Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. II. Comparison between parameters assessing the efficacy of immunotherapy

A clinical index: a new method to assess efficacy of allergen immunotherapy

Assessment of efficacy in immunotherapy trials is difficult: a number of parameters can be measured; these may give conflicting results and it is not clear which best represents the clinical state. We therefore derived a Clinical Index (CI), by combining five individual parameters-diary card symptom score, visual analogue symptom score, drug score, nasal challenge and skin prick test-by rank analysis. The CI has been used to express the results in a trial of house dust mite (D. pteronyssinus) immunotherapy for allergic rhinitis, comparing two active treatments, Pharmalgen and Allpyral, with placebo. The derived index correlated well with all parameters measured. Correlations between the five individual parameters were variable: with the exception of the skin test, good correlations were seen, each parameter correlating with two or three of the others, but the visual analogue showed the closest association with other parameters. Results from a single parameter taken alone could be misleading, e.g. in the Allpyral group, nasal challenge improved significantly, but symptoms assessed either by visual analogue or diary card score did not. The CI showed significant improvement in the Pharmalgen group but not in the Allpyral group. The CI gave a more reliable measure of outcome than individual parameters.

Changes in skin reactivity, specific IgE and IgG levels after one year of immunotherapy in olive pollinosis

Changes in specific skin reactivity, specific IgE and specific IgG after immunotherapy (IT) were investigated in olive pollinosis. Thirty patients, receiving IT with commercial extracts, were studied in comparison with a control group of seven patients, receiving only drug therapy. Skin reactivity, IgE and IgG were assessed before starting IT and 1 year later. Definite changes in the three considered parameters occurred in patients given IT with Olea europaea extracts; no variation was observed in the control group. The specific skin reactivity, evaluated by means of quantitative skin prick tests, significantly decreased (Skin Index geometrical mean from 2.73 to 0.88, P less than 0.001); the specific IgE, measured by RAST, were surprisingly decreased (from 7.76 to 4.74 PRU/ml, P less than 0.001); the specific IgG, measured by ELISA, in basic conditions were detectable only in nine patients of 30, while, after IT, they were found in almost all patients with a remarkable increase (from 5.48 to 266.89 AU/ml, P less than 0.001). No correlation was found among the changes in the considered parameters, suggesting that, at least in olive pollinosis, specific skin reactivity, specific IgE and specific IgG are three variables depending on IT but reciprocally independent.

Differences in clinical and immunologic reactivity of patients allergic to grass pollens and to multiple-pollen species. II. Efficacy of a double-blind, placebo-controlled, specific immunotherapy with standardized extracts

The IgE response of patients only allergic to grass pollens differs from response of patients allergic to multiple-pollen species. The IgE immunoblots to orchard-grass pollens confirmed that polysensitized patients had more proteins revealed than patients only allergic to grass pollens. To determine if both groups of patients present a different response toward specific immunotherapy (IT), a double-blind, placebo-controlled study was performed in 70 patients. Patients receiving the active treatment had a rush IT with either a standardized orchard grass-pollen extract or with a standardized mixed-pollen extract prepared, depending on the sensitivity of the patients. The maintenance dose was defined as that dose effective in grass-pollen IT in previous experiments. The same equipotent maintenance dose was administered for all pollen species. Symptom-medication scores during the pollen season and nasal challenge with orchard grass-pollen grains demonstrated that grass pollen-allergic patients had a significantly improved efficacy by comparison to placebo treatment, whereas polysensitized patients had a nonsignificant improvement. Serum grass-pollen IgG was significantly increased after IT in both treated groups. This study demonstrate that the response toward specific IT differs in patients only allergic to grass pollens by comparison to polysensitized patients.

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. IV. Comparison of the safety and efficacy of two dosages of a high-molecular-weight allergoid

Specific immunotherapy is still widely used in grass-pollen allergy, but its side effects may limit its use. We tested the safety and efficacy of a formalinized high-molecular-weight allergoid prepared from a mixed grass-pollen extract with two injection schedules in a double-blind, placebo-controlled study. Eighteen patients received placebo, 19 received the low-dose schedule (maximal dose: 2000 PNU) and 20 received the high-dose schedule (maximal dose: 10,000 PNU). Only one patient presented a systemic reaction of moderate severity for a dose of 1200 PNU. Before the onset of the pollen season, patients had a nasal challenge with orchard grass-pollen grains, a skin test titration, and the titration of serum-specific IgG. Both groups of patients presented a significant reduction in nasal and skin sensitivities and a significant increase in IgG compared to placebo. Symptoms and medications for rhinitis and asthma were studied during the season, and both groups receiving allergoids had a significant reduction of symptom-medication scores for nasal and bronchial symptoms. There was a highly significant correlation between nasal symptom-medication scores during the season and the results of nasal challenges. High-molecular-weight allergoids are safe and effective.

Double-blind, placebo-controlled rush immunotherapy with a standardized Alternaria extract

Specific immunotherapy is ineffective with unstandardized mold extracts. A double-blind, placebo-controlled study was performed in 24 patients (5 to 56 years of age) only allergic to Alternaria. The extract was standardized by isoelectric focusing, crossed immunoelectrophoresis, crossed radioimmunoelectrophoresis, RAST inhibition, and skin tests and contained allergen Alternaria major allergen a I and antigen B. Thirteen patients received the active treatment, and 11 received the placebo. Immunotherapy was started by a 2-day rush protocol; maintenance injections were administered for 1 year. The patient's self-evaluation of the treatment was significantly (p less than 0.001) lower in the placebo-treated group. Global symptom-medication scores, including asthma and rhinoconjunctivitis, were significantly (p less than 0.005) lower in the actively treated group. Nasal challenges with Alternaria extract were performed before immunotherapy and after 1 year of treatment. There was no difference in the placebo-treated group and a significantly (p less than 0.01) increased mean provocative dose in the actively treated group. Skin tests were significantly reduced in the actively treated group. Specific IgG increased significantly in the actively treated group and were stable in the placebo-treated group. There was a significant correlation between nasal challenges and nasal symptom-medication scores (p less than 0.03) or the patient's self-evaluation of efficacy (p less than 0.05). This study demonstrated that patients only sensitized to Alternaria benefit from specific immunotherapy with a standardized Alternaria extract.