Immune responses of non-atopic individuals to prolonged immunisation with ragweed extract

Immunotherapy to deciduous tree pollens: specific IgE and IgG antibody patterns

Thirty-nine children with birch pollinosis were given immunotherapy (IT) for 3 years with a purified, characterized and biologically standardized pollen preparation made from either birch or a mixture of birch, alder and hazel. Levels of IgE antibodies against birch, alder and oak increased early during IT (P less than 0.01) and then decreased below the initial level (P less than 0.01). Birch-specific IgG antibodies also increased (P less than 0.01) but not as rapidly as birch-specific IgE antibodies and the levels remained increased throughout IT. There were only weak correlations between immunochemical findings before IT or during early IT on one hand and the improvement during IT on the other hand. The ratio birch-specific IgG:IgE after 1.5 and 2.5 years of IT correlated with symptom scores the following season (P less than 0.01). In 60% of the children below 13 years of age, new IgE specificities developed during IT as demonstrated with crossed radioimmunoelectrophoresis. No such new IgE specificities were found in older children. These 'new sensitivities' did not appear to have any clinical implication.

The natural history of mountain cedar pollinosis

During the winter months, pollen from the mountain cedar (MC) (Juniperus sabinoides) causes severe respiratory tract allergy in central Texas. We have been impressed with the fact that many of our MC-allergic patients had only allergic rhinitis and were only sensitive to MC pollen. We therefore studied 234 unselected MC-allergic patients at the end of the MC season. The main criteria for inclusion into the study was a bona fide history of MC pollinosis confirmed by a positive skin test. All patients completed a detailed history questionnaire, were prick skin tested by using 1:20 w/v, extracts, and had a total IgE determined with commercially available reagents (PRIST). Thirty-four percent of patients were found to be allergic only to MC and 66% were allergic to MC and other aeroallergens. As a group, patients allergic only to MC had significantly lower total IgE levels (84 IU/ml vs. 360, p less than 0.001) (normal less than 180), required much longer exposure intervals to cedar pollen before developing MC pollinosis (14.4 yr vs. 5.69, p less than 0.001), had less of a family history of allergic disease (43% vs. 88%, p less than 0.001), had less of a history of asthma or eczema (11% vs. 39%, p less than 0.001), and developed allergic disease at a later age (39 yr vs. 13, p less than 0.001) when compared to patients with multiple allergies. These results suggest that the MC pollen may be unique in causing allergic rhinitis in patients who have no other sensitivities. A possible explanation may lie in the carbohydrate nature of the main allergen of the MC pollen, which may facilitate allergen transport through the respiratory tract mucosa and subsequent sensitization.

Humoral and cell-mediated immune responses to fractions of birch pollen extract

IgE and IgG antibodies (ab) and lymphocyte transformation (LT) were studied in untreated and hyposensitized birch pollen allergic subjects and in non-atopic controls using whole extract and fractions obtained by gel filtration of birch pollen extract. All the allergic subjects had positive IgE ab, IgG ab and LT responses to the whole extract. Both the untreated and the hyposensitized subjects had peak IgE ab and LT responses against the allergenic fractions of the extract, while negative responses were obtained in the non-atopic controls. Only hyposensitized subjects had developed high IgG ab responses to the allergenic fractions. Most of the treated and untreated subjects showed IgG ab and LT responses to the high molecular weight fractions with low allergenic activity. Significantly higher IgE ab responses to these fractions were observed in the treated subjects than in the untreated ones, indicating potentiation of IgE ab responses against some antigens during immunotherapy. Some of the allergic subjects also responded to the fractions of low molecular size (mol. wt. 2000-5000) with low allergenic activity. Both IgE ab, IgG ab and LT responses to these fractions were observed.