Immunotherapy (IT) was performed for 12 months with a purified and standardized preparation of Dermatophagoides farinae. Twenty adults with rhinoconjunctivitis sensitive to house-dust mite were given IT, and a similar group of 11 patients served as open controls. A total of 512 injections were given. Twenty-eight episodes of allergic side-effects occurred, 13 general and 15 local, most of them during the initial incremental dose period. No severe reactions started later than 30 min after the injection. One patient suffered anaphylactic shock. In this patient, specific antibodies fell immediately, followed by an increase within 1 week. The therapy group improved significantly in relation to the open controls in patients' subjective evaluation of symptoms (P < 0.028) and skin (P < 0.0001) and conjunctival (P < 0.001) sensitivity. Specific IgE increased in controls (P < 0.0001) but not in IT-treated patients during the "mite season"; that is, there was a significant difference in change during the observation period (P < 0.0001). There was also a difference in change of specific IgG between the groups during the first 4-5 months and the whole year (P < 0.0001), but not from 4-5 months to 12 months. In contrast to changes in antibody titers (IgG, P = 0.04), changes in conjunctival (P < 0.01) and especially skin sensitivity (P < 0.005) correlated well with subjective improvement. This implies that the skin prick test and the conjunctival test can be recommended for follow-up of IT.(ABSTRACT TRUNCATED AT 250 WORDS)

Background: Parallel line bioassay (PLBA) has been acknowledged to be the gold standard for estimation of changes in reactivity, e.g., in RAST and ELISA inhibition tests. Objective: To study correlations between two simple methods for evaluation of changes in skin prick test (δSPT), using the slope of the allergen dose response (drr a) in relation to PLBA. Methods: Skin prick test data from two published immunotherapy trials were used. In a D. farinae trial we used duplicate tests with three fixed tenfold concentrations and in a P. judaica trial three tenfold individually chosen allergen concentrations causing wheals of similar size to that of histamine dihydrochloride 10 mg/mL, tenfold lower and tenfold higher concentration. Evaluation of the δSPT by PLBA, and two simple methods were correlated. In the D. farinae trial δSPT was compared to the change of conjunctival threshold concentration. Results: The δSPT as measured by both the simple methods gave similar results to that of PLBA (p<0.001). The δSPT was around 30-fold, i.e., about 3% of the pre-treatment reactivity. The δSPT correlated with the δCPT threshold concentration. Conclusions: Estimation of the δSPT during therapy expressed as change in concentration using simple methods based on the slope of the drr a correlated well to changes by PLBA and CPT and should therefore be used both in clinical research and in practice.

House dust mite D. farinae and Der f II‐specific IgG and IgG subclass responses were evaluated in 32 adults with perennial rhinitis undergoing immunotherapy for 1 year by means of IgG‐RAST and ELISA. The ELISA method, which is based on subclass‐specific monoclonal antibodies, could detect 0.5–1.5 ng/ml of specific antibodies. D. farinae and Der f II‐specific IgG4 antibodies increased continuously as immunotherapy proceeded, while total IgG and IgG1 antibodies reached a plateau value 6 months after the start of immunotherapy, followed by a slow decrease during maintenance therapy. During the early phase of treatment the concentration of IgG, and IgG4 antibodies rose, even though the increase of IgG4 antibodies dominated. The positive clinical outcome as measured by the decrease in conjunctival sensitivity was associated with an increased ratio of specific IgG4/IgG, antibodies as well as the magnitude of the IgG4 subclass response. Quantitation of IgG subclass antibodies in patients undergoing immunotherapy may be of some clinical value, but the clinical usefulness needs to be demonstrated for each type of allergen and possibly also for each assay system.

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