Dynamic T-Cell Changes in Peripheral Blood and Bronchoalveolar Lavage after Antigen Bronchoprovocation in Asthmatics

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Abstract
We previously demonstrated decrease of peripheral blood CD4+ cells 48 to 72 h after antigen-induced bronchoprovocation in asthmatic subjects. To determine if this was accompanied by reciprocal changes in bronchoalveolar lavage (BAL) fluid, we sampled BAL before and 48 h after antigen administration. Peripheral blood lymphocytes (PBL) and BAL T-cell subset composition were examined in eight extrinsic asthmatics during three different weeks. During control week (CW) BAL was preformed at baseline, and PBL subsets were followed for 3 days. During placebo week (PW) a placebo inhalation was followed by a BAL at 48 h and daily PBL for 3 days. Asthmatic attacks were induced by inhalation of a relevant antigen at the start of antigen week (AW) and followed by examining the BAL at 48 h and PBL daily for 72 h. We found that BAL as a stimulus had no effect on T-cell composition of the PBL after the procedure. After induction of an asthmatic attack there was a reduction of PBL CD4+ cells from a baseline mean of 52.6% to 38.8% at 48 h (p less than 0.05). At the same time BAL CD4+ cells increased from 35.6% at PW to 47.3% in AW (p less than 0.05). These data are compatible with specific recruitment of PBL CD4+ cells into the respiratory system in atopic subjects undergoing antigenic bronchoprovocation.