Allergic asthma in childhood.

122

The radioallergosorbent test (RAST) was applied for quantitative estimation of IgE antibodies to various common allergens. The results could be expressed in per mille of a reference serum containing IgE antibodies to birch allergen. Since the allergen extracts vary considerably both on a quantitative and qualitative basis, the results cannot, with few exceptions, be compared between different allergens. However, for each type of allergen the results can be compared between samples obtained from different individuals or at different times. Birch and dandelion allergen extracts were found to be potent and give rise to allergen excess in the systems used. A comparison between these two allergens showed that a group of allergic children had on the average approx. 15 times more circulating IgE antibodies to birch than to dandelion allergen.

Section: Fig 3 Rast Analyses Of Serial Dilutions Of a Reference Sersupporting

confidence: 81%

In vitro Diagnosis of Atopic Allergy

Johansson

Bennich

Berg

1971

122

“…Recent reports have suggested that the presence in serum of a specif ic reagin is not necessarily of clinical importance [Aas, 1969;A as and J ohansson, 1971]. This might be explained by the local production and tissue fixation of IgE antibody [Ishizaka and N ew comb, 1970;T ada and T urner et al, 1970;D onovan et al, 1970;J arrett and Stew art, 1973], In addition to this, however, one cannot ex clude the possiblities that there may be some differences of the ability of the target cells to release histamine among allergic individuals or shock tissues on reaginic reactions.…”

Section: Introductionmentioning

confidence: 99%

Correlation between in vitro Anaphylactic Histamine Release from Tissues and Reagin Titer in Rat

Yamamoto¹,

Seo²,

Fujiwara³

et al. 1974

The magnitude of antigen-induced histamine release from actively sensitized rat tissues in vitro was compared with the amount of specific reagin in the serum. There was no quantitative correlation between either, suggesting that the antigen-induced histamine release from sensitized tissues might depend on the ability of sensitized target cells to release histamine. In addition, the magnitude of antigen-induced histamine release was different in each tissue of sensitized rats. This also suggested that there might be some differences in the ability of sensitized target cells in each tissue to release histamine by antigen.

“…However, a positive skin test in the absence of a positive RAST result may indicate an allergy, the clinical importance of which must be proven by a provocation test. A positive skin test does not in itself imply a manifest state of hypersensitivity [1], This fact, however, does not mean that skin testing should be excluded from the diagnostic arsenal, mainly in the form of prick testing, it still ful fills a valuable role in the diagnosis of allergy in children.…”

Section: Discussionmentioning

confidence: 99%

In vitro Diagnosis of Atopic Allergy

Berg¹,

Johansson²

1976

The radioallergosorbent test (RAST) has been used for in vitro diagnosis of allergy in a selected group of children with asthma and allergic rhinoconjunctivitis. The results were compared with those of provocation tests and also with the results of skin tests. Where the results of RAST and the provocation tests differed, repeated tests were performed, initially in vitro and secondly in vivo. Selected commercial allergens of good quality were used and, for the most part, the same allergen batches were used in RAST, in the provocation tests and in the skin tests. A 76% correlation between RAST and provocation tests was found on preliminary investigation before divergent results were repeated. This degree of correlation is similar to that obtained previously in unselected patients using RAST as a part of the routine diagnostic. On repeated examination, agreement was obtained in an additional 16% of the cases. The major part of the improvement (13%) was due to conversion of preliminary RAST results from negative to positive in children with positive provocation tests. To a minor extent, the improvement was due to the fact that, in some children with positive RAST, negative provocation tests became positive when repeated. Finally, in one case an originally positive RAST in a child with a negative provocation test was found to be negative on re-examination. Comparing the final revised results of RAST and provocation tests there were no cases where a negative provocation test was combined with a positive RAST. Nearly all the children with positive provocation tests in spite of a negative RAST were shown to have low degree allergy. Although circulating reaginic antibodies are not always present, it seems that, on repeated investigations, the great majority of children with asthma and hay fever can be shown to have such antibodies even though the serum concentration may be low or very low. In doubtful cases repeated RAST examinations may be of value.