Pollen in Bangkok metropolis: II. allergenic importance and cross reactivity among pollen.

ABSTRACT

By the intracutanous test using 14 different kinds of pollen extracts in 1,007 allergic rhinitis patients, we have found that 84.72 percent of these patients gave more than two plus reaction to Bermuda grass extract, 82.10 percent to careless weed, 79.10 percent to Para grass, 76.51 percent to cane, 70.60 percent to Sedge, 68.11 percent to Acacia and 61.50 percent to Ferns. Other pollen extracts gave less than 50 percent of positive skin test reaction; they are English plantain, Pyrethrum, Johnson grass Crysanthemum, Corn, Sunflower and Palm listed in decreasing order. There was no direct relationship between the incidence of atmospheric pollen and the positive skin test reaction. However, grass and weed pollen are the most frequently encountered and also the most potent allergenic pollen. It was also proved that there was significant correlation between the skin test reaction of different kinds of grass pollen and also between weeds and pollen other than grass. This implied that there was probable cross-reactivity among all kinds of pollen which was relevant to the findings from other studies using more sophisticated test methods. But it should be emphasized that although they share some allergens, each kind of pollen also possesses its unique allergen.