Positive Prick Test Research Articles

The relationship between bronchial histamine reactivity and atopic status.

It has been proposed that increased production of IgE, a feature of atopy, is a cause of the non-specific bronchial hyper-reactivity that is characterisitc of asthma. This hypothesis was examined by selecting groups of subjects with asthma or rhinitis and a group of healthy control subjects and studying the relationship between their bronchial histamine reactivity and their atopic status. In none of the groups tested was there a significant association between the degree of bronchial histamine reactivity and either the serum level of total IgE or the number of extracts of aeroallergens giving positive prick test reactions.

CYSTIC FIBROSIS HETEROZYGOSITY IN THE PATHOGENESIS OF ALLERGY

47% of cystic fibrosis (C.F.) heterozygotes had positive prick skin tests to 1 or more of 9 antigens and 53% had histories of allergic disease, both occurring significantly more often than in a control group. Since 1 in 20 of the population are C.F. carriers, this would contribute considerably to allergy in the community.

PRICK‐ AND RADIOALLERGSORBENT TESTS (RAST) TO ALCALASE® IN A POPULATION NOT EXPOSED TO ENZYME DETERGENTS

A total of 301 persons in a population unexposed to enzyme detergents (Rumania) were prick-tested with Alcalase, and RASTs were performed on their sera. The material consisted of three groups, one atopic, the second non atopic, and the third healthy. In the first two groups the percentage of positive prick-test reactions amounted to 6 and 5% respectively. Only one positive RAST was found (second group). In the third group no positive prick-tests were found and no positive RASTs. The majority of the positive prick-tests were considered non specific, and no correlation was found between results of prick-tests and RASTs in this material of non exposed individuals.

Isolation and characterization of cal allergens.

A crude (saline soluble) extract of cat skins capable of eliciting a strong positive prick skin test in cat sensitive individuals was fractionated on Sephadex G200. Active fractions were pooled and successively fractionated on isoelectric focusing gradients of pH 3-5 and pH 4-5. Allergenic activity was localized in two peaks with mean isoelectric points of 4-1 and 4-35 respectively. On immunoelectrophoresis the allergen with pI = 4-35 was associated with a protein which was subsequently found to be immunologically indistinguishable from serum albumin and to have a molecular weight of 69,000 daltons. The allergen with pI = 4-1 migrated in the alpha2-region on immunoelectrophoresis and had a mean molecular weight of 55,000 daltons. This allergen was isolated and analysed for amino acid and carbohydrate content. A combined extract of both allergens coupled to microcrystalline cellulose and used a RAST procedure readily distinguished between two groups of individuals classified as skin test positive and skin test negative to cat allergen.

Cystic fibrosis--immunological reactions to A. fumigatus and common allergens.

Immunological studies of forty-three patients with cystic fibrosis showed that positive prick tests to at least one common allergen were obtained in 70%, to multiple allergens in 28% and to A. fumigatus in 50%. Specific IgE antibodies against these allergens were found in the appropriate subjects. In spite of this evidence of type 1, IgE, sensitization none of the patients had a history of infantile eczema. Intracutaneous tests with A. fumigatus extract gave types 1 and 3 reactions in sixteen patients (37%), only seven of whom were among the sixteen (37%) who gave positive precipitin tests. Raised levels of total serum IgG and IgA were found as compared with healthy controls and asthmatic subjects. No differences were found in total serum IgM and IgD levels. The high incidence of allergy to A. fumigatus in cystic fibrosis is confirmed.

An analysis of skin prick test reactions in 656 asthmatic patients.

Of 656 asthmatic patients referred specifically for allergy assessments, 544 (84 percent) gave positive immediate skin prick tests to at least one of 22 common allergens used routinely. Comparison of these skin test positive patients with the 102 (16 percent) who were skin test negative showed a number of significant differences. The majority of the skin test positive patients (52 percent) were less than 10 years old at the time of onset of the asthma, whereas, of the skin test negative patients, 56 percent were aged over 30 years at the time of onset. Seventy per cent report rhinitis compared with 48 per cent of the skin test negative patients, and 29 per cent reported infantile eczema compared with 9 per cent. Symptoms attributed to house dust, pollens, and animals were noted two to three times more frequently by the skin test positive patients, while corticosteroid drugs had been used more commonly by the skin test negative patients (45 percent compared with 35 percent). No significant differences were observed with the other factors studied, namely, history of urticaria or angio-oedema, family history of "allergic" disease, and awareness of sensitivity to foods, aspirin or penicillin. Prick test reactions in the skin test positive patients were most commonly seen to house dust or the acarine mite, Dermatophagoides farinae (82 percent), followed by pollens (66 percent), animal danders (38 percent), foods (16 percent), Aspergillus fumigatus (16 percent), and other moulds (21 percent). There was a highly significant association of positive history with positive prick test for all allergens studied.

Serum IgE-concentrations in patients with contact sensitization.

In 123 patients with contact sensitization (cs), of whom 23 had positive histories of atopy and/or positive prick tests (csa), the serum IgE-concentrations were determined and the following results were obtained: 1. A remarkable dispersal of IgE-concentrations was noted in cs--patients (1-3080 U/ml); 12% of them displayed IgE-concentrations of more than 1000 U/ml, even though they had no histories of clinical manifestations of atopy, liver of kidney diseases, or parasitic infestations. Their mean IgE-value of 396 U/ml +/- 60 differed considerably from the one of a comparable control group of healthy individuals. No statistically significant differences were noted between the IgE-levels, the age of our patients, the type and number of contact allergens, and the duration of skin lesions. 2. On an average, there were higher IgE-levels noted in cases of acute and extensive skin lesions than in cases of subacute to chronic, localised skin lesions. Controls of the serum IgE-concentrations and histologic examinations by means of immunofluorescence suggested that, depending on the individual patient, skin lesions might lead to an (unspecific?)activation of IgE-synthesising round cells. 3. In csa-patients with sensitization to metal, the skin lesions were of localised subacute to chronic character, while skin lesions of acute and extensive character were exceptional (5.9%).

Allergy diagnosis with the radioallergosorbent test: A comparison with the results of skin and provocation tests in an unselected group of children with asthma and hay fever

The radioallergosorbent test (RAST) has been used for in vitro diagnosis of asthma and hay fever in children as an integrated part of the routine procedure for allergy diagnosis. A positive RAST test was combined with a positive prick test in 196 235 (80 per cent) tests and with a positive provocation test in 163 182 (90 per cent) tests. When the provocation test was positive to dry pollen, the stock solution ( 1 10 w./v. or 10,000 PNU) of the allergen extract RAST was quite often negative, a fact that explains the lower degree of correlation for a negative RAST test. A comparison between the prick test and the provocation test revealed a high proportion, 54 146 (37 per cent), of positive prick tests that could not be confirmed by the provocation test. RAST is a simple, reliable test for IgE antibodies that is very useful for in vitro diagnosis of atopic allergy on a routine basis. RAST is harmless and less traumatic than skin testing and therefore suitable for use even on very small children. The information obtained on the patient's hypersensitivity is more relevant than that from regular skin testing, probably comparable to skin test titration with selected allergens but not quite as good as provocation testing of the shock organ involved. Whenever a provocation test cannot be performed for each suspected allergen, an RAST test, possibly completed with a prick test, is recommended.

Egg-white sensitivity and atopic eczema

Thirty-four children with atopic eczema were studied for egg-white sensitivity. Clinical manifestations, skin reactivity to egg-white antigen, IgE, by radioimmunoassay (RIA), and specific reaginic IgE antibodies to egg white by the radioallergosorbent test (RAST) were evaluated. Patients were divided into two groups on the basis of clinical sensitivity to egg-white antigen. Of 13 eczematous patients in Group I with known clinical egg sensitivity, 2 had RAST levels between 0 and 24 per cent, 6 between 25 and 100 per cent, and 5 had levels greater than 100 per cent. In this group, 5 had positive prick skin tests to egg white. Of 21 eczematous patients in Group II with no demonstrated clinical egg sensitivity, 17 had RAST levels of 0 to 24 per cent, 3 had RAST levels between 25 and 100 per cent, and one had an RAST level greater than 100 per cent. In this group, 3 had positive prick tests to egg white. The egg-white RAST showed a significant correlation with clinical egg sensitivity (p = 0.0005) and with a prick skin test of the same antigen (p = 0.036) but not with total serum IgE levels. However, no correlation was found between clinical egg sensitivity and egg-white prick skin test.

IgE--antibodies and skin test reactions to a detergent--enzyme in Swedish consumers.

SummaryThe frequency of raised levels of IgE antibodies against a detergent enzyme—subtilisin‐A—was investigated in adult Swedish consumers. Of 1132 patient sera which were sent to the laboratory for routine RAST testing against various allergens a positive RAST to subtilisin was found in twenty‐one (1.9%). Of 391 blood donors two had a positive RAST and one a doubtfully positive reaction. A positive prick test to subtilisin was obtained in four out of 122 patients with symptoms of allergic airways disease. Sensitization occured more often among patients with an atopic constitution. About four out of five of the patients in whom IgE antibodies to the enzyme was found were women. Thirty‐five patients (seventeen with a positive and eighteen with a negative RAST to subtilisin) were further investigated in order to see if results of RAST and skin test with subtilisin were correlated with clinical symptoms. Eight patients with positive RAST and skin test reported symptoms of an immediate allergic type in connection with exposure to enzyme detergents. Three patients had symptoms which could be attributed to residues of subtilisin in the laundry after washing. In six patients the sensitization did not seem to have any clinical significance. Taking into account the general use of enzyme detergents, sensitization has not been found to be a major clinical problem.

A follow-up study of children with asthmatoid bronchitis. I. Skin test reactions and IgE antibodies to common allergens.

SUMMARYEighty‐one children, 2–66 months old, with asthmatoid bronchitis were followed for 15–40 months (mean 31 months). The children were physically examined 3–4 times a year. Blood samples were taken on these occasions. Skin prick tests were done at the beginning and at the end of the investigation period. Antibodies of the IgE class, as measured by RAST, were found against animal danders, pollens or house dust in 5 children at the first examination and during the follow‐up period in another 5 children. Strongly positive prick test reactions were accompanied by a positive RAST in 86%, smaller wheals less frequently. IgE antibodies to egg white or cow's milk were found in 26 children, in many cases during the first year of life and occasionally as early as at the age of 3 months. As the children grew older the titres decreased and the antibodies seemed to be of clinical importance only in a few cases with high titres to the egg white extract. In contrast, IgE antibodies to animal danders were not detected until 11/2 years of age and those to pollen not until 3 years of age. These antibodies showed increasing titres with time and they seemed to be of clinical importance in all but a few cases with very low titres.

TRANSIENT IgA DEFICIENCY AND PATHOGENESIS OF INFANTILE ATOPY

IgA deficiency at 3 months was associated with the development of atopy (eczema and positive prick tests) within the first year in the offspring of reaginic parents. At 1 year the IgA levels were higher in the atopic than the non-atopic infants. These findings suggest that a brief period of allergen avoidance during a symptomfree vulnerable period might prevent much atopic disease.

The increased prevalence of allergic disease in anhidrotic congenital ectodermal dysplasia

Anhidrotic congenital ectodermal dysplasia (ACED) is a sex-linked recessive disorder which is characterized by anodontia or severe hypodontia, anhidrosis or severe hypohidrosis, and hypotrichosis. Afflicted individuals may also demonstrate evidence of hypoplastic changes in the respiratory mucosa. Seven male patients with ACED were found to have a statistically significant increased prevalence of extrinsic bronchial asthma and/or allergic rhinitis and an increased prevalence of positive prick test reactions to common inhalant allergens when compared with a control population examined in the Tecumseh Community Health Study. Four patients with ACED and allergic disease had no consistent abnormality in serum IgG, IgA, or IgM levels, and both transport piece and IgA were demonstrable in their salivary secretions or parotid fluid. It is postulated that the increased prevalence of allergic disease in patients with ACED may be due to an abnormality of the nasal mucosa resulting in an increased permeability to or decreased destruction of inhaled allergens.

Factitious wealing at the site of previous cutaneous response.

SUMMARY.— When a weal evoked as a cutaneous allergic response has disappeared, that area of skin, although appearing normal, shows factitious wealing: this tendency persists for 72–96 hr. The phenomenon is present after weals caused by positive intradermal prick tests from various substances, after weals from certain insect bites, and on the site of fading lesions of acute urticaria. Weals caused by intradermal histamine are not followed by this factitious wealing, nor is it present on skin which has been the site of a weal in chronic urticaria.