Diagnosis and immunotherapy of mould allergy. VI. IgE-mediated parameters during a one-year placebo-controlled study of immunotherapy with Cladosporium.

The IgE-response was evaluated by skin prick test, bronchial provocation test and RAST in a 1-year placebo-controlled double-blind immunotherapy study. Eleven adult asthmatics were treated with a Cladosporium allergen preparation and 11 comparable patients received histamine placebo. The bronchial sensitivity (PC20) decrease greater than 0.5 log step in 8/11 (73%) Cladosporium-treated versus 3/11 (27%) in the placebo group. Corresponding figures for skin prick test sensitivity was 10/11 (91%) and 1/11 (9%) respectively. Circulating IgE showed a temporary boost in the Cladosporium group and then values approaching the pretreatment value. Only minimal and insignificant changes were found in the placebo-treated patients. Changes in IgE-reactivity were not related to allergen dose, clinical efficacy or to the occurrence of side effects. Some interrelation between changes in skin prick test, bronchial provocation test and RAST was found indicating a differentiated effect of immunotherapy on various IgE compartments. In spite of the pathogenetic role of IgE in allergic diseases, changes in IgE-reactivity do not seem directly involved in the mechanisms underlying the clinical efficacy of immunotherapy but might be of importance in a complex interaction with other immunological parameters.