Anne K. Sobotka

Insect allergy: the state of the art.

There has been significant recent progress in the diagnosis and treatment of patients with Hymenoptera sensitivity.‘-” Many problems remain, and, indeed, the introduction of new information has raised additional questions. Treatment is highly efficacious but expensive, of long duration, and has an unknown degree of long-term side effects. The question of whom to treat, therefore, becomes critical. With the commercial availability of venoms for immunotherapy, the practicing allergist will need to make a series of difficult decisions. With this in mind, it seems appropriate to present our clinical and laboratory experience during the last five years and to summarize our suggestions concerning the management of patients with an allergy to insect stings. Our recommendations are derived from experience with the evaluation of over 500 patients and the therapy, including inhospital sting, of over 300 adults and children. A degree of controversy persists in this field, and additional data must be gathered before a fully defined position can be established. We have tried to make what follows as precise a statement of what is and is not known as is currently possible. Whole body extract therapy In the first volume of the

Allergy to insect stings. II. Phospholipase A: the major allergen in honeybee venom.

In order to determine the proteins of major allergenic importance in honeybee venom (Apis mellifera) it was chromatographed on G-50 Sephadex. The four major protein peaks eluted were identified as hyaluronidase, phospholipase, melittin, and apamin. Testing these preparations on the leukocytes of 6 honeybee-sensitive patients, with the in vitro method of histamine release, revealed that all individuals were most sensitive to phospholipase A. IgE antibodies against phospholipase A (RAST) were found in the sera of honeybee-sensitive patients and IgG antibodies to this venom component were found in the sera from beekeepers and venom-treated patients. Melittin appeared to be allergenic in several patients, but the results were variable and were possibly due to contamination with phospholipase. All patients were insensitive to the hyaluronidase and apamin preparations. We conclude that phospholipase A is the major allergen of honeybee venom and, since this protein is readily available, it should be useful for diagnostic and therapeutic studies as well as for the standardization of materials used in the management of honeybee-sensitive patients.

Effect of theophylline and terbutaline on immediate skin tests

A questionnaire survey of board-certified allergists revealed that conflicting ideas exist as to the effect that drugs such as theophylline and beta 2 agonists have an immediate skin tests. Approximately half of the respondents felt these drugs would obscure a skin response; the remainder would not withdraw the drugs prior to testing. As a result of this difference in opinion, we studied the effects of these drugs on skin tests in seven subjects taking terbutaline (5 mg three times daily) and 13 subjects taking theophylline (3 to 5 mg/kg every 6 hr). Neither an acute loading dose nor chronic administration of either drug singly produced significant changes in wheal size in response to histamine, ragweed, or grass allergens. We conclude that theophylline and terbutaline administered singly at these doses have no effect on immediate skin tests.

IgE-induced changes in human basophil cyclic AMP levels.

We studied a unique patient with 77% basophils, not different from normal by a number of criteria, in order to measure the changes in cyclic AMP level associated with IgE-mediated histamine release. In accordance with previous hypothesis and circumstantial evidence, anti-IgE challenge led to a significant fall in the cyclic AMP level which preceded histamine release.

IgE-Mediated Basophil Phenomena: Quantitation, Control, Inflammatory Interactions

In this review, we will describe our recent work directed toward understanding the nature of IgE-mediated histamine release from human basophils. While the work covered will be primarily that from this laboratory, relevant observations by others are included to provide somewhat broader coverage. Three areas of interest will be dealt with: (1) quantitative aspects of the relationship between IgE antibody and histamine release; (2) control of antigeninduced histamine release; and (3) interrelationships between IgE-mediated basophil phenomena and other cell types which participate in the inflammatory reaction.

Modulation of the rate of histamine release from basophils by cyclic AMP

Rates of histamine release from human basophil leukocytes have been studied in response to three different stimuli: antigen, ionophore A23187 and strontium ions. Dibutyryl cycle AMP and other agents which are assumed to cause a rise in intracellular levels of cyclic AMP accelerate the release of histamine induced by all of the stimuli. In addition, dibutyryl cyclic AMP caused an inhibition of the maximum release obtainable with antigen stimulation but no inhibition of the maximum release obtainable with ionophore A 23187 or with strontium ions alone.