PT - JOURNAL ARTICLE AU - M Majori AU - S Bertacco AU - ML Piccoli AU - R Melej AU - V Pileggi AU - A Pesci TI - Specific immunotherapy downregulates peripheral blood CD4 and CD8 T-lymphocyte activation in grass pollen-sensitive asthma AID - 10.1183/09031936.98.11061263 DP - 1998 Jun 01 TA - European Respiratory Journal PG - 1263--1267 VI - 11 IP - 6 4099 - http://erj.ersjournals.com/content/11/6/1263.short 4100 - http://erj.ersjournals.com/content/11/6/1263.full SO - Eur Respir J1998 Jun 01; 11 AB - Several lines of evidence indicate that specific immunotherapy may act by modifying the immune responses of T-lymphocytes to the antigen. To evaluate the effect of specific immunotherapy on the activation of T-lymphocytes by cluster of differentiation cells (CD4+ and CD8+) in peripheral blood, the expression of two surface activation markers, the p55 interleukin-2 receptor (CD25) and human leucocyte antigen (HLA)-DR, was studied prospectively on circulating CD4+ and CD8+ T-cell subsets in subjects with grass-pollen sensitive asthma before and after 1 yr of treatment with specific immunotherapy. Twenty five asthmatic patients with pollen sensitivity other than grass, studied out of their pollen season, served as the control group. Specific immunotherapy improved clinical indices of disease activity including symptom scores and medication use during the pollen season of the treatment year. It had a marked effect in reducing the expression of the two activation markers, CD25 and HLA-DR, in both CD4+ (p=0.002 and p=0.005, respectively) and CD8+ (p=0.01 and p=0.01, respectively) T-cell subsets, in parallel with a significant decrease in CD23 expression on B-cells (p=0.008) and in grass-specific immunoglobulin E levels (p=0.01) in the peripheral blood of subjects with grass pollen-sensitive asthma. The decreased T-lymphocyte activation observed in immunotherapy-treated subjects after the treatment year was significant (p=0.05) in comparison with the control group. These data add to the view that the efficacy of specific immunotherapy may be attributed to the downregulation of T-cell responses.