EFFECT OF MIXING ALLERGENIC EXTRACTS CONTAINING HELMINTHOSPORIUM, DERMATOPHAGOIDES-FARINAE, AND COCKROACH WITH PERENNIAL RYEGRASS

Allergenic extracts used for immunotherapy often contain mixes of diff erent allergens. Studies have shown that certain allergenic extracts c ontain enzymes that can cause a decrease in grass pollen allergenicity when mixed with grass extracts. Glycerin and buffered saline with phe nol (BSP) extracts containing Helminthosporium interseminatum, D. fari nae, and cockroach were mixed with perennial ryegrass extracts and ana lyzed 7, 30, 60, and 90 days after mixing to determine the mixing effe ct of these extracts on the ryegrass pollen potency. Analysis was perf ormed using RAST inhibition, SDS-PAGE and, to determine biologic poten cy, a quantitative intradermal skin test technique. All tests showed s ignificant decreases in ryegrass potency when mixed with Helminthospor ium and cockroach. This decrease was not seen with the D. farinae mix. Glycerin seemed to have some protective effect. Even in the situation showing the most decrease in ryegrass potency (Helminthosporium mixed with ryegrass in a BSP extract), the resulting extract still containe d an estimated biologic potency of 10,000 AU/mL. This may explain why such mixes, which have been used clinically for many years, appear to give adequate therapeutic results. The study also suggests that clinic ians may be well advised not to mix grass pollen extracts with extract s that may contain proteolytic enzymes.