Specific reactions and cross reactions of anti-penicilloyl antibodies

In human sera the specific reactions and cross reactions of antibodies directed against the penicilloyl groups were determined using different penicilloyl derivatives as antigen. The penicilloyl group providing the highest litre in one Ig class was said to define the specific reaction for this Ig class. This criterium was justified by the fact that antibodies evoked by long-term treatment with benzylpenicillin showed specific reaction to the benzylpenicilloyl group. Moreover, specific reactions of antibodies of different Ig classes in one serum were the same. Both the side chain and the thiazolidine ring of the penicilloyl group can serve as antigenic determinants.     

Dermatologic drug reactions

Cutaneous drug reactions have a variety of clinical presentations. This review focuses on the most common or severe cutaneous reaction patterns. Knowledge of the clinical morphology and the most commonly associated medication aids in rapid diagnosis and institution of the appropriate therapy.     

Crosslinking reactions in the molten state: Interpolymeric condensation reactions

Chemical reactions leading to crosslinking were followed by rheometrical studies during curing at different temperatures and compositions of compatible species. The condensation reactions between two copolymers of styrene and maleic anhydride, and several α,ω-dihydroxyoligostyrenes, lead to an experimental variation of the elastic modulus (G′)_t. A kinetic scheme is proposed, selecting the most reliable reactions, which describes the experimental behaviour adequately. According to this scheme, the rate constants of interpolymeric condensation reactions were evaluated. It appears that the values obtained for grafting and crosslinking are quite the same. They depend mainly, in absence of a catalyst, on the molecular weight of the oligomer and on the local viscosity, which is a function of composition. In presence of a catalyst, there is a large increase of the constant, indicating that the chemical step is dominating the diffusion process.     

Papain-induced allergic reactions

Papain is a proteolytic enzyme with elastolytic activity, which produces emphysemalike lesions when introduced into the airways of animals. It is encountered by humans in numerous occupations, medications and domestic products. Sensitization to papain in two subjects in different occupations was confirmed with skin tests with chemical-grade papain and radioallergosorbent tests (RAST), with a papain which had been chemically inactivated by selective active site blockade. Skin tests and RAST were negative in non-symptomatic co-workers. Withdrawal from occupational exposure to papain resulted in an improvement in symptoms. In a survey of 330 subjects at the time they were receiving routine allergy skin tests, seven reacted to papain. Sensitization was confirmed by the RAST. Serum IgG antibodies to papain were detected among sensitized individuals and also in five out of 266 sera obtained from a clinical hospital laboratory. The findings illustrate immune responses to papain in humans in the form of atopic sensitization and serum IgG antibodies. Moreover, recurrent respiratory symptoms in the presenting persons served to illustrate that they and their co-workers were repeatedly exposed to air-borne papain. In view of the potential danger from the proteolytic effects of papain, these observations illustrate the need for further investigations of the effects of human exposure to air-borne papain.     

Photoallergic drug reactions

Drug-induced hypersensitivity reactions include phototoxic and photoallergic reactions. Photoallergic reactions, which develop as cell-mediated immune responses to a light-activated compound, are described in this review article. The main topics include photobiology, list of common drugs inducing photoallergic reactions, immune response, clinical features, diagnostic and therapeutic approach. Photoallergic drug reactions can be avoided in most cases if the potential photoallergens are known and appropriate photoprotection is used.     

Correlation of initial food reactions to observed reactions on challenges.

BACKGROUND: Food allergies occur in 2% to 3% of the pediatric population. These reactions can vary from mild cutaneous manifestations to severe life-threatening reactions. Limited information is available on which specific factors may predict the severity of subsequent reactions. OBJECTIVE: To determine whether the organ system or the specific food involved in the initial allergic reaction predicts the outcome of subsequent food challenge. METHODS: Retrospective review of all food sensitive children who underwent food challenges at The Children's Hospital of Philadelphia, Philadelphia, PA, in a 5-year period (n = 998 challenges). The specific food, initial symptom on presentation, and reaction on open challenges were recorded. RESULTS: A total of 413 of 998 food challenges produced positive results. Milk, egg, and peanut were the most common foods to be associated with a positive challenge result. The most common presentation of food allergy was cutaneous followed by multiorgan reactions. Peanut, milk, and egg sensitivities were more likely to cause a multiple-organ system reaction on challenge than wheat or other foods. Patients with egg allergy were more likely to have a different reaction on rechallenge than other foods. CONCLUSIONS: Milk, egg, and peanut are the most common foods associated with food challenges. Patients will typically experience similar reaction on re-exposure to the initial reaction. However, multiple-organ system reactions can occur after any initial clinical presentation, with milk, egg, and peanut having more multiple-organ reactions than other foods.