LEUKOTRIENE B-4 AND C-4 GENERATION BY HUMAN-LEUKOCYTES AFTER EX-VIVO STIMULATION WITH CA-IONOPHORE AND OPSONIZED ZYMOSAN IN CHILDREN WITH ATOPIC ASTHMA

The ex vivo release of leukotriene B-4 (LTB(4)) and leukotriene C-4 (L TC(4)) from leukocytes was evaluated after stimulation with both Ca-io nophore (Ca-I) and opsonized zymosan (OZ) in children with atopic asth ma. Twenty-seven patients with asthma of varying severity were evaluat ed and divided into three groups: 1) moderate to severe asthma using i nhaled steroids and symptom-free for the last 3 weeks (n = 8), 2) mild asthma with sporadic symptoms, only using inhaled beta(2)-agonists < 3 times/week (n = 8), and 3) acute asthmatic attacks admitted to hospi tal (n = 11). A group of children without atopic disease or any other known disease served as controls (n = 15). Total serum IgE levels were significantly increased in the children with asthma compared with the control group. LTC(4) production was only significantly increased in the group of children with moderate to severe asthma after stimulation with Ca-I, when compared with controls. In the same group, a trend to wards increased LTC(4) production after stimulation with OZ was found. LTB(4) was not significantly increased in any patient group compared with the control group. A significant correlation between LTC(4) produ ction after stimulation with Ca-I, but not OZ, and the relative blood eosinophil count was found in all subjects. LTC(4) generation per eosi nophilic cell after stimulation with Ca-I or OZ was not statistically different in any patient group compared with the controls. We conclude that the increased leukotriene (LT) levels found after the stimulatio n of peripheral white blood cells sampled from atopic children with as thma are mainly the result of increased numbers of LT-producing cells, rather than due to increased releasability from these cells.