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Notes: Sera from 59 patients with hypogammaglobulinaemia (hypogamma) were assessed for lymphocytotoxic activity. The activity was compared wilh that found in sera from patients with systemic lupus erythematosus (SLE) in titre, class of antibody, target cell, and complement requirements. Sera from patients with hypogamma showed cytotoxic activity when compared with sera from normal donors; however, the activity was far less than that in sera from SLE patients. The cytotoxic titre of both hypogamma and SLR sera was greater against T cells than non-T cells. Sera showing activity could be used to sensitize lymphocytes and render them susceptible to subsequent lysis, but IgM was not detectable on the surface of the sensitized cells. Following sucrose density gradient fractionalion of the sera the lymphocytotoxic activity was recovered in those fractions that contained IgM. Lymphocy-lotoxic activity was dependent on classical complement pathway activity. In all the experiments the hypogamma sera showed the same pattern of activity as the SLE sera, but the activity was always far weaker than that found in SLE sera. The evidence does not suggest that lymphocytotoxicity is likefy to be important in the pathogenesis of hypogamma.

Notes: The hygiene hypothesis states that a reduced exposure to allergens in early life is solely implicated in the growing propensity for allergy sensitization. Important elements of the hypothesis include helminth infection, exposure to endotoxins, exposure to pets and growing up on a farm. However, the hygiene hypothesis alone does not provide an adequate explanation for the observed increase in allergic disease. For example, in North American inner cities, asthma is increasing among children who live in very poor housing, which might be assumed to be somewhat dirty. In order to explain the increase in asthma, we need to take a broader view and also consider alterations related to the adoption of a western lifestyle. It has been suggested that lifestyle changes related to obesity (e.g. a change in diet) are associated with asthma. Other changes include a progressive decrease in physical activity. This lifestyle factor seems to correlate best with the recent increase in asthma. Clearly, the link between physical activity and asthma needs to be investigated in more detail.

Notes: Background:  Controversial data have emerged regarding the question whether cat exposure in childhood favours or decreases the risk of sensitization and allergic airway disease. In a prospective birth-cohort study, we assessed the association between longitudinal cat allergen exposure, sensitization (immunoglobulin E, IgE), IgG antibody (ab) levels to cat and the development of asthma in children up to the age of 10 years.Methods:  Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 10 years were available for 750 children. Assessments included yearly measurements of specific serum IgE to cat and at age 6 and 18 months, 3, 4 and 10 years measurement of cat allergen Fel d 1 in house dust samples. Additionally, Fel d 1-specific IgG ab were determined in 378 serum samples of 207 children. Endotoxin exposure in mattress dust was measured in a subgroup of 153 children at age 10 years. From age 4 years on, International Study of Asthma and Allergy in Childhood (ISAAC) questionnaires were completed yearly in order to assess the prevalence of wheeze and asthma.Results:  Serum IgG-levels to cat showed a large variation, however, intraindividually values showed rather constant concentration over a longer time period. The IgG levels at school-age correlated with cat allergen exposure during the first 2 years of life. Specific IgE to cat was clearly associated with wheeze ever, current wheeze and bronchial hyperresponsiveness (BHR), this was also observed for children with specific IgE ab to cat (〉0.35 kU/l) plus IgG levels above 125 U/ml. A large percentage of very highly exposed children showed high IgG but no IgE responses to cat, however, not all highly exposed children were found to be protected from sensitization. Children with IgG but without IgE ab to cat showed the lowest prevalence of wheeze ever and current wheeze despite high cat allergen exposure, however, this trend did not achieve significance. While homes of cat owners showed higher Fel d 1 concentrations than homes without cats, homes of cat owners were not found to have higher endotoxin levels in carpet dust samples than homes without cats.Conclusions:  We could confirm that high cat allergen exposure in a cohort with lower community prevalence of cats is associated with higher serum IgG and IgE levels to cat in schoolchildren. Sensitization to cat allergen (IgE) is a risk factor for childhood asthma. While exposure to cat allergen during infancy is associated with sensitization (IgE), only in the very highly exposed children the likelihood of sensitization (IgE) is decreased and high IgG levels to cat without IgE were associated with low risk of wheeze. However, cat-specific IgG ab levels did not protect children with IgE-mediated sensitization from wheeze.

Notes: In pokeweed (Pa-1)-stimulated human lymphocyte cultures, T cells are essential for the survival, proliferation, plasma-cell development, and high-rate Ig secretion of B cells. Their effects are T-cell-specific in the sense that B-Cell stimulation does not take place in the absence of T cells even when fibroblasts or monocytes are provided. The experimental system is the most effective model for activation of human B lymphocytes so far described. Plasmablast development requires approximately 7 days in culture. In T + B-cell cultures established at 1 × 106/ml (1 × 104/mm2) initial cell density, plasma cells can secrete, on the average, as much as 40–70 pg IgM or IgG per cell per day. When the initial T-cell density is increased well above 1.0 × 106/ml, a T-cell-mediated depression of Ig synthesis becomes predominant. Thus, in the pokeweed model T-cell effects represent a balance of helper and suppressor influences. The study also shows that B cells are heterogeneous. A non-adherent IgG-committed (smIg−?) tonsil B-cell population seems to be less susceptible to T suppressor effects than normal tonsil B cells. This subset proliferates particularly well and synthesizes large quantities of IgG in the presence of large initial proportions of T cells.

Notes: A group of 20 mite allergic asthmatic children aged 6-12 years old. living in Sao Paulo, Brazil, was studied regarding their degree of sensitization to house dust mites and exposure to mite allergens in their homes. In 18 out of 20 houses at least one dust sample was obtained which contained 〉 10 μg Der p I/g of dust. The highest levels of Dermatophagoides pteronyssinm allergens, Der p I and Group II, were measured in bedding samples (geometric mean 38.4 and 36.6 μg/g, respectively), followed by bedroom floor, TV room and kitchen. Mite allergen levels in Brazilian houses were as high as those reported to be associated with sensitization and acute attacks of asthma in other parts of the world. In keeping with previous reports that D. farinae is rarely found in Brazil, Der fl was undetectable or found in very low levels (〈0.5 μg/g). Levels of cat allergen Pel d I of 〉 8 μg/g of dust were obtained only in 2 houses only. Cockroach allergen Bia g I was detected in five out of 20 houses. Levels of IgE antibodies to D. pteronyssinus were 〉 200 RAST U/ml in 19 out of 20 children (geometric mean 1588 RAST U/ml). IgE antibodies to cat, cockroach, A. fumigatus, ragweed and rye grass pollens were undetectable or 〈80 RAST U/ml. IgE antibodies to the mite Blomia tropicalix were also measured, and levels 〉200 RAST U/ml were observed in 13 out of 20 sera. Immunoabsorption studies demonstrated that the bulk of the IgE- antibody to B. tropicafis (64%) was to species-specific allergens and that 36% were cross-reactive with D. pteronyssinus. The implication of our results is that management of children with asthma in São Paulo should include skin testing for allergy to both Dermatophagoides and B. tropicalis as well as recommendations about environmental control of house dust mite exposure.

Notes: This article presents a nomenclature system for allergens which has been officially recommended by the International Union of Immunological Societies (IUIS). The nomenclature is based on proposals of the IUIS Sub-Committee for Allergen Nomenclature and is applicable to highly purified, well-characterized allergens and to non-purified or partially purified allergenic extracts.

Notes: Successful hyposensitization to Dermatophagoides pteronyssinus in perennial childhood asthma was associated with a slight mean rise of serum IgG antibody to the mite antigen in contrast to a placebo group in whom this antibody fell slightly. No relationship was detected between the effect on asthma and the magnitude of this change, Nor was there any consistent effect on IgE or IgA antibody.There was a wide range of total serum IgE and IgE, IgG and IgA antibody to D. pteronyssinus before treatment; this level did not predict the effect of treatment. Some patients lacked IgA antibody.IgE antibody to timothy grass pollen was raised in some but not others. These levels did not change systematically during the study and improvement occurred in those who had this antibody as well as IgE antibody to D. pteronyssinus.IgG and IgE antibodies to D. pteronyssinus were significantly correlated in the pre-treatment samples.Lymphocyte thymidine uptake was lower after 8 weeks of treatment than in the control group, not only after stimulus with D. pteronyssinus antigen, in vitro, but also with antigen from Candida albicans. This was not a serum effect.The late bronchial provocation response was lost only in those with serum IgA less than the log mean for age.

Notes: House dust mite sensitivity is very common in patients with bronchial asthma, yet dust mite avoidance frequently receives little attention in clinical management. It is likely that any reduction in allergen levels associated with routine cleaning is insufficient to allow clinical improvement. In the present study the acaricide pirimiphos methyl is shown to reduce the levels of Dermatophagoides pteronyssinus, antigen P1 in homes. Following a single application the level of antigen P1 in dust from carpets was reduced by up to 73% and by more than 50% in soft furnishings. Serial sampling showed a reduction for 6 weeks under conditions where carpets and chairs treated with solvent showed a progressive rise in allergen level. Furthermore the survival of mites in cultures or infested carpet segments was markedly inhibited, with antigen PI accumulation reduced by 〉90%. These results suggest major reductions in house dust mite allergen levels in the home can be achieved.