Henning Løwenstein

Immunotherapy with cat- and dog-dander extracts: IV. Effects of 2 years of treatment

Thirty-five patients (20 children and 15 adults) with animal-dander asthma completed 2 years of immunotherapy with partly purified and standardized cat- or dog-danger extracts. The first year of the study was performed double-blind with a placebo-treated control group. These 15 patients were transferred to active treatment for a second year. All patients were followed by use of the skin prick test (SPT), allergen and histamine bronchial challenges, and tests for allergen-specific IgE, IgG1, and IgG4 levels. In the group treated with active extracts for 2 years (group A), the previously reported decrease in bronchial responsiveness to cat extract (p less than 0.001) and histamine (p less than 0.01) was even more pronounced after the second year. After 1 year of active treatment in the original placebo group (group B), a significant decrease in the bronchial responsiveness to cat extract was noted (p less than 0.001). The responsiveness to histamine was decreased only in the patients treated with cat-dander extracts (p less than 0.05). A significant decrease in the SPT (p less than 0.001) and an increase in the allergen-specific IgE (p less than 0.001) and IgG4 (p less than 0.001) was also noted in patients (group B) treated with cat-dander extracts. The side effects in the two groups (A and B) were negligible, except for some systemic side effects, especially among the children during the initial phase of immunotherapy. The symptoms were mild and responded promptly to treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunotherapy with cat- and dog-dander extracts

Abstract Thirty-five patients (20 children and 15 adults) with animal-dander asthma completed 2 years of immunotherapy with partly purified and standardized cat- or dog-danger extracts. The first year of the study was performed double-blind with a placebo-treated control group. These 15 patients were transferred to active treatment for a second year. All patients were followed by use of the skin prick test (SPT), allergen and histamine bronchial challenges, and tests for allergen-specific IgE, IgG1, and IgG4 levels. In the group treated with active extracts for 2 years (group A), the previously reported decrease in bronchial responsiveness to cat extract ( p p p p p p p

Prospective estimation of IgG, IgG subclass and IgE antibodies to dietary proteins in infants with cow milk allergy. Levels of antibodies to whole milk protein, BLG and ovalbumin in relation to repeated milk challenge and clinical course of cow milk allergy.

Prospectively, serum levels of IgE, specific IgE antibodies (AB) to whole cow milk protein (CMP), bovine se‐albumin, bovine immunoglobulin, bovine lactoferrin, bovine lactalbumin and beta‐lactoglobulin (BLG), IgG and IgG subclass antibodies to ovalbumin (OA) and BLG, and IgG4 RAST to CMP (bovine whey) were measured in 39 infants with cow milk protein allergy (CMPA) at birth (cord blood), at time of diagnosis and before and after milk challenge at the age of 12 months. Immunological measurements were also undertaken in 33 control infants without CMPA at birth, at 6 months and at 18 months. At no time, were differences found between the levels of IgG and IgG subclass AB to OA and BLG in control versus infants with CMPA. In the 39 infants with CMPA no correlation was found between the levels of IgE, IgG and IgG subclass AB in cord blood and subsequent levels of these values, irrespective of the type of CMPA (IgE‐mediated (CMA) or non‐IgE‐mediated (CMI)), and irrespective of whether remission had occurred. In cord blood 25/33 (76%) of the infants with CMPA had specific IgE‐AB to one or more of the bovine milk proteins indicating a prenatal intrauterine sensitization to cow milk protein. At 6 months the frequency of specific IgE‐AB to bovine milk proteins was significantly (p<0.05) higher in infants with CMA versus CMI, and at 12 months total serum‐IgE and the increase of these specific IGE‐AB and RAST to CMP were significantly higher (p<0.05) in infants with persistent CMA. From 6 to 12 months withholding milk resulted in a significant fall in specific IgE‐AB to CMP, and IgG, IgG, and IgG4 anti‐BLG followed by an increase after milk challenge. Decreasing levels of IgG anti‐OA from birth to 6 months reflect passive maternal transfer of IgG through the placenta, and increasing levels of IgG anti‐BLG, already from birth to 6 months, may represent an early exposure to CMP in all infants. Significantly higher levels (p<0.05) of IgG anti‐OA AB, IgG, and IgG4 anti‐BLG AB were found in infants with persistent CMA, indicating a close relation between the synthesis of IgE and IgG and between IgE and IgG subclasses (IgG, and IgG4) in symptomatic cow milk‐allergic individuals. Determination of IgG AB and IgG subclass AB (IgG, and IgG4) to BLG and bovine whey in cord blood appears unable to discern infants at high risk of development of CMPA. However, infants with persistent CMPA have an increased antibody response of specific IgE and IgG subclasses (IgG, and IgG4) to CMP exposure.

Allergen‐Specific IgE Antibodies against Antigenic Components in Cow Milk and Milk Substitutes

Crossed radioimmunoelectrophoresis (CRIE) was used to study the presence of scrum IgE against antigenic components of Cow milk in 21 selected milk‐allergic patients. The amount of each IgE specificity was estimated by a scoring system. The milk‐allergic children had mainly IgE against α‐lactalbumin, β‐lactoglobulin, albumin and immuno‐globulin, the four major proteins of bovin whey as well as IgE against three cascin components. A serum pool from 1000 normal adults had IgE against the same whey protein, but in smaller amounts, and no IgE against the casein components. Eight cow milk‐based formulae, commonly used for infant feeding, and goat milk were studied by the same method. It was found that six of the milk substitutes did not differ significantly from cow milk in antibody binding, but the two hydrolysed casein products. Nutramigen® and Pregestimil®, consisted of such small molecules that the rabbit antisera could not precipitate the Indrolysed proteins in the gels on the CRIE plates. It was therefore not possible to study their IgE binding, if any, by this method.

An investigation of the possible immunological relationship between allergen extracts from birch pollen, hazelnut, potato and apple.

In a retrospective study on a selected group of patients, the coincidence of birch pollen allergy and a clinically relevant positive prick test reaction to apples and potatoes was confirmed.

Assay for the major dog allergen, Can f I: Investigation of house dust samples and commercial dog extracts

Monospecific rabbit antibodies were used to develop a sensitive two-site enzyme immunoassay to measure a major dog hair and dander allergen, Can f I. This Can f I assay demonstrated no reaction with 17 heterologous allergen sources, including dog albumin, cat, guinea pig, and horse. Analysis of serial dilutions of purified Can f I and the international standard for dog was parallel. The assay was considered specific for Can f I with a lower limit of detection at 0.03 micrograms/ml. Total imprecision was from 2% to 6%. Commercial dog extracts for specific immunotherapy contained from 0.7 to 290 micrograms of Can f I per milliliter. The assay was used to measure Can f I in 136 house dust samples collected from 103 homes across the United States. Concentration of the dog allergen was expressed as micrograms of Can f I per gram of dust. Prevalence of Can f I in the dust samples ranged from less than 0.3 to 10,000 micrograms/gm. Serial dilutions of samples containing Can f I were parallel to the standard. The median Can f I value for homes with a dog in residence was 120 micrograms/gm, and for homes with no dog, 3 micrograms/gm. With few exceptions, homes with no dog in residence had less than 10 micrograms/gm. This Can f I assay will provide useful information for assessing commercial extracts as well as monitoring dog-allergen exposure and allergen-control methods.

Identification and clinical significance of allergenic molecules of cat origin: part of the DAS 76 study

Freeze‐dried extracts from cat dander and the corresponding rabbit antibodies were used for establishing the CIE reference pattern for cat dander extracts. Anti‐Cat Ag 1 and anti‐cat albumin were used for identification of the corresponding antigens. CRIE on sera from selected groups of American and Danish cat‐allergic patients demonstrated antigen‐specific IgE binding to 10 of 15 cat dander antigens (Cat Ag 1 being the major allergen). Only minor differences were found between the two groups. Four of these allergens were serum proteins. Variable amounts of many of the 10 allergens were measured by QIE in saliva, serum, urine and three cat pelt extracts. However, extremely wide ranges for content of the serum allergens and the non‐serum allergens were found. This was exemplified by an albumin/cat Ag 1 ratio between 1 and 400, smallest in cat dander. Immunoabsorption using anti‐cat dander, anti‐cat albumin and anti‐Cat Ag 1 indicated that the anti‐cat dander, anti‐cat albumin, and the anti‐Cat Ag 1 absorbed approximately 90%, 25%, and 56%, respectively, of the dander RAST activity, and 87%, 11%, and 45%, respectively, of the saliva RAST activity, confirming the major importance of Ag 1. It is concluded that cat allergenic extracts should contain only modest amounts of serum albumin and other serum‐derived antigens and that any relevant standardization must include quantification of at least Cat Ag 1 and cat albumin.

Identification of allergens in Dermatophagoides pteronyssinus mite body extract by crossed radioimmunoelectrophoresis with two different rabbit antibody pools.

An extract of purified Dermatophagoides pteronyssinus mite bodies was investigated by crossed radioimmunoelectrophoresis (CRIE), using sera from 29 mite‐allergic patterns. Two CRIE series consisting of rabbit antibodies to (1) whole mite culture and to (2) purified mite bodies were run simultaneously, showing 27 and 29 precipitates, respectively. Cases of major discrepancy between the two series were ascribed to absence of antibody 10 allergenic components and to artefactual radiostaining due to inclusion of allergen in precipitates representing other antigens. Carefully performed controls were necessary to establish the reliability of CRIE. Specific response patterns in the studied set of sera were found to several of the represented antigens. Two major allergens appeared in both CRIE systems. Two intermediate and several minor allergens were further identified.

A collaborative study on the first international standard of Dermatophagoides pteronyssinus (house dust mite) extract

A collaborative study was carried out to assess the suitability of a preparation to serve as the International Standard for Dermatophagoides pteronyssinus (house dust mite) extract. The proposed international standard of D. pteronyssinus, two additional freeze-dried extracts, and a commercially available skin testing solution were tested in the study. Nineteen laboratories in 11 different countries participated. The assay methods used included RAST inhibition, crossed immunoelectrophoresis/crossed radioimmunoelectrophoresis, isoelectric focusing, quantitative skin testing, and various other methods for assessing total allergenic activity. In addition, six laboratories measured the quantity of antigen P1, and three laboratories measured antigen DpX in each of the preparations. On the basis of the results from this study, the World Health Organization established the preparation as the International Standard for D. pteronyssinus extract with an assigned unitage of 100,000 IU per ampule. The units refer both to the total allergenic activity of the ampule and to that of the individual allergens, such as P1 and DpX.

Identification and purification of an important cross-reactive allergen from American (Periplaneta americana) and German (Blattella germanica) cockroach

Aqueous whole body extracts from two major domiciliary cockroaches, the American, Periplaneta americana, and the German, Blattella germanica, were analyzed in crossed immunoelectrophoresis and immunoblotting. Forty-five antigens were found in P. americana and 29 in B. germanica. IgE-binding antigens were identified by crossed radioimmunoelectrophoresis with sera from 30 cockroach-allergic patients. Seven and three precipitates from P. americana and B. germanica bound significant amounts of IgE. A cross-reactive, apparently homologous allergen, from P. americana and B. germanica bound IgE from 100% and 70%, respectively, of the patients. These important allergens were tentatively named Per a I and Bla g I. The allergens were purified by sequential ion exchange, gel filtration, and isoelectric focusing. Both allergens had a molecular size of 33 to 37 kd in Sephadex G-75 gel filtration, and 28 kd in high-performance liquid chromatography gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a minor band at approximately 25 kd, and most of the protein at 6 kd. The isoelectric point of both allergens was found be to 3.5. In amino acid analysis, the allergens were highly similar. Skin test revealed the allergens to be important in vivo sensitizing agents. The allergens may be used for environmental assays for cockroach exposure in the homes of allergic subjects.