Specific
immunotherapy has been successfully used in the treatment of allergic diseases for years. In this study, we examined the clinical efficacy of specific
immunotherapy and its effect on
cysteinyl leukotriene releasability by blood leukocytes in house dust mite allergic subjects with
asthma and
allergic rhinitis. In an open, parallel study, 13 subjects were treated with specific
immunotherapy for 12 months and five patients served as the control group. Before specific
immunotherapy treatment, and 1 and 12 months after, patients were evaluated with respect to total
immunoglobulin (Ig) E levels, Dermatophagoides pteronyssinus specific
IgE levels, symptom scores, usage of rescue medicines, lung function tests, nasal challenge scores, skin reactivity to D. pteronyssinus and
cysteinyl leukotriene releasability by blood leukocytes. At the 12th month of specific
immunotherapy, total
asthma symptom scores,
bronchodilator requirement, number of sneezes following nasal challenge and immediate skin reactivity to D. pteronyssinus was decreased, while FEV1 increased compared to the pretreatment values (p < 0.05 for each). These parameters remained unchanged in the control group. In vitro
cysteinyl leukotriene releasability by blood leukocytes in response to D. pteronyssinus
antigen and
anti-IgE antibody remained unchanged both in the specific
immunotherapy group and the control group. However, in the treated group, there were six patients who showed at least a 50% reduction in their symptoms after specific
immunotherapy. In five of these,
cysteinyl leukotriene release induced by both HACM
buffer and D. pteronyssinus were decreased by more than 50% of the baseline values. The other patient demonstrated only a marked decrease (more than 50%) in background. Our results suggest that specific
immunotherapy is effective in the treatment of
allergic rhinitis and
bronchial asthma due to
house dust mite allergy and that the clinical response to specific
immunotherapy may be associated with decreased
cysteinyl leukotriene releasibility by blood leukocytes in some patients.