BACKGROUND: The efficacy of immunotherapy is still controversial. To elucidate the mechanisms of immunotherapy, we studied mite-specific induction of IL-2 receptor (IL-2R) expression on T lymphocytes from children with mite-sensitive asthma. METHODS: Peripheral blood mononuclear cells were obtained from 28 children with mite-sensitive asthma: 13 had never received house dust immunotherapy (nonimmunotherapy group), 15 had been receiving house dust immunotherapy at the time of the study (immunotherapy group). After a 6-day culture with or without Dermatophagoides farinae (Df) antigen, the expression of IL-2Rp55 (CD25) and p75 on CD4+ or CD8+ T lymphocytes was measured by flow cytometry. RESULTS: The nonimmunotherapy group showed significant Df-specific CD25 induction on CD4+ T lymphocytes (delta CD4+ CD25+) but little induction on CD8+ T lymphocytes (delta CD8+ CD25+). delta CD4+ CD25+ was correlated with the severity of the disease. In the immunotherapy group delta CD8+ CD25+ was significantly higher than in the nonimmunotherapy group or in normal subjects and correlated with Df-specific IgG4 and cumulative doses of house dust extract, whereas delta CD4+ CD25+ was similar in the nonimmunotherapy and the immunotherapy groups. IL-2Rp75 was not induced either on CD4+ or CD8+ T lymphocytes. CONCLUSIONS: Our data suggest that house dust immunotherapy may have induced Df-specific CD8+ T lymphocytes in patients with mite-sensitive asthma and that the efficacy of immunotherapy may be attributed to the generation of Df-specific CD8+ T lymphocytes.
BACKGROUND: The efficacy of immunotherapy is still controversial. To elucidate the mechanisms of immunotherapy, we studied mite-specific induction of IL-2 receptor (IL-2R) expression on T lymphocytes from children with mite-sensitive asthma. METHODS: Peripheral blood mononuclear cells were obtained from 28 children with mite-sensitive asthma: 13 had never received house dust immunotherapy (nonimmunotherapy group), 15 had been receiving house dust immunotherapy at the time of the study (immunotherapy group). After a 6-day culture with or without Dermatophagoides farinae (Df) antigen, the expression of IL-2Rp55 (CD25) and p75 on CD4+ or CD8+ T lymphocytes was measured by flow cytometry. RESULTS: The nonimmunotherapy group showed significant Df-specific CD25 induction on CD4+ T lymphocytes (delta CD4+ CD25+) but little induction on CD8+ T lymphocytes (delta CD8+ CD25+). delta CD4+ CD25+ was correlated with the severity of the disease. In the immunotherapy group delta CD8+ CD25+ was significantly higher than in the nonimmunotherapy group or in normal subjects and correlated with Df-specific IgG4 and cumulative doses of house dust extract, whereas delta CD4+ CD25+ was similar in the nonimmunotherapy and the immunotherapy groups. IL-2Rp75 was not induced either on CD4+ or CD8+ T lymphocytes. CONCLUSIONS: Our data suggest that house dust immunotherapy may have induced Df-specific CD8+ T lymphocytes in patients with mite-sensitive asthma and that the efficacy of immunotherapy may be attributed to the generation of Df-specific CD8+ T lymphocytes.