Yunginger, John W.

Abstract We previously found that sera of patients immunized with ragweed pollen extract contained a factor that interfered with the binding of IgE antibodies to solid-phase allergens in the radioallergosorbent test (RAST). We now describe an assay, RAST interference, to measure this factor, and we present evidence that the factor is IgG blocking antibody. Sera from immunized allergic patients were heated at 56 degrees C for 4 hr to destroy heat-labile Fc determinants on IgE and were tested for their ability to prevent binding of additional IgE antibody to solid-phase allergens in the RAST. Eight of 10 sera from allergic immunized patients gave RAST interference dose-response curves that did not differ from the arbitrary standard. The factor causing interference showed specificity for the immunizing antigen, was heat-stable, eluted from Sephadex G-200 in the 7S peak, was present only in sera of immunized patients, and rose after initiation of immunization. These results indicated that RAST interference can be used to measure IgG blocking antibodies with the same reagents employed for the measurement of IgE antibodies, provided the antiserum to IgE is specific for the heat-labile FC determinants on IgE.

Abstract We compared the quantities and avidities of IgE and IgG antibodies from three phospholipase-A (PLA) sensitive patients during honeybee venom immunotherapy. IgG antibody was purified by affinity chromatography through a Sepharose anti-IgE Column followed by ionexchange chromatography on DEAE Sephadex. IgE antibody was obtained by elution from the Sepharose anti-IgE column with 4 M guanidinium HCl and by passage of the eluate over Sepharose anti-IgG. Absolute amounts of IgE and IgG antibody to PLA were determined by immunoabsorption and radioimmunoprecipitation, respectively. IgE antibody to PLA accounted for 25.1% to 28.7% (X̄ = 27.0%) of the total IgE protein; IgG antibody accounted for 0.073% to 0.210% (X̄ = 0.130%) of the total IgG protein. The relative avidities of IgE and IgG antibodies were assessed by the ability of equimolar amounts to bind radioiodinated PLA. In two patients, avidities of IgE and IgG antibody for PLA were comparble, whereas in the third, IgG antibody bound PLA more avidly than IgE antibody. The valence of IgE antibody was greater than 1.9, assuming that PLA behaved as a univalent ligand in extreme antigen excess. IgG antibody was able to inhibit binding of IgE antibody in the PLA radioallergosorbent test (RAST) from 10% to 40% at a molar excess of 10- to 1000-fold. The results indicate that: 1) IgE antibody to PLA accounts for a high percentage of total IgE protein; 2) the avidities of IgE and IgG antibodies are similar (two of three patients); 3) the valence of IgE antibody approaches two; and (4) IgG antibody can interfere with the measurement of IgE antibody in the PLA RAST.

Allergic reactions to insect stings occur in approximately 0.4% of the general population.1,2 Severe anaphylactic reactions may occur in sensitive patients, and estimates suggest that 40 persons die during such reactions each year in the United States.3 From the standpoint of allergy the Hymenoptera order of insects is the most important; this order includes the bees (honeybees and bumblebees), vespids (wasps, yellow jackets, and hornets), and fire ants. CLASSIFICATION OF STING REACTIONS Insect sting reactions may be grouped into immediate (within two hours) or delayed (more than two hours) categories. Immediate reactions can be subdivided into local, large local, or systemic reactions, depending on the severity and extent of the reaction. Local reactions are normal reactions—a sting will cause transient pain, redness, and swelling at the sting site. In large local reactions the reaction is much more extensive, although all signs and/or symptoms produced are contiguous with the sting site. For example, a sting on the finger may produce swelling of the entire forearm or extremity. In a systemic reaction signs and/or symptoms occur at sites remote from the sting site. For example, a sting on the finger may produce angioedema of the eyelids or generalized urticaria. Toxic reactions are nonimmunologic reactions produced when an individual is stung by multiple insects within a short period of time; signs and symptoms are those of a systemic allergic reaction, but are due to the physiologic effects of vasoactive materials in the venom. Systemic allergic reactions are immunologic reactions produced by vasoactive materials released from the blood basophils or tissue mast cells as a result of interaction between venom components and specific IgE antibodies fixed to the basophils or mast cells.

Abstract To establish a useful laboratory protocol to investigate possible cases of fatal anaphylaxis, we measured mast-cell-derived tryptase levels and allergen-specific immunoglobulin E (IgE) antibody levels in sera obtained prior to or within 24 h after death from 19 anaphylaxis victims. Elevated serum tryptase levels (range = 12 ng/mL to 150 μg/mL) were found in nine of nine Hymenoptera sting fatalities, six of eight food-induced fatalities, and two of two reactions to diagnostic/therapeutic agents. Tryptase levels were normal (<10 ng/mL) in 57 sequential sera obtained postmortem from six control patients. Tryptase could not be measured by pleural or pericardial fluids for technical reasons. Serum IgE antibodies were elevated in five of the nine Hymenoptera sting fatalities and in eight of the eight fatal food reactions; assays were unavailable for the two diagnostic/therapeutic agents. If elevated, the victim's serum IgE antibodies to food could be used to identify allergens in uneaten portions of foods consumed shortly before the anaphylactic event. IgE antibodies were moderately stable during storage in a variety of anticoagulants at room temperature for up to 11 weeks. Elevated mast-cell-derived tryptase levels in postmortem sera reflect antemortem mast cell activation and may be used as a marker for fatal anaphylaxis. If assays are available for IgE antibodies to relevant allergens, such assays provide evidence for antemortem sensitization; these assays may be modified to identify allergens in foods consumed by victims of food-induced anaphylaxis.

Experiments were designed to determine the endothelium-dependent and endothelium-independent responses to aggregating platelets in porcine pulmonary arteries. Isolated rings with and without endothelium from large (5-7-mm-diameter) and small (2-3-mm-diameter) pulmonary arteries were suspended in modified Krebs-Ringer bicarbonate solution bubbled with 95% O2-5% CO2 in the presence of indomethacin. Aggregating platelets caused relaxations in rings with endothelium but contractions in rings without endothelium, both of which were significantly larger in small versus large pulmonary artery rings. Serotonin and ADP caused concentration-dependent endothelium-augmented relaxations that were unaffected by ketanserin. Methiothepin, but not apyrase, significantly decreased the platelet-induced endothelium-dependent relaxations; the residual relaxation was abolished when rings were incubated with methiothepin, apyrase, and theophylline but was unaffected if apyrase was absent, indicating that ADP is responsible for the residual relaxation caused by aggregating platelets. Quiescent rings, with and without endothelium, contracted in a dose-dependent manner to norepinephrine and histamine but not to serotonin or vasopressin. The contraction to aggregating platelets was blocked by methiothepin, pyrilamine, and diphenhydramine but was unaffected by phentolamine, ketanserin, or incubation of the platelets with dazoxiben. These data indicate that, in large and small porcine pulmonary arteries, serotonin and ADP are the major contributors to the endothelium-dependent relaxation caused by aggregating platelets, while histamine appears to be responsible for the contraction that platelets cause in rings without endothelium.

Hypersensitivity pneumonitis is infrequently reported in children. This article describes a 15-year-old girl who presented with insidious onset of dyspnea and weight loss. A hamster and doves were housed in her bedroom. Chest radiographs showed bilateral nodular infiltrates. Pulmonary function tests showed a restrictive pattern with O 2 desaturation at rest. The diagnosis was substantiated by the presence of precipitating antibody to dove serum and droppings and by clinical improvement, along with marked improvement in pulmonary function test, after the doves were removed from her environment. The importance of making an early diagnosis to prevent debilitating fibrotic lung disease is emphasized. A detailed environmental history is essential.

Abstract Fracture risk among patients diagnosed with asthma in childhood is greater in males and oral corticosteroid users, but most fractures are of the appendicular skeleton and may relate to impaired skeletal development. Introduction: There are no population-based data on fracture outcomes among the growing number of patients with asthma diagnosed in childhood. Materials and Methods: We conducted a population-based retrospective (historical) cohort study among 279 Rochester, Minnesota, residents who were <35 years of age (mean, 6.2 years) when first diagnosed with asthma. Fractures were ascertained by review of comprehensive community medical records, and cases were compared directly with age- and sex-matched controls in a stratified proportional hazards model. Risk factors for fractures among the asthma cases were assessed using Andersen-Gill time-to-fracture regression models. Results: During 6649 person-years of follow-up (median, 24.3 years/subject), 107 asthma patients experienced 189 fractures, for a crude fracture incidence rate of 2.8 per 100 person-years. The actuarially estimated cumulative fracture incidence after 20 years was 40% compared with 34% among controls (p = 0.122). There was no significant increase in overall fracture risk among cases compared to their age- and sex-matched controls (hazard ratio [HR], 1.3; 95% CI, 0.9-1.9), but males with asthma had a 2.6-fold greater risk of hand and finger fractures than control males. The independent predictors of overall fracture risk among the asthma patients included male gender (HR, 2.2; 95% CI, 1.5-3.2) and use of oral corticosteroids (HR, 2.0; 95% CI, 1.2-3.1) or anti-cholinergic agents (HR, 3.9; 95% CI, 1.5-10). Conclusions: Rather than osteoporotic fractures of the axial skeleton, oral corticosteroid therapy was associated here with limb fractures, suggesting a relationship with impaired development of a biomechanically competent skeleton. Additional studies are needed to assess this possibility.

Objective. Anaphylaxis after immunization, although rare, is serious and potentially life-threatening. Understanding risk factors for this reaction is therefore important. Gelatin is added to many vaccines as a heat stabilizer. Japanese researchers have demonstrated a strong association between immediate hypersensitivity reactions to measles, mumps, rubella, varicella, and Japanese encephalitis immunizations and subsequent detection of anti-gelatin immunoglobulin E (IgE) antibodies. They suggested that previous receipt by these patients of diphtheria-tetanus-acellular pertussis vaccines with trace amounts of gelatin was responsible for the sensitization. We aimed to assess whether a similar association exists for vaccinees in the United States who reported anaphylaxis after receipt of measles-mumps-rubella (MMR) or measles vaccines and to review recent trends in reporting of hypersensitivity reactions. Methods. We conducted a retrospective case-control study. Cases of anaphylaxis that met a predefined case definition were identified from the US Vaccine Adverse Event Reporting System (VAERS). Mayo Clinic patients who received MMR vaccine uneventfully served as controls. The study subjects were interviewed to obtain the history of allergies. Sera from study subjects and their matched controls were tested for IgE antibodies to gelatin, whole egg, and vaccine viral antigens using solid-phase radioimmunoassay. Data from the Biologics Surveillance System on annual numbers of doses of MMR and varicella vaccines distributed in the United States were used to evaluate possible changes in reporting of selected allergic adverse events. Results. Fifty-seven study subjects were recruited into the study and interviewed. Of these, 22 provided serum samples for IgE testing. Twenty-seven subjects served as a comparison group and provided a sample for IgE testing; 21 of these completed an allergy history questionnaire. Self-reported history of food allergies was present more frequently in the interviewed study subjects than in the controls, whereas the proportions of people with other characteristics were similar in both groups. None of the interviewed people had a history of food allergy to gelatin. The level of anti-gelatin IgE antibodies was significantly higher among study subjects than among controls, whereas the levels of IgE antibodies against egg and all 3 viral antigens did not differ significantly. Of 22 study subjects, 6 (27%) tested positive for anti-gelatin IgE, whereas none of the 27 controls did. The rate of anaphylactic reactions reported to VAERS after measles virus-containing immunization in the United States between 1991 and 1997 is 1.8 per 1 million doses distributed. No substantial increase in the number of reported allergic events after frequently used gelatin containing MMR and varicella vaccines could be observed during the first 4 years (1997–2000) since the introduction of diphtheria-tetanus-acellular pertussis vaccines for use in infancy. Conclusion. Anaphylactic reactions to MMR in the United States are rare. The reporting rate has the same order of magnitude as estimates from other countries. Almost one fourth of patients with reported anaphylaxis after MMR seem to have hypersensitivity to gelatin in the vaccine. They may be at higher risk of developing anaphylaxis to subsequent doses of other gelatin-containing vaccines. These people should seek an allergy evaluation before such immunization.