our aims were to study the long-term effectiveness and safety of oral CM desensitization, and the prognostic value of Skin Prick Test (SPT) and specific serum CM IgE. The 21 children were called back (one dropped out). The allergic history and other information on CM intake over the last 4-5 yr were recorded. Children underwent SPT, and end-point SPT, with casein and alpha-lactoalbumin. Specific CM IgE was also measured. At follow-up, 14/20 children totally (n = 13, 65%) or partially (n = 1, 5%) tolerated CM. None of the recalled children reported use of emergency care. SPT positivity to casein and/or alpha-lactoalbumin decreased significantly (p < 0.01), and all the negative SPT referred to the tolerant children. Cutaneous sensitivity to both casein and alpha-lactoalbumin (end-point SPT) significantly decreased after the 6-month desensitization period of the previous study (p < 0.001), but did not decrease significantly at follow-up. A significant reduction of serum-specific CM IgE was also observed (p < 0.05). Clinical tolerance induced by oral CM desensitization persists in time. Negativization of SPT and reduction of specific CM IgE could be considered prognostic indicators of CM tolerance. Oral CM desensitization seems to be a promising method to treat CM food allergy. This protocol is time-consuming but offers the advantage that it can be performed at home. This methodology must only be used by trained staff.

Diagnosis of leptospirosis by recombinant antigen based single serum dilution ELISA.

BACKGROUND & OBJECTIVES: Leptospirosis, a zoonosis with a worldwide distribution is an acute febrile illness caused by spirochaetes of the pathogenic Leptospira interrogans. Microscopic agglutination test (MAT), the reference method for diagnosis was successively done to evaluate the modified ELISA which was developed with the recombinant LipL32 antigen for the detection of anti-leptospiral antibodies in human serum samples. METHODS: The recombinant LipL32 antigen was developed from the serovar Pomona strain Pomona of the pathogenic L. interrogans species. The predicted titre at a single working dilution was plotted against the observed antiserum titre. Subsequently, predicted antibody activity titres were determined directly from the standard curve by solving the regression line equation. The relative sensitivity, specificity and accuracy of the single dilution ELISA for the detection of anti-leptospiral antibodies were determined in comparison to the MAT. RESULTS: A linear relationship was found between the predicted antibody titres at a single working dilution of 1:250 and the corresponding observed serum titres by the standard serial-dilution method. Regression analysis was used to determine a standard curve from which an equation was derived that allowed demonstration of the mentioned correlation. The equation was then used to convert the corrected absorbance readings of the single working dilution directly into the predicted ELISA antibody titres. A high level of sensitivity of 96 per cent and specificity of 91 per cent between ELISA and MAT titres was found. The kappa value was almost 1.0 indicating perfect agreement. INTERPRETATION & CONCLUSIONS: The r LipL32 ELISA was proved to be sensitive, specific and accurate as compared to the standard MAT and the test could be efficiently utilized as a screening test for a large number of human serum samples for the detection of leptospiral antibodies.

Comparison of intradermal dilutional testing, skin prick testing, and modified quantitative testing for common allergens.

OBJECTIVES: To compare and correlate wheal size using the Multi-Test II applicator with the endpoint obtained by intradermal dilutional testing (IDT) for 5 common allergens. To examine the safety of modified quantitative testing (MQT) for determining immunotherapy starting doses. STUDY DESIGN: Prospective comparative clinical study. SUBJECTS AND METHODS: A total of 134 subjects were simultaneously skin tested for immediate hypersensitivity using the Multi-Test II device and IDT. RESULTS: There was a 77% concordance between results from IDT and results from MQT. When there was a difference, MQT predicted a safer endpoint for starting immunotherapy in all but 2 cases. CONCLUSION: Wheal size by SPT is predictive of endpoint by IDT. MQT is nearly as effective as formal IDT in determining endpoint. SIGNIFICANCE: Modified quantitative testing appears to be a safe alternative to IDT for determining starting doses for immunotherapy.

Use of intradermal dilutional testing and skin prick testing: clinical relevance and cost efficiency.

OBJECTIVES/HYPOTHESIS: The objective was to determine the agreement of the positive results from a multiple skin prick test (SPT) device with the ability to determine a definable endpoint through intradermal dilutional testing (IDT) to compare semiquantitatively the degree of positivity of SPT results with quantitative results from IDT and to analyze the cost of immunotherapy based on SPT compared with IDT guided by SPT. STUDY DESIGN: Retrospective review of clinical data (random accrual). METHODS: One hundred thirty-four patients underwent allergy screening using a multiple SPT device. Antigens testing positive by skin prick device were tested using IDT on a separate day. Antigens testing negative by SPT were not evaluated by IDT. Regional allergy testing practice patterns were determined, and a cost analysis using Medicare rates was performed RESULTS: There was good agreement between an antigen testing positive by SPT and the determination of a definable endpoint (93.33%, n = 1,334 antigens). The degree of positivity from the SPT correlated poorly with the final endpoint concentration (r = 0.40, P < .0001). Blended testing techniques were similar in cost when compared with several commonly used allergy testing protocols. CONCLUSIONS: Antigens which show reactivity to a multiple SPT device usually have a treatable endpoint that is independent of the degree of positivity of the SPT result. IDT is an important step in the determination of the strongest starting dose of immunotherapy that may be safely administered. Initiating immunotherapy in this manner may potentially create significant health care savings by shortening the time required for a patient to reach their individual maximally tolerated dose. The use of a relatively large screening panel is cost effective and does not increase the average number of antigens treated by immunotherapy. Blended allergy testing techniques that include IDT in their protocol are comparable in cost with commonly used allergy testing protocols.

Comparison of intradermal dilutional testing with the Multi-Test II applicator in testing for mold allergy.

OBJECTIVES: To compare and correlate wheal size using the Multi-Test II applicator with the endpoint obtained by intradermal dilutional testing (IDT) for common mold allergens. To validate the safety and efficacy of modified quantitative testing (MQT) for determining immunotherapy starting doses. STUDY DESIGN AND SETTING: Prospective study of 86 subjects with Multi-Test II and IDT for 6 common mold antigens. RESULTS: There was 84% concordance between IDT results and the results expected from the MQT method. When IDT and MQT results differed, the MQT algorithm predicted a safer endpoint for starting immunotherapy in all but 2 cases. CONCLUSION: The correlation between Multi-Test II and IDT is not strong enough to infer IDT endpoint from Multi-Test II results for molds. MQT is nearly as effective as formal IDT in determining endpoint. SIGNIFICANCE: MQT appears to be a safe method for determining starting doses for immunotherapy with fungal allergens.

ImmunoCAP and HY*TEC enzyme immunoassays in the detection of allergen-specific IgE compared with serial skin end-point titration by receiver operating characteristic analysis.

OBJECTIVES: In this study, we compared 2 different immunoassays, HY*TEC enzyme immunoassay (Hycor Biomedical Inc, Garden Grove, CA) and Pharmacia Upjohn ImmunoCAP (Pharmacia and Upjohn, Kalamazoo, MI) using skin end-point titration as a gold standard by receiver operating characteristic analysis. MATERIALS: One hundred patients were enrolled in this study and were tested with the above 3 modalities. The results were analyzed by receiver operating characteristic analysis, in which the curves give a decision criterion for any diagnostic test relative to its sensitivity and specificity against an accepted gold standard test. Only inhalant allergens (Dermatophagoides pteronyssinus, Dermatophagoides farina, cat dander, giant ragweed, English plantain weed, timothy grass, Alternaria tenuis, Aspergillus fumigatus, meadow fescue, oak tree, white ash tree, and lamb's-quarter weed) were studied. RESULTS: The results obtained with both ImmunoCAP and HY*TEC showed a good correlation with skin end-point titration for D pteronyssinus, D farina, cat dander, giant ragweed, timothy grass, A tenuis, and meadow fescue, with sensitivities ranging from 71% to 88%. However, the sensitivity of both tests to English plantain weed, lamb's-quarter weed, oak tree, and white ash tree was lower (66% down to 39%). Additionally, HY*TEC results were not satisfactory for detecting specific IgE to A fumigatus (30% sensitivity). The overall sensitivity for each test was 65.67% for the HY*TEC and 71.25% for the ImmunoCAP. CONCLUSION: The 2 in vitro testing systems are comparable for most of the allergens, except for A fumigatus, English plantain, lamb's-quarter, and white ash tree; ImmunoCAP and HY*TEC would benefit from improved technology for detecting these specific IgE antibodies. The HY*TEC assay did not give acceptable results for A fumigatus. The overall assay characteristics were good to excellent for each system tested.

Prevalence of hypersensitivity to specific fungal allergens as determined by intradermal dilutional testing.

OBJECTIVE: To determine fungal allergen reactivity prevalence by intradermal dilutional testing in patients with and without chronic rhinitis or rhinosinusitis symptoms. STUDY DESIGN: Prospective comparison of fungal allergen reactivity prevalence in symptomatic and asymptomatic patients. SETTING: University medical center. METHODS: Group I (chronic rhinitis and/or rhinosinusitis symptoms) and Group II (asymptomatic) patients underwent intradermal dilutional testing with usual and fungal allergens. RESULTS: Fungal reactivity occurred in 65% (13/20) of Group I, and 13% (4/30) of Group II (P < 0.0002 by chi(2) testing). Group I was more reactive to non-fungal allergens (85% vs. 33%, p < 0.0004), and to all allergens considered together (95% vs. 40%, p < 0.0001). CONCLUSIONS: Patients with chronic rhinitis and rhinosinusitis symptoms were more reactive to fungal and nonfungal allergens. Fungal allergens were as likely as nonfungal to elicit reactivity. SIGNIFICANCE: These findings suggest a role for fungal hypersensitivity in chronic rhinitis and chronic rhinosinusitis.

Efficacy of immunotherapy based on skin end-point titration.

OBJECTIVE: The purpose of this study is to examine the efficacy of skin end-point titration (SET) as a method of assessing skin responsiveness, selecting antigens, and initiating treatment for successful inhalant immunotherapy. STUDY DESIGN: This study is a prospective, randomized, controlled, double-blind investigation. Eighteen patients were randomly assigned to 1 of 2 groups: an experimental group treated for all positive antigens, and a control group treated for all positive antigens, with the exception of the study antigens. Quality of life was assessed with 3 dependent measures, and response to nasal challenge and nasal endoscopic evaluations were conducted. Ten patients completed the 6-month study. RESULTS: There were significant improvements in the emotional component of sinus-related disability, in response to nasal challenge, and in the endoscopic appearance of the mucosa, regardless of patient group. There was a trend toward improved quality of life among experimental subjects. CONCLUSIONS: SET-based immunotherapy reduces self-rated disability over time. In addition, SET-based immunotherapy allows decrease in nasal reactivity and normalizes the endoscopic appearance of the nose.

Introduction to in vivo allergy testing.

Available in vivo skin tests for assessment of hyperreactivity are essentially similar in principle, in that they rely on the reactivity and sensitivity of dermal mast cells sensitized with specific immunoglobulin E to reflect allergic sensitivity. In this article the immunology of skin testing is examined and the various factors that may influence reactivity are noted. In addition, the respective benefits and drawbacks of such familiar epicutaneous skin tests as the scratch and prick tests and intradermal (or intracutaneous) methods, including skin end point titration, are explored. Efforts to standardize testing technology are also discussed. It is concluded that each method of in vivo skin testing is associated with both advantages and disadvantages and that the most important factors are sensitivity and reproducibility.

Low doses of animal antigen attenuates the late asthmatic reaction.

Five subjects with a history of asthma after exposure to cat or dog underwent a trial of low-dose antigen injection followed by bronchoprovocation with the relevant antigen. The neutralization dose of antigen was determined by serial and point dilution skin testing. In a crossover protocol, patients received this antigen or placebo injections. They then underwent bronchoprovocation with the same antigen. The results of the early and late reaction to bronchoprovocation were compared, with each patient serving as her own control. As measured by the number of breath units to lower the FEV1 by 20%, placebo group tolerated only 6.9 +/- 2 breath units, whereas the neutralization group tolerated 29 +/- 3 breath units (p less than 0.05). The maximum decline in FEV1 during the late reaction was 27 +/- 13% after injection of placebo and 12 +/- 12% after injection of antigen (p less than 0.05). In this model of antigen-induced asthma, injection of low doses of allergen immediately preceding bronchoprovocation blunted the immediate and delayed asthmatic reaction.

Comparison of Multi-Test II skin prick testing to intradermal dilutional testing.

OBJECTIVES/HYPOTHESIS: Intradermal dilutional testing (IDT) has been considered more sensitive than prick testing for detecting low-level allergies. Multi-Test II is one of the most sensitive and reproducible prick testing methods available. This study compares Multi-Test II prick testing with IDT. DESIGN: Retrospective chart review and data analysis on patients who had allergy testing with both Multi-Test II and IDT. SETTING: Outpatient allergy clinic in the otolaryngology department of an academic tertiary care medical center. POPULATION: Forty adult patients had complete allergy testing with both Multi-Test II and IDT for a standard panel of twelve antigens between January 2002 and April 2002. INTERVENTION: Analysis and comparison of test results on Multi-Test II and IDT for each antigen separately and across all antigen tests together. RESULTS: Forty patients had complete testing for all antigens during the time period for the study. Six of these patients did not react to the positive control on Multi-Test II and were eliminated from the main analysis. Of the 34 patients included in the main analysis, all were positive for at least one antigen on IDT; one half (17/34) were negative for all antigens on Multi-Test II. A significantly greater number of patients were positive on IDT than Multi-Test II for all antigens except dog (P < 0.05). There was a statistically significant correlation between IDT endpoint and Multi-Test II score for several antigens (P < 0.05). Of 408 total antigen tests performed, 339 (83.1%) were negative on Multi-Test II. Of these 339 negative Multi-Test II tests, 148 (43.7%) were negative on IDT and 191 (56.3%) were positive on IDT; 174/339 (51.3%) had an IDT endpoint of 2 or 3 and 17/339 (5.0%) had an IDT endpoint > or = 4. A significantly greater number of antigen tests were positive on IDT than on Multi-Test II (P < 0.001). The overall Spearman correlation coefficient between IDT endpoint and Multi-Test II score was 0.370 (P < 0.001). CONCLUSION: Patients were more likely to have a positive test on IDT than on Multi-Test II. IDT therefore may be a more sensitive testing technique for inhalant allergies than Multi-Test II prick testing. In addition, Multi-Test II score may not be a good predictor of IDT endpoint. Although a statistically significant correlation is demonstrated between Multi-Test II score and IDT endpoint, the correlation coefficient is low enough that clinical application may not always be safe or appropriate. The clinical significance of positive IDT results in the presence of negative Multi-Test II results is not known.

Prevalence of allergy in patients with chronic rhinosinusitis.

OBJECTIVES: The purpose of this study was to provide further evidence that allergic rhinitis is an important factor in chronic and recurrent acute rhinosinusitis. Specifically, this study shows that perennial allergens play a more significant role than seasonal allergens. STUDY DESIGN AND SETTING: Census by chart review of patients with chronic and recurrent acute rhinosinusitis presenting to the Department of Otolaryngology at the MetroHealth Medical Center, Cleveland, OH. METHODS: All participants had allergy testing done either by RAST or intradermal skin endpoint titration utilizing a battery of seasonal and perennial antigens. RESULTS: Of the 48 voluntary participants analyzed in this study, 57.4% had a positive allergy test. Most patients in the study were sensitive to more than one allergen. Of the patients with a positive allergy test, 92% demonstrated sensitivity to one or more perennial allergens-most prominently, molds and dust mites. CONCLUSIONS: Perennial allergy has a statistically significant association with chronic and recurrent acute rhinosinusitis. SIGNIFICANCE: The diagnosis and management of perennial allergies may be beneficial when treating chronic sinus disease.

Comparison of mRAST and CAP with skin end point titration for Alternaria tenuis and dermatophagoides pteronyssinus.

There has been a recent explosion of new in vitro tests for the diagnosis of allergies. At present there is no general agreement on which type of in vitro test is best. Recently our hospital switched in vitro testing from the modified radioallergosorbent system (mRAST) to the Pharmacia CAP system (CAP). While changing in vitro testing techniques, 47 patients were tested with both the mRAST and CAP tests. Comparisons were made between the mRAST and CAP results of Alternaria tenuis and Dermatophagoides pteronyssinus allergens. These results were then compared with the results of patients who also underwent intradermal skin testing based on end point titration techniques.

Correlation of modified radioallergosorbent test scores and skin test results.

In addition to a significantly increased sensitivity as compared with the initial Phadebas radioallergosorbent test, a major advantage of the Fadal-Nalebuff modified RAST is its correlation with skin testing using skin end point titration. This correlation allows physicians to use both these modalities in the diagnosis and treatment of allergic disorders. However, it has been anecdotally believed that the correlation of radioallergosorbent test classes and skin test end points varied somewhat with different antigens. Fifty-three patients were tested by radioallergosorbent test for 12 inhalant antigens common to the North Texas region. These patients subsequently underwent confirmation of their radioallergosorbent test results by application of intradermal tests at a concentration of one fivefold step weaker than the corresponding radioallergosorbent test level (a "RAST minus one" dilution). The relationship between radioallergosorbent test and skin test results will be critically analyzed.

Skin endpoint titration. Still the standard?

Skin endpoint titration, being both quantitative and calibrated in accordance with the patient's own reactivity, may still be considered the most sophisticated means of identifying an allergenic offender. Other forms of skin testing, simpler to perform, are rapidly becoming more uniform and quantitative. Laboratory tests provide more specific information and improved convenience. All occupy important positions in allergy diagnosis.

Blending skin endpoint titration and in vitro methods in clinical practice.

The definitive diagnosis of allergy involves proving the presence of allergen-specific IgE. This had traditionally been done by skin testing, the most precise method being skin endpoint titration. In vitro diagnostic methods offer advantages over skin tests and have become increasingly popular with both patients and physicians. However, thorough knowledge of skin testing techniques and interpretation of results is necessary for the physician using in vitro test methods and also allows moving back and forth between the two modalities in the preparation of antigen treatment sets and adjustment of immunotherapy dosage.

Experience with RAST-based immunotherapy.

During its 80 year history, allergen immunotherapy has been used essentially as Noon and other early investigators described it. Immunotherapy is practiced mainly as an art based on uncontrolled clinical observations of individual patients treated in private practice. Dosing schedules and skin test interpretations are based primarily on the biases of the treating physicians. In an effort to improve the results obtained from immunotherapy, different approaches have evolved. Serial dilution skin endpoint titration (SET), practiced mostly by otolaryngologists, became popularized in the 1960s out of the need to optimize immunotherapy dosing regimens. SET can be viewed as a forward step in the direction of more aggressive yet safe initial immunotherapy doses. With the discovery of IgE in 1966 as the prime carrier of reaginic hypersensitivity in humans came the availability of a remarkable set of in vitro assays for the measurement of total and allergen-specific IgE reactivity. The radioallergosorbent test (RAST), which has been shown to correlate reliably with the major variants of the atopic state, was modified in 1977 in such a way as to enhance the sensitivity of the assay with minimal alteration of specificity. The modified RAST (MRT) has been carefully investigated and has shown reliable concordance with the major parameters of clinical allergy. Since its development only 14 years ago, the MRT has become a dependable adjunct for the determination of initial and in many cases final immunotherapy doses. An important contribution of RAST-based immunotherapy is that only patients with quantifiable serum titers of allergen-specific IgE qualify as candidates for immunotherapy. The fact that fewer allergens are used for treatment at higher initial doses and that potential reactors are identified before starting therapy are yet other advantages of RAST-based immunotherapy. The use of RAST as a method of allergen standardization only reinforces its value in patient management.