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Biomedical subjects

L Berrens

Publications and source records attributed to L Berrens.

At least 19 recordsLinked to original sources
PubMed1991

Estimation of the allergen content of house dust samples by enzymatic assay.

House dust extracts contain protease and acid phosphatase activities which can be shown to be related to the content of major allergens for humans. A study of the quantitative association between measured enzyme activities and the potency of the extracts to bind IgE antibodies from the serum of house-dust-allergic patients is presented. Since major allergens from mites and other insects contributing to the allergenic potential of household dust on chemical isolation coincide with proteolytic enzymes, and since the bulk of pollen allergenic activity is related to acid phosphatase, the method presented here allows the quantitative appraisal of the contribution of the biomass of animal and plant origin to the allergenic potency of environmental dust samples without the use of human blood samples as sources of specific antibodies.

Acid Phosphatase↗
PubMed1991

Estimation of IgE antibodies to the common allergens by reverse enzyme immunoassay. Comparison with the radioallergosorbent test.

A reverse enzyme immunoassay (REINA) is described, in which polystyrene microtiter wells are sensitized with murine monoclonal anti-human IgE, and then sequentially allowed to react with patient's serum, peroxidase-labeled allergens and substrate. The results obtained with the sera of patients allergic to Lolium perenne grass pollen, the tree pollens of Betula alba and Olea europea, the epithelia of cat and dog, the mite Dermatophagoides pteronyssinus, or to the foodstuffs cow's milk, chicken eggwhite or peanut were compared with the analytical data from the ratio allergosorbent test (RAST). The results show a good correlation between these two laboratory techniques.

Allergens↗
PubMed1991

Relationship between IgE and IgG antibodies in type I allergy.

Serum samples of human patients with immediate type allergy were examined for both IgE (by radioallergosorbent test) and IgG (by enzyme immunoassay) antibodies to several of the common inhalant and food allergens. The results show a statistically significant correlation between the titers of anti-allergen antibodies of both isotypes. The data indicate that immune stimulation in atopic individuals is not restricted to the IgE isotype, but equally affects the IgG-producing antibody systems. The statistical relationship observed may either be due to common pathways in the production of both antibody classes in atopic people, or may be explained by preferential binding of allergens to circulating IgE-IgG immune complexes.

Allergens↗
PubMed1990

Enzyme immunoassay for pigeon breeders' disease without the use of extraneous antibody.

A rapid enzyme immunoassay technique is described for the detection in human sera of antibodies of any class to pigeon antigens. The method is based on binding human antibodies in excess to polystyrene-fixed antigens from pigeon droppings or pigeon serum, followed by capture of the same antigens coupled to peroxidase. A very good correlation was found of titers obtained by means of this 60-min assay with traditional sandwich immunoassay and with precipitation- and complement - fixation tests.

Animals↗
PubMed1990

Cross-reactivity among the pollen proteins of birch and apple trees.

In the spring of 1986, the pollen were collected from apple trees in full blossom, and were investigated for their allergenicity. The patients selected for study were subjects with a combined inhalant allergy to birch pollen and an oral allergy to apple fruit. The apple pollen extract yielded about the same percentage of nondialysable substance as obtained from birch pollen. In contrast to the latter, UV-spectroscopy revealed no flavonoids adsorbed to the apple pollen proteins. Patients with a combined allergy to birch pollen and apple fruit showed positive skin reactions to both birch and apple pollen extract. Inhibition of IgE-binding in RAST to birch pollen was observed by apple pollen extract at a 1000-fold lower potency than the homologous birch allergens. Immunoblotting demonstrated IgG-antibodies in birch-allergic sera cross-reactive with apple pollen components. It is concluded that minor allergenic determinants cross-reactive with birch pollen epitopes occur not only in the fruit, but also in the pollen of the apple tree.

Cross Reactions↗
PubMed1989

Intracutaneous tests with pityrosporon extract in atopic dermatitis.

In patients with atopic dermatitis and in a control group prick and intracutaneous tests were performed with Pityrosporon extracts. Moreover, specific IgE against Pityrosporon was determined in these patients. Significant differences existed between the results obtained with these methods in both groups of patients. Therefore, both skin tests with Pityrosporon extract and IgE determinations may contribute to a diagnosis of AD; moreover, it is likely that Pityrosporon may be of significance in the pathogenesis of AD.

Allergens↗
PubMed1989

Blood groups ABO and grass-pollen hayfever.

The frequency distribution of the blood group phenotypes ABO was examined in retrospect in a selected group of 241 Patients with grass pollen hayfever. A relative deficiency in blood group O was found, with a shift toward an over-represented B-phenotype as compared to the general population. This shift appeared to be largely due to the contribution from the female patients with pollinosis. Comparison with literature data confirmed a lower frequency of the O-phenotype in atopic patients in general, irrespective of the specific sensitivities.

ABO Blood-Group System↗
PubMed1987

House dust extracts contain potent immunological adjuvants.

A crude aqueous extract of house dust and two house dust subfractions were tested for adjuvant activity in a sensitivity assay performed in mice. Evidence is presented that house dust contains at least two potent immunological adjuvants. One of these, present in both subfractions, was probably endotoxin and acted in a complement-independent way. The immunostimulatory effect of the other adjuvant was abrogated by prior complement depletion of the animals. This apparently complement-dependent adjuvant needs further identification.

Adjuvants, Immunologic↗
PubMed1987

Antibodies to bird serum proteins in confectionery workers exposed to egg spray.

In an extended study of group of confectionery workers sensitized by exposure to egg spray, it was found that their blood serum contained antibodies to avian serum proteins. Comparison of the ratio of IgG antibodies determined by ELISA to egg yolk 'livetins' and pigeon serum in these patients and in pigeon breeders showed that the phenomenon is entirely due to immunological cross-reactivity among avian blood serum proteins. These avian serum proteins in hens' eggs, not ovalbumin, were identified as the major sensitizing antigens.

Egg Proteins↗
PubMed1986

The presence of IgE molecules on epidermal Langerhans cells in patients with atopic dermatitis.

Skin sections of clinically involved and clinically normal-looking skin from patients with atopic dermatitis were incubated with anti-human IgE antibodies using the indirect immunoperoxidase technique. Apart from positive dermal anti-IgE staining, positive epidermal anti-IgE staining was also observed. The morphology of the epidermal staining cells suggested the involvement of dendritic cells. This was confirmed by positive immuno-double labelling with OKT6 and anti-IgE. This phenomenon seemed to be specific for atopic dermatitis since skin sections from normal non-atopic controls, patients with allergic asthma, contact dermatitis, and schistosomiasis showed no epidermal anti-IgE staining. To further elucidate the nature of the epidermal anti-IgE staining cells, epidermal cell suspensions were prepared from clinically involved skin from patients with atopic dermatitis. These cell suspensions also showed positive anti-IgE staining cells and positive immuno-double labelling with OKT6 and anti-IgE. Immunogold electron microscopy with anti-IgE on epidermal cell suspensions from patients with atopic dermatitis showed gold particles on the cell membranes of cells containing Birbeck granules, being Langerhans' cells. Epidermal cell suspensions from normal non-atopic controls were negative. The presence of IgE molecules on epidermal Langerhans' cells, which seems to be specific for patients with atopic dermatitis, provides an explanation for the high frequency of positive patch test reactions to inhalant allergens.

Adolescent↗
PubMed1986

Antibodies against hen's egg proteins in pigeon breeder's disease.

The serum of patients with pigeon breeder's lung (PBL) contains IgG-class antibodies against pigeon serum proteins. These antibodies cross-react strongly with the sera of other avian species. Cross-reactivity, as demonstrated by precipitation, complement fixation, haemagglutination and microELISA, is also exhibited with the water-soluble proteins in hen's egg yolk and egg white. The phenomenon appears to be due to the presence of hen serum proteins in the eggs, which occur particularly concentrated among the water-soluble proteins in the yolk ('livetins'). It is proposed that anti-egg antibodies may explain the frequent serological finding of 'false-positive' asymptomatic pigeon breeders.

Alveolitis, Extrinsic Allergic↗
PubMed1979

A modified sandwich technique for the measurement of IgE.

The paper radioimmunosorbent test (PRIST) has been described as the method of choice for determining low serum IgE levels; the radioimmunosorbent test (RIST) as the method of choice for determining normal and elevated serum IgE levels. By replacing the 125I-labelled anti-IgE antibody used in the paper radioimmunosorbent test by the 125I-labelled anti-IgE reagent used in radioallergosorbent test (RAST) and by changing the serum dilution and the incubation time, this modified sandwich technique (MST) became comparable to the RIST in the normal and elevated IgE-region and showed results similar to the PRIST in the very low IgE-region. The affinity of the 125I-labelled anti-IgE of the RAST proved to be about 2.6 times higher than the antibody used in the PRIST, which explains the improved results in the normal and the good results in the very low IgE-region. The lowest serum IgE level measurable by this method was as low as 0.05 I.U./ml, as determined in 20 cord sera. The mean IgE level in cord sera was 0.45 I.U./ml (range 0.05--2.63 I.U./ml). The results of this study suggest replacement of the antiserum used in PRIST by the one available for RAST.

Asthma↗