[Study on the clinical usefulness of RAST using insect and mite allergen discs]

In order to examine the usefulness of mite and insect RAST, RAST was carried out on 79 asthmatic patients using mite, cockroach, mosquito and larval chironomid midge (Chironomus thummi thummi, CTT) allergen discs supplied from Pharmacia AB, and discs of two species of adult chironomid midge (Tokunagayusurika akamusi, TA and Chironomus yoshimatsui, CY in Japan) which were prepared in our laboratories. The results were as follows. 1) The positive rate of RAST in 65 randomly selected asthmatic patients was 62% in the case of mite, 25% for TA, 20% for CY, 14% for cockroach, 11% for CTT, 8% for silk and 6% for mosquito. The positive rates of silk and mosquito RAST were low. However, these RAST seemed to be clinically useful when patients were positive to these RAST. 2) The rate of coincidence between skin test and RAST was 86.5% in the case of mite and 30% in the case of silk. The rate of coincidence between prick test using adult CY and RAST using larval CTT was 46.5%. 3) The positive rate of larval CTT RAST was about half that of adult TA or adult CY. However, larval CTT RAST seemed clinically useful when patients were positive to the RAST, because all the patients who were positive to larval CTT RAST were also positive to both adult TA and CY RAST. 4) A significant correlation was found among the three kind of chironomid midge RAST and also between cockroach RAST and any of the three kinds of chironomid midge RASTs.