Positive Skin Test Reactions Research Articles

Identification of allergens in the venom of the common striped scorpion

The common striped scorpion, Centruroides vittatus, is endemic to the southwestern United States and causes thousands of human stings annually. Immediate hypersensitivity reactions to C. vittatus venom have been reported. To identify specific IgE in 11 patients with immediate hypersensitivity to C. vittatus and to characterize the allergens present in the venom. Skin testing to dialyzed, filtered venom was performed in 5 patients. Immunoglobulin E immunoblots to whole milked venom was accomplished with serum samples from 8 patients. Enzymatic properties of whole venom were also determined. C. vittatus venom was found to contain 150 microg/microL of protein. Four of 5 patients tested had positive skin test reactions to the purified venom extract, with no late reactions. In all 8 patients, sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated multiple proteins, 9 of which were identified as allergens on IgE immunoblots, ranging in size from 30 to 170 kD. Enzymatic activity was found to include phospholipase A, alkaline phosphatase, esterase, esterase lipase, and acid phosphatase. C. vittatus envenomation may result in immediate hypersensitivity reactions in susceptible individuals. Venom specific IgE can be identified by using skin tests and IgE immunoblots. The allergens identified in these patients had molecular weights distinct from those of known scorpion neurotoxins. A safe and effective skin testing extract can be prepared from dialyzed pure venom and may lead to the widespread ability to diagnose C. vittatus venom allergy.

Anaphylaxis to algae

Rationale Cyanobacteria (blue green algae) have been shown to cause allergic respiratory disease but systemic anaphylaxis has not been previously described. We report the case of a previously nonatopic 7 year-old girl who experienced urticaria of the legs on 3 successive weeks after swimming in a lake. The cove in which she swam had an extensive growth of algae. On the 4th week, she swallowed a small amount of lake water after water entered her nose while swimming. Within a few minutes, she developed generalized urticaria, laryngeal edema, and wheezing. She recovered after treatment in a local emergency department. Methods Lake water was filtered through filter paper. The filter paper with the collected algae was allowed to dry, placed in buffered saline and extracted for 3 days. The extract was centrifuged, and both the filtered lake water and extract supernatant were concentrated and sterile filtered. The patient was prick skin tested to histamine, saline, lake water and algae extract. Three healthy subjects served as controls. Results The 3 control subjects showed no reaction to the lake water or algae extract. The patient showed markedly positive skin test reactions to lake water and algae. Conclusions This is the first report of systemic anaphylaxis to algae. We postulate that contact urticaria of the legs occurred on 3 occasions while swimming and ingestion of lake water resulted in anaphylaxis.

Tuberculin Skin Testing and Interpretation in Children

Tuberculosis is the most frequently occurring infectious disease in the world. The tuberculin skin test using 5 TU of purified protein derivative (PPD) applied by the Mantoux technique remains the primary method of identifying children infected with Mycobacterium tuberculosis or Mycobacterium bovis. PPD is injected intradermally, and induration is measured 48-72 hours after application. Interpretation of the skin test reaction depends on the age of the child and presence or absence of risk factors for acquisition of tuberculosis, irrespective of previous immunization with bacille Calmette-Guerin (BCG). False-positive and false-negative skin test reactions can occur. Following identification of a positive tuberculin skin test reaction, a complete history, physical examination, chest radiographs, and laboratory studies are necessary to determine the appropriate chemotherapeutic agents to treat tuberculosis infection or disease. Epidemiologic investigation of the child's contact with active tuberculosis is v...

Comparing Nasal Secretion Eosinophil Count with Skin Sensitivity Test in Allergic Rhinitis in Ibadan, Nigeria

Objectives—The aim of this prospective study was to assess the usefulness of nasal smear eosinophilia compared with a skin sensitivity test for the diagnosis of allergic rhinitis and to determine the degree of correlation between the tests.Material and Methods—Fifty patients with a clinical history suggestive of nasal allergy and 20 controls were studied. A range of allergens were used for the skin sensitivity test in both groups. Nasal smears were examined by light microscopy.Results—A positive skin test reaction was demonstrated in 90% of the study population and 25% of the controls, whereas 76% of the patients and 15% of the controls demonstrated significant nasal smear eosinophilia. There was 66% correlation between the skin test and nasal eosinophilia, although this was not statistically significant (correlation coefficient–0.187 p = 0.193). This study does, however, demonstrate that both tests are sensitive for the diagnosis of allergic rhinitis, with sensitivities of 0.90 (95% CI 0.82–0.98) for the skin test and 0.76 (95% CI 0.64–0.88) for nasal eosinophilia.Conclusion—Both the skin-prick test and the nasal smear eosinophilia showed correlation with the clinical history, although the skin-prick test was more sensitive. No statistically significant correlation was demonstrable between the two tests.

Decus et Tutamen.

It is a truism to say that most of our interaction with the environment depend on surface contacts of one kind or another. The nature of many of the interactions of any individual with his or her environment depend on the skin, and thus we come to a critical argument against adopting the Euro. The amount of nickel is regulated in products that come into prolonged or repeated contact with the skin, because of the contact allergies produced. One- and two-euro coins induce positive skin-test reactions in sensitive individuals, and remarkably, release 240–320 times more nickel than is allowed in the European Union Nickel Directive.1 The electrode potential between the two metals that form the coins is an important part of the sweat-related galvanic release of nickel that occurs. The authors of this study (from Switzerland)1 point out that the effect is not seen with the Swiss franc, which contains 25% nickel but which is, of course, a more dependable currency. The law of unintended consequences has played an important part in a number of discoveries (notably with many valuable side-effects of drugs) and is one of the most potent arguments to be deployed against the use of the Precautionary Principle in regulation. What is self-evident …

From IgE to anti-IgE: where do we stand?

From IgE to anti-IgE: where do we stand?

Metallurgy: high nickel release from 1- and 2-euro coins.

The amount of nickel is regulated in European products that come into direct and prolonged contact with human skin because this metal may cause contact allergy, particularly hand eczema. Here we show that 1- and 2-euro coins induce positive skin-test reactions in sensitized individuals and release 240-320-fold more nickel than is allowed under the European Union Nickel Directive. A factor contributing to this high release of nickel is corrosion due to the bimetallic structure of these coins, which generates a galvanic potential of 30-40 mV in human sweat.

Insulin-induced Drug Eruptions and Reliability of Skin Tests

Allergic reaction to insulin preparations seemed to have decreased since the introduction of contaminant-free, human preparations. The role of protamine sulfate in decreasing the prevalence of allergy is unclear. This study examines the causative components of insulin allergy along with the value of skin tests for diagnosis. Eleven patients with insulin allergy and 53 patients receiving insulin but without an insulin allergy were included as controls. Intradermal skin tests were conducted using preparations containing various concentrations of insulin [Neutral protamine Hagedorn (NPH) insulin, regular insulin (RI)] and protamine sulfate. Of the 11 patients studied, 3 had anaphylaxis and 8 displayed localized reactions. All of the patients reacted positively during skin testing. Five patients showed positive intradermal skin test reactions to protamine sulfate, and 4 reacted to insulin. Two patients that were not tested with protamine sulfate reacted positively to NPH insulin. In the case of protamine sulfate, 4 patients with localized symptoms displayed positive reactions at concentrations of 10 microg/ml, 3 microg/ml or 0.3 microg/ml. One patient with anaphylaxis reacted positively to a concentration as low as 0.03 ng/ml. In the case of insulin protein, 3 patients reacted positively to a 100-fold dilution (1 UI/ml). Eight of the 53 controls experienced pruritus and/or skin lesions. However, none of the controls reacted at a concentration of NPH insulin of less than 10 U/ml or to protamine sulfate at less than 30 microg/ml. Allergic reactions to protamine sulfate are common and should not be ignored. This study shows a good correlation between clinical manifestations and skin test reactions for insulin allergy.

Evaluation of children with recurrent pneumonia diagnosed by World Health Organization criteria.

A World Health Organization (WHO) case management approach has been used to identify and treat children with pneumonia worldwide since 1987. Many children are treated repeatedly: 23% of children with pneumonia in our rural Haitian district had met the WHO criteria on two or more occasions; but underlying disease in such children has not been systematically studied. We enrolled 103 children who had been diagnosed with pneumonia on 3 or more occasions by community health workers using WHO criteria. We compared them with 138 children similarly evaluated but never diagnosed with pneumonia, matching by health worker and age. We administered questionnaires to parents and performed complete physical examinations, tuberculin skin tests and serologic testing for HIV on all subjects and chest radiographs on case children. Two percent of case children and 1.5% of controls had positive tuberculin skin test reactions. None of the children tested was HIV-seropositive. Ninety-four case children had normal baseline chest radiographs and three had focal infiltrates. A history of wheezing was reported for 79% of case children and 61% of controls (P = 0.002), and wheezing with exercise was reported for 36% and 22%, respectively (P = 0.02). Most children in Haiti with recurrent pneumonia diagnosed by WHO criteria do not have evidence of tuberculosis, HIV infection or pulmonary anomalies, but they may be more likely to have asthma, and this should be considered as an alternative diagnosis. This information should help direct evaluation of such children in other settings and prompt further study of asthma in developing countries.

Pulmonary functions in atopic and nonatopic asthmatic children

we examined how lung function and certain clinical and laboratory characteristics in asthmatic children were changed according to skin test positivity to aeroallergens. a skin prick test was conducted using standardized extracts of 10 different allergens in 56 children with bronchial asthma, aged 5-15 years, in Dicle University Hospital. Lung function was measured by Microplus spirometer. among the 56 subjects, asthma was classified as mild in 16, moderate in 42 and severe in 3. At least one skin prick test was positive (monosensitized) in 35 subjects (62 %) and positive reactivity to two or more aeroallergens (polysensitized) was found in 17 subjects (30 %). Positive skin test reactions to aeroallergens were associated with a decrease (as percentage of the predicted decrease) in FEV1, FVC and PEF values. Significant differences were also found between prick test-positive and -negative asthmatics in duration of breastfeeding (8.5 5 months vs 15 7 months, respectively, p < 0.007), age at which cow's milk had been started (5.7 1.6 vs 10.5 5.4, p = 0.004); total serum IgE concentration (350 221 IU/ml vs 234 164 IU/ml, p = 0.02), age at onset of asthma symptoms (2.5 1.9 years vs 4.1 2.2 years) and number of asthma attacks per year (7.0 3.1 vs 5.2 3.5, p = 0.012). When one-way ANOVA and a post-Hoc test were used, asthma attacks were more frequent and severe and allergic conjunctivitis symptoms were more frequent in the polysensitized group than in the nonsensitized and monosensitized groups (p = 0.03). children with positive skin prick test results, especially those with combined sensitivity to dust mite, cat and dog, were at increase risk of more severe asthma.

Onset and persistence of childhood asthma: predictors from infancy.

Onset and persistence of childhood asthma: predictors from infancy.

The risk of adenoid hypertrophy in children with allergic rhinitis

Adenoid hypertrophy (AH) may cause significant morbidity in children but its relationship to allergic rhinitis (AR) has not been studied. To determine the risk factor of AH in patients with AR. We studied 315 children (ages 1 to 18 years) who had AH and AR. We compared them with 315 age-matched controls who had AR alone. To identify risk factors, they were divided into four groups according to age and clinical parameters, including the prevalence of otitis media, sinusitis, lower respiratory infection, exposure to smoking, sleep disorders, use of antihistamine/decongestants, and results of allergy skin testing. The prevalence of upper or lower respiratory infections was higher in the group with AR and AH, but not in all age groups. A high prevalence of exposure to smoking and skin test reactivity against house dust mites were found in both groups. However, the prevalence of positive reactivity to molds was significantly higher in the group with AH and AR (P ranged from 0.013 to <0.0001 and the relative risk ranged from 1.609 to 2.375). Further, the risk of AH was positively correlated with number of skin test reactivity to mold spores (P ranged from 0.0035 to 0.0001). Positive skin test reactivity to animal danders or seasonal allergens failed to predict the risk of AH. Sensitivity to mold allergens is an important risk factor for AH in children with AR; therefore, early prevention of exposure to molds may help reduce occurrence of AH.

Sensitization to common allergens and its association with allergic disorders at age 4 years: a whole population birth cohort study.

Atopy is defined as the genetic propensity to develop immunoglobulin E antibodies in response to exposure to allergens and assessed by skin prick test responses to common allergens. Although it is generally agreed that atopy is an important risk factor for allergic diseases such as asthma, rhinitis, and eczema, the extent to which atopy accounts for these diseases is controversial. We aim to describe the prevalence of sensitization to common allergens and investigate the degree of association of atopy (as defined by positive skin prick test to 1 or more common allergens) to asthma, rhinitis, and eczema in a birth cohort at the age of 4 years. A birth cohort of 1456 children was recruited over a 14-month period (1989-1990). These children have been seen previously at 1 and 2 years of age. At 4 years, 1218 children were reviewed and an interview was administered or postal questionnaire was completed for the presence of allergic diseases (asthma, rhinitis, and eczema). Additionally, in 981 children, skin prick tests with a battery of 12 common allergens were performed. Allergens were house dust mite (Dermatophagoides pteronyssimus), grass pollen mix, cat, dog, Alternaria alternata, Cladosporium herbarum, cow's milk, hen's egg, soya, cod, wheat, and peanut. A mean wheal diameter of at least 3 mm greater than the negative control was taken as positive. This analysis is confined to the 981 (67% of the original population) who also had skin prick tests to the standard battery. chi(2) tests were used to test the univariate association between each allergic disease and positive skin test. Multiple logistic regression analysis was performed to obtain the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the independent effect of sensitization to each allergen on allergic disease, adjusting for the effect of sensitization to other allergens. To ascertain how much of allergic disease is attributable to atopy, we estimated the population-attributable risk. This was calculated with the formula: P(R - 1) where R is the OR for the allergic disease under consideration and P is the proportion of atopy in children with that disease. Children who were skin prick-tested at 4 years were similar in most characteristics to the rest of the population, except that they had a higher prevalence of allergic disease. Allergic disorders (asthma, rhinitis, and eczema) were present in 276 (28.1%) of 981. One hundred ninety-two (19.6%) children were atopic (positive reaction to 1 or more allergens). Sensitization to inhalant allergens was relatively common (19.2%) as compared with food allergens (3.5%). House dust mite (11.9%), grass pollen (7.8%), and cat (5.8%) were the most common positive reactions. A test to the 4 most common allergens (house dust mite, grass pollen, cat, and A alternata) could detect 94% of the atopic children. Sensitization to the 4 most common allergens was strongly associated with the presence of allergic disorders. There was a graded effect with the potent allergens, such as house dust mite, having the greatest impact. For example, 50% of children sensitized to house dust mite had asthma as opposed to 44% sensitized to cat, 42% sensitized to grass pollen, and 32% sensitized to A alternata. Overall, 68.4% of children sensitized to house dust mite had asthma, eczema, and/or rhinitis. The respective figures for grass pollen, cat, and A alternata were 64.9%, 66.7%, and 57.4%. The proportion of children sensitized to cat was not higher in households with cat ownership (households with cats: 5.1% [19/374]; households without cats: 6.2% [36/580]; not significant [NS]). Similarly, no difference was seen in sensitization to dog in households with and without dogs (households with dogs: 1.8% [5/282]; households without dogs: 2.8% [19/673]; NS). Boys were atopic more often than girls at this age (male: 112 of 497 [22.5%] vs female: 80 of 484 [16.5%]; OR: 1.47, 95% CI: 1.07-2.02). Male preponderance was observed with most allergens, but this was statistically significant only for house dust mite (male: 75/497 [15.1%] vs female: 42/484 [8.7%]; OR: 1.87; CI: 1.25-2.79) and grass pollen (male: 51/497 [10.3%] vs female: 26/484 [5.4%]; OR: 2.01; CI: 1.23-3.29). An independent effect of allergen sensitization on asthma was observed only with house dust mite with an OR of 8.07 (CI: 4.60-14.14). The highest independent risk for rhinitis was sensitization to grass pollen (OR: 5.02; CI: 2.21-11.41), and for eczema, sensitization to peanut (OR: 4.65; CI: 1.02-21.34). The majority of children (98/192) were sensitized to >1 allergen. A graded effect was observed with the risk of allergic disease in the child increasing with the number of positive skin prick test reactions. This effect was consistent throughout the spectrum of allergic diseases (asthma, eczema, and rhinitis). (ABSTRACT TRUNCATED)

Infant's Airway Responsiveness Predicts Asthma at 6 Years of Age

Pulmonology| July 01 2001 Infant’s Airway Responsiveness Predicts Asthma at 6 Years of Age AAP Grand Rounds (2001) 6 (1): 9–10. https://doi.org/10.1542/gr.6-1-9 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Infant’s Airway Responsiveness Predicts Asthma at 6 Years of Age. AAP Grand Rounds July 2001; 6 (1): 9–10. https://doi.org/10.1542/gr.6-1-9 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: airway device, airway structure, asthma, histamine, wheezing Source: Palmer LJ, Rye PJ, Gibson NA, et al. Airway responsiveness in early infancy predicts asthma, lung function, and respiratory symptoms by school age. Am J Respir Crit Care Med. 2001;163:37–42. The purpose of this study by investigators at the University of Western Australia and the TVW Telethon Institute for Child Health Research in Perth, Australia, was to determine the relationship between airway hyper-responsiveness in healthy neonates at 1 month of age and the subsequent development of asthma, atopy, lower respiratory tract symptoms, and lung function at 6 years of age. The subjects were randomly recruited from a metropolitan hospital prior to birth between 1987 and 1991. Initial pulmonary function and histamine challenge were performed at approximately 1 month of age, prior to any lower respiratory tract infection or clinical illness. Of the initial 253 children, 120 could be contacted and all agreed to participate in follow-up studies on about their sixth birthday. Comparing the infants available for follow-up with those lost to follow-up identified no significant differences at 1 month of age for any parameters of interest. The infant pulmonary function testing was achieved by the rapid thoracic compression technique measuring maximal flow at functional residual capacity (VmaxFRC). The histamine challenge consisted of increasing doses of nebulized histamine from .125g/L to a maximum of 8.0g/L; the provocation concentration producing a 40% decrease in VmaxFRC was estimated from the log dose-response curve. Skin reactivity was assessed for dust mites, rye grass, cow’s milk and egg white. Pulmonary function testing at 6 years of age was done by conventional spirometry according to American Thoracic Society standards. Repeated pulmonary function testing after increasing nebulized doses of histamine was used to establish the dose-response slope to histamine challenge. Skin testing at this time included the same allergens as before in addition to mixed grass, cat and dog. Careful family histories for respiratory and allergic diseases were obtained at both data intervals. Generalized linear models were constructed to investigate the relationships between the histamine responsiveness at 1 month of age and the respiratory outcome at age 6 years. Of the 120 6-year-olds, 14.2% reported wheezing apart from colds, 35.0% reported wheezing with colds, 25.8% had a usual cough and 32.5% had current or previous physician-diagnosed asthma. The histamine sensitivity at 1 month of age was significantly associated with physician-diagnosed asthma (ever) (P=.003), physician-diagnosed current asthma (P<.001), wheeze with colds (P=.003), wheeze apart from colds (P<.001), and usual cough (P=.05). The subjects with the greatest response to histamine at both 1 month and 6 years of age had the lowest forced expiratory volume at 1 second (FEV1) at 6 years of age. There was no significant association between the histamine sensitivity at 1 month and the atopy-associated factors such as eosinophil count, total serum IgE, and positive skin test reactivity assessed at 6 years of age. The authors conclude from this data that airway... You do not currently have access to this content.

Changes over 13 years in skin reactivity to histamine in cohorts of children aged 9-13 years.

Several studies report substantial differences in the prevalence of skin test reactivity to allergens in children from adjacent geographic areas; others report an increased prevalence over time. To find out whether these differences depend on variations in skin reactivity to histamine, we determined the time trend of histamine wheal sizes in successive cohorts of unselected children living in the same area (Viterbo, Italy). We conducted three epidemiologic surveys, each including children aged 9 and 13 years. The 1983-7 study investigated 170 children (150 were tested twice); the 1992 study, 158 children; and the 1996 study, 208 children. In both age groups, the mean diameter of the wheal induced by histamine skin prick tests (10 mg/ml) increased significantly over time (9-year-olds: 3.25 mm in 1983, 4.68 in 1992, and 5.89 in 1996; 13-year-olds: 3.89 mm in 1987, 5.18 in 1992, and 6.50 in 1996) (P < 0.001 between subsequent studies). The distribution of the wheal diameters for both ages showed a trend to a right shift in the three successive studies (P < 0.001). The dose-response curves for three histamine concentrations (0.2, 1, and 10 mg/ml) had significantly steeper slopes in 1996 than in 1983-7 (P < 0.001). The marked time-related increase in the size of the histamine wheals could help to explain the trend toward an increased prevalence of positive allergen skin test reactions reported during the past years. The causes of increased skin reactivity to histamine remain conjectural.

Can medical surveillance measures improve the outcome of occupational asthma?

Occupational asthma (OA) has been reported to account for 3% to 20% of all asthma cases in studies that have included populations in Europe, North America, Australia, New Zealand, and Japan.1 Even after the diagnosis has been confirmed and the worker removed from ongoing exposure to the causative work agent, it can still be associated with ongoing asthma, significant morbidity,2 and even mortality.3 For some workplace sensitizers the risk of OA in the workplace can be reduced by primary prevention, particularly control of workplace respiratory exposure. It has been shown for several workplace sensitizers4-6 that the population risk of sensitization relates to the airborne exposure level. Reduced inhalation exposure levels have been achieved as a result of process or product changes (eg, for detergent enzymes by encapsulation of the enzymes7 and for natural rubber latex by powder-free lowprotein glove use8). Other measures may include use of alternative nonsensitizing agents (elimination/substitution), occupational hygiene measures of ventilation, robots in high-exposure areas, and appropriate respirators. Regulations to control and monitor airborne concentrations of common sensitizers such as diisocyanates may enhance the likelihood of reducing work exposures to safer levels. An additional method for primary prevention of OA would be to identify workers at risk of sensitization to specific workplace agents at the time of pre-employment and exclude their exposure to these agents. Unfortunately, at present those at risk cannot be predicted with sufficient sensitivity and specificity for this to be practical: although risk markers for those exposed to sensitizers, such as genetic markers, atopy, and smoking history9

Testes cutâneos de hipersensibilidade imediata com o evoluir da idade

OBJETIVO: avaliacao da positividade aos testes cutâneos de hipersensibilidade imediata em criancas com asma bronquica e/ou rinite alergica em diferentes faixas etarias. CASUISTICA E METODOS: foi observada a positividade aos testes cutâneos de hipersensibilidade imediata, por testes de puntura, frente a diferentes alergenos de mesma procedencia: poeira total e Dermatophagoides sp, Dermatophagoides pteronyssinus, Dermatophagoides farinae e Blomia tropicalis, Penicillium sp, Alternaria alternata, Cladosporium herbarium, Aspergillus fumigatus, grama bermuda, capim de pasto, epitelio de cao, epitelio de gato, penas, Blatella germanica, la. Foram selecionadas 713 criancas divididas em grupos conforme a faixa etaria: grupo I (6 a 11 meses), II (1 a 3 anos e 11 meses), III (4 a 8 anos e 11 meses) e IV (9 a 15 anos). Para analise estatistica utilizou-se o calculo do qui-quadrado. RESULTADOS: o total de diferencas significativas entre os varios grupos foi: I e II = 5; II e III = 5; II e IV = 5; III e IV = 6; I e III = 10 e I e IV = 10 CONCLUSAO: concluiu-se que a positividade ao teste de hipersensibilidade imediata foi maior com o evoluir da idade, havendo positividade ja aos doze meses de vida, sendo esta positividade significativamente maior a partir de quatro anos de idade.

Positive skin test and age

OBJECTIVE: To evaluate positive responses to skin tests for immediate hypersensitivity to allergens in children with asthma and rhinitis at different ages. METHOD: We observed positive skin test reactivity in prick tests using fifteen allergens of same origin (total dust and Dermatophagoides sp.; Dermatophagoides pteronyssinus; Dermatophagoides farinae; Blomia tropicalis; Penicillium sp; Alternaria alternata; Cladosporium herbarium; Aspergillus fumigatus; Bermuda grass; forage grass; dog and cat epithelia; feathers; Blatella germanica and wool). We placed 713 selected patients into different age groups - Group I: 6 to 11 months; Group II: 1 to 3 years and 11 months; Group III: 4 to 8 years and 11 months; and Group IV: 9 to 15 years. We used the chi-square test for statistical analysis. RESULTS: The total significant differences between these groups were: I to II = 5; II to III = 5; II to IV = 5; III to IV = 6; I to III = 10; and I to IV = 10. CONCLUSION: Skin test reactivity is acquired progressively with age, and can be observed as early as at 12 months. Reactivity is significantly more positive from the age of 4 on.

Mycobacterial cervical lymphadenitis in children: clinical and laboratory factors of importance for differential diagnosis.

The role of epidemiological and clinical features for the early differential diagnosis between Mycobacterium tuberculosis (MTB) complex and non-tuberculous mycobacterial (NTM) cervical lymphadenitis in children was examined in this study. From 1982 to 1997, 24 MTB complex cases and 26 NTM cases were diagnosed, of which 75% and 25%, respectively, presented during the first half of the study period. Epidemiological and lymph-node features and anatomical areas were not helpful in the differential diagnosis between the 2 groups. Fulfilment of 2 out of 3 criteria (positive tuberculin skin test reaction, abnormal chest radiograph, contact with a person with infectious tuberculosis) was associated with 92% sensitivity for the diagnosis of MTB lymphadenitis. 37.5% of the MTB cases and 88.5% of the NTM cases were culture-confirmed; all inconclusive cultures concerned patients with spontaneous drainage and fistula. Surgical intervention was required in 67% of the MTB cases. All NTM cases were managed by surgery alone. Fistulae or cheloids occurred in all patients in whom incision and drainage were applied instead of total excision. Excellent aesthetic results were achieved in patients who presented within 1 month following the onset of lymphadenitis. The spectrum of mycobacterial cervical lymphadenitis in children in Greece has changed during the 1990s. Early and prompt treatment contributes to the diagnosis and response.

Effective DNA vaccination of cattle with the mycobacterial antigens MPB83 and MPB70 does not compromise the specificity of the comparative intradermal tuberculin skin test

The current tuberculin test and slaughter strategy for the control of bovine tuberculosis in cattle has failed to prevent a sharp rise in cases over recent years, especially in the south-west of England. A recent scientific review has concluded that the development of a cattle vaccine holds the best prospect for tuberculosis control in British herds. In order to continue with test and slaughter-based control strategies, the development of TB vaccines that do not compromise the specificity of the tuberculin skin test are required. This report describes results of cattle vaccination experiments with TB DNA vaccines expressing the mycobacterial antigens MPB70, MPB83, and Ag85A and constitutes the first published vaccination study with DNA vaccines undertaken in a target host species. All calves vaccinated with the MPB83 expressing plasmid demonstrated potent cellular immune responses, characterised by CD4 + T cells producing interferon-gamma as well as humoral immunity characterised by IgG1 biased specific antibodies. Vaccination with MPB70 was less effective with immune responses only observed in half of the vaccinated animals, while vaccination with Ag85A did not result in vaccine-induced immune responses. Intramuscular vaccination was found to stimulate stronger cellular responses than intradermal immunisation. Significantly, the specificity of tuberculin skin testing was not compromised by DNA vaccination since none of the vaccinated calves showed positive skin test reactivity.