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Leukocyte histamine release and humoral changes during oral and subcutaneous hyposensitization of grass pollen allergic children.

Thirty-one children with seasonal hay fever, sensitive to rye grass by skin test, RAST, and leukocyte histamine release, received preseasonal hyposensitization with a rye grass pollen extract either subcutaneously (cumulative dose 40,000 PNU) or orally (cumulative dose 400,000 PNU). While there was a significant (p less than 0.005) increase in specific serum IgG-antibodies and a decrease (p less than 0.005) of leukocyte sensitivity in the subcutaneously treated group, oral treatment with an aqueous pollen extract could not be demonstrated to be immunologically effective.

Adolescent↗

Hyperreactivity to bee stings: reevaluation.

(a) A survey of beekeepers in Israel did not show that they differed allergy-wise from the general population. (b) Twenty-eight non-beekeeper systemic reactors to bee stings were not necessarily more allergic or more exposed to stings than the others. These systemic reactors had a spontaneous kinin system hyperreactivity and in some of them changes in the immune system and a complement defect were detected. We think that predisposition may enhance the likelihood of a systemic reaction to bee stings. Thus the common denominator for the hyperreactivity to bee stings is not their exposure to stings nor their allergic background but rather the spontaneous kinin activity and a possible defect in their immunological system.

Adult↗

Suppressive versus stimulatory effects of allergen/cholera toxoid (CTB) conjugates depending on the nature of the allergen in a murine model of type I allergy.

Recent reports have demonstrated that feeding small amounts of antigen conjugated to the B subunit of cholera toxin (CTB) suppress immune responses in experimental models of certain Th1-based autoimmune diseases. We have established a model of aerosol sensitization leading to Th2-mediated allergic immune responses in BALB/c mice. In the present study two different antigens, the dietary antigen ovalbumin (OVA) and the inhalant allergen Bet v 1 (the major birch pollen allergen), chemically coupled to recombinant CTB were tested for their potential to influence Th2-like immune responses. Intranasal administration of OVA-CTB prior to sensitization with OVA led to a significant decrease of antigen-specific IgE antibody levels, but a marked increase of OVA-specific IgG2a antibodies as compared to non-pretreated, sensitized animals. Antigen-specific lympho-proliferative responses in vitro were reduced by 65% in the pretreated group; IL-5 and IL-4, but not IFN-gamma, production were markedly decreased in responder cells of lungs and spleens of nasally pretreated mice. In contrast, mucosal administration of rBet v 1-CTB conjugates prior to sensitization led to an up-regulation of allergen-specific IgE, IgG1 and IgG2a, increased in vitro lympho-proliferative responses as well as augmented production of IL-5, IL-4, IL-10 and IFN-gamma. Intranasal administration prior to sensitization of unconjugated allergens showed also contrasting effects: OVA could not significantly influence antigen-specific antibody or cytokine production, whereas intranasal pretreatment with unconjugated Bet v 1 suppressed allergen-specific immune responses in vivo and in vitro. These results demonstrated that the two antigens--in conjugated as in unconjugated form--had different effects on the Th2 immune responses. We therefore conclude that the tolerogenic or immunogenic properties of CTB--and probably also other antigen-delivery systems--strongly depend on the nature of the coupled antigen-allergen.

Adjuvants, Immunologic↗

A double-blind study of hyposensitization with an alginate conjugated extract of D. pteronyssinus (Conjuvac) in patients with perennial rhinitis. 1. Clinical aspects.

The efficacy of hyposensitization with a standardised extract of Dermatophagoides pteronyssinus (D. pteronyssinus) conjugated to alginate and containing known amounts of antigen P1 (Conjuvac) was tested in a double blind, placebo controlled, multi-centre study in 66 adult patients with perennial rhinitis. Patients received 11 weekly injections of increasing concentrations of Conjuvac containing from 56 x 10(1) to 448 10(3) IU D. pteronyssinus or placebo injections of the alginate diluent to some of which 5 micrograms of histamine has been randomly added. This was followed by 15 monthly injections of Conjuvac or placebo. The severity of nasal blockage, sneezing and rhinorrhoea was recorded twice daily in a diary and visual analogue assessments (VAS) made at each clinic visit. Nasal provocation testing (NPT) was performed with increasing concentrations of the same extract of D. pteronyssinus as used in the hyposensitization injections, and changes in nasal airways resistance measured by passive anterior rhinomanometry. VAS was recorded and NPT was performed on entry to the study and after the fifth, ninth and final monthly injection. Conjuvac injections were well tolerated. Large local reactions (greater than 5 cm) occurred within 30 min in only 1% of patients but later in 23%. No systemic reactions or anaphylaxis occurred within 30 min of injections, but urticaria or worsening of asthma and rhinitis was reported later in 3% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗