Biomedical subjects

M H Lessof

Publications and source records attributed to M H Lessof.

At least 37 records · Page 2Linked to original sources

PubMed1989

The subclass of IgG antibody in allergic disease: II. The IgG subclass of antibodies produced following natural exposure to dust mite and grass pollen in atopic and non-atopic individuals.

In an attempt to understand the role of the different IgG subclasses in allergic disease, we have studied the subclass of IgG antibody to dust mite (HDM) and grass pollen (GP) produced as a result of natural exposure. Studies were carried out on 40 atopic children and 100 atopic adults who had never received immunotherapy. Thirty-two non-atopic adult controls were also studied. The specificity of the assay for IgG antibodies to dust mite was confirmed by inhibition with the homologous extract but not mite culture medium or fetal calf serum. IgG1 antibodies to HDM could be detected in most atopics (94%) and non-atopics (97%), and similar results were obtained for GP (81% and 100%, respectively). IgG4 antibodies to HDM were detected in more atopics (66%) than non-atopics (53%) and the difference was more marked for GP (72% vs. 19%). While the levels of IgG1 antibodies were not significantly different in the two groups, the levels of IgG4 antibodies were much lower in the non-atopics (P less than 0.001, Mann-Whitney U-test). These data show that all subjects were capable of recognizing and mounting an IgG1 antibody response to these inhaled antigens. Atopic individuals differed from normal subjects in the frequency with which they made IgG4 antibodies in response to natural exposure to both dust mites and pollen.

Adult↗

PubMed1989

Comparison of a new type of skin test (Phazet) with existing skin test methods and the radioallergosorbent test (RAST).

A new skin test method (Phazet) for diagnosis of immediate-type allergic disease was tested in 232 patients attending the Guy's Hospital Allergy Clinic, and compared with conventional skin test methods, using Bencard and Pharmalgen allergen solutions, and with serum IgE antibody tests (RAST). Six allergens (cat, dust mite, Cladosporium, grass pollen birch pollen and plantain pollen) were used, as well as histamine and a negative control. Phazet proved easy to use and was popular with inexperienced operators (medical and dental students). For the majority of allergens there was reasonably good agreement with the different tests, but overall Phazet and RAST produced fewer positive results than the other skin tests methods. In particular, the frequency of positive histamine tests was lower with Phazet (82%) than with Bencard or Pharmalgen (99%), but this discrepancy was lower in the second part of the study when the minimum time for the insertion of the needle (1 sec) was more scrupulously observed. Phazet offers a convenient and practical alternative to conventional 'wet' skin test methods.

Allergens↗

PubMed1989

IgG and IgE antibodies after immunotherapy with bee and wasp venom.

IgG and IgE antibody levels have been followed for a period of 2 years in patients receiving immunotherapy with bee and wasp venom. 106 adult patients who had had anaphylactic reactions to wasp stings had initially low IgG antibody levels to wasp venom which rose with therapy (p less than 0.001). IgE antibody levels also showed an initial rise but subsequently fell (p less than 0.001). The pattern was similar to that previously reported in children who had had anaphylactic reactions to bee stings, but who, after a course of immunotherapy, were able to tolerate stings with impunity. 60 adults who had had anaphylactic reactions to bee stings showed a different pattern, with initially high IgG antibody levels which did not rise further. Since two thirds of this group were beekeepers or members of beekeeper's families, the high initial IgG antibody levels could have been a response to the frequent stings to which such individuals are prone. The fact that high levels did not protect against anaphylaxis shows, however, that the classical concept of 'blocking antibody' is in need of revision.

Bee Venoms↗

PubMed1989

Histamine release from peripheral blood leukocytes with purified bee venom allergens: effect of hyperimmune beekeeper plasma.

The response of 15 strongly bee-venom-allergic patients to highly purified venom allergens was compared using skin prick test titration, peripheral blood leukocyte (PBL) histamine release and radioallergosorbent test with three highly purified bee venom allergens: phospholipase (PLA2), hyaluronidase (HYAL) and acid phosphatase (ACID P). Sensitivity to the three allergens ranked in the same order for all three tests and in each case PLA2 was found to the most potent allergen. In the presence of hyperimmune beekeeper plasma, maximum histamine release was reduced significantly for all three allergens (p less than 0.001). Furthermore, hyperimmune beekeeper plasma increased the amount of allergen required for a comparable release of histamine (mean shift in dilution curve PLA2 917-fold; HYAL, 492-fold; ACID P, 61-fold). The release of histamine from whole blood was also compared with PBL + 10% normal human serum (NHS). For all three allergens maximum release was much lower from whole blood compared with washed cells + 10% NHS (p less than 0.001). These data confirm PLA2 as the major bee venom allergen by all three tests. Hyperimmune beekeeper plasma reduces maximum histamine release and increases its threshold. Histamine release in response to ACID P appears harder to block with hyperimmune beekeeper plasma than that provoked by PLA2 or HYAL (p less than 0.01). Whole blood releases less histamine and requires more allergen than washed cells, indicating that sensitivity of PBL in vivo is unlikely to be as great as washed PBL in vitro.

Adult↗

PubMed1988

Allergy to castor bean. I. Its relationship to sensitization to common inhalant allergens (atopy).

The IgE response to castor bean (Ricinus communis) was studied in 96 castor bean-allergic patients from Marseilles, France. All had positive skin tests to castor bean. The IgE response to grass, cat, dust mite, olive, and Parietaria was also measured, and a positive RAST to one or more of these allergens was taken to indicate atopic status. Castor bean-specific IgE antibodies, measured by RAST, were found in 87 (91%) of the castor bean-allergic patients, in two of 13 atopic Marseilles residents living close to the castor bean mills, in three of 42 allergic subjects who had no known contact with castor bean, and in none of a control group of 111 Marseilles blood donors. Very high levels of castor bean-specific IgE (maximum class 4 readings on the Phadebas RAST score) were found in 54 (56%) of the castor bean-allergic patients, but the level of IgE antibody to castor bean was not significantly different in atopic and nonatopic subjects. The frequency of a positive serological test (RAST) for atopy in castor bean-allergic subjects (32%) was very similar to that found in the local population (36%). These data indicate that castor bean is an extremely potent sensitizer for both atopic and nonatopic individuals. The magnitude of the specific IgE antibody response is not related to the atopic status of the patient and may be a function of the physiochemical characteristics of the allergen itself.

Adolescent↗

PubMed1988

The generation and cellular distribution of leukotriene C4 in human eosinophils stimulated by unopsonized zymosan and glucan particles.

Human eosinophils (EOSs) stimulated under optimal conditions with 5 X 10(8) unopsonized zymosan particles at 37 degrees C for 30 minutes produced an average total immunoreactive leukotriene (LT) C4 of 1.6 ng per 10(6) EOSs, and 30% to 60% of the generated product remained cell associated. The dose-response characteristics of zymosan-induced LTC4 generation were different from those of phagocytosis, suggesting that the two events were independent. Pretreatment of EOSs with 10(-8) mol/L of formyl-methionyl-leucyl-phenylalanine for 30 minutes led to a twofold to fivefold augmentation of LTC4 generation by cells subsequently activated by unopsonized zymosan. Optimal EOS activation with 1 mumol/L of the calcium ionophore A23187 at 37 degrees C for 15 minutes produced more than 100 times greater quantities of LTC4 than with zymosan. The amount of immunoreactive LTC4 that remained cell associated after calcium ionophore A23187 stimulation reached a maximum after 5 minutes and then declined. Of the relatively small amount generated in the first minute, 71% was cell associated, but this figure declined to 9% after 15 minutes, by which time there had been a redistribution of the LTC4 to the supernatant. Inflammatory leukocytes may respond to zymosan because the cells recognize either one or both of its major polysaccharide components, glucan and mannan. Glucan, but not mannan, stimulated EOSs to generate LTC4 in a dose- and time-dependent manner. Under optimal conditions, there was no significant difference in the total quantities of LTC4 elaborated by EOSs stimulated by glucan and by unopsonized zymosan. This suggests that zymosan may induce leukotriene generation in the human EOS through a glucan recognition mechanism.

Calcimycin↗

PubMed1988

IgE and IgG antibody response to purified bee-venom antigens and peptides in four patients who had adverse reactions to immunotherapy.

The immunological response to individual bee-venom allergens was studied in blood samples collected at frequent intervals from four bee-venom allergic patients who had suffered systemic allergic reactions to injections of bee venom during immunotherapy. All had high IgE antibody levels, at the upper end of the range found in bee-sting allergic patients, and all had antibodies to the minor allergens at the time of the reactions. These did not, however, provide a simple explanation for the reactions that occurred. We were able to observe two interesting phenomena--in one patient IgE antibodies to the individual venom antigens appeared to be 'switched off' sequentially. In another, IgE antibodies to hyaluronidase rose substantially after 4 years of therapy. We believe that these results provide evidence to support the view that the regulation of IgE antibodies is controlled by mechanisms that are both isotype- and antigen-specific.

Acid Phosphatase↗

PubMed1988

Clinical reactions to food.

Sensational claims have been made about allergy to food and food additives, to the point where the predominant reaction in the medical profession has been one of scepticism. Nevertheless, some patients experience severe reactions caused by foods, for which they may find it difficult to obtain treatment through the National Health Service. This is a subject which needs to be reappraised.

Food Additives↗

PubMed1987

Allergy testing.

Explore the source record for details and available documents.

Animals↗

PubMed1987

How reliable are commercial allergy tests?

The ability to diagnose allergic disease was studied in 9 fish-allergic and 9 control subjects, who provided specimens of blood and hair for testing. All fish-allergic subjects had previously been shown at Guy's Hospital to have a positive skin prick test to fish. The specimens were submitted as coded, duplicate samples to five laboratories which all offer a commercial service in carrying out diagnostic tests for allergy. All five laboratories were not only unable to diagnose fish allergy but also reported many allergies in apparently non-allergic subjects and provided inconsistent results on duplicate samples from the same subject.

Adult↗

PubMed1987

Plasma esterase activity in patients with aspirin-sensitive asthma or urticaria.

Plasma aspirin esterase activity and cholinesterase activity were reduced in patients with aspirin sensitive asthma and aspirin sensitive urticaria compared to asthmatic and dermatological controls. Phenylacetate (non specific) esterase activities, were however unaltered in these patients. The reason for the lower activity is uncertain but it does not appear to be due to genetically determined lower cholinesterase or due to the avoidance of aspirin by sensitive patients. A low aspirin esterase activity may be a contributory factor in precipitating these aspirin sensitive reactions.

Aspirin↗

PubMed1987

Oral allergy syndrome (OAS): symptoms of IgE-mediated hypersensitivity to foods.

Eighty highly atopic patients were selected for study because they had either atopic eczema (fifty cases) or atopic reactivity to foods, as judged by a positive skin-prick test (thirty cases). In all, sixty-five out of eighty subjects (81%) described symptoms of some kind provoked by foods, but correspondingly positive skin tests were found in only half of these, thirty-three out of eighty (41%). The symptoms experienced by thirty-one of the thirty-three patients with positive skin tests were immediate in onset (within 1 hr) and were at first confined to the upper gastrointestinal tract, the most frequent symptoms being oral irritation and throat tightness. In a proportion of these patients, further symptoms such as urticaria, asthma or anaphylaxis developed following the initial oral symptoms, which suggested the term 'oral allergy syndrome'. In the absence of the oral allergy, symptoms such as asthma, urticaria, migraine or eczema starting later than 1 hr after food were seldom associated with positive skin tests. In the oral allergy syndrome, the characteristic symptoms (strong association with positive skin tests and RAST, time of onset and sites at which symptoms are expressed) suggest a causative relationship between exposure to food antigens and specific IgE-induced release of mediators. In cases of food intolerance that lack a characteristic symptom pattern and a positive skin test or radio-allergo-sorbent test, it seems appropriate to consider non-IgE-mediated causes.

Adolescent↗

PubMed1987

The relationship between total serum IgE and castor-bean-specific IgE antibodies in castor-bean-sensitive patients from Marseilles.

The relationship between serum IgE and castor bean (Ricinus communis)-specific IgE was studied in a group of dockworkers and other residents of Marseilles who were diagnosed as having castor bean allergy. The diagnosis was made because they had asthma or other allergic symptoms together with a positive skin test to castor bean. Total serum IgE was found to be higher in castor-bean-allergic patients (mean = 174 IU/ml) than in a control group of local blood donors (mean = 66 IU/ml). IgE levels were not as high as those found in the sera of a previously identified group of castor-bean-allergic dockworkers from Port Sudan (mean = 902 IU/ml). Castor-bean-specific IgE was demonstrated in the serum of 91% of the allergic group and there was some correlation with total IgE (r = 0.53, p less than 0.01). The proportion of IgE antibody specific for castor bean was determined in 20 castor-bean-sensitive patients using the radioallergosorbent test and was found to vary between 9 and 64% (mean = 38% or 265 ng/ml). No castor-bean-specific IgE antibody was detected in the control group.

Ricinus communis↗

PubMed1987

Plasma level of histamine in aspirin-sensitive urticaria.

Twelve patients with a history of aspirin-induced urticaria and/or angioedema were studied before and after the provocation of symptoms with aspirin. The resting plasma histamine levels in these patients (0.95 +/- 0.25 ng/mL) were significantly higher than in 30 control subjects (0.21 +/- 0.02 ng/mL) (P less than .0005) and nine patients with non-aspirin-sensitive urticaria (0.27 +/- 0.06 ng/mL) (P less than .01). The plasma histamine levels fell significantly at the time of adverse reactions to aspirin (P less than .01). The high resting histamine levels, like the high venous prostaglandin F2 alpha levels that we have previously reported in the same group of patients and the high plasma histamine levels we have found in aspirin-sensitive asthmatics suggest an abnormality of mediator release in aspirin-sensitive patients.

Adult↗

PubMed1987