Modulation of venom-induced leukocyte histamine release by mononuclear cells: effect of venom immunotherapy

Comparative safety and efficacy of short ragweed extracts differing in potency and composition in the treatment of fall hay fever. Use of allergenically bioequivalent doses by parallel line bioassay to evaluate comparative safety and efficacy

One high potency (HP) and two low potency (LP) commercial whole short ragweed (WSR) extracts were assayed for relative potency (RP) by antigen E (AgE-Amb a 1), RAST inhibition, and parallel line bioassay (PLBA). The RP of the HP extract (300 micrograms AgE) was equal to the reference WSR, but the LP extracts were only approximately 0.01 of the RP of the reference. Each extract was administered to fall hay fever patients with skin sensitivity to WSR (less than or equal to 10(-3) micrograms/ml AgE for sum of erythema = 50 mm) to the maximum tolerated dose, or 0.5 cc of the concentrate, by either a 9- or 40-dose regimen. HP-treated patients had significantly lower symptom scores than untreated controls. No significant difference was noted in the total symptom scores between HP and LP extract-treated patients. Despite approximately 100-fold differences in the RP of HP versus LP extracts, both produced similar frequencies of severe systemic and severe late phase local reactions. Furthermore, when RP of HP and LP extracts were estimated by PLBA, both reached similar peak dosages, similar dosage for IgG WSR antibody response, and comparable IgG WSR antibody levels, indicating that the WSR dose estimates based on RP were bioequivalent. The 9-dose HP regimen produced fewer late phase local and systemic reactions per patient than the 40-dose HP regimen. Most patients experiencing severe systemic reactions were among those most skin sensitive to WSR. The number of systemic reactions per injection was significantly higher at higher WSR doses. One LP extract produced a high incidence of systemic reactions in the initial three injections. With respect to HP, its RP varied approximately 10-fold depending on the skin sensitivity of the patient to heat-stable ragweed allergens, demonstrating that it was compositionally different. However, when the dose of this extract was estimated by RP based on the skin sensitivity of each patient, the peak dose of the extract as well as the doses associated with late phase and systemic reactions were found to be similar to the HP doses. This indicated that immunizing dose estimates of compositionally different WSR extracts based on RP by PLBA were also bioequivalent.

Relevance of basophil histamine release changes during venom immunotherapy

We investigated the effect of rush and long-term venom immunotherapy on histamine release parameters in bee venom allergic patients. Ten patients received rush venom immunotherapy, and histamine release data were obtained immediately before and after treatment. 17 patients were assessed by histamine release 24 to 63 months after termination of long-term venom immunotherapy. A control group of 10 non-allergic subjects was included in this study. Histamine released from whole blood was determined in a sensitive radio-enzymatic assay using a single isotope technique. Bee venom phospholipase A-induced histamine release from whole blood proved to be a test procedure of high specificity and sensitivity. Eight of 10 untreated patients and no control subject showed significant antigen-induced histamine release. Results obtained from patients immediately after successful rush venom immunotherapy showed an important decrease (mean 45.9%) of total histamine content of basophil leukocytes in all patients. Antigen-induced maximum histamine release was found to be increased in one, decreased in two and unchanged in seven patients. In patients who received long-term immunotherapy cell sensitivity to phospholipase A was significantly lower than in a group of untreated patients (P less than or equal to 0.002). These results suggest that even years after discontinuation of immunotherapy, histamine release parameters reflect patients' protection from systemic sting reactions as assessed by sting challenges. Histamine depletion of basophils induced by rush immunotherapy may play an important role in patients' protection immediately after termination of the rush regimen.

Blocking activity of mite-specific IgG antibodies studied by skin tests

The aim of the study was to determine whether IgG antibodies from patients on specific immunotherapy could inhibit skin test reactivity of allergens when mixed with them prior to testing. In a preliminary double-blind study, mite extracts were incubated with glycero-saline solution or non-specific IgG and used in testing 15 patients. Wheal and flare diameters produced with the two mite extracts did not differ significantly. In a second double-blind study with 15 other patients, skin tests using mite extracts incubated with either non-specific IgG or specific IgG showed significantly decreased diameters when mite extracts were preincubated with specific IgG. This result, in vivo, confirms the antigen neutralizing capacity of specific IgG demonstrated in vitro.

Hymenoptera venom immunotherapy. II. T proliferative and T suppressive activities induced by Vespula immunotherapy: effects on long-term antibody responses

Thirty-five children who had exhibited major clinical reactions to yellow jacket stings were desensitized during an 8-day rush immunotherapy (RIT). Maintenance treatment was continued for at least 1 year in all cases and for 2 years in 21 cases. Blood samples, obtained before, during, and after RIT, were analyzed for specific T proliferative (TP) and T suppressive (TS) cell activities and for specific IgE, IgG1, and IgG4 levels. TS and TP cell activities increased during RIT (p less than 0.001) and remained elevated throughout the 2-year follow-up. There were transient rises in specific IgG1 and IgE during RIT, but the levels of both decreased thereafter. Specific IgG4 increased throughout the follow-up period. The data indicate that the levels of specific IgE and specific IgG1 were correlated with TP cell responses (inducers) and TS cells responses (suppressors) and therefore might be controlled by them; data also suggest that TS cell responses should play a role in the IgG4 response. These changes in TS and TP cell responses and antibody responses have been incorporated into a model of antibody-response regulation by cell-mediated immunity in this type of allergy.

Hymenoptera venom immunotherapy. I. Induction of T cell-mediated immunity by honeybee venom immunotherapy: relationships with specific antibody responses

The specific cell-mediated and humoral immune responses of 14 children allergic to honeybee venom were studied. An 8-day rush venom immunotherapy induced an increase in T proliferative (p less than 0.04) and T suppressive (p less than 0.003) cell-specific activities. Antibody variations, an increase in specific IgG4 (p not equal to 0.05), and a decrease in specific IgE (p less than 0.01) were observed 1 year later. Initial high T suppressive cell activity prevents T proliferative cell increase during rush venom immunotherapy. High initial levels of specific IgG1 and specific IgG4 have opposing effects on the increase in T suppressive cell activity, the former being positively correlated with intensive increase (r = 0.840; p less than 0.005), the latter negatively with T suppressive cell increase (r = -0.709; p less than 0.001). These data indicate that there are interrelationships between the cell-mediated immunity and the antibody responses in honeybee allergy.

Identification of a histamine release inhibitory factor (HRIF) and an inhibitor of histamine releasing factor synthesis (IHS) produced by guinea pig lymphoid cells

Guinea pig spleen cells, thymocytes, and blood mononuclear cells have been shown to produce a histamine releasing factor (HRF) spontaneously or after stimulation with PHA or specific antigens. In this study we have shown that antigenic stimulation of spleen cells obtained from animals immunized with high doses of antigen suppresses the spontaneous HRF production. Likewise, stimulation with Con A of spleen cells also inhibits the spontaneous HRF production. When the supernatants from Con A- and antigen-stimulated cultures were added to fresh thymocyte cultures, a significant inhibition of HRF production was observed. These supernatants also inhibited HRF-induced histamine release from mast cells. We have identified an inhibitor of HRF synthesis (IHS) and also a histamine release inhibitory factor (HRIF) by gel chromatography. Virtually all mitogen- and antigen-stimulated culture supernatants elaborated the activities of HRF, IHS, and HRIF in various quantities depending on the dose of antigen and the kind of adjuvant used for immunization. IHS has a MW of 22K-35K and 10K. This cytokine also inhibits DNA synthesis by thymocytes. HRIF has a MW of 15K-20K and 10K. It inhibits both HRF- and antigen-induced histamine release from lung mast cells. These results suggest that lymphocytes produce a variety of factors which function to regulate histamine release from mast cells.

The glucocorticosteroid, budesonide, partially blocks histamine release from human lung tissue in vitro

IgE-receptor dependent, but not A23187-induced, histamine release from passively sensitized chopped human lung tissue, or from a dispersed lung cell population obtained from the tissue after enzymatic digestion, is reduced after incubation overnight of cells/tissue with the glucocorticosteroid budesonide (10(-7) M). Since the inhibitory effect of budesonide is reduced in the continuous presence of diluted reagin-rich serum used for passive sensitization, but not in the presence of heat-inactivated serum, it is suggested that the glucocorticosteroid acts by reducing the binding of IgE-antibody to the target cell(s).

Is there a functional heterogeneity among IgE-type mast-cell-sensitizing antibodies?

It has recently been established that mast cells display functional heterogeneity. The question then arises whether the IgE-type of antibody, which avidly binds to and thereby sensitizes mast cells and basophils for allergen-induced release of mediators, also expresses functional heterogeneity. In the present article we bring together several experimental observations, mainly from the rat system, which are difficult to explain unless one postulates that mast cell/basophil-sensitizing antibodies of the IgE-type are heterogeneous in their cell-binding properties.

Insect allergy. A comparative study including case histories and immunological parameters

One hundred and seventeen persons all stung by yellow jacket (YJ) and/or bee were examined by means of skin prick test with venom of these insects, skin prick test with 10 inhalant allergens and analyses of total IgE, specific IgE and IgG against honey bee and YJ venom. Eighty-seven persons had had a systemic reaction to YJ or bee sting, the rest had reacted normally or with a large local reaction. Positive correlations (P less than 0.05) were found between results of skin prick tests and specific IgE against venoms and, for YJ, between the severity of symptoms after sting and the size prick test with the venom. That some of the more severe symptoms could have been caused by non-immunological mechanisms could explain why a significant correlation was present only between the results of the prick test and specific IgE and not between these tests and the clinical symptoms. Specific IgE values against YJ and honey bee venom showed covariation, although no correlation could be demonstrated between the clinical symptoms after stings from these insects, or between skin prick test results using the two different extracts. The severity of the sting reactions was not correlated to age, atopic disposition, amount of total IgE, number of stings during life, or positive skin prick test to inhalant allergens. It is concluded that in insect allergy, specific IgE analysis and skin prick tests are supplementary.

Inhibitory effect of glucocorticosteroids on anti-IgE-induced histamine release from human basophilic leukocytes: evidence for a dual mechanism of action

Anti-IgE-induced histamine release from human leukocytes is inhibited when the cells before challenge are cultured overnight in the presence of glucocorticoids (GCSs). The present report suggests that the GCSs might exert their effect by at least a dual mechanism of action. Histamine release was induced by a suboptimum concentration of anti-IgE. When the release recorded in the presence of the steroid is plotted against the release recorded in its absence, the data points of several experiments fit a regression line characterized by two parameters: its slope and its intercept with the abscissa. Structure-activity examination with selected GCSs indicates that the orders of potency for affecting these two parameters are not identical. Furthermore, pulse experiments suggest that the cells require different times of contact with the steroid to express inhibition according to the two parameters. The removal of adherent cells or platelets did not markedly affect the degree of leukocyte histamine release or its inhibition by a given GCS, suggesting that the steroid interacts directly with the basophil. Finally, steroid-induced inhibition was not affected by the putative phospholipase A2-inhibitor p-bromophenacylbromide (BPB) or the 5-lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA).