Mucosal immunity in extrinsic allergic alveolitis: salivary immunoglobulins and antibody against inhaled avian antigens among pigeon breeders

BACKGROUND: Inhaled antigens from pigeons can cause extrinsic allergic alveolitis (EAA); a model disease of pulmonary inflammation. Among pigeon breeders, serum antibody and sensitized lymphocytes specific for these antigens have been described primarily, but not always, with disease. Antibody activity within the lung may have a closer association with disease, however, sampling by alveolar lavage at bronchoscopy is impractical for screening, therefore we used saliva to quantify the mucosal antibody response. OBJECTIVE: To establish: (a) if antibody activity against inhaled avian antigens was detectable in the saliva of pigeon breeders, (b) if the distribution of saliva antibody and total immunoglobulin levels were quantitatively or qualitatively different from serum, and (c) whether the hypersensitivity symptoms of EAA were associated more with the mucosal or the systemic humoral immune response. MEASURES: Saliva and serum total and avian antigen-specific IgG, IgA (IgA1 and IgA2) antibody activity in 87 pigeon breeders and 24 control subjects with no avian exposure. Albumin levels were used as a protein reference and cotinine levels confirmed smoking status. Specific hypersensitivity symptoms and various exposure indices to pigeons were established by interview. RESULTS: Absolute levels and relative proportions (vs albumin) of IgG, IgA and IgA1 in saliva, and IgG in serum, were significantly higher in pigeon breeders compared with controls, suggesting mucosal inflammation. Avian antigen-specific antibody of all isotypes was readily demonstrable in saliva (predominantly IgA) and serum (predominantly IgG) from pigeon breeders, and there were no significant titres in controls. The levels of IgG antibody in saliva and in serum correlated significantly (r = 0.52, P < 0.001), and both correlated with the raised immunoglobulin levels. In both saliva and serum the IgG rather than the IgA antibody activity was associated with symptoms of EAA. CONCLUSIONS: Antibody activity in saliva and serum, representing the mucosal and systemic responses, respectively, were both strongly stimulated by inhaled antigens. The IgG antibody titres of saliva and serum correlated significantly and were a useful index of inflammation, as measured by the raised total immunoglobulin levels, and symptoms. This suggests that IgG antibody in serum may reflect clinical and immunological sensitization of the lung mucosa. Collecting saliva is noninvasive, and saliva antibody measurement is a convenient method for monitoring EAA, especially in children, and will facilitate sampling for example in epidemiological studies of antibody prevalence.     

Blood flow in histamine- and allergen-induced weal and flare responses, effects of an H1 antagonist, α-adrenoceptor agonist and a topical glucocorticoid

Allergen has previously been shown to induce a continuous increase in local dermal blood flow after a prick test in allergic subjects, whereas histamine induced, initially, similar peak increases in blood flow of much shorter duration. Blood flow changes induced by histamine and allergen have now been evaluated (i) after pretreatment with a local corticosteroid cream, clobetasole-17-propionate; (ii) after oral administration of the H1-antihistamine loratadine; and (iii) after oral pretreatment with the alpha 1-adrenoceptor agonist pseudoephedrine. Blinded placebo-controlled designs were used in the substudies. Laser doppler flowmetry was used for non-invasive recording of changes in local blood flow intermittently for 24 h after the topical corticosteroid, 6 h for the substudies on loratadine and pseudoephedrine. The size of the immediate weal and flare reactions, as well as late phase reactions, were also determined. Pretreatment with clobetasole-17-propionate cream on the skin for 1 week prior to prick tests did not affect the blood flow response elicited by histamine or allergen, in either the initial part (up to 1 h) or the protracted 24 h determinations. The size of the weal and flare reactions decreased. Loratadine and pseudoephedrine did not reduce the initial allergen-induced increase in blood flow, while lower blood flow compared with placebo pretreatment was noted for the protracted (1-6 h) determinations. Blood flow changes after histamine were unaffected. The histamine-induced weal and flare was inhibited by loratadine more effectively than the corresponding allergen-induced reaction. The weal and flare reactions after histamine and allergen were not changed after pseudoephedrine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extrinsic allergic bronchiolo-alveolitis in children

Fifteen children, 6–14 years old, who were heavily exposed to pigeon droppings, presented with cough, chills and breathlessnes on mild exertion. Twelve gave immediate positive skin test reactions to pigeon droppings. Ten of the fifteen also gave a late (Arthus) reaction, and seven gave a positive delayed reaction which was maximal at 24–72 hr. Nine children had precipitins against avian droppings. In ten patients who were tested for lymphocyte transformation, five gave positive responses to both serum and pigeon droppings. Radiological findings of the chest showed parenchymatous infiltrations and diffuse interstitial reticulations, suggestive of extrinsic allergic alveolitis. In a control group of fifteen heavily-exposed children who had no symptoms, immediate and late skin reactions occurred respectively in five and two. One only had a positive precipitin test, and one of five tested had a positive lymphoblastic transformation. In a non-exposed comparable group of children, all tests were negative except for one immediate positive skin response. Children heavily exposed to the inhalation of avian antigens can develop extrinsic allergic bronchiolo-alveolitis.     

Intracutaneous and Skin Prick Testing with Serotonin and Histamine

Skin prick and intracutaneous tests were performed with serotonin, histamine and a mixture of both in 32 normal persons, two rhinitis patients and 12 asthmatics. Skin prick tests with serotonin produced a triple response, but the weal reactions were small. Serotonin had no potentiating effect on the histamine reaction. Intracutaneously, serotonin tests also induced a triple response, but with smaller weal reactions than with histamine, and the weal surfaces were wrinkled. Constriction of the large subcutaneous veins was observed locally after serotonin injection. No quantitative or qualitative difference in reaction to serotonin was observed between normal subjects and allergics. The role of serotonin in the immediate allergic reaction in the skin was minimal.     

Atopy may be related to exercise-induced bronchospasm in asthma

BACKGROUND: Recent studies suggest that atopy may be associated with exercise-induced bronchospasm (EIB) in asthma. However, it is not clear whether atopy is related to EIB, regardless of airway hyper-responsiveness (AHR) to methacholine, because asthmatic subjects often show AHR to exercise and methacholine simultaneously. OBJECTIVE: To investigate whether atopy is related to EIB in asthmatic subjects, independently of AHR to methacholine. METHODS: Fifty-eight male asthmatic subjects were studied. Initial spirometry was performed. Skin prick test was carried out, using 53 common allergens including mites dust antigen. Atopy score was defined as a sum of mean weal diameters to all allergens tested. Methacholine bronchial provocation testing was performed. Twenty-four hours later, free running test was performed. Positive EIB was defined as a 15% reduction or more in FEV1 from baseline after exercise. RESULTS: All subjects had AHR to methacholine. The degree of AHR to methacholine in asthmatics with EIB was similar to that in asthmatics without EIB. However, atopy score and skin reaction to Dermatophagoides pteronyssinus significantly increased in asthmatics with EIB compared with those without EIB (P < 0.05, respectively). Furthermore, the degree of EIB significantly correlated with atopy score in all subjects (r = 0.35, P < 0.01). This relationship was maintained even after the exclusion of EIB-negative asthmatic subjects. CONCLUSION: Atopy defined as skin test reactivity may contribute to the development of EIB in asthma, independently of AHR to methacholine.     

Reproducibility of the skin prick test

Reproducibility of the skin prick method of testing for allergy was studied in 20 subjects examined by four nurses. Hypodermic needles were used for pricking and the test panel included a histamine control, a diluent control, and nine allergens. The reproducibility of the method was best when the size of the weal reaction caused by an allergen was expressed as the geometric area of the weal. When the weal reaction was expressed as the ratio of the weal reaction caused by an allergen to that caused by histamine, the reproducibility of the method was decreased considerably. When the ratios were further classified into three class ratings, reproducibility was very low. The reduction in reproducibility was due to the low reproducibility of histamine reactions. According to these results, at least in epidemiological studies the weal reactions should be expressed as geometric areas. In clinical practice it might also be preferable to express prick test results as the diameters of the weals without adjusting them by histamine reactions.     

Relationship of Allergen-Specific IgE Antibodies, Skin Prick Tests and Allergic Disorders in Unselected Adolescents

The relationship between serum levels of allergen-specific IgE (RAST) and skin prick test reactivity and allergic disorders was evaluated in 137 subjects randomly selected from an adolescent population. All subjects were prick tested with six common allergens, interviewed and physically examined. In addition, serum was collected for RAST analysis with three to six allergens. At least one positive RAST result (score 1-4) was observed in 40% and at least two positive RASTs in 22% of the subjects. Boys experienced more RAST reactions and generally with higher scores than girls. For instance, 26% of boys but only 11% of girls were RAST positive to timothy grass pollen. The correlation between prick test and RAST results was better with pollens than with house dust and animal epithelia. When the test results were discordant, the skin test was usually positive and RAST negative. Many of the small skin reaction (weal diameter 3-4 mm) were accompanied by a negative RAST. Respiratory allergy was closely connected with both positive skin test and RAST reactivity, while atopic dermatitis was less related. In 17% of the adolescents positive skin tests and in 14% positive RASTs occurred in the absence of any allergic symptoms. We conclude that a positive RAST score 3-4 to inhaled allergens is a strong indicator of clinical allergy but low scores 1-2 are frequently found in healthy young people.     

Immediate and late phase allergic cutaneous reactions are not inducers of unspecific or specific local hyperreactivity

The present study evaluates the possibility of allergen-induced unspecific and specific dermal hyperreactivity with special reference to the presence of late cutaneous reactions and allergen-induced nasal hyperreactivity. Twenty-six patients with strictly seasonal allergic rhinitis participated. All had a positive skin prick test for birch (Betula verrucosa) and/or timothy (Phleum pratense). Ten patients had previously displayed an allergen-induced nasal hyperreactivity and six patients a late cutaneous reaction. An initial skin prick test with a relevant pollen allergen was done in triplicate. The immediate skin reactions were recorded after 15 min and any late-phase reaction after 6 h. Twenty-four hours later the patients were retested. The same pollen allergen was sited in the first flare reaction from the previous day. A histamine prick test was sited in the weal as well as in the third reaction from day 1. A histamine control was also performed in a previously unaffected area. The allergen-induced weal reactions decreased significantly at rechallenge compared with the results from the previous day (P less than 0.05). The histamine tests resulted in similar skin reactions regardless of whether or not they were done on a previous allergen test site. This was true for both specific and unspecific reactions when the subgroups of patients with previously demonstrated allergen-induced nasal hyperreactivity or late-phase skin reactions were evaluated separately. These results indicate that allergen-induced hyperreactivity is not a general feature of allergic inflammation but is a phenomenon restricted to specific sites, such as the airway mucosa.     

Passive cutaneous anaphylaxis (PCA) and specific IgE in cystic fibrosis and their heterozygotes

The serum from 75% of the patients with cystic fibrosis (C.F.) who had a positive prick test in their skin to at least one or more antigens, together with elevated concentrations of total serum IgE, also gave strong immediate PCA reactions in the baboon skin to Aspergillus fumigatus, bovine serum albumin and egg albumin. Of the C.F. patients, 37% also had elevated serum specific IgE to A. fumigatus whereas only 8–10% had either raised specific IgE or PCA reaction to Dermatophagoides pteronyssinus. Abolition of the PCA activity by incubating the C.F. sera or sputum at 56°C suggested that the reaginic antibody was IgE rather than IgG4. PCA reactions to a number of allergens could be detected in both the C.F. sputum and saliva. Several of the C.F. heterozygotes had a strongly positive history of allergy and a significant number of these heterozygotes had an elevated serum total IgE as well as positive PCA to Timothy grass pollen or to D. pteronyssinus similar to the patients with asthma or hay fever. Three C.F. patients who died gave strong prick test reactions to several allergens and their sera also had raised serum IgE and positive PCA to at least three different allergens, suggesting that immediate hypersensitivity is of some significance in patients with C.F.     

Evidence of an affinity threshold for IgE‐allergen binding in the percutaneous skin test reaction

BACKGROUND: Atopy is an aberrant immune response involving allergen-specific IgE production, though serum IgE concentration is not an entirely reliable diagnostic tool, particularly for epidemiological and genetic studies. There is no clear correlation between IgE and other indicators of atopy such as skin prick tests (SPT)s, and physiological associations are difficult to justify in cases with detectable IgE but negative SPT results. OBJECTIVE: IgE reflects the number of molecules available to produce an atopic response, but the degree of the response is determined by the binding strength (affinity) between receptor-bound IgE and the allergen. We sought to determine if there was an association between binding affinity and SPT results in people with histories of atopy. METHODS: Standard SPTs (whole allergen extracts) were administered to people with histories of sensitivities to ragweed and house dust mite. The concentrations and affinities of serum allergen-specific IgEs were determined using the purified allergens Amb a 1 and Der p 1. RESULTS: There was a positive correlation between weal area and allergen-specific IgE among SPT-positive donors. However, for those individuals with detectable amounts of allergen-specific IgE, there was considerable overlap of IgE values between SPT-positive and -negative groups. Among sensitized donors, IgE-allergen interactions were characterized by two or three specific reactions of very high affinity (K(A) range 10(8) -10(11) M). Negative SPT reactions were associated with lowered IgE binding affinities to major allergens. This delimited two groups with atopic disorders: specific IgE(+)/ SPT(+) and specific IgE(+)/SPT(-). CONCLUSION: The product of antibody affinity and concentration, which we define as antibody capacity (CAP = K(A) x IgE), is more informative with regard to describing allergen sensitivity than antibody concentration alone. Antibody binding capacity provides physiological evidence of atopy in some subjects who do not test positively by common methods and suggests an affinity threshold to produce a positive SPT reaction.     

Comparative serological and clinical findings in subjects exposed to environmental allergens

Serological tests of healthy atopic and non-atopic subjects were carried out during medical surveillance of 288 workers in detergent and food manufacturing factories in the same highly industrialized area. Correlations between the serological parameters and various aspects of the clinical history were compared for subgroups in these and control populations. The value of serological tests as aids in the diagnosis of allergic reactivity to the detergent enzyme Alcalase was given particular attention. There was no indication that employment in the detergent factory significantly increased the amount of serum total IgG, IgA or IgM. There was a positive correlation between the amount of serum total IgE and atopy as defined. The need for new standards of normality in the amount of serum total α₁-antitrypsin in women receiving oral contraceptives was confirmed. No subjects had a homozygous deficiency of α₁-antitrypsin. There was a statistically significant correlation between the level of allergen-specific antibody measured by the RAST and skin prick test weals of 3·0 mm diameter or greater, which were obtained using standardized skin prick test procedure and reagents. The significance of small skin prick test reactions has been evaluated critically. The results of various tests for allergen-specific precipitating antibodies indicated the need for caution in interpreting the results of such tests with allergens such as Alcalase, which contain several antigenic components. Alcalase-specific IgG antibodies were only detected in the sera of persons exposed to enzyme dusts in factories. They were evidence of exposure to the antigens, not of a clinical allergic response, and probably reflect the natural formation of antibody shown to occur with numerous environmental antigens.     

Skin Prick Test Reactivity to Common Allergens in Finnish Adolescents

We studied 708 adolescents aged 15–17 years in the 9th grade of school in Imatra. Of the eligible population born in 1962 77% were included. All were skin prick tested with 16 extracts from two manufacturers with 12 common allergens, which included pollens, epithelia, mite, house dust and fish. At least one positive, immediate reaction (weal diameter 3 mm or larger) occurred in 49% and at least two positive reactions in 43% of those studied. The boys were observed to be significantly more reactive than the girls. The allergen preparations to which positive reactions were most prevalent were house dust, cat and horse epithelium, and mite extract. Large differences in the prevalence of positive reactions were observed with different preparations of the same allergen. Pollen allergens tended to cause the largest positive weal reactions, and the weal size distribution with some pollens was distinctly bimodal. A scheme for calculating allergen potency in histamine-equivalent-prick (HEP) units is presented. It is noted that the result is greatly dependent on the population group chosen for testing.     

Seasonal variation of antibody levels among pigeon fanciers

IgG antibody against avian antigens was measured by quantitative radioimmunoassay in serum samples obtained regularly from twenty pigeon fanciers over a 1-year period. A seasonal variation was seen in nine antibody-positive subjects; eight of whom had symptoms of pigeon breeder's disease (PBD), and a clear peak of antibody production occurred during late summer, corresponding with the period of maximum avian contact in the sporting season. All subjects with insignificant specific IgG levels were asymptomatic and displayed minimal changes throughout the year despite a similar exposure pattern to antigen for all individuals. Raised total IgG was a feature of six symptomatic subjects, two of whom had raised total IgA. Three of these six subjects had maximum hypergamma-globulinaemia coinciding with peak specific-antibody levels, but in general the total imrnunoglobulin levels tended to remain high throughout the year with only marginal fluctuations. The total immunoglobulin levels in the other individuals were within normal limits and displayed no remarkable changes during the year. The subjects with pigeon breeder's disease had a more active immune responsiveness to avian contact, and the association of the highest levels with periods of maximal contact with antigen may have an important bearing on the dynamic nature of this condition.     

Immunologic evaluation of shrimp-allergic individuals

Thirty-three individuals with a history of immediate hypersensitivity reactions after shrimp ingestion and 29 nonshrimp-sensitive control subjects were evaluated for evidence of crustacea-specific immunity by skin prick test titration end point, RAST, and ELISA, with extracts of shrimp, crab, crayfish, and lobster. Individuals were categorized as either atopic or nonatopic on the basis of history and skin test reactivity to common inhalant allergens. Most (28/33) shrimp-sensitive subjects had positive skin prick tests to shrimp extract, whereas skin tests were negative in 27/29 control subjects. Eighty-one percent of atopic and 41% of nonatopic shrimp-sensitive subjects had elevated shrimp-RAST ratios. The RAST ratios of atopic individuals were significantly higher than ratios of nonatopic individuals, and there was a significant correlation between shrimp-RAST ratios and historical clinical symptom scores. RAST determinations of all control subjects were negative. Shrimp-sensitive subjects also had significantly elevated serum levels of shrimp-specific IgG and IgA as compared to control individuals. Both IgG and IgA shrimp-specific reactivity demonstrated a significant positive correlation with shrimp-RAST ratios. These studies indicate that IgE-mediated, type I mechanisms, detected by positive shrimp skin tests and RASTs, appear to be operative in crustacea-sensitive individuals, particularly those with concurrent respiratory allergy. Although the role of shrimp-specific IgG and IgA antibodies in the immunopathogenesis of crustacea allergy remains unclear, such antibodies appear to represent increased immunologic recognition of shrimp allergens/antigens in shrimp-sensitive subjects.     

Absence of association between delayed type hypersensitivity to tuberculin and atopy in children in The Gambia

BACKGROUND: An inverse association between delayed type hypersensitivity to tuberculin and atopy has been observed in children, suggesting that exposure to mycobacteria may influence the immune response to allergens. OBJECTIVE: To investigate the relationship between tuberculin responses and atopy in children living in three different environments in The Gambia. METHODS: In this cross-sectional study a total of 507 school-aged children were recruited from rural, urban poor or urban affluent communities. They were assessed for skin responses to five common allergens and tuberculin, presence of bacille Calmette-Guérin (BCG) scar, presence of intestinal parasites, and total serum IgE. Atopy was defined as the presence of a skin prick test response > or = 3 x 3 mm to at least one allergen. RESULTS: The overall prevalence of atopy was 33% but there was a significant variation among the three study groups. The prevalence of atopy was 22% in urban poor, 36% in urban affluent, and 43% in rural children. Controlling for potential confounding factors, children in the rural community had a significantly higher odds ratio, 3.3 (95% confidence interval 1.8-6.0) of being atopic than children from the urban poor community. No association between atopy and tuberculin response or BCG scar was observed in any of the three groups. Serum IgE levels were higher among children of the urban poor group but were not associated with tuberculin response or BCG scar in any of the groups. CONCLUSION: Environmental factors have an important influence on the development of atopy in children in The Gambia but delayed type hypersensitivity to tuberculin is not a protective factor.     

Modulation of Type I immediate and Type IV delayed immunoreactivity using direct suggestion and guided imagery during hypnosis

Cutaneous reactivity against histamine skin prick test (Type I) and purified tuberculin protein derivative (Mantoux reaction, Type IV) was studied in eight volunteers under hypnosis. Types I and IV immunoreactivity were modulated by direct suggestion (Type I) and guided imagery (Type IV). The volunteers were highly susceptible subjects, selected by means of the Harvard Group Scale of Hypnotic Susceptibility, Form A. When the volunteers underwent hypnotic suggestion to decrease the cutaneous reaction to histamine prick test, a significant (P less than 0.02) reduction of the flare reaction (area of erythema) was observed compared with control histamine skin prick tests. The wheal reaction did not respond to hypnotic suggestion. Neither wheal nor flare reaction could be increased in size by hypnotic suggestion compared with control histamine skin prick tests. A hypnotic suggestion of increasing the Type IV reaction on one arm and decreasing the reaction on the other revealed a significant difference in both erythema size (P less than 0.02) and palpable induration (P less than 0.01). In two cases the reactions were monitored by laser doppler blood flowmetry and skin thickness measurement by ultrasound. The difference between the suggested increased and decreased reaction was 19% for the laser doppler bloodflow (in favor of the augmented side), and 44% for the dermal infiltrate thickness. This study objectively supports the numerous uncontrolled case reports of modulation of immunoreactivity in allergic diseases involving both Type I and Type IV skin reactions following hypnotic suggestions.     

Elevated levels of IgG and IgG4 to Malassezia allergens in atopic eczema patients with IgE reactivity to Malassezia

BACKGROUND: The opportunistic yeast Malassezia is considered to be one of the factors that can contribute to atopic eczema (AE). Elevated serum IgE levels, T-cell proliferation and positive skin prick test (SPT) and atopy patch test (APT) reactions to Malassezia are found among AE patients. METHODS: Sera from 127 AE patients, 14 patients with seborrheic dermatitis (SD) and 33 healthy controls were investigated for IgE and IgG4 to M. sympodialis extract and four recombinant Malassezia allergens; rMala s 1, rMala s 5, rMala s 6, and rMala s 9. In addition, IgG to the recombinant allergens was analyzed. The IgG and IgG4 levels were compared to IgE levels and in vivo reactions (SPT and APT) to Malassezia. RESULTS: AE patients with serum IgE levels >0.35 kU/l to M. sympodialis extract had significantly higher IgG4 levels to M. sympodialis extract than AE patients without detectable serum IgE to M. sympodialis extract, SD patients and healthy controls. Among the AE patients with and without detectable serum IgE to M. sympodialis extract, respectively, there were no differences in IgG4 levels between patients with positive or negative in vivo reactions to M. sympodialis extract. IgG4 to the rMala s allergens was almost exclusively found among patients with IgE to the same allergen. Within the four tested rMala s allergens, most IgG4 reactions were found to rMala s 6, an allergen with homology to cyclophilin. CONCLUSIONS: Elevated serum IgG4 to M. sympodialis extract accompanies elevated serum IgE to the extract. This is further confirmed by the association between IgG/IgG4 and IgE to recombinant Malassezia allergens.     

Atopy, intestinal helminth infection and total serum IgE in rural and urban adult Gambian communities

BACKGROUND: The rarity of atopy in traditional societies has been attributed to high parasite-driven blocking IgE concentrations. Information is lacking on the relationship between atopy, IgE and intestinal helminth infection in African populations. OBJECTIVE: To determine the prevalence of atopy and intestinal helminth infection and to relate these to wheeze history and serum total IgE in a community sample of adults from an urban (Banjul) and a rural (Farafenni) area of the Gambia. METHODS: Six hundred and ninety-three adults were interviewed about respiratory symptoms using a modified version of the IUTLD questionnaire, and had skin prick testing using four allergens. Stools were examined after formol-ether concentration. Total serum IgE concentration was measured in a subset of participants. RESULTS: The prevalence of atopy (mean weal diameter > or = 3 mm) in the urban and rural area was 35.3% and 22.5% (P = 0.05); D. pteronyssinus and Mold mix being the common sensitizing allergens. Prevalence of wheeze in the previous 12 months was 4.4% and 3.5% for the urban and rural areas, respectively. Wheezing was not significantly associated with atopy. Seventeen per cent of urban and 8.2% of rural subjects had helminths detected in stools. There was an inverse association between atopy and intestinal helminth infection; 7% of atopic subjects had helminths, compared to 13% of non-atopic subjects (unadjusted odds ratio 0.51, 95%CI 0.24-1.1, P = 0.09; adjusted odds ratio 0.37, 95%CI 0.15-0.92, P = 0.03). Non-atopics had total serum IgE concentrations about 2.5 times the upper limit of the reference range in non-atopic Western populations. Geometric mean total serum IgE concentration was significantly higher among atopic subjects (570 IU/mL, IQR 91-833) than non-atopic subjects (259 IU/mL, IQR 274-1303) (P < 0.001). IgE concentration was not associated with the presence of helminth infection. CONCLUSION: Further studies are needed to clarify why asthma is still relatively uncommon in spite of the prevalence of atopy in Gambian adults. Our data are also compatible with the idea that atopy might protect against helminth infection.     

Effect of cigarette smoking on the antibody response to inhaled antigens and the prevalence of extrinsic allergic alveolitis among pigeon breeders

There was a reduced prevalence of symptoms of Extrinsic Allergic Alveolitis (EAA) among the cigarette smokers in a survey of 102 volunteer pigeon breeders. These smokers had a significantly lower antibody response against the inhaled antigens associated with the disease; only one of twenty-three smokers (4.3%), but thirty-nine of sixty-five non-smokers (55.4%) had elevated serum IgG antibody levels, despite similar degrees of avian exposure in each group. The appearance of antibody in six of fourteen ex-smokers (42.9%) suggested that the apparent inhibitory effect of smoking on the antibody response was reversible. The smoking group had lower total serum IgG and IgA, higher serum IgD, and their total IgM and IgE levels were similar to the non-smokers.     

Prevalence of positive skin prick tests, allergic asthma, and rhinoconjunctivitis in teenagers in northern Sweden

The prevalence of positive skin prick tests (SPT) for common allergens and symptoms of allergic rhinoconjunctivitis or asthma was investigated in Umeå in northern Sweden in 1987. Skin prick tests with 10 allergens common in Sweden and a questionnaire were used to examine 1112 teenagers. All subjects with a positive skin prick test or symptoms were interviewed, and they were further investigated by a serum specific IgE test, a ventilatory lung function test, and a physical examination. At least one skin prick test was positive in 43% of the subjects. Ninety-three percent had at least one positive skin prick test to one of the three most common allergens: cat, timothy grass, and birch. The prevalence of current allergic rhinoconjunctivitis was 17%, current allergic asthma 2.8%, and current asthma (both allergic and nonallergic) 6.8%. Multiple logistic regression analysis showed that the most important risk factors for current asthma were sex (being a girl) and atopy. Heredity of asthma or rhinoconjunctivitis and being born in the winter (October-March) also increased the risk. In atopic subjects, having a mother who smoked and heredity of asthma increased the risk. For allergic rhinoconjunctivitis, heredity increased the risk of getting rhinoconjunctivitis.