Increase of lymphocytes with Fc receptors for IgE in patients with allergic rhinitis during the grass pollen season.

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RESUMO

Peripheral blood lymphocytes from 10 nonallergic donors and 7 patients suffering from seasonal allergic rhinitis and receiving desensitization therapy were analyzed by rosette assays for Fc receptors for IgE (Fc epsilon R) and IgG (Fc gamma R) before, during and after the grass pollen season. Six of seven patients had moderately elevated IgE levels (330 +/- 268 IU/ml), all had high titers of skin sensitizing antibodies to grass pollens and serum IgE antibodies as measured by radio-allergosorbent tests (RAST). Seven of the nonallergic donors had 2-30 IU/ml IgE and negative RAST, whereas three had 91-267 IU/ml IgE and two were RAST positive to the grass pollens. In March, when the patients were asymptomatic, the mean +/-SD of the Fc epsilon R+ lymphocytes did not significantly differ from the nonallergic control group: nonallergic Fc epsilon R+ 1.2 +/- 0.9% (29 +/- 20/,mm3), allergic Fc epsilon R+ 2.0 +/- 3.1% (48 +/- 52/mm3). In contrast, during the grass pollen season in May and June, when the patients developed symptoms of allergic rhinitis, they had significantly (P less than 0.01) more Fc epsilon R+ lymphocytes than the controls: nonallergic Fc epsilon R+ 1.7 +/- 1.9% (40 +/- 46/mm3), allergic Fc epsilon R+ 4.7 +/- 1.2% (134 +/- 69/mm3). In the postpollen period, August-October, most of the patients again had low numbers of Fc epsilon R+ lymphocytes: nonallergic Fc epsilon R+ 1.4 +/- 0.9% (26 +/- 13/mm3), allergic Fc epsilon R+ 2.1 +/- 1.9% (62 +/- 82/mm3). The nonallergic control donors with elevated IgE levels and positive RAST always had low numbers of Fc epsilon R+ lymphocytes. In contrast, two other nonallergic donors, who had a 2-7 IU/ml IgE and negative RAST, showed significant increases of Fc epsilon R+ lymphocytes over several weeks during the grass pollen season. No statistically significant changes in Fc gamma R+ lymphocytes occurred in both nonallergic and allergic donors. The total and specific IgE serum levels did not vary much in the nonallergic donors and patients during the period of study and any changes that did occur did not correlate with the changes in Fc epsilon R+ lymphocytes. The data demonstrate that Fc epsilon R+ peripheral blood lymphocytes increase in allergic patients during natural antigen exposure and active disease in the absence of measurable increases of total and specific serum IgE. Because two nonallergic control donors also had temporary increases of Fc epsilon R+ lymphocytes, an increase of peripheral blood Fc epsilon R+ lymphocytes may be a sensitive indicator of an ongoing IgE immune response.

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