Lymphocyte subsets, sIL2-R and sICAM-1 in blood during allergen challenge tests in asthmatic children.

In order to study cell activation in peripheral blood on bronchial allergen provocation up to 24 h, we investigated 32 asthmatic children, sensitive to house-dust mites. Six healthy young adult volunteers served as controls. Lymphocyte subsets (CD3, CD19, CD4, CD8) and activation markers (CD25-T, HLADR-T, CD23) in peripheral blood as well as soluble IL2-R and soluble ICAM-1 in serum were evaluated. In terms of clinical reaction, 23 children exhibited a DAR, 6 an EAR, 6 a LAR and 3 children did not show a bronchoconstrictor response to allergen challenge with house-dust mite extract (NAR). In comparison to controls, asthmatic children showed a significantly higher expression of CD23 on B-lymphocytes (p < 0.05). Other subsets were in the same range in both groups. After provocation there was a significant increase of CD4/CD8-ratio only in asthmatic children. Serum levels of sIL2-R were significantly higher in asthmatic children compared to controls at baseline as well as at 12 and 24 h after provocation, without variation during observation period. No differences were noted for sICAM-1. Our results confirm the hypothesis that lymphocytes, as important cells in regulation of allergic immune response, are recruited into peripheral blood under allergen challenge conditions in sensitized asthmatic children.